SECTION 14 Detailed Directory

SECTION 14: Detailed Directory

DETAILED DIRECTORY 14-1

MANUAL FOR SEPTIC SYSTEM PROFESSIONALS IN MINNESOTA

DETAILED DIRECTORY

INTRODUCTION............................................................................................1-1How to Use This Manual ..............................................................................................................1-1

Understanding Septic Systems ..................................................................................................... 1-1Why Are Septic Systems Necessary? .........................................................................................................................1-1

What Do Septic Systems Do?..........................................................................................................1-2

How Does a Septic System Work? ..................................................................................................1-2

Plumbing..............................................................................................................................................1-3Septic tank ..........................................................................................................................................1-3Soil treatment area ..............................................................................................................................1-4Enhancements .....................................................................................................................................1-5

How Is The Sewage Treated? .........................................................................................................1-6

Why Do Septic Systems Fail? .........................................................................................................1-7

Improper maintenance ......................................................................................................................1-7Overuse of water .................................................................................................................................1-7Improper design or installation ........................................................................................................1-7

Cleaning up a Sewage Back-up .......................................................................................................1-8

Clean up tips: ..............................................................................................................................................1-8Compliance Inspections ...........................................................................................................................1-8Abandonment ............................................................................................................................................1-9

Operation and maintenance tips .....................................................................................................1-9

Control water use ...............................................................................................................................1-9Eliminate harmful products from the system .................................................................................1-9Do not use additives ...........................................................................................................................1-9Regularly clean/pump and inspect the septic tank ........................................................................1-9Maintain pumps and filters properly .............................................................................................1-10Protect the soil treatment area ........................................................................................................1-10

14-2 DETAILED DIRECTORY

Items to Keep Out of a Septic System ...........................................................................................1-10

Odor Issues and Onsite Sewage Treatment Systems ....................................................................1-11

1. Odors in the home ...............................................................................................................................1-112. Odors near the septic tank .................................................................................................................1-123. Odors near a pretreatment unit .........................................................................................................1-124. Odors near the soil treatment area ....................................................................................................1-125. Odors in the yard .................................................................................................................................1-12

System Performance vs. Program Performance ............................................................................1-13

Local Ordinance Requirements to Permit Performance-Based Systems ..................................1-13Designer Responsibilities: Providing Information to the Homeowner ..............................................................1-13

I. Pre-Design Communication ...............................................................................................................1-13A. Pre-design meeting with system owner ....................................................................................1-13

II. Post-Design Communication ...........................................................................................................1-14A. Final design review ......................................................................................................................1-14B. Management Plan ....................................................................................................................1-14

Installer Responsibilities: Providing Information to the Homeowner ...............................................................1-15I. Pre-Installation Tasks ..........................................................................................................................1-15

A. Agree on establishing the vegetative cover and topsoil. .........................................................1-15B. Septic System Management Plan (select one box) ...................................................................1-16

II. Post-Installation Tasks .......................................................................................................................1-16A. Discuss ponding, run-off, and surfacing. .................................................................................1-16B. Explain and show the system to the homeowner. ..................................................................1-16C. Discuss household water and product use tips with the homeowner. ..................................1-18

Maintainer & Service Provider Responsibilities: Providing Information to the Homeowner ........................1-19A. Septic system Management Plan ..............................................................................................1-20B. During service call, accomplish these tasks and discuss these topics with a homeowner. 1-20C. Communication with the homeowner. .....................................................................................1-21D. Discuss household water and product use tips with the homeowner. .................................1-22

Household Product and Water Use Guidelines for Homeowners ......................................1-22More Information About Septic Systems ...............................................................................................................1-23

Local and Regional .......................................................................................................................1-23

State and National ........................................................................................................................1-24

Publications and DVDs ................................................................................................................1-24

University of Minnesota Bookstore bookstores..umn.edu ................................................................................................................1-25

For More Information .................................................................................................................1-25

References ...................................................................................................................................................................1-25


ADMINISTRATION .......................................................................................2-1Federal Requirements ................................................................................................................... 2-1

Overview .......................................................................................................................................................................2-1Management Guidelines .............................................................................................................................................2-1Class V Systems ............................................................................................................................................................2-2Land Application Requirements ...............................................................................................................................2-2

State Agencies ............................................................................................................................... 2-3Overview .......................................................................................................................................................................2-3

Minnesota Pollution Control Agency .............................................................................................2-3

Overview of Minnesota’s SSTS Rules ......................................................................................................2-4System Classifications ...............................................................................................................................2-5

Type I systems .....................................................................................................................................2-6Type II systems....................................................................................................................................2-7Type III systems ..................................................................................................................................2-7Type IV systems ..................................................................................................................................2-8Type V systems .................................................................................................................................2-10Product development permits ........................................................................................................2-10

Compliance Criteria ................................................................................................................................2-10Imminent Threat to Public Health or Safety (ITPHS) .................................................................2-11Failing to protect groundwater .......................................................................................................2-12

Cesspool, seepage pit, leaching pit, drywell ...........................................................................2-13Limiting layer ....................................................................................................................................2-15

Systems Not Operated or Maintained Properly ...................................................................................2-16Systems with flows greater than 2,500 gpd ...........................................................................................2-17Compliance criteria for systems with partial component replacement ...........................................2-17Non-Code System ....................................................................................................................................2-17Inspection Process ...................................................................................................................................2-17Disclosure vs. Inspection ........................................................................................................................2-197083 Certification and Licensing Requirements .................................................................................2-19

Certification ......................................................................................................................................2-20Licensing Exemptions .....................................................................................................................2-20Types of certification and corresponding responsibilities .........................................................2-21

Responsibilities ..........................................................................................................................2-22Responsibilities ..........................................................................................................................2-22

Designer .............................................................................................................................................2-23Responsibilities ..........................................................................................................................2-23


Inspector ..........................................................................................................................................2-23Responsibilities ..........................................................................................................................2-24

Training .............................................................................................................................................2-24Continuing education ......................................................................................................................2-24Exam ...................................................................................................................................................2-25Experience .........................................................................................................................................2-25

Designer Experience – .............................................................................................................2-25Installer Experience – ..............................................................................................................2-25Inspector Experience - .............................................................................................................2-25Maintainer Experience - ..........................................................................................................2-26

Other Minnesota Regulatory Bodies ......................................................................................... 2-26Board of Architecture, Engineering, Land Surveying, Landscape Architecture, Geoscience and Interior Design ...........................................................................................................................2-26

Board of Water and Soil Resources ..............................................................................................2-26

Department of Health ..................................................................................................................2-26

Existing Conditions – Wells and SSTS ..................................................................................................2-27Isolation Distances ...................................................................................................................................2-27Sewers .......................................................................................................................................................2-27Sumps, Lift Stations, Grinder Pumps ....................................................................................................2-27Setbacks to Sensitive Wells .....................................................................................................................2-27Water Supply Pipes ..................................................................................................................................2-29Abandoned Wells and Abandoned SSTSs ............................................................................................2-29System Compliance .................................................................................................................................2-29

Before July 1, 1974 ............................................................................................................................2-29July 1, 1974 to June 31, 1989 ...........................................................................................................2-29July 1, 1989 to present ......................................................................................................................2-30

Environmental Wells ...............................................................................................................................2-30Variances from the Well Code ...............................................................................................................2-30Source Water Protection ........................................................................................................................2-31

Wellhead Protection .........................................................................................................................2-31Source Water Assessments .............................................................................................................2-34

Department of Labor and Industry ..............................................................................................2-34

Plumbing Code ........................................................................................................................................2-34Occupational Safety and Health ...........................................................................................................2-36Boilers Operator License ........................................................................................................................2-37

Department of Natural Resources.................................................................................................2-37

Department of Transportation .....................................................................................................2-39


Local Ordinances .......................................................................................................................... 2-39System Performance vs. Program Performance ....................................................................................................2-40Local Ordinance Requirements for Performance Programs ................................................................................2-41Type I-III Systems ......................................................................................................................................................2-42Type IV-V Systems ....................................................................................................................................................2-42Management ...............................................................................................................................................................2-41References ...................................................................................................................................................................2-44

SEWAGE TREATMENT UTILIZING SOIL .......................................................3-1Impacts of Effluent on Groundwater.........................................................................................................................3-2Soil Treatment Processes ............................................................................................................................................3-2

Biomat ............................................................................................................................................3-3

Soil Treatment ................................................................................................................................3-4

Pathogen Removal .....................................................................................................................................3-4Nutrient Removal ......................................................................................................................................3-5

Nitrogen ...............................................................................................................................................3-5Phosphorus ..........................................................................................................................................3-6

Residence Times .............................................................................................................................3-6

Soil Science Basics ......................................................................................................................... 3-7Soil Defined ..................................................................................................................................................................3-7

What is Soil? ...................................................................................................................................3-7

Components of Soil ........................................................................................................................3-7

Soil Texture ..................................................................................................................................................................3-7Described ....................................................................................................................................................3-7Soil Textural Classification .......................................................................................................................3-8

The twelve soil textural classes ..........................................................................................................3-9Field Determination of Soil Texture ......................................................................................................3-10

Procedure ..........................................................................................................................................3-11Soil Structure ..............................................................................................................................................................3-13

Soil Structure in Minnesota ..........................................................................................................3-13

Soil Structure Description ............................................................................................................3-13

Shape .........................................................................................................................................................3-14Size .............................................................................................................................................................3-15Grade .........................................................................................................................................................3-15

Consistence .................................................................................................................................................................3-17Soil Colors ...................................................................................................................................................................3-17

Significance of Color ....................................................................................................................3-17


Determining Soil Colors ...............................................................................................................3-18

Conditions for Measuring Color ...........................................................................................................3-19Reading the Color ....................................................................................................................................3-20

Mottles ..........................................................................................................................................3-22

Redoximorphic Features ...............................................................................................................3-23

Redoximorphic Feature Formation .......................................................................................................3-23Redoximorphic Feature Description .....................................................................................................3-24

Other Soil Features .......................................................................................................................3-24

Nodules and Concretions ................................................................................................................3-24Soft accumulations ...........................................................................................................................3-24Soft rock fragments ..........................................................................................................................3-24Surface features .................................................................................................................................3-24Roots and root traces .......................................................................................................................3-24

Soil Profile ...................................................................................................................................................................3-24Soil Horizons ..............................................................................................................................................................3-25

Determining Boundaries ..............................................................................................................3-26

Soil Morphology ........................................................................................................................................................3-26Soil Pores .....................................................................................................................................................................3-26Soil Permeability ........................................................................................................................................................3-26Saturated Hydraulic Conductivity ...........................................................................................................................3-26Infiltration ...................................................................................................................................................................3-27Plastic Limit ................................................................................................................................................................3-28

Procedure for Determining Plastic Limit in the Field ..................................................................3-28

Porosity .......................................................................................................................................................................3-29Bulk Density ...............................................................................................................................................................3-29Percolation Rate .........................................................................................................................................................3-29Soil Formation ...........................................................................................................................................................3-29

Parent Materials............................................................................................................................3-30

Lacustrine .................................................................................................................................................3-30Alluvium ...................................................................................................................................................3-30Colluvium .................................................................................................................................................3-31Glacial Outwash ......................................................................................................................................3-31Glacial Till ................................................................................................................................................3-31Loess ..........................................................................................................................................................3-31Organic Soils ............................................................................................................................................3-32Bedrock .....................................................................................................................................................3-32


Types ..................................................................................................................................................3-32Issues ..................................................................................................................................................3-32

Karst ............................................................................................................................................3-33Preferential flow .........................................................................................................................3-33Soft bedrock ...............................................................................................................................3-33Restrictive ...................................................................................................................................3-33

Climate .........................................................................................................................................3-34

Precipitation .............................................................................................................................................3-34Temperature .............................................................................................................................................3-34

Time of Soil Formation ................................................................................................................3-34

Vegetation and Organisms ............................................................................................................3-35

Plants .........................................................................................................................................................3-35Microorganisms and Soil-Dwelling Animals ......................................................................................3-35

Topography ..................................................................................................................................3-35

Minnesota Soils ..........................................................................................................................................................3-35References ...................................................................................................................................................................3-37

SITE EVALUATION ........................................................................................4-1Overview of Site Evaluation Process ........................................................................................... 4-1

Purpose .........................................................................................................................................................................4-1Overview of requirements ..........................................................................................................................................4-1

Preliminary Evaluation .................................................................................................................. 4-2Gathering Information ................................................................................................................................................4-2Soil Survey Reports and Geologic Atlases ................................................................................................................4-2

Soil Survey Vernacular ....................................................................................................................4-2

Soil Survey In Preliminary Site Evaluation .....................................................................................4-3

Hard Copy Soil Surveys ............................................................................................................................4-4Online Soil Surveys ...................................................................................................................................4-4Detailed Soil Survey Maps ........................................................................................................................4-5

Online availability .............................................................................................................................4-6Saturated Hydraulic Conductivity ...........................................................................................................4-6Linear Extensibility ...................................................................................................................................4-6Water Features ............................................................................................................................................4-6Soil Treatment Areas - Trench, At-Grade, Mound ................................................................................4-7Drainage Classification .............................................................................................................................4-7Slope Phases ...............................................................................................................................................4-7Reading the Soil Survey ............................................................................................................................4-7


Map unit inclusions ............................................................................................................................4-8Soil Series Limitations ....................................................................................................................4-9

Sand and Rock Fragment Treatment Concerns ....................................................................................4-9High clay content soils: acceptance and smearing concerns ................................................................4-9

Plastic limit ..........................................................................................................................................4-9Above ground system required .......................................................................................................4-10

Slopes ............................................................................................................................................4-10

Water table depths ........................................................................................................................4-10

Permeability..................................................................................................................................4-10

Property Limitations .................................................................................................................................................4-10Determining Homeowner Preferences ..........................................................................................4-10

Setbacks ........................................................................................................................................4-11

Unknown Buried Items ...........................................................................................................................4-13Property lines ...............................................................................................................................4-13

Lot line verification (survey) ..................................................................................................................4-13Easements .....................................................................................................................................4-13

Road right-of-ways ..................................................................................................................................4-13Utility easement .......................................................................................................................................4-13

Dwellings ......................................................................................................................................4-13

Lakes, rivers, streams ....................................................................................................................4-13

Wells .............................................................................................................................................4-14

Ownership ....................................................................................................................................4-14

Legal Land Survey Description ..............................................................................................................4-14Zoning ..........................................................................................................................................4-15

Field Evaluation ........................................................................................................................... 4-16Landscape Position ....................................................................................................................................................4-18

Landscape/Topography ................................................................................................................4-18

Landform ......................................................................................................................................4-18

Hillslope Position and Slope Shape ..............................................................................................4-18

Slope ............................................................................................................................................................................4-19Slope determination......................................................................................................................4-19

Upslope conditions–run-on/diversions .........................................................................................4-19

Slopes, elevations, and benchmarks ..............................................................................................4-19

System orientation to slope ....................................................................................................................4-20Benchmark ...............................................................................................................................................4-20Contours ...................................................................................................................................................4-20


Flooding ......................................................................................................................................................................4-20Distance from floodplain ..............................................................................................................4-21

Floodway, flood fringe, and floodplain identification ..................................................................4-21

Vegetation ...................................................................................................................................................................4-22Soil Observations .......................................................................................................................................................4-22

Soil Observations Procedure .........................................................................................................4-23

Soil Observation Log ....................................................................................................................4-24

Limiting layer identification .....................................................................................................................................4-25Redoximorphic features ................................................................................................................4-25

Formation .................................................................................................................................................4-25Identification ............................................................................................................................................4-25Limitations ................................................................................................................................................4-25Recognition of problem soils .................................................................................................................4-26

Red parent material ..........................................................................................................................4-26Thick topsoil ......................................................................................................................................4-26Elluvial horizons ...............................................................................................................................4-27Lamellae .............................................................................................................................................4-27

What do lamellae indicate? ......................................................................................................4-27Is there a thickness criteria where lamellae become limiting? ............................................4-27

Calcareous .........................................................................................................................................4-27Highly decomposed bedrock ..........................................................................................................4-28

Saturated soils ...............................................................................................................................4-28

Water Tables .............................................................................................................................................4-28Soil color determination ..................................................................................................................4-29Soil color implications .....................................................................................................................4-29

Bedrock ........................................................................................................................................4-29

Restricting soil conditions ............................................................................................................4-29

Flood Elevation ........................................................................................................................................4-29Disturbed Areas .......................................................................................................................................4-30

Fill Soils ..............................................................................................................................................4-30Cut Areas ..................................................................................................................................................4-31

Soils, Impacts on ISTS Design ..................................................................................................... 4-31Soil Texture .................................................................................................................................................................4-31

Constructability ............................................................................................................................4-31

Smearing ...................................................................................................................................................4-32Compaction ..............................................................................................................................................4-32


Soil structure - Preferential movement ...................................................................................................................4-32Soil water movement .................................................................................................................................................4-32

Unsaturated water movement .......................................................................................................4-32

Saturated hydraulic conductivity ..................................................................................................4-33

Determination of percolation rates of most restrictive horizon ..........................................................................4-34The Percometer and the Hook Gauge ...................................................................................................4-35Percolation Test Data Sheet ....................................................................................................................4-35Steps in a Percolation Test ......................................................................................................................4-35Use soil observations to locate suitable area ........................................................................................4-35

Locate an adequate number of test holes.......................................................................................4-36Dig the Test Holes ....................................................................................................................................4-36Prepare the Test Holes .............................................................................................................................4-36Distinguish Between Saturation and Soil Swelling .............................................................................4-37Measure the Percolation Rate .................................................................................................................4-37Calculate the Percolation Rate ...............................................................................................................4-38

Groundwater mounding ...............................................................................................................4-39

Soil Loading Rate .......................................................................................................................................................4-39Soil texture ....................................................................................................................................4-39

Soil structure ................................................................................................................................4-39

Soil consistence .............................................................................................................................4-39

Percolation rate.............................................................................................................................4-39

Basic predictive assessment methods ............................................................................................4-40

Assumptions .............................................................................................................................................4-40Parameters ................................................................................................................................................4-40Application ...............................................................................................................................................4-40Advanced assessment methods ..............................................................................................................4-40

Hydraulic Linear Loading Rate ....................................................................................................4-40

Proper protection of tested area ..............................................................................................................................4-40Staking the Site .............................................................................................................................4-40

Special equipment needed ........................................................................................................................................4-41Equipment limitations ............................................................................................................................4-41Traffic patterns to minimize compaction .............................................................................................4-41Maximum lift/of typical pump trucks ...................................................................................................4-41Winter operation and protection from freezing ..................................................................................4-41

Site Evaluation Reporting Requirements .................................................................................. 4-41Soil and Site Additional Reporting [Over 2,500 gpd] ...........................................................................................4-43


Mounding evaluation ...................................................................................................................4-43

Method ......................................................................................................................................................4-43Results .......................................................................................................................................................4-43

Nutrient evaluation .......................................................................................................................4-44

Problem soils assessment ..............................................................................................................4-44

Topographic and site variability evaluation ..................................................................................4-44

Soil property variation and interpretation ...................................................................................4-44

Water table monitoring basics ......................................................................................................4-44

Equipment ................................................................................................................................................4-44Duration ....................................................................................................................................................4-44Proper location .........................................................................................................................................4-45

Problem Sites and Soils .............................................................................................................. 4-45Type I, II, III, IV, and V Systems .................................................................................................. 4-45

Rapidly Permeable Soils ............................................................................................................................................4-45Sands and Gravels .........................................................................................................................4-45

Loamy, Medium, and Fine Sands .................................................................................................4-46

Small Lots ....................................................................................................................................................................4-46General Description ......................................................................................................................4-46

Solutions .......................................................................................................................................4-46

Reduce water consumption or reuse ....................................................................................................4-46Small field with holding tank .................................................................................................................4-46Pretreatment to reduced size drainfield ................................................................................................4-46Time dosing from large pump tank ......................................................................................................4-46Box mound/vertical side wall mound ...................................................................................................4-47

Lack of Unsaturated Soil ..........................................................................................................................................4-47Pretreatment technologies ............................................................................................................4-47

Reduced hydraulic linear loading rate ..........................................................................................4-47

Texture break ................................................................................................................................4-47

Designed perimeter drain tile/curtain drain .................................................................................4-47

Reduce water consumption or reuse ............................................................................................4-48

Disturbed Soil .............................................................................................................................................................4-48Soil modification methods ............................................................................................................4-48

Options ......................................................................................................................................................4-48Excavate out the disturbed soil .......................................................................................................4-48Use of the disturbed soil ..................................................................................................................4-49Manipulate the disturbed soil .........................................................................................................4-49


Limitations ................................................................................................................................................4-49Effects ........................................................................................................................................................4-49

Design pressure distribution with varying elevation .....................................................................4-49

Valving with management ......................................................................................................................4-49Varying perforation sizes and spacing with valving and management ............................................4-49

Flooding ......................................................................................................................................................................4-49Slowly Permeable Soils ..............................................................................................................................................4-50

60 to 120+ mpi .............................................................................................................................4-50

Soil Descriptions .......................................................................................................................... 4-51Texture ........................................................................................................................................................................4-51Structure .....................................................................................................................................................................4-51Color ............................................................................................................................................................................4-51Landscape ...................................................................................................................................................................4-51References ...................................................................................................................................................................4-52

Appendix 1 - Minnesota Wetland Conservation Act Contractor Responsibility and Landowner Statement Form ............................................................................................. 4-53

WASTEWATER SOURCES AND FLOWS ........................................................5-1Wastewater Sources .....................................................................................................................................................5-1

Sewage ............................................................................................................................................5-1

Definition ...................................................................................................................................................5-1Non sewage sources ..................................................................................................................................5-2

Clear water additions .........................................................................................................................5-2Water softeners....................................................................................................................................5-3Iron filters ............................................................................................................................................5-3How do iron filters work? ..................................................................................................................5-3Can a water softener be used to remove iron? ................................................................................5-4Challenges ...........................................................................................................................................5-4Options ...............................................................................................................................................5-5Reverse Osmosis .................................................................................................................................5-5High-efficiency furnaces ....................................................................................................................5-6Industrial wastewater ........................................................................................................................5-6

Other Establishments .....................................................................................................................5-7

Code Requirements ............................................................................................................................5-8Related Licensing Requirements ......................................................................................................5-8Apartment buildings ..........................................................................................................................5-9Day cares ............................................................................................................................................5-10


Commercial kitchen .........................................................................................................................5-10Campgrounds ....................................................................................................................................5-11

Privies ..........................................................................................................................................5-11RV Dump Stations .....................................................................................................................5-11

Laundromats .....................................................................................................................................5-12Office Buildings ................................................................................................................................5-12Schools and Churches ......................................................................................................................5-12Hotels and Motels .............................................................................................................................5-12Medical Facilities ..............................................................................................................................5-12Beauty Salons and Barbers ..............................................................................................................5-13Automotive Garages .........................................................................................................................5-13Filling Stations, Service Stations, Car Washes ..............................................................................5-13Class V Inventory Form (EPA regulations) ..................................................................................5-14

Hydraulics – Flow Rates .............................................................................................................. 5-147080 Versus 7081 .......................................................................................................................................................5-14General Hydraulic Considerations ..........................................................................................................................5-15

Design Process for Flow Equalization...................................................................................................5-16Estimates of Flow for Dwelling Design ..................................................................................................................5-16

Current Use ......................................................................................................................................5-18Architectural Issues ..........................................................................................................................5-18LGU ordinance considerations ......................................................................................................5-19Financial considerations .................................................................................................................5-19Sample bedroom determinations ..................................................................................................5-19

Estimated Flow- Class II – IV Dwellings ..............................................................................................5-20Class II ...............................................................................................................................................5-20Class III ..............................................................................................................................................5-20Class IV .............................................................................................................................................5-20

Measuring Flow for Design and Management .......................................................................................................5-20Water Meters ................................................................................................................................5-21

Installation .........................................................................................................................................5-21Event counter (cycle counter) .......................................................................................................5-22

Elapsed time meter .......................................................................................................................5-22

Other Establishments and MSTS Hydraulic Determinations .......................................................5-23

1. Dwellings ..............................................................................................................................................5-23Per capita applicability .....................................................................................................................5-23

2. Other Establishments ..........................................................................................................................5-24


Measured Flow ..................................................................................................................................5-27Design Process for Determining Flow ...........................................................................................5-28Design best-practices checklist .......................................................................................................5-29

3. Infiltration from the Collection System ...........................................................................................5-29Waste Characteristics: Waste Strength Components ............................................................... 5-30

Components of Wastewater ..........................................................................................................5-30

Waste Strength .............................................................................................................................5-30

Biochemical Oxygen Demands (BOD5), Dissolved Oxygen, and Total Suspended Solids (TSS) ...................5-31Types of BOD ...............................................................................................................................5-32

Biochemical Oxygen Demand ........................................................................................................5-32Biochemical Oxygen Demand (BOD5) .........................................................................................5-32Carbonaceous Biochemical Oxygen Demand (CBOD) ..............................................................5-33Nitrogenous Biochemical Oxygen Demand (NBOD) .................................................................5-33Ultimate Biochemical Oxygen Demand (UBOD) .......................................................................5-33

Source and Impact of BOD5 on Systems.......................................................................................5-33

Chemical Oxygen Demand (COD)................................................................................................5-34Total Suspended Solids (TSS) .......................................................................................................5-34

Impact of TSS on systems ................................................................................................................5-35Fats, Oils and Grease (FOG) .........................................................................................................5-35

Sources of FOG .................................................................................................................................5-35Impact of FOG on systems ..............................................................................................................5-36

Fat ................................................................................................................................................5-36Oils ..............................................................................................................................................5-36Grease .........................................................................................................................................5-37

Design Process for HSW.........................................................................................................................5-37Biological Treatment Processes ................................................................................................. 5-38

Wastewater Oxygen States ............................................................................................................5-38

Dissolved Oxygen (DO) ..................................................................................................................5-39pH .......................................................................................................................................................5-40Temperature ......................................................................................................................................5-41Alkalinity ...........................................................................................................................................5-42

Pathogens .....................................................................................................................................5-42

Fecal Coliform (FC) .........................................................................................................................5-42Category A Products and Treatment Levels .........................................................................................5-43Category B Products and Treatment Levels .........................................................................................5-44Nutrient Listing ........................................................................................................................................5-45


Nutrients ....................................................................................................................................... 5-45MN Rule Treatment Requirements for Nutrients ........................................................................5-45

Nitrogen .......................................................................................................................................5-46

The Nitrogen Cycle in Soil-Groundwater Systems .............................................................................5-471. Nitrogen Fixation ........................................................................................................................5-472. Ammonification ..........................................................................................................................5-473. Synthesis .......................................................................................................................................5-474. Nitrification ...................................................................................................................................5-475. Denitrification ...............................................................................................................................5-47

Health Effects from Groundwater Contamination with Nitrates .....................................................5-48Methemoglobinemia .......................................................................................................................5-48Carcinogenesis .................................................................................................................................5-48Birth Defects ....................................................................................................................................5-48

Surface Water Pollution with Nitrogen ................................................................................................5-49Eutrophication .................................................................................................................................5-49Oxygen Demand through Nitrification ........................................................................................5-49Ammonia Toxicity to Aquatic Organisms ...................................................................................5-49

Biological Nitrification ............................................................................................................................5-49Process Microbiology ......................................................................................................................5-50

Dissolved Oxygen Requirements and Organic Loading Rates .........................................................5-50Suspended Growth Systems ...........................................................................................................5-50Attached-Growth Systems ...............................................................................................................5-51pH and Alkalinity Effects on Nitrification ....................................................................................5-52Temperature Effects .........................................................................................................................5-52Effect of Inhibitors ...........................................................................................................................5-52

Example: Calculation of alkalinity and oxygen requirements for nitrification .................5-52Summary of Nitrification Processes .....................................................................................................5-53Biological Dentrification ........................................................................................................................5-54

Heterotrophic Dentrification .........................................................................................................5-54Wastewater as Carbon Source..................................................................................................5-54Heterotrophic ............................................................................................................................5-54Example: Calculation of stoichiometric equations for nitrate ............................................5-54

Example: Recalculation of stoichiometric equations for nitrate reduction using the wastewater as the carbon source .........................................................................................................................5-55External Carbon Source ...................................................................................................................5-56Example: Design of dentrification system using methanol as the carbon source ....................5-57


Example: Design of dentrification system using acetic acid as the carbon source ..................5-58Phosphorus ..................................................................................................................................5-60

Other Components of Wastewater ................................................................................................5-61

Pharmaceuticals ................................................................................................................................5-61Chemicals and hazardous waste .....................................................................................................5-61

Monitoring Wastewater Characteristics ................................................................................... 5-62Certified Labs ...............................................................................................................................5-62

Sampling .......................................................................................................................................5-62

References ...................................................................................................................................................................5-63Appendix 1 ................................................................................................................................... 5-67

Biological Hazards in Wastewater: FAQs for Septic System Professionals ........................................................5-67

PLUMBING AND COLLECTION ....................................................................6-1Introduction ................................................................................................................................... 6-1Definitions ...................................................................................................................................... 6-1

Plumbing .......................................................................................................................................................................6-1Basement sump, grinder and effluent pumps..................................................................................6-1

Non-flush toilets ........................................................................................................................................6-2Flammable waste and sediment traps ..............................................................................................6-3

Maintenance ................................................................................................................................................................6-3Sediment Traps ..........................................................................................................................................6-3Flammable waste interceptor ..................................................................................................................6-5

Maintenance ........................................................................................................................................6-5 Bottom Sand/Sediment Layer Management ...................................................................................6-6

Collection ....................................................................................................................................... 6-6Building sewer ................................................................................................................................6-6

Definition, description, rule requirement .............................................................................................6-6Building sewers ............................................................................................................................................................6-7

Pipe material ...................................................................................................................................6-7

Design............................................................................................................................................................................6-7Pumps in the basement .............................................................................................................................6-7Separation technology ...............................................................................................................................6-7Flammable waste separator ......................................................................................................................6-6Clay and Orangeburg Pipe .......................................................................................................................6-8Ductile Iron ................................................................................................................................................6-8High Density Polyethylene .......................................................................................................................6-8Acrylonitrile Butadiene Styrene ..............................................................................................................6-9


Polyvinyl Chloride ....................................................................................................................................6-9PVC Standard Dimensions and Materials ..............................................................................................6-9

Nominal Diameters ............................................................................................................................6-9Iron Pipe Standard - IPS ..................................................................................................................6-10Material Codes ..................................................................................................................................6-10

ASTM International ..................................................................................................................6-10ASTM D1785 - Schedule 40, 80, and 120 ......................................................................................6-10ASTM D2241 - Pressure Rated, Standard Dimension Ratio PVC Pipe ....................................6-10

SDR and Schedule Comparison ..............................................................................................6-11Additional Plastic Pipe Standards ...........................................................................................6-11PW and DWV ............................................................................................................................6-11

Storage and Handling .......................................................................................................................6-12Pipe Marking and Identification .....................................................................................................6-12Pipe Colors ........................................................................................................................................6-12Fittings and Joints .............................................................................................................................6-12Fittings ...............................................................................................................................................6-13

Slope/Grade ................................................................................................................................................................6-14Cleanouts ....................................................................................................................................................................6-14

Setbacks ....................................................................................................................................... 6-15Collection Design .........................................................................................................................6-16

Installation ..................................................................................................................................................................6-17Beginning excavation ..............................................................................................................................6-18

Pipe Cutting .................................................................................................................................6-18

Excavation and Backfilling ......................................................................................................................................6-18Embedment ..................................................................................................................................6-19

Embedment Methods ..............................................................................................................................6-20Finishing ...................................................................................................................................................6-21

Connecting Pipe and Fittings .......................................................................................................6-21

Solvent-Welding .......................................................................................................................................6-21Threaded Connections ............................................................................................................................6-23Mechanical Joints ....................................................................................................................................6-23Gaskets ......................................................................................................................................................6-24Thrust Blocks ............................................................................................................................................6-24

O&M and Troubleshooting ......................................................................................................................................6-24Plugging ....................................................................................................................................................6-25Freezing .....................................................................................................................................................6-25


SEPTIC TANKS .............................................................................................7-1Definition and Description ........................................................................................................................................7-1

Physical processes ...........................................................................................................................7-1

Biological and chemical processes...................................................................................................7-2

Treatment achieved with domestic sewage ..............................................................................................................7-2Factors affecting septic tank performance ..............................................................................................7-2

Setbacks .........................................................................................................................................................................7-3Design Impacts and Options ......................................................................................................................................7-3

Tank Sizing for Dwellings ..............................................................................................................7-4

Garbage Disposal and Pumps in Basements ...................................................................................7-5Determining Tank Capacities ...........................................................................................................7-5

Multiple Tanks ............................................................................................................................................7-6Compartmentalization of Single Tanks .................................................................................................7-7

Septic tank sizing for MSTS and other establishments ...........................................................................................7-8Lint filters, effluent screens, and pressure filters ...........................................................................7-8

Tank geometry ..........................................................................................................................................7-9Special considerations in septic tank design ............................................................................................................7-9

External grease interceptors ............................................................................................................7-9

Restaurants ...................................................................................................................................7-10

Laundromats .................................................................................................................................7-10

Slaughterhouses ............................................................................................................................7-11

Dairies, milkhouses ......................................................................................................................7-11

Tank Location and Bury Depth ...............................................................................................................................7-11Insulating Tanks .......................................................................................................................................7-13Vehicular Traffic .......................................................................................................................................7-13

Septic tank alarms ......................................................................................................................................................7-13Tees and baffles ...........................................................................................................................................................7-14

Access risers and inspection ports .................................................................................................7-16

Septic Tank Effluent Screens ....................................................................................................................................7-18Tank Construction........................................................................................................................ 7-20

Overview .....................................................................................................................................................................7-20Sewage tank registration ...........................................................................................................................................7-20Materials .....................................................................................................................................................................7-20Structural soundness .................................................................................................................................................7-21

Tank storage, transport, and use ...................................................................................................7-21

Precast concrete septic tanks and sealing materials .......................................................................7-22


Pipe penetrations for precast concrete tanks .......................................................................................7-23Rotationally molded polyethylene/polypropylene septic tanks ....................................................7-24

Fiberglass reinforced plastic septic tanks ......................................................................................7-24

Constructing pour-in-place tanks .................................................................................................7-25

Overall Quality of Precast Concrete, FRP, and Poly Septic Tanks.......................................................................7-25Watertightness testing ..................................................................................................................7-26

Hydrostatic testing .......................................................................................................................7-28

Hydrostatic testing procedure for tanks: ..............................................................................................7-28Vacuum testing .............................................................................................................................7-29

Visually examining existing tanks .................................................................................................7-30

Tank labeling ................................................................................................................................7-30

Tank installation ........................................................................................................................................................7-31Safety ............................................................................................................................................7-31

Planning and excavation ...........................................................................................................................................7-31Setting and securing a tank ..........................................................................................................7-31

Installation in high water table conditions ...................................................................................7-32

Dimension/capacity check and the use of existing tanks ..............................................................7-34

Placing and bedding tanks .......................................................................................................................................7-34Insulating tanks ............................................................................................................................7-35

Pipe penetrations .........................................................................................................................7-35

Baffling ........................................................................................................................................7-36

Sealing between joints, inlet and outlet pipes ...............................................................................7-37

Access risers and inspection pipes .................................................................................................7-37

Cleaning accesses .....................................................................................................................................7-37Tank Venting ................................................................................................................................7-38

Backfilling tanks ...........................................................................................................................7-38

Supply pipe ...................................................................................................................................7-39

Final grading ................................................................................................................................7-39

Operation and Maintenance ....................................................................................................................................7-39Tank cleaning .............................................................................................................................................................7-39

Effluent screens .............................................................................................................................7-41

Myths and additives ...................................................................................................................................................7-41Tank inspections and troubleshooting ....................................................................................................................7-42

Odor ..........................................................................................................................................................7-42Evaluating sewage tank performance ....................................................................................................7-43Flow, settling and bacterial action .........................................................................................................7-44


Effluent quality .........................................................................................................................................7-45Watertightness ..........................................................................................................................................7-46Baffles ........................................................................................................................................................7-47

Supply lines ................................................................................................................................................................7-48Outlet sewer ..................................................................................................................................7-48

Management of supply lines .........................................................................................................7-49

Tank abandonment ....................................................................................................................................................7-49Holding Tanks, Privies and Graywater Systems ....................................................................... 7-51

Holding Tanks ............................................................................................................................................................7-51Definition .....................................................................................................................................7-52

Rule Requirements .......................................................................................................................7-53

Setbacks and location ...................................................................................................................7-53

Application and Design ................................................................................................................7-54

Capacity ........................................................................................................................................7-54

Floodplain areas .......................................................................................................................................7-54Application and Design ................................................................................................................7-54

Capacity ........................................................................................................................................7-54

Floodplains ...............................................................................................................................................7-54Reduced-size systems ....................................................................................................................7-54

Holding Tank with Drainfield: An Alternative ....................................................................................7-56Installation ...................................................................................................................................7-56

Operation, Maintenance and Troubleshooting ............................................................................7-56

Inspection and Abandonment .......................................................................................................7-56

Privies ..........................................................................................................................................................................7-56Definition .....................................................................................................................................7-56


Design and Setbacks .....................................................................................................................7-57

Ventilation ................................................................................................................................................7-57Operation and Maintenance ....................................................................................................................................7-58

Odor Control ............................................................................................................................................7-58Keeping wood odor-free .........................................................................................................................7-58

Troubleshooting ...........................................................................................................................7-59

Odors .........................................................................................................................................................7-59Inspection ....................................................................................................................................7-59

Abandonment ...............................................................................................................................7-59

Graywater Systems .....................................................................................................................................................7-59


Definition and Applications .........................................................................................................7-59


The following text is courtesy of the Model Decentralized Wastewater Practitioner Curriculum Technology Overview ......................................................................................................................7-61

Segregation of wastewater flows ....................................................................................................7-61

Non-flush toilets ...........................................................................................................................7-63

Incinerating toilet ....................................................................................................................................7-63Composting toilet ....................................................................................................................................7-63Chemical toilet .........................................................................................................................................7-64

References ..................................................................................................................................................................7-65

TANK MANAGEMENT AND LAND APPLICATION .......................................8-1Tank Maintenance .......................................................................................................................................................8-1

Cleaning .........................................................................................................................................8-1

Scum and Sludge Accumulations ............................................................................................................8-1Septic Tank Cleaning Procedure ...............................................................................................................................8-2

How to Clean a Tank......................................................................................................................8-2

1. Locate Maintenance Hole .....................................................................................................................8-22. Open Maintenance Hole .......................................................................................................................8-23. Inspect Contents ....................................................................................................................................8-34. Remove All Tank Contents ...................................................................................................................8-3

Cleaning Procedure ............................................................................................................................8-3Mechanical Mixing ......................................................................................................................8-4Back Flush ....................................................................................................................................8-4

5. Inspect Tank ..........................................................................................................................................8-4Baffles ...................................................................................................................................................8-4Water tightness....................................................................................................................................8-5Inflow from System ............................................................................................................................8-5

6. Replace Maintenance Hole Cover ......................................................................................................8-57. Restore Yard ............................................................................................................................................8-58. Get Paid ...................................................................................................................................................8-59. Proper Land Application of the Septage .............................................................................................8-510. Receipt ...................................................................................................................................................8-611. Improper Maintenance Notice...........................................................................................................8-6

Effluent screens ...............................................................................................................................8-6

Cleaning an effluent screen .............................................................................................................8-7

Troubleshooting an Effluent Screen ...............................................................................................8-8


Problems: Professional Cleaning, Not Additives .....................................................................................................8-8Effect of Using Hydrogen Peroxide ................................................................................................8-9

Safety Keys for Maintainers .....................................................................................................................................8-10Safety gear for Maintainers .....................................................................................................................8-10

Safety for Confined Spaces ...........................................................................................................8-11

Hydrogen Sulfide (H2S) ...................................................................................................................8-11Carbon Dioxide (CO2) .....................................................................................................................8-11 Gasoline Fumes ................................................................................................................................8-11

Electricity Hazards ........................................................................................................................8-11

Explosion Hazards ............................................................................................................................8-12Infectious Disease Hazards .............................................................................................................8-12Structural Collapse Hazards ............................................................................................................8-12

Introduction to Land Application ...........................................................................................................................8-12Definitions ....................................................................................................................................8-13

Septage Treatment ....................................................................................................................................................8-16Septage and Its Characteristics .....................................................................................................8-16

Variability of Septage ....................................................................................................................8-20

Restaurant Grease Trap Wastes ....................................................................................................8-20

Potential Complications ..................................................................................................................8-21Transferring Septage and Restaurant Grease Trap Waste to a Publicly Owned Treatment Works (POTW) .............................................................................................................................................8-22

Septage Storage Requirements ......................................................................................................8-23

Land Application Requirements for Septage ................................................................................8-23

Requirements for Pathogen Control and Vector Attraction Reduction .............................................................8-23Pathogen Control Requirements ..................................................................................................8-23

Vector Attraction Reduction Requirements .................................................................................8-25

Lime Stabilization Treatment ......................................................................................................8-25

Pathogen Reduction Alternative #1 for Domestic Septage with pH Treatment Applied to Non-Public Contact Sites .............................................8-28

Crop Restrictions .....................................................................................................................................8-28Grazing Restrictions ................................................................................................................................8-28Site Restrictions........................................................................................................................................8-28

Pathogen Reduction Alternative #2 for Domestic Septage without Additional Treatment Applied to Non-Public Contact Sites ..........................8-29

Crop Restrictions .....................................................................................................................................8-29Grazing Restrictions ................................................................................................................................8-29Site Restrictions........................................................................................................................................8-29


Vector Attraction Reduction Alternatives for Domestic Septage Applied to Non-Public Contact Land ........8-29Alternative 1: Injection ...........................................................................................................................8-30Alternative 2: Incorporation ...................................................................................................................8-30Alternative 3: pH Adjustment ................................................................................................................8-30

Site Suitability Requirements for Septage Application .........................................................................................8-31Soil Terminology: Definitions for Septage Application ................................................................8-31

Site Selection ............................................................................................................................................8-32Using the Soil Survey ..............................................................................................................................8-33

Soil Survey Tables: Useful Information for Determining Suitability of Soils for Septage Application ........................................................................................................................................8-34

General Site Management .........................................................................................................................................8-35Allowable Application Rates .........................................................................................................8-35

Land Spreading .............................................................................................................................8-35

Septage Application Rate Limits ...................................................................................................8-36

Additional Nitrogen Management Requirements ...............................................................................8-37EXAMPLE 1: MANA rate determined using option 1 ................................................................8-37EXAMPLE 2: MANA rate determined using option 1 ...............................................................8-37EXAMPLE 3: MANA rate determined using option 2 ...............................................................8-38EXAMPLE 4: MANA rate determined using option 2 ..............................................................8-38

Truck Calibration .........................................................................................................................8-38

EXAMPLE CALIBRATION: ..........................................................................................................8-39Specific Nitrogen Management Requirements: ...................................................................................8-39Hydraulic Loading Rate Limits ..............................................................................................................8-40Maintainer Qualifications .......................................................................................................................8-40

Record Keeping ..........................................................................................................................................................8-40Requirements for Land Application of Restaurant Grease Trap Waste ..............................................................8-42References ...................................................................................................................................................................8-43

Minnesota Pollution Control Agency Offices ......................................................................................8-43

PUMPING SYSTEMS ....................................................................................9-1Overview ........................................................................................................................................ 9-1Pumping Applications .................................................................................................................. 9-1

Pumping in Gravity Systems ......................................................................................................................................9-1Pumping in Pressure Systems ....................................................................................................................................9-3

Sump and Pump Tank Specifications ........................................................................................... 9-4Sump Basket .................................................................................................................................................................9-4Specifications ................................................................................................................................................................9-5


Construction ..............................................................................................................................................9-5Discharge line .............................................................................................................................................9-5Sumps for buildings ...................................................................................................................................9-5Covers ..........................................................................................................................................................9-5Single family dwellings ..............................................................................................................................9-5Sump vent ...................................................................................................................................................9-5Clear water sumps .....................................................................................................................................9-6

Pump Tank....................................................................................................................................................................9-6Definition ....................................................................................................................................................9-6Requirements .............................................................................................................................................9-8

Dosing Regimens: Demand vs. Timed .....................................................................................................................9-8Demand Dosing..............................................................................................................................9-9

Timed Dosing .................................................................................................................................9-9

Flow Equalization .........................................................................................................................9-10

Pumps ........................................................................................................................................... 9-11Rule Requirements ....................................................................................................................................................9-11

Pumps for Gravity Distribution ..................................................................................................9-11

Pumps for Pressure Distribution ..................................................................................................9-11

Water Meters and Event Counters ................................................................................................9-12

Type of Pumps..............................................................................................................................9-12

Raw Sewage Pumps .................................................................................................................................9-12Other Pumps ............................................................................................................................................9-13

Friction Loss in a Pipe ..................................................................................................................9-13

Friction Loss Example:.....................................................................................................................9-14Sensors for Pumps ...................................................................................................................................9-14Pump Controls .........................................................................................................................................9-14Alarm.........................................................................................................................................................9-15

Dual Pumps ...............................................................................................................................................................9-15Designing Pumping Systems ...................................................................................................... 9-17

Selecting Pumps ........................................................................................................................................................9-17Pump Curves ................................................................................................................................9-17

Head requirements .......................................................................................................................9-19

Fittings as Equivalent Straight Pipe ........................................................................................................................9-19Method 1: Estimating a percentage .......................................................................................................9-19Method 2: Calculating actual losses ......................................................................................................9-20

Example: ...........................................................................................................................................9-20


Sizing the Pump Tank ...............................................................................................................................................9-20Dose volume .................................................................................................................................9-20

1. Determining Area and Gallons per Inch .........................................................................................9-202. Determining Tank Capacity ..............................................................................................................9-203. Setting the Dose Volume ...................................................................................................................9-21

Example .............................................................................................................................................9-21Example .............................................................................................................................................9-21

Float and Timer Setting ............................................................................................................................................9-22Demand Dosing .......................................................................................................................................9-22

Example .............................................................................................................................................9-22Cylindrical Tanks ......................................................................................................................9-22Rectangular Tanks .....................................................................................................................9-22

Time Dosing .............................................................................................................................................9-23Timer On ...........................................................................................................................................9-23Timer Off ...........................................................................................................................................9-23

Installing Pumps and Pump Tanks ............................................................................................. 9-24Pump Tank..................................................................................................................................................................9-24

Buoyancy ......................................................................................................................................9-24

Pump Discharge Assembly ......................................................................................................................................9-25Sensors ........................................................................................................................................................................9-25Controls .......................................................................................................................................................................9-26Pump and Alarm .......................................................................................................................................................9-27

Accessible ..................................................................................................................................................9-27Replaceable ...............................................................................................................................................9-27Properly Wired .........................................................................................................................................9-28Materials for Outdoor Wiring ................................................................................................................9-28Boxes and Panels ......................................................................................................................................9-29Wiring from the pump and alarm controls to the pump and switches ............................................9-30NEMA type 1 ...........................................................................................................................................9-31NEMA type 3R .........................................................................................................................................9-31NEMA type 4 ...........................................................................................................................................9-31NEMA type 4X non-metallic, corrosion-resistant ..............................................................................9-31

Operation, Maintenance and Troubleshooting ........................................................................ 9-32Pumping Costs .........................................................................................................................................9-32Calculating Flow ......................................................................................................................................9-32

Demand Dosed vs. Timed Dosed ................................................................................................9-32


Dose volume verification ........................................................................................................................9-33Pump delivery rate ...........................................................................................................................9-33

Troubleshooting .......................................................................................................................................9-34The Pump Will Not Start .................................................................................................................9-34Effluent Stays in the Tank ................................................................................................................9-34

Inspection .....................................................................................................................................9-34

Evaluating the Pump Tank and Components ...............................................................................9-34

Safety precautions ....................................................................................................................................9-34Abandonment ...............................................................................................................................9-35

PRETREATMENT ........................................................................................10-1Application ................................................................................................................................... 10-1Performance ................................................................................................................................. 10-2Management of the System ....................................................................................................... 10-3

Designing with Management in Mind ....................................................................................................................10-3Economics ...................................................................................................................................................................10-4

Product Review and Registration Process ................................................................................ 10-4Overview .....................................................................................................................................................................10-4

Types of Pretreatment Units ..................................................................................................... 10-6Aerobic Treatment Units...........................................................................................................................................10-6

Definition and Description ...........................................................................................................10-6

Rule Requirements and System Classification ..............................................................................10-6

Treatment Processes .....................................................................................................................10-7

Design Basis and Operational Theory ..........................................................................................10-8

Types of ATUs ..............................................................................................................................10-9

Fixed film ..................................................................................................................................................10-9Suspended growth .................................................................................................................................10-10Sequencing batch reactor ......................................................................................................................10-10Membrane Bioreactors ..........................................................................................................................10-11

Performance Levels .....................................................................................................................10-12

Applications ................................................................................................................................10-12

Management ...............................................................................................................................10-14

Management plan ..................................................................................................................................10-14Installation..................................................................................................................................10-15

Troubleshooting .........................................................................................................................10-15

Compliance Inspections ..............................................................................................................10-16

Abandonment .............................................................................................................................10-17


Media Filters .............................................................................................................................................................10-17Definition ...................................................................................................................................10-17

Treatment Process in Media Filters ............................................................................................10-17

Types of Media Filters and Operation ........................................................................................10-17

Single pass media filters ........................................................................................................................10-17Recirculating Media Filters .................................................................................................................10-18

Applications and Performance ....................................................................................................10-20

Rule Requirements .....................................................................................................................10-22

Design .....................................................................................................................................................10-23Single Pass Sand Filters .........................................................................................................................10-23

Daily Flow ........................................................................................................................................10-24Sizing ................................................................................................................................................10-25Media ...............................................................................................................................................10-26Underdrain and inspection ports .................................................................................................10-27Choosing the containment vessel .................................................................................................10-29

Peat Filters .............................................................................................................................................10-29Final Treatment and Dispersal .............................................................................................................10-31Design .....................................................................................................................................................10-32Recirculating Media Filters .................................................................................................................10-32Recirculating Sand Filter Specifications .............................................................................................10-35

Installation of Media Filters .......................................................................................................10-38

Containment Vessels .............................................................................................................................10-38Media Filter System Management ..............................................................................................10-39

Management plan ..........................................................................................................................10-40Operation Costs of Media Filters ................................................................................................10-41

Abandonment of Media Filters ...................................................................................................10-41

Troubleshooting Media Filters ...................................................................................................10-42

Compliance Inspections for Media Filters ..................................................................................10-42

Constructed Wetland Systems ..............................................................................................................................10-43Definition and Description .........................................................................................................10-43

Types of Constructed Wetland Systems ......................................................................................10-43

Open water ......................................................................................................................................10-43Hydroponic .....................................................................................................................................10-43Subsurface flow ...............................................................................................................................10-44

Treatment Processes ...................................................................................................................10-44

Design ........................................................................................................................................10-45


Performance ................................................................................................................................10-47

Applications ................................................................................................................................10-48

Final Dispersal of Effluent ..........................................................................................................10-49

Installation..................................................................................................................................10-50

Troubleshooting .........................................................................................................................10-50

Management Plan .......................................................................................................................10-52

1. Effluent levels ..............................................................................................................................10-522. Vegetation ...................................................................................................................................10-523. Effluent quality ............................................................................................................................10-524. Air supply ....................................................................................................................................10-525. Control of nuisance pests and insects. ....................................................................................10-526. Maintenance of berms and dikes. ............................................................................................10-52

Winter Operation ..................................................................................................................................10-52Compliance Inspections .......................................................................................................................10-53Abandonment ........................................................................................................................................10-53

Final Treatment and Dispersal of Effluent After Pretreatment Units ...............................................................10-53Disinfection Systems ...............................................................................................................................................10-54

Definition and Rules ...................................................................................................................10-54

Disinfection Processes and Design Considerations.....................................................................10-57

Methods of Disinfection .............................................................................................................10-57

Chlorination ...........................................................................................................................................10-57Ultraviolet ...............................................................................................................................................10-58Ozone ......................................................................................................................................................10-59

Applications ................................................................................................................................10-60

Management ...............................................................................................................................10-60

Chlorine ..................................................................................................................................................10-61UV............................................................................................................................................................10-61Ozone .....................................................................................................................................................10-62Troubleshooting .....................................................................................................................................10-62

References .................................................................................................................................................................10-63

DISTRIBUTION OF EFFLUENT .....................................................................11-1Distribution .................................................................................................................................. 11-1

Supply Pipes ................................................................................................................................................................11-2Materials .......................................................................................................................................11-2

Schedule 40 and ASTM 3034 ................................................................................................................11-3Existing Piping .........................................................................................................................................11-3


Size ...............................................................................................................................................11-3

Slope .............................................................................................................................................11-4

Installation .................................................................................................................................................................11-4Freeze Protection ..........................................................................................................................11-6

Cleaning, Priming, and Gluing Joints ..........................................................................................11-7

Cleanout Requirements and Maintenance ....................................................................................11-7

Gravity Distribution ..................................................................................................................................................11-8Rule Requirements, Definition and Description ..........................................................................11-8

Serial Distribution ........................................................................................................................11-9

Application ...............................................................................................................................................11-9Drop Boxes ...............................................................................................................................................11-9

Management of systems with drop boxes ...................................................................................11-13No drop box ....................................................................................................................................11-14

Continual Distribution .........................................................................................................................11-14Valve Boxes .............................................................................................................................................11-14

Parallel Distribution ...................................................................................................................11-15

Application .............................................................................................................................................11-15Distribution Boxes .................................................................................................................................11-15

Distribution Box Modifications ....................................................................................................11-16Management ............................................................................................................................11-17

Manifolds and other distribution methods .................................................................................11-17Installation of Gravity Distribution Components ......................................................................11-17

Pressure Distribution ..............................................................................................................................................11-18Purpose and Application ............................................................................................................11-20

Pipe Specifications ......................................................................................................................11-21

Supply Pipe and Manifold Requirements ..........................................................................................11-21Designing the Pressure Distribution System .......................................................................................................11-24

Steps to designing the pressure distribution system ..................................................................11-26Design for pipes at different elevations .................................................................................................................11-29Installation ................................................................................................................................................................11-30

Manifold construction ...................................................................................................................11-30Distribution piping construction .................................................................................................11-30Perforations .....................................................................................................................................11-30

Management .............................................................................................................................................................11-31Drip Dispersal ..........................................................................................................................................................11-32

Definition and Description ..................................................................................................................11-34


Rule Requirements ................................................................................................................................11-36Purpose and Application ......................................................................................................................11-36Design Basis and Operational Theory ................................................................................................11-37

Sizing ...............................................................................................................................................11-38Installation .......................................................................................................................................11-38

O&M and Troubleshooting .................................................................................................................11-39References .................................................................................................................................................................11-41

SOIL TREATMENT SYSTEMS ......................................................................12-1Overview ...................................................................................................................................... 12-1

General Requirements ............................................................................................................................12-3Setbacks ........................................................................................................................................12-5

Below-Grade Systems ................................................................................................................................................12-7Below-Grade Systems: Specifications ......................................................................................................................12-8

Trenches ....................................................................................................................................................12-8Shallow trenches ..............................................................................................................................12-9

Seepage Beds ..........................................................................................................................................12-10General Specifications .................................................................................................................12-11

Media Choices ........................................................................................................................................12-11Soil treatment system size & long-term performance ...............................................................12-11Distribution pipe ............................................................................................................................12-12Rock/Geotextile ..............................................................................................................................12-12

Geotextile Fabric ....................................................................................................................12-13Nonrock Soil Treatment System Media .......................................................................................12-14Chambers .........................................................................................................................................12-14Gravelless pipe ................................................................................................................................12-15Polystyrene beads ...........................................................................................................................12-16Other soil treatment media ...........................................................................................................12-16

Design Basis and Operational Theory ........................................................................................12-17

Design of Trenches and Seepage Beds ........................................................................................12-17

Example Trench Design ........................................................................................................................12-21Dual Field Systems .....................................................................................................................12-22

Zoning of Cluster Systems ..........................................................................................................12-24

Type II – V Trenches and Seepage Beds .....................................................................................12-24

Above–Ground Systems ..........................................................................................................................................12-24Above-Ground Rule Requirements .....................................................................................................12-25Above-Ground System Siting ...............................................................................................................12-25


At-grades .....................................................................................................................................12-25

Definition and Description ..................................................................................................................12-25General Specifications ...........................................................................................................................12-26Design of At-Grade Systems ................................................................................................................12-27

Example at-grade design ...............................................................................................................12-32Mound Systems ........................................................................................................................................................12-34

Definition and Description ..................................................................................................................12-34Locating Mounds ...................................................................................................................................12-36General Specifications ..........................................................................................................................12-38

Mound Design ...............................................................................................................................12-40Example mound system design ....................................................................................................12-46

Type III Above-Ground ..............................................................................................................12-47

Box Mounds ....................................................................................................................................12-48Replacing Mounds ..........................................................................................................................12-48

Installing Soil Treatment Systems (STA) ..............................................................................................................12-48General Soil Treatment Installation Principles ..................................................................................12-48Cover, Topsoil and Vegetation Requirements ....................................................................................12-51Trench and Seepage Bed Installation .................................................................................................12-51

Above-Ground System Installation .............................................................................................12-52

Construction Equipment ......................................................................................................................12-53Soil Surface Preparation ........................................................................................................................12-53Media Placement ...................................................................................................................................12-55Cover Material .......................................................................................................................................12-57Inspection of Soil Treatment Systems .................................................................................................12-57

New Systems ....................................................................................................................................12-57Existing Systems .............................................................................................................................12-59

Troubleshooting Below-ground Systems ............................................................................................12-60Troubleshooting Above-Ground Soil Treatment Systems ...............................................................12-62

Reasons for system malfunctions .................................................................................................12-62Malfunction due to poor-quality materials..........................................................................12-62Malfunction due to poor siting .............................................................................................12-63Malfunction due to errors in design .....................................................................................12-63Malfunction due to construction errors ...............................................................................12-63Malfunction due to system misuse by homeowners ...........................................................12-63

Management of All Soil Treatment Systems ...............................................................................12-64

Management Plans ................................................................................................................................12-64


Site planning, preparation, documentation, and contracting ............................................. 12-65Reading a Drawing ..................................................................................................................................................12-65Equipment ................................................................................................................................................................12-65Survey Techniques ...................................................................................................................................................12-66As-Builts ....................................................................................................................................................................12-67Photographing Installation ....................................................................................................................................12-68

Notating Your Photographs ........................................................................................................12-68

Building Sewer and Tanks ..........................................................................................................12-68

Pump Tank .................................................................................................................................12-68

Soil Treatment Site .....................................................................................................................12-68

Soil Separation .......................................................................................................................................12-68Site Preparation ......................................................................................................................................12-68Sand .........................................................................................................................................................12-69Distribution Media ................................................................................................................................12-69Pressure Laterals ....................................................................................................................................12-69

Special Considerations ................................................................................................................12-69

Finished Product ........................................................................................................................12-69

Contracts ...................................................................................................................................................................12-69Landscaping Septic Systems ..................................................................................................... 12-70

Introduction .............................................................................................................................................................12-70Guidelines for Planting On and Near Septic System ..........................................................................................12-71Vegetation tables ......................................................................................................................................................12-72

Seeding .............................................................................................................................................12-74Sodding ............................................................................................................................................12-74

Trees and Shrubs ......................................................................................................................................................12-74References .................................................................................................................................................................12-76

FORMS AND REFERENCE SECTION ...........................................................13-1Table IX and IXa: loading rates and absorption ratios from MN Rules Chapter 7080.2150, Subp. 3 (E) .......................................................................................................................................... 13-1

Estimate of Waste Strengths from Other Establishments ............................................................. 13-2

Equations and Constants .................................................................................................................. 13-3

Documents

SECTION 14 Detailed Directory