Your Aerobic Your Aerobic Treatment System is Treatment System is

part of the Familypart of the Family

Texas AgriLife Extension ServiceTexas AgriLife Extension Service

OverviewOverview

Wastewater flows to the treatment system.Wastewater flows to the treatment system. All system have two loading rates.All system have two loading rates. How much water do you use (hydraulic How much water do you use (hydraulic

loading)?loading)? How much waste do you generate How much waste do you generate

(organic loading)?(organic loading)? How activities in the home impact the How activities in the home impact the

treatment system.treatment system.

Aerobic Treatment Unit with Aerobic Treatment Unit with Spray DistributionSpray Distribution

MicrobesMicrobes Microbes Microbes

Provide treatmentProvide treatment Must keep them healthyMust keep them healthy

• WaterWater• Food Food • pHpH• Dissolved Oxygen - DODissolved Oxygen - DO• TemperatureTemperature

Types of MicrobesTypes of Microbes Anaerobic – no DOAnaerobic – no DO Aerobic – need DOAerobic – need DO Facultative – either wayFacultative – either way

Healthy microbes result in Healthy microbes result in happy customershappy customers

What’s in Wastewater?What’s in Wastewater? 99.9 % water 99.9 % water 0.1 % pollutants or constituents of concern0.1 % pollutants or constituents of concern

Organics/InorganicsOrganics/Inorganics SolidsSolids PathogensPathogens Nutrients Nutrients Fats, oils, greaseFats, oils, grease MetalsMetals Persistent organic chemicalsPersistent organic chemicals

Hydraulic and Organic LoadingHydraulic and Organic LoadingWastewater

Hydraulic LoadingHydraulic Loading

Flow quantityFlow quantity VolumeVolume

Flow periodFlow period DailyDaily WeeklyWeekly MonthlyMonthly SeasonalSeasonal

Special eventsSpecial events

Residential Wastewater UsageResidential Wastewater UsageTexas 30 TAC Chapter 285Texas 30 TAC Chapter 285

Type of Facility

Usage Rate, Gallons/Day

(without water saving

devices)

Usage Rate, Gallons/Day (with water

saving devices)

Single family dwelling (one or two bedrooms) - less than 1,500 square feet.

225

180

Single family dwelling (three bedrooms) - less than 2,500 square feet. 300 240

Single family dwelling (four bedrooms) - less than 3,500 square feet. 375 300

Single family dwelling (five bedrooms) - less than 4,500 square feet. 450 360

Single family dwelling (six bedrooms) - less than 5,500 square feet. 525 420

Greater than 5,500 square feet, each additional 1,500 square feet or increment thereof.

75 60

Estimating Hydraulic LoadingEstimating Hydraulic Loading

Number of bedroomsNumber of bedrooms Square footage of a Square footage of a

facilityfacility Water conserving Water conserving

devicesdevices Special fixturesSpecial fixtures

Multi-head showersMulti-head showers Garden tubsGarden tubs

Distribution of mean household daily per capita indoor water use for 1,188 data-logged homes (EPA 2002: Onsite Wastewater Treatment System Manual)

0%

2%

4%

6%

8%

10%

12%

14%

16%

18%

0 10 20 30 40 50 60 70 80 90 100

110

120

130

140

150

160

170

180

190

200

Mor

e

Mean Indoor Gallons Per Capita Per Day

Rel

ativ

e F

req

uen

cy

Organic LoadingOrganic Loading

BOD – Biochemical Oxygen DemandBOD – Biochemical Oxygen Demand TSS – Total Suspended SolidsTSS – Total Suspended Solids FOG – Fats, Oil and GreaseFOG – Fats, Oil and Grease Oxygen DemandOxygen Demand Oxygen StatesOxygen States

Organic MaterialOrganic Material Waste from plant or animal sourcesWaste from plant or animal sources

Can be dissolved, a solid Can be dissolved, a solid or a liquidor a liquid

Broken down and Broken down and consumed by microbes consumed by microbes (aerobes and anaerobes) (aerobes and anaerobes)

As it decays, dissolved As it decays, dissolved oxygen is depletedoxygen is depleted

Biochemical Oxygen DemandBiochemical Oxygen Demand

Biochemical oxygen demand, or BOD is Biochemical oxygen demand, or BOD is the amount of oxygen used during the the amount of oxygen used during the breakdown of organic materialbreakdown of organic material Take sample to commercial laboratoryTake sample to commercial laboratory Measured as a five-day laboratory testMeasured as a five-day laboratory test

BOD is considered an indirect measure of BOD is considered an indirect measure of the organic content of a samplethe organic content of a sample

Biochemical Oxygen DemandBiochemical Oxygen Demand

Amount of oxygen consumed by microbes Amount of oxygen consumed by microbes during decomposition of organic matterduring decomposition of organic matter

Indicates overall organic strength of Indicates overall organic strength of wastewater wastewater

High BODHigh BOD55 means high levels of organics means high levels of organics Expressed in mg/L (ppm)Expressed in mg/L (ppm) Domestic wastewater ranges from Domestic wastewater ranges from

100 to 300 mg/L BOD100 to 300 mg/L BOD55

Oxygen DemandOxygen Demand The oxygen demand is the The oxygen demand is the

amount of oxygen required amount of oxygen required to aerobically oxidize a to aerobically oxidize a materialmaterial Aerator delivers the oxygen to Aerator delivers the oxygen to

meet demandmeet demand

Organic materialOrganic material NitrogenNitrogen Other compoundsOther compounds Water (low DO)Water (low DO)

Oxygen StatesOxygen States Dissolved oxygenDissolved oxygen

Free OFree O22

Oxygen that has been Oxygen that has been incorporated into waterincorporated into water

Many aquatic animals Many aquatic animals require it for their require it for their survivalsurvival

Bound oxygenBound oxygen Attached to other Attached to other

compounds, NOcompounds, NO33

Anaerobic microbes Anaerobic microbes break oxygen bondsbreak oxygen bonds

Wastewater Loading RatesWastewater Loading Rates

lbs BOD5/cap/day

Class

Persons Per Unit

gal/cap/day

Average

with Garbage

Grinder

BOD5 (mg/L)

Subdivisions, Higher Cost 3.5 100 0.17 0.25 205

Subdivisions, Average 3.5 90 0.17 0.23 220

Subdivisions, Low Cost 3.5 70 0.17 0.20 290

Motels, Hotels, Trlr. Pks. 2.5 50 0.17 0.20 400

Apartment Houses 2.5 75 0.17 0.25 225

Resorts, Camps, Cottages 2.5 50 0.17 0.20 400

Hospitals per bed 200 0.30 0.35 200

Factories or Offices per person 20 0.06 - 360

Factories with showers per person 25 0.07 - 340

Restaurants per meal 5 0.02 0.06 450

Goldstein and Moberg, 1973

Mass loading (lbs) = # people (4) x BOD loading (0.23 lbs/cap/day) = 0.92 lbs/day

Feeding the SystemFeeding the System Water – Hydraulic loadWater – Hydraulic load

Flow volume, gpdFlow volume, gpd Flow rate, gpm or gphFlow rate, gpm or gph Appropriately sized Appropriately sized

systemsystem Food – Organic loadFood – Organic load

BODBOD• Concentration, mg/LConcentration, mg/L• Mass, Pounds per dayMass, Pounds per day• Appropriately sized systemAppropriately sized system

Food to Microorganism Food to Microorganism Ratio - ConsistencyRatio - Consistency

Other CompoundsOther Compounds

Impacts on Feeding ATU Impacts on Feeding ATU by Water Use by Water Use

Effects on hydraulic loadingEffects on hydraulic loading Whirlpool tubs Whirlpool tubs Water treatment devices Water treatment devices Clear waterClear water DishwasherDishwasher Laundry Laundry

Whirlpool TubsWhirlpool Tubs

Use large volumes of Use large volumes of waterwater

Add hydraulic surgesAdd hydraulic surges

New larger capacities New larger capacities can be greater than can be greater than the design flow for the the design flow for the homehome

Clear Water FlowsClear Water Flows

Water Treatment Water Treatment DevicesDevices Water SoftenersWater Softeners Reverse OsmosisReverse Osmosis Other?Other?

Other FlowOther Flow Condensate - AC Condensate - AC Ice MachinesIce Machines Basement drainsBasement drains Footing drains Footing drains

Water SoftenersWater Softeners

DIR – Demand Initiated DIR – Demand Initiated RegenerationRegeneration September 1, 2003 – date September 1, 2003 – date

requiring - DIRrequiring - DIR

May bypass the May bypass the pretreatment component.pretreatment component.

Connect directly to the Connect directly to the pump tank.pump tank.

Must go through a p-trapMust go through a p-trap

Reverse OsmosisReverse Osmosis

Point of UsePoint of Use Under the sinkUnder the sink Connect to OSSFConnect to OSSF No upgrade requiredNo upgrade required

Point of EntryPoint of Entry Whole house systemWhole house system Greater volumeGreater volume Need to add to size of Need to add to size of

OSSFOSSF

Laundry - 20% of FlowLaundry - 20% of Flow

Use should be spread Use should be spread outout

Liquid soap is Liquid soap is recommendedrecommended Use lessUse less Remove risk of fillers Remove risk of fillers

in powdersin powders

DishwasherDishwasher Adds surges of Adds surges of

wastewaterwastewater Hydraulically Hydraulically

overload systemoverload system Homeowner Homeowner

should space out should space out loadsloads

Organic loadOrganic load Clean/Scrape Clean/Scrape

dishesdishes

Impacts on Feeding ATU Impacts on Feeding ATU by Organics by Organics

Effects on organic strength (loading)Effects on organic strength (loading) Water-saving devices Water-saving devices Garbage disposalGarbage disposal Using wastewater system as a trash can.Using wastewater system as a trash can.

Water Conserving FixturesWater Conserving Fixtures

Water Saving DevicesWater Saving Devices 60 gallons/person/day60 gallons/person/day

Reduce Flow (lower hydraulic loading)Reduce Flow (lower hydraulic loading) Increase strength (same organic loading Increase strength (same organic loading

unless change of habits)unless change of habits)

Garbage DisposalGarbage Disposal

Increases total solids: scum, sludgeIncreases total solids: scum, sludge System should be pumped 1-2 years System should be pumped 1-2 years

sooner than without a garbage disposalsooner than without a garbage disposal Increases Organic LoadingIncreases Organic Loading

Organic matter had not been digested, so it Organic matter had not been digested, so it will take longer to break downwill take longer to break down

More water is used to wash out sinkMore water is used to wash out sink Smaller particles will take longer to settleSmaller particles will take longer to settle Potential for fats and oilsPotential for fats and oils

Impacts by Feeding System Impacts by Feeding System

General Adverse EffectsGeneral Adverse Effects Prescription antibiotics and drugs Prescription antibiotics and drugs Bath and body oils Bath and body oils In-home businessesIn-home businesses Antibacterial soap Antibacterial soap ChemicalsChemicals Cleaners Cleaners Trash and non-digestible materialTrash and non-digestible material

Prescription Drugs and AntibioticsPrescription Drugs and Antibiotics

Can kill microbes living Can kill microbes living in systemin system Won’t discriminate against Won’t discriminate against

organisms living in the organisms living in the systemsystem

Additional treatment Additional treatment components may be components may be necessarynecessary

Increase maintenanceIncrease maintenance

Bath and Body OilsBath and Body Oils

Increases FOGIncreases FOG If usage is great, may need more maintenanceIf usage is great, may need more maintenance

In-Home Businesses/HobbiesIn-Home Businesses/Hobbies

Add stronger wasteAdd stronger waste Add chemicalsAdd chemicals Increase flowIncrease flow

Examples of Businesses:Examples of Businesses: Home photography Home photography

developing labdeveloping lab Barber shopsBarber shops Day careDay care BakeryBakery Dog groomingDog grooming TaxidermyTaxidermy ArtistArtist

Hand Washing SoapHand Washing Soap Antibacterial soap Antibacterial soap

affects biology of tankaffects biology of tank Liquid soaps tend to Liquid soaps tend to

be overusedbe overused

CHEMICALSCHEMICALS

All problemsAll problems

Kill microbesKill microbes Upset systemUpset system

Appliances and Cleaning ProductsAppliances and Cleaning Products

Look at Labels!Look at Labels! DANGER;DANGER; Means the chemical will kill the Means the chemical will kill the

bacteria, and its use should be minimized bacteria, and its use should be minimized or eliminatedor eliminated

WARNING;WARNING; Means limited use should Means limited use should have a minimal impact on the system.have a minimal impact on the system.

CAUTIONCAUTION:: Typically means the product Typically means the product will have little effect.will have little effect.

Septic System AdditivesSeptic System Additives

Not been proven to be Not been proven to be beneficial to system beneficial to system performanceperformance

Not recommendedNot recommended Break up particles that are Break up particles that are

settled at the bottom and settled at the bottom and make them suspendedmake them suspended

Potential solids loading to Potential solids loading to downstream componentsdownstream components

Cleaning ProductsCleaning Products

List commonly used brandsList commonly used brands CleaningCleaning AntibacterialAntibacterial

They have cumulative effects on system They have cumulative effects on system performanceperformance

Drain CleanerDrain Cleaner

Toxic drain Toxic drain cleaners can cleaners can impact ability to impact ability to properly treat properly treat wastewaterwastewater

Affect bacteria Affect bacteria activityactivity

Toilet CleaningToilet Cleaning

Product brandProduct brand Automatic cleanersAutomatic cleaners

Not recommendedNot recommended Continual impact causes long-term problemsContinual impact causes long-term problems

Toilet PaperToilet Paper

Number of rolls used Number of rolls used per weekper week

Results in faster Results in faster sludge build upsludge build up

Treated toilet paper Treated toilet paper (with lotions) prevents (with lotions) prevents paper from settlingpaper from settling

Wet wipe disposal is Wet wipe disposal is discourageddiscouraged

Bathroom - 60% of FlowBathroom - 60% of Flow

Only urine, feces, soap, Only urine, feces, soap, toilet paper and limited toilet paper and limited amounts of cleaner should amounts of cleaner should be going down drainbe going down drain

No feminine products, No feminine products, prophylactics, cigarette prophylactics, cigarette butts, etcbutts, etc

No every-flush toilet bowl No every-flush toilet bowl sanitizers or every shower sanitizers or every shower cleanercleaner

Feeding the SystemFeeding the System

If it will hurt the system,If it will hurt the system,

don’t let it go down the drain!don’t let it go down the drain!

Extended AbsencesExtended Absences

• No or low flows for an No or low flows for an extended period of timeextended period of time

•Low or no microbial activityLow or no microbial activity

•Caution needs to be used Caution needs to be used upon returnupon return

SummarySummary

Wastewater flows to the treatment system.Wastewater flows to the treatment system. All systems have two loading rates.All systems have two loading rates. How much water do you use (hydraulic How much water do you use (hydraulic

loading)?loading)? How much waste do you generate How much waste do you generate

(organic loading)?(organic loading)? How activities in the home impact the How activities in the home impact the

treatment system.treatment system.

Questions?Questions?