6/12/2011

1

`t~|Çz bâÜ VÄ|xÇàá fâvvxááyâÄ

2011 Idaho Water Reuse ConferenceBoise, IdahoMay 24-25

Mark Holtzen, P.E.J-U-B ENGINEERS, Inc.

Twin Falls, ID(208) 733-2414

1. Background2. Planning and Modeling3. WWTP Improvements4. WWTP Performance5. Lessons Learned6. Questions

6/12/2011

2

Rural Community in South Central Idaho

Located on Canyon Rim Above Snake River

1. Background

Murtaugh

1. Background

Cell #1 Cell #2

RI Basin #1

RI Basin #2

Influent

6/12/2011

3

Parameter 2008 2028Service Population 235 350

Flow (gpd)

Average Day 27,900 41,700

Max Month 36,100 53,800

Peak Day 56,00 83,400

BOD (ppd)

Average Day 69 102

Max Month 120 177

Peak Day 165 244

1. Background

0

25

50

75

100

125

150

175

200

225

250

Sep-

02

Mar

-03

Sep-

03

Mar

-04

Sep-

04

Mar

-05

Sep-

05

Mar

-06

Sep-

06

Mar

-07

Sep-

07

Mar

-08

Sep-

08

Mar

-09

TSS

(mg/

L)

Effluent TSS

Reuse Permit Limit

1. Background

6/12/2011

4

0

10

20

30

40

50

60

70

Sep-

02

Mar

-03

Sep-

03

Mar

-04

Sep-

04

Mar

-05

Sep-

05

Mar

-06

Sep-

06

Mar

-07

Sep-

07

Mar

-08

Sep-

08

Mar

-09

Tota

l-Nitr

ogen

(mg/

L)Effluent Total Nitrogen

Reuse Permit Limit

1. Background

November 2006 City Entered into Consent Order with IDEQ

October 2007 Complete Facilities PlanDecember 2008 Complete Plans and SpecsApril 2009 Begin ConstructionApril 2010 Commissioning

1. Background

6/12/2011

5

IDEQ → Continued Use of Lagoons and RI Basins Not a Likely Option

Surface Water Discharge Not Feasible Limited Waste Load Allocation Available

Initial Improvement Alternatives1. Upgrade Existing Lagoons, Winter Storage, and

Slow-Rate Land Application2. Mechanical Plant with RI Basins3. Regional Treatment

2. Planning and Modeling

AlternativeCapital Cost ($Million)

Annual O&M Costs ($Million)

Monthly User Rate A($/month)

Lagoons & Slow-RateLand Application

$2.2 - $2.5 $0.053 $103 - $166

Mechanical WWTP $2.5 - $3.1 $0.107 - $0.113 $160 - $250

A – Dependent on Amount of Grant and Loan Funds Provided for Project

All Costs in 2008 Dollars.

2. Planning and Modeling

6/12/2011

6

Costs for Traditional Solutions Not Feasible City and IDEQ Agreed to Investigate a

Potential Variance to the Reuse Standards for Nitrogen and TSS Continue Using Existing Lagoons and RI Basins with

Improvements to Optimize their Performance?

Identify Key Design Parameters1. Nitrogen Impacts on Groundwater2. Phosphorus Impacts on Surface Water3. TSS Impacts on RI Basin Operation

Analyze System Performance1. Nitrogen and Phosphorus Removal

and Transport Modeling2. TSS Management Strategies

2. Planning and Modeling

Nitrification/Denitrification in RI Basins Soil Characteristics Effluent Carbon/Nitrogen Ratio RI Basin Management Predicts Dosing/Resting Periods and C:N Ratio’s

Nitrogen Impacts on Groundwater Modeled Using Mixing Zone Analysis

2. Planning and Modeling

6/12/2011

7

NH3

NH3

NH3

NH3

NH3

Dosing Cycle

Lagoon Effluent

Upper 2’-3’ of Soil

Lower Soil/Rock

2. Planning and Modeling

Resting Cycle

Percolate

Oxygen

Upper 2’-3’ of Soil

Lower Soil/Rock

NH3

NH3

NH3

NH3

NH3NO3

NO3NO3

NO3NO3

2. Planning and Modeling

NH3

NO3

6/12/2011

8

Lagoon Effluent/Carbon

Dosing Cycle

Upper 2’-3’ of Soil

Lower Soil/Rock

N2 NO3

NO3NO3

NO3NO3 N2

N2

N2

N2NH3NH3NH3

NH3

Nitrogen Gas

2. Planning and Modeling

Parameter Model Output Typical ValueDosing Period 8 – 11 days 7 – 12 days

Resting Period 5 – 7 days 10 – 16 days

Min. BOD for Denitrification 11.2 mg/L 87 mg/L

Nitrogen Removal 60 – 80% 50 – 80%

Percolate Nitrogen 4.6 – 9.3 mg/L -

2. Planning and Modeling

6/12/2011

9

Parameter Units60% N

Removal80% N

Removal

Upgradient Groundwater Nitrogen

mg/L 2.3 2.3

Percolate Nitrogen mg/L 9.3 4.6

Mixed Groundwater Nitrogen

mg/L 3.3 2.6

Increase in Downgradient Groundwater Nitrogen

mg/L 1.0 0.3

Acceptable to IDEQ? mg/L

2. Planning and Modeling

Phosphorus Removal Mechanisms Filtration, Adsorption, Precipitation, Etc. Generally Termed “Sorption”

30 – 100% Phosphorus Removal (EPA) Langmuir Isotherm Analysis

Phosphorus Sorption Capacity RI Basin #1 – 1,377 ug/g RI Basin #2 – 1,054 ug/g

2. Planning and Modeling

6/12/2011

10

2. Planning and Modeling

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

10,000

2005 2010 2015 2020 2025 2030 2035 2040

Phos

phor

us L

oadi

ng (l

bs)

Year

RIB #1 Cumulative P Loading

RIB #1 Max P Sorption Capacity

RIB #2 Cumulative P Loading

RIB #2 Max P Sorption Capacity

Discharge Effluent At Night Avoid Discharging During Algal

Blooms Provide Sufficient Drying Periods

Between Discharge Maintain Plant Growth in RI Basins Scarify Surface of RI Basins as

Needed) Install Mechanical Surface Aerators A. Source: WEF Natural Systems for

Wastewater Treatment, 2nd Edition

Average Annual TSS Effluent Loading Rate(lbs/acre-d)

Typical Design

Loading Rate A

(lbs/acre-d)

25 40 - 158

2. Planning and Modeling

6/12/2011

11

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

2005 2010 2015 2020 2025 2030 2035 2040

Hyd

raul

ic L

oadi

ng (i

n/d)

Year

RI Basin #1RI Basin #2Design Hydraulic Loading Rate

2. Planning and Modeling

IDEQ Granted a Variance to the Reuse Rules in March 2009

New Reuse Permit Limits (30-Day Averages) Total Nitrogen – 30 mg/L TSS – 150 mg/L

Revise O&M Manual for TSS Management Reuse Activities Cannot Cause a Violation of

Idaho Groundwater Quality Rule

3. WWTP Improvements

6/12/2011

12

3. WWTP Improvements

Cell #1 Cell #2

RI Basin #1

RI Basin #2

Influent Coarse Screen & Flow Measurement

RI Basin #3 (1 acre)

Surface Aerators (4)

AlternativeCapital Cost ($Million)

Annual O&M Costs ($Million)

MonthlyUser Rate A($/month)

Lagoons & Slow-RateLand Application B

$2.2 - $2.5 $0.053 $103 - $166

Mechanical WWTP B $2.5 - $3.1 $0.107 - $0.113 $160 - $250

Upgrade Lagoons & New RI Basin C

$0.54 $0.039 $41 - $48

A – Dependent on Amount of Grant and Loan Funds Provided for Project

B – Costs in 2008 Dollars.

C – Costs in 2010 Dollars.

3. WWTP Improvements

6/12/2011

13

3. WWTP Improvements

3. WWTP Improvements

6/12/2011

14

0

25

50

75

100

125

150

175

200

225

250

Mar

-02

Sep-

02

Mar

-03

Sep-

03

Mar

-04

Sep-

04

Mar

-05

Sep-

05

Mar

-06

Sep-

06

Mar

-07

Sep-

07

Mar

-08

Sep-

08

Mar

-09

Sep-

09

Mar

-10

Sep-

10

Mar

-11

Sep-

11

TSS

(mg/

L)

Effluent TSSOld Reuse Permit LimitNew Reuse Permit Limit

4. WWTP Performance

0

10

20

30

40

50

60

70

Mar

-02

Sep-

02

Mar

-03

Sep-

03

Mar

-04

Sep-

04

Mar

-05

Sep-

05

Mar

-06

Sep-

06

Mar

-07

Sep-

07

Mar

-08

Sep-

08

Mar

-09

Sep-

09

Mar

-10

Sep-

10

Mar

-11

Sep-

11

Tota

l-Nitr

ogen

(mg/

L)

Effluent Total NitrogenOld Reuse Permit LimitNew Reuse Permit Limit

4. WWTP Performance

6/12/2011

15

RI Basins are a Viable Option for Small Lagoon Systems

Water Quality Variances May be an Alternative Solution

Operation, Management, and Monitoring are Critical

Work Closely with Regulatory Agencies

5. Lessons Learned

6. Questions

Mark Holtzen, P.E.mholtzen@jub.com

115 Northstar Avenue | Twin Falls, Idaho 83301Ph (208) 733-2414 | Fax (208) 733-9455