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Read an extension publication from The Education Store
Store Search pesticide Select and read one of the articles listed (there
were 85 to choose from when I checked) Quiz on Monday, Oct. 15, 2012. You will be required
to give:◦ Title◦ Publication number◦ What was the article about – problem &
recommendations
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Reading Assignment
Change for Group AA (Hession, D. – McSherry + B. Easter): We will meet in NLSN 1195 at 3:30 on Friday, Oct. 12
Group A (Barry – Hershberger) should attend this lab
Anyone from Group AAA may attend this lab if it fits your schedule better.
See me if you are in Group A and cannot attend the computer lab this Friday (10/5)
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Computer Lab
Onsite Waste Disposal October 10, 2012
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Give your best guess Correct as needed, during the lecture
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Complete the study guide
Historical sewage treatment◦ Washed away and diluted by rain and surface water
◦ Early human habitations were often built near rivers or oceans for conveyance and sewage disposal
As population densities increased sewer collection and conveyance systems were developed. ◦ First sanitation system was found southeast of Iran,
used in palaces in Crete, Greece (3,000 years old & still works)
◦ As populations rose, systems became more complex
Rome had complex sewer networks between 46BC-400AD5
Human Waste Disposal
Most cities in early times had no sewers and relied on nearby rivers or occasional rain to wash away sewage. In some cities, waste water simply ran down the streets.
The growth of cities quickly caused polluted streets and became a constant source of disease. Even as recently as the late 1800’s street sewerage systems and individual cesspits were common.
Rain often caused the cesspits to overflow leaving the pavements awash with foul sewage and caused water-borne diseases such as cholera and typhoid.
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Human Waste Disposal
Because of the Industrial Revolution, populations in European and North American cities grew rapidly
Often led to crowding and increasing concerns about public health
Many cities developed municipal sanitation programs and constructed extensive sewer systems to help control outbreaks of disease in the late 19th and early 20th centuries
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Human Waste Disposal
Initially these systems discharged sewage directly to surface water, without treatment
Water pollution became a concern so cities added sewage treatment
Rural American families and many in towns and small cities:◦ Outhouses were common until about 50 years ago
◦ Then, septic systems became common and added:
Convenience
Public health
Environmental protection
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Human Waste Disposal
Ag Research facilityNiger, August, 2007
About a third of all Indiana homes use septic systems
Septic systems remove pathogens from wastewater ◦ Shigella
◦ Giardia
◦ Escherichia coli (E. coli)
Most (~ 85%) of these systems are conventional septic-absorption fields
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Who Uses Septic/Onsite Systems?
Typical Systems
◦ Wastewater is drained in a septic tank
◦ Grease and oils rise to the top
◦ Solids settle to the bottom where they decompose
The clarified effluent is channeled to an absorption field.
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Septic Systems (Onsite systems)
Septic Tank
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Sewagefrom Home
Vent
Sludge Layer
Liquid Layer
Scum Layer
Tank care: septic tanks should be pumped every 3-5 years
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Conventional Onsite Dispersal System
SepticTank
Soil Absorption Field
Soils effectively treat effluent through the following processes
◦ Chemical,
◦ Physical
◦ Biological
The best soil for an absorption field is a deep, well-drained soil
Oxygenated soil is necessary for waste degradation
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Indiana Soils & Septic Systems
Soil texture and structure affects the speed that water moves through soil
Problems for absorption fields:◦ High water tables◦ Dense or impermeable subsoil (transmit water too slow)◦ Sandy soils (transmit water too fast)
Prime Ag land (land that is good for crop production) usually does not make a good septic absorption field.
58% of Indiana is considered prime Ag land, second only to Illinois at 59%. (IA=52%, OH & KS=45%)
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Indiana Soils & Septic Systems
Soil A is well drained (oxygen rich) and suitable for a conventional trench septic system.
Soil C is poorly drained (oxygen deprived) and saturated with water most of the time.
Soil B is saturated briefly during the year. Soils B and C are unsuitable for
conventional trench septic systems.15
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This map shows the percent of land that is estimated as unsuitable for conventional onsite (septic) systems, unless the site or the system is modified.
Prior to 1977◦ No septic system regulations in Indiana
(construction or placement)◦ Construction practices varied widely
Current Standards◦ Wastewater must not
Contaminate groundwater Contaminate surface water Interfere with household plumbing
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Septic System Regulations
Conserve water to avoid overloading your septic system
Toilets◦ 1992 US Energy Policy and Conservation
Act requires 1.6 gallon/flush “ultra low-flow toilets”
◦ 2007: US government is now promoting 1.3 gal/flush toilets
Do not use caustic drain openers for a clogged drain (use boiling water or a drain snake to open clogs)
More to follow…
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Onsite System Care
CleanersUse commercial bathroom cleaners and laundry
detergents in moderation. Use a mild detergent or baking soda when possible.
Do not flush anything other than human wastes and septic safe toilet paper (no diapers, medications, etc…. Your septic system is not a trash can)
Do not use a garbage disposal (compost instead)
More to follow…
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Onsite System Care
Avoid dumping grease or fats down your kitchen drain
Keep latex paint, varnishes, thinners, waste oil, photographic solutions, pesticides, or other hazardous chemicals out of your septic system
Do not use septic tank additives, commercial septic tank cleanser, yeast, sugar, etc. ◦ These products are not necessary and some may
be harmful to your septic system
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Onsite System Care
Water from roof drains, basement drainage sump pumps, hot tubs, and swimming pools should not enter the septic system
According to Indiana state regulations:◦ Water softener backwash must be treated as
sewage◦ Water wasted from reverse osmosis water
treatment must also be treated as sewage.
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Water Conservation
Treatment and percolation of wastewater depends on presence of 24” of undisturbed, uncompacted, unsaturated soil below the trench
Never allow anything heavier than a riding lawnmower on soil absorption area.Heavy vehicles on the drain field before, during, or
after construction and when the soil is saturated can damage soil’s ability to absorb wastewater
Compaction drives frost deep into the soil and prevents effective treatment in winter
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No soil compaction
Water conservation Effluent filters Lower high water tables with perimeter
drains Use elevated systems (e.g., sand mounds) Shallow trenches Use shallow drip irrigation (requires pre-treat) Connect to existing central sewer system Alternative sewer and cluster systems
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Overcoming Septic Limitations
Mound system Effluent filters Constructed subsurface wetlands Recirculation media filters Aeration treatment units Drip irrigation Cluster systems
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Practical Alternatives for Indiana
Mound System
Benefits Costs
Allows use of septic systems in areas with poor soils, shallow bedrock, or high water tables
Operates in all climates
• More space needed• Limited use on slopes• Requires pump maintenance • Higher installation cost than
conventional absorption fields (~ $10,000)
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Effluent Filter
In Flow
Septic Tank
Out Flow
Sludge
Riser
Effluent Filter
Effluent Filters
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Protects disposal field from solids overflow
Requires routine maintenance Additional cost for installation
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Question: Why is routine maintenance especially important to people with an effluent filter?
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Effluent Filters
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Constructed Subsurface Wetlands
SepticTank
Soil Absorption Field
PumpChamber
ConstructedWetland
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Constructed Subsurface Wetlands
18” Deep
HomeSepticTank
Cleanouts
ConstructedWetland
Level AdjustSump
DisposalField
Constructed Wetland Treatment
Benefits Costs
• Works for both large, continuous flows and for individual residences
Relatively large land area required, 150 sq ft/bedroom
Requires regular maintenance and monitoring
Affected, but only slightly, by seasons
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Media Filter Treatment
SepticTank
Soil Absorption Field
RecirculationTank
(recirculating)
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2” sand around 1/2” plywood box
2 feetsand
From tank
1” of 1/4” gravel
3/4”-1”gravel(5” deep, mound
over pipe)
4” PVC pipe underdrain
3/8” peagravel
(3” deep)
Drain pipe to recirculation
tank or absorption field
1” dia. pressurized pipe 2’ apart with 1/8” holes 2’ o.c.
orifice shield
Manifold
2” of 3/4-1” gravel
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Sand, Gravel, Peat
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Why Use a Media Filter?
Benefits Costs
Limited area needed for the absorption field (about 30 ft2 per bedroom)
Can replace a failed conventional absorption field when there is not enough room for a new one
Can be used with high groundwater, shallow bedrock, poor soils, or other site restrictions
Will keep N out of groundwater
These systems are more expensive, so they are generally used only when necessary and centralized treatment unavailable or too expensive
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Aeration Treatment Units
Benefits Costs
Often used to renovate failing systems in other states
Effective when ATU is placed before a septic tank or an effluent filter is used after ATU to keep solids out of absorption field in case of malfunction (overflow must go to the soil absorption area)
Relatively inexpensive to install
Electricity and alarm required (relatively costly to power aerator)
Professional maintenance required every 3-6 months
Widely fluctuating flows can cause problems.
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Aeration Treatment Units (ATU)
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Frequent application of small quantities of wastewater just below soil surface with applicators along distribution line (less than 1 gal/hr per ft of pipe)
Drip systems have been used in agriculture for 30 years
Drip Irrigation
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Benefits Benefits
Easy to design and install
Wastewater is slowly and uniformly distributed over the entire absorption area
More water moves laterally through capillary action, reducing deep percolation so the wastewater is placed in biologically active soil
Only 12” deep so helps overcome limitations of seasonal high water tables & slow permeability
Water and nutrients can be reused by vegetation
Reduces nitrogen percolation to groundwater
Can be used on very steep slopes (with pressure compensators)
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Drip Irr., Benefits
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98% of soil biological activity is in top 16” of soil.
Drip Irrigation, Costs
Costs Costs
More expensive (pipe with drip emitter is 50-60 cents/ft)
Potential plugging problems. Higher operational cost Maintenance needed 3-4 times/year Septic tank effluent must be treated and filtered
before drip disposal
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Read an extension publication from The Education Store
Store Search pesticide Quiz on Monday
◦Title◦Publication number◦What was the article about – problem &
recommendations
44
Reading Assignment
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Stopped Here, 10/10/12
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Definition – Collective household sewage and transport to a large soil absorption area for treatment and disposal by multiple neighboring homes.
Typically used in areas with some poor soil conditions or where home lots are too small for replacement systems.
The central disposal site must be carefully selected to handle the large flow.
Cluster Systems
Cluster Systems
Benefits Costs
Cheaper than large diameter sewers, central treatment and discharge systems
More costly than individual septic systems.
No Indiana cost-share on non-discharging systems.
A mechanism must be set up to manage and collect costs (installation and continuing maintenance).
It is different from what regulators and people are used to.
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Primary treatment – separates large solids from the waste stream, using metal grates and a grit tank (where sand and gravel settle out). The waste stream goes to the primary sedimentation tank where about half the suspended, organic solids settle out as sledge.
Secondary treatment – effluent from the primary treatment flows into a trickling filter bed, aeration tank, or sewage lagoon for biological degradation of the dissolved organic compounds.
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Municipal Sewage Treatment
Tertiary treatment removes plant nutrients, especially nitrates and phosphates.
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Municipal Sewage Treatment
Primary treatmentSecondary treatment
Tertiary treatment
Primary sedimentation tank
sand gravel Organic solids
trickling filter bed, aeration tank, or sewage lagoon
biological degradation of the dissolved organic compounds
removes plant nutrients, especially nitrates and phosphates
Did you already know this information?
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How Did You Do?
Read an extension publication from The Education Store
Store Search pesticide Quiz on Monday
◦Title◦Publication number◦What was the article about – problem &
recommendations
51
Reading Assignment
