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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 1
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) 2
October 10, 2012 3
Give your best guess Correct as needed, during the lecture 4
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-400AD 5
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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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 7
◦ ◦ 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 Ag Research facility Niger, August, 2007 8
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 9
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. 10
Vent Sewage from Home
Scum Layer Liquid Layer Sludge Layer
Tank care: septic tanks should be pumped every 3-5 years 11
Soil Absorption Field Septic Tank Conventional Onsite Dispersal System 12
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 13
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%) 14
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.
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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.
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◦ ◦ 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 17
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… 18
Cleaners Use 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… 19
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 20
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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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 22
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 23
Mound system Effluent filters Constructed subsurface wetlands Recirculation media filters Aeration treatment units Drip irrigation Cluster systems 24
Allows use of septic systems in areas with poor soils, shallow bedrock, or high water tables Operates in all climates Benefits • • • • More space needed Limited use on slopes Requires pump maintenance Higher installation cost than conventional absorption fields (~ $10,000) Costs 25
In Flow
Sludge
Septic Tank Riser Out Flow Effluent Filter 26
Protects disposal field from solids overflow Requires routine maintenance Additional cost for installation 27
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Question: Why is routine maintenance especially important to people with an effluent filter?
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Septic Tank Pump Chamber Constructed Wetland Soil Absorption Field 30
Home Septic Tank Constructed Wetland Cleanouts Disposal Field Level Adjust Sump
18” Deep 31
• Works for both large, continuous flows and for individual residences Benefits Relatively large land area required, 150 sq ft/bedroom Requires regular maintenance and monitoring Affected, but only slightly, by seasons Costs 32
(recirculating) Soil Absorption Field Septic Tank Recirculation Tank 33
From tank 1” dia. pressurized pipe 2’ apart with 1/8” holes 2’ o.c. Manifold 2” of 3/4-1” gravel orifice shield 1” of 1/4” gravel
2 feet sand
3/4”-1”gravel (5” deep, mound over pipe) 4” PVC pipe underdrain 3/8” pea gravel (3” deep) 2” sand around 1/2” plywood box Drain pipe to recirculation tank or absorption field 34
Sand, Gravel, Peat 35
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one Can be used with high other site restrictions groundwater Benefits These systems are more expensive, so they are generally used only when necessary and centralized treatment unavailable or too expensive Costs 37
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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.
Benefits Costs 39
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 40
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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 98% of soil biological activity is in top 16” of 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) Benefits Benefits
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 Costs Costs 43
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
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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.
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Cheaper than large diameter sewers, central treatment and discharge systems Benefits 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.
Costs 47
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. 48
Tertiary treatment removes plant nutrients, especially nitrates and phosphates. Primary treatment Secondary 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 49
Did you already know this information?
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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 51