Household Wastewater Systems

Typical Waste Water System Well Renovated Wastewater

Minimum Lot Size for Wastewater Disposal Systems Disposal System Type Water Supply Source Private Well Public Supply Aerobic w/ sprinklers ¾ acre ½ acre ET/Absorption Trench 1 acre Subsurface (fast perc.) ¾ acre ½ acre Subsurface (slow perc.) 1 acre Lagoon 2 ½ acres

Wastewater System Components Water-tight sewer linesWater-tight sewer lines Septic tankSeptic tank Disposal systemDisposal system –Subsurface drain field Absorption trenchesAbsorption trenches Infiltration chambersInfiltration chambers –ET/Absorption trenches –Aerobic system with sprinkler –Total retention lagoons –Pre-approved alternative disposal systems

Household Plumbing Sewer and Vent System Sewer lines in the house collect waste water for conveyance to the septic tankSewer lines in the house collect waste water for conveyance to the septic tank Roof vents and the traps under sinks, tubs, showers, toilets and wall/floor drains prevent sewer gas from entering the house.Roof vents and the traps under sinks, tubs, showers, toilets and wall/floor drains prevent sewer gas from entering the house. Screen vent pipe opening to prevent blockage by birds, squirrels, etc. Main Sewer Pipe

Septic Tank All household wastewater systems will have a septic tankAll household wastewater systems will have a septic tank Microbial action digests solid wastesMicrobial action digests solid wastes Liquids flow through tank to disposal areaLiquids flow through tank to disposal area Tank sizeTank size –1000 gallon liquid capacity (4-BR house or less) –Add 250 gallons per additional bedroom

House Foundation Typical Septic Tank Installation Two-Chamber Tank Baffles

Effluent Disposal Area Options Absorption fieldAbsorption field –Absorption trenches –Infiltration chambers –ET/Absorption trenches LagoonsLagoons Aerobic systemsAerobic systems Authorized alternative systemsAuthorized alternative systems

Subsurface Absorption Field Approval Percolation TestPercolation Test –3 test holes in drainage area perc at a rate of 60 min/inch of water or faster Soil Profile DescriptionSoil Profile Description –3 test holes without any of the following: (1) impervious material (bedrock, clay pan) (1) impervious material (bedrock, clay pan) (2) water saturated soil (discoloration) (2) water saturated soil (discoloration) (3) loamy coarse sand or coarser soil, or (3) loamy coarse sand or coarser soil, or (4) sandy clay or finer soil (4) sandy clay or finer soil

Cross-Section of Subsurface Absorption Trench Perforated Pipe 8-ft minimum distance to center of next trench

150’ MAX.

Lateral lines following the slope contour 150’ max. length

Aerobic Systems Used to treat septic tank effluent where subsurface disposal is not possibleUsed to treat septic tank effluent where subsurface disposal is not possible Bubbling air through effluent supports aerobic bacteria for further digestionBubbling air through effluent supports aerobic bacteria for further digestion Exposure to oxygen kills most pathogensExposure to oxygen kills most pathogens Chlorination allows surface land application of wastewater through sprinklersChlorination allows surface land application of wastewater through sprinklers

(Septic Tank) Onsite Aerobic Treatment System Onsite aerobic treatment systems treat septic tank effluent further by aerobic digestion, chlorination to kill pathogens, and surface application through a spray head sprinkler system.

Typical Aeration Chamber of Aerobic Treatment System DIFFUSER EFFLUENT FROM SEPTIC TANK WASTEWATER TO CHLORINATOR & SPRINKLERS

Pump Chamber and Surface Application System Pump Pump Control & Alarm Floats Access Hatch Spray Heads

Regular green stripes in a dry lawn are the lateral lines

Household Water Use Typical Usage: gallons/person-dayTypical Usage: gallons/person-day –Clothes washer: gallons/load –Dishwasher: 7-15 gallons/load –Garbage Disposal: gallons/day –Shower/Bathtub: gallons/use –Ordinary toilet: gallons/flush –Water softener: gallons/regeneration

Septic System Additives Biological BacteriaBacteria YeastYeast EnzymesEnzymes CombinationCombinationChemical AcidsAcids BasesBases Organic SolventsOrganic Solvents FlocculantsFlocculants

Biological Additives Will not eliminate need for tank pumpingWill not eliminate need for tank pumping 20% of sludge is inorganic (indigestible)20% of sludge is inorganic (indigestible) Billions of bacteria live in septic tanks-- a few million more have little effectBillions of bacteria live in septic tanks-- a few million more have little effect If natural bacteria have been killed, added bacteria will die alsoIf natural bacteria have been killed, added bacteria will die also Normal population is restored in hours even if 99.99% has been killedNormal population is restored in hours even if 99.99% has been killed

Waste Water System Failures Common Causes Hydraulic overloading (too much water)Hydraulic overloading (too much water) Solids migration to drain fieldSolids migration to drain field –Failure to pump tank on schedule –Baffle failure Root intrusion into sewer linesRoot intrusion into sewer lines Traffic damage to drain fieldTraffic damage to drain field Garbage disposal overuseGarbage disposal overuse

Reducing Hydraulic Loading Equipment AdjustmentsEquipment Adjustments –Low flow toilets (1.6 gpf and 0.6 gpf) –Water-saving showerheads –Front-loading washing machines Lifestyle AdjustmentsLifestyle Adjustments –Shower vs. bath –Distribute laundry loads throughout week –Distribute bathing morning & evening –Full loads only for washer & dishwasher

If you don’t maintain your on-site wastewater system, it will demand your attention when it is most inconvenient.