Design Considerations for Design Considerations for High Strength WastewaterHigh Strength Wastewater

Bruce LesikarBruce LesikarTexas AgriLife Extension ServiceTexas AgriLife Extension Service

Presentation OverviewPresentation Overview

Wastewater characteristicsWastewater characteristicsManaging common processes of Managing common processes of flocculation, bulking and sloughing flocculation, bulking and sloughing Building treatment trains for a site specific Building treatment trains for a site specific facility incorporating sustainability & facility incorporating sustainability & recovery featuresrecovery featuresHow to work through design/loading How to work through design/loading challengeschallenges

Wastewater Loading Wastewater Loading Wastewater quantityWastewater quantity

Hydraulic loadingHydraulic loadingResidential 100Residential 100--150 150 gallons per bedroomgallons per bedroom

Wastewater qualityWastewater qualityOrganic loadingOrganic loadingResidential < 300 Residential < 300 mg/L BODmg/L BOD55

Oxygen demandOxygen demandResidential and Residential and commercial facilitiescommercial facilities

Wastewater QuantityWastewater QuantityTypes of FlowTypes of Flow

ResidentialResidentialCommercialCommercial

DesignDesignDaily FlowDaily Flow

AverageAverageSurge Surge PeakPeakSeasonalSeasonal

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

Commercial WastewaterCommercial Wastewater

StrengthStrengthUsually greater Usually greater than residentialthan residentialOperation basedOperation based•• Food Food

preparationpreparation•• RestroomsRestrooms•• LaundryLaundry

WASTEWATER QUALITYWASTEWATER QUALITYBODBOD

Biochemical Biochemical oxygen demandoxygen demand

TSSTSSTotal suspended Total suspended solidssolids

FOGFOGFats, oils & greaseFats, oils & grease

High Strength WastewaterHigh Strength Wastewater

1) Influent having 1) Influent having BODBOD55 >> 300 mg/L, (CBOD > 300 mg/L 300 mg/L, (CBOD > 300 mg/L -- TCEQ)TCEQ)and/or TSS and/or TSS >> 200 mg/L, (TSS > 350 mg/L 200 mg/L, (TSS > 350 mg/L -- TCEQ)TCEQ)and/or fats, oils, and grease (FOG) and/or fats, oils, and grease (FOG) >> 50 mg/L 50 mg/L entering a pretreatment component entering a pretreatment component

2) Effluent from a septic tank or other 2) Effluent from a septic tank or other pretreatment component that has:pretreatment component that has:

BODBOD55 >> 140 mg/L, 140 mg/L, and/or TSS and/or TSS >> 60 mg/L, 60 mg/L, and/or (FOG) and/or (FOG) >> 25 mg/L and is applied to an 25 mg/L and is applied to an infiltrative surface.infiltrative surface.

Mass Loading CalculationMass Loading CalculationResidential strengthResidential strength

Calculate mass loading to a systemCalculate mass loading to a systemConcentration in wastewaterConcentration in wastewaterVolume of wastewaterVolume of wastewater

Mass (lb) = 140 (mg/L) x 200 (gpd) x 0.00000834Mass (lb) = 140 (mg/L) x 200 (gpd) x 0.00000834

Mass (lb) = 0.23 lbs per dayMass (lb) = 0.23 lbs per day

Commercial strengthCommercial strengthMass (lb) = C (mg/L) x Q (gpd) x 0.00000834Mass (lb) = C (mg/L) x Q (gpd) x 0.00000834Mass (lb) = 600 (mg/L) x 500 (gpd) x 0.00000834Mass (lb) = 600 (mg/L) x 500 (gpd) x 0.00000834

Mass (lb) = 2.5 lbs per dayMass (lb) = 2.5 lbs per day

Mass LoadingMass LoadingCalculate mass loading to a systemCalculate mass loading to a system

Number of people (capita)Number of people (capita)Organic loading rateOrganic loading rate

Mass (lb) = P (# of people) x OMass (lb) = P (# of people) x OLL (lbs per capita(lbs per capita-- day)day)Mass (lb) = 5 (# of people) x 0.17Mass (lb) = 5 (# of people) x 0.17 (lbs per capita(lbs per capita-- day)day)

Mass (lb) = 0.85 lbs per dayMass (lb) = 0.85 lbs per day

lbs BOD5/cap/day

Class

Persons Per Unit

gal/cap/day

Average

with Garbage

Grinder Subdivisions, Higher Cost 3.5 100 0.17 0.25 Subdivisions, Average 3.5 90 0.17 0.23 Subdivisions, Low Cost 3.5 70 0.17 0.20

(Goldstein and Moberg, 1973)

Comparative Biological Loads Comparative Biological Loads (BOD(BOD55))

0.6

13.67

32.1

44.4

0

5

10

15

20

25

30

35

40

45

Poun

ds p

er D

ay

Home (3 Bdrm) Restaurant Supermarket Large Restaurant

Waste SourceAqua Test, Inc.

Flow Estimate Using Various Flow Estimate Using Various ReferencesReferences

1175

2040

884

2890

0

500

1000

1500

2000

2500

3000

Gal

lons

per

Day

Actual Data M&E (Meals) EPA (Meals) MSTP (Meals)

Fast Food RestaurantAqua Test, Inc.

BODBOD55 Load Estimates Using Load Estimates Using Various ReferencesVarious References

13.67

3.41.5

4.8

0

2

4

6

8

10

12

14

Poun

ds p

er D

ay

Actual Data M&E (Meals) EPA (Meals) MSTP (Meals)

Fast Food RestaurantAqua Test, Inc.

Flow Estimates Using Flow Estimates Using Various ReferencesVarious References

4401

2594

21151922

0

500

1000

1500

2000

2500

3000

3500

4000

4500

Gal

lons

per

Day

Actual Data M & E EPA MSTP

SupermarketAqua Test, Inc.

BODBOD55 Load Estimates Using Load Estimates Using Various ReferencesVarious References

32.01

4.3 3.5 3.2

0

5

10

15

20

25

30

35

Poun

ds p

er D

ay

Actual Data M&E (Meals) EPA (Meals) MSTP (Meals)

SupermarketAqua Test, Inc.

Flow Estimates Using Various Flow Estimates Using Various ReferencesReferences

7497

6363

1838

6009

0

1000

2000

3000

4000

5000

6000

7000

8000

Gal

lons

per

Day

Actual Data M&E (Meals) EPA (Meals) MSTP (Meals)

Large Full Service RestaurantAqua Test, Inc.

BODBOD5 5 Load Estimates Using Load Estimates Using Various ReferencesVarious References

41.84

10.6

3.1

10

0

510

152025

303540

45

Poun

ds p

er D

ay

Actual Data M&E (Meals) EPA (Meals) MSTP (Meals)

Large Full Service RestaurantAqua Test, Inc.

Trimmed Restaurant BOD DataTrimmed Restaurant BOD Data

N= 284N= 284Removed Removed 11 values 11 values between between 4,100 and 4,100 and 20,100 20,100 mg/Lmg/L9 values 9 values TSS/FOGTSS/FOG

0%

2%

4%

6%

8%

10%

12%

14%

16%

18%

20%

020

040

060

080

010

0012

0014

0016

0018

0020

0022

0024

0026

0028

0030

0032

0034

0036

0038

0040

0042

00Concentration (mg/l)

Rel

ativ

e Fr

eque

ncy

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

Gam

ma

Valu

edata gamma

Lesikar et. al (2006)

Trimmed Restaurant TSS DataTrimmed Restaurant TSS Data

N = 312N = 312Removed 4 Removed 4 values values between between 15,100 and 15,100 and 91,800 91,800 mg/Lmg/L16 values 16 values BODBOD55/FOG/FOG

0%

5%

10%

15%

20%

25%

30%

010

020

030

040

050

060

070

080

090

010

0011

0012

0013

0014

0015

0016

0017

0018

0020

0024

0028

0032

0036

00

Concentration (mg/l)

Rel

ativ

e Fr

eque

ncy

0

0.05

0.1

0.15

0.2

0.25

0.3

Gam

ma

Valu

e

data gamma

Lesikar et. al (2006)

Trimmed Restaurant FOG DataTrimmed Restaurant FOG Data

N = 311N = 311Removed Removed 13 values 13 values between between 1,129 and 1,129 and 700,000 700,000 mg/Lmg/L7 values 7 values BODBOD55/TSS/TSS

0%

5%

10%

15%

20%

25%

30%

35%

0 50 100

150

200

250

300

350

400

450

500

550

600

650

700

750

800

850

900

950

1000

1050

Concentration (mg/l)

Rel

ativ

e Fr

eque

ncy

0

0.05

0.1

0.15

0.2

0.25

0.3

Gam

ma

Valu

e

data gamma

Lesikar et. al (2006)

Summary StatisticsSummary StatisticsRaw Data Trimmed Data

Mean 1,584 1,040Std. Dev. 2,902 690

Geometric Mean 932 833Geo. Mean + Std Dev. 3,834 1,523

Mean 1,030 358Std. Dev. 7,113 430

Geometric Mean 257 234Geo. Mean + Std Dev. 7,370 664

Mean 4,520 123Std. Dev. 51,400 107

Geometric Mean 108 90Geo. Mean + Std Dev. 51,508 197

Mean 18 18Std. Dev. 11 10

Geometric Mean 15 15Geo. Mean + Std Dev. 26 25

BOD5

(mg/L)

TSS (mg/L)

Flow (gal/seat)

FOG (mg/L)

Lesikar et. al (2006)

Percent of Data Captured Percent of Data Captured (28 Restaurants)(28 Restaurants)

(Geometric Mean plus One Std. Dev.)(Geometric Mean plus One Std. Dev.)

ParameterParameter Value (mg/L)Value (mg/L) % Data Covered% Data Covered

BODBOD55 15231523 8282

TSSTSS 664664 8787

FOGFOG 197197 8181

Lesikar et. al (2006)

Soil TextureSoil Texture

Soil Organic LoadingSoil Organic LoadingSoil ClassificationSoil Classification Hydraulic Loading Hydraulic Loading

(g/ft(g/ft22--d) d) RRaa

Organic Loading Organic Loading Rate lb/ftRate lb/ft22--dd

RROLOL

IbIb 0.380.38 0.000440.00044

IIII 0.250.25 0.000290.00029

IIIIII 0.200.20 0.000230.00023

IVIV 0.100.10 0.000120.00012

Organic loading rate based on the assumption of BODOrganic loading rate based on the assumption of BOD55 =140 mg/L=140 mg/L

Infiltrative surface area based on Infiltrative surface area based on organic loadingorganic loading

1st approach1st approachAAOLOL = [(BOD= [(BODEffEff / 140) x (Q / Ra)] / 0.77 / 140) x (Q / Ra)] / 0.77

Where:Where:AAOLOL =Infiltrative surface area (For high strength =Infiltrative surface area (For high strength wastewater based on organic loading) wastewater based on organic loading) –– ftft22BODBODEffEff = Facility BOD = Facility BOD –– mg/Lmg/LQ = Flow Q = Flow -- gpdgpdRa = hydraulic acceptance rate Ra = hydraulic acceptance rate -- gpd/ ftgpd/ ft22

0.77 = Safety factor0.77 = Safety factor

Note: This equation uses an example assumed value for septic tanNote: This equation uses an example assumed value for septic tank k effluent of 140. If the local code Ra values are based on an effluent of 140. If the local code Ra values are based on an assumed BODassumed BOD55 other than 140 mg/L, use that value insteadother than 140 mg/L, use that value instead..

Infiltrative surface area for high Infiltrative surface area for high strength wastewaterstrength wastewater

Example Cont.Example Cont.Area based on hydraulic loading rate:Area based on hydraulic loading rate:

Area = Q /RArea = Q /Raa

Area = 500 gallons per day / 0.25 gallons Area = 500 gallons per day / 0.25 gallons per ftper ft22--daydayArea = Area = 2000 ft2000 ft22

Infiltrative surface area for high Infiltrative surface area for high strength wastewaterstrength wastewater

Example Cont.Example Cont.Area based on organic loading rate (Method 1):Area based on organic loading rate (Method 1):

Organic loading rate:Organic loading rate:AAOLOL =[(BOD=[(BODEff Eff / 140) x (Q / Ra)]/0.77/ 140) x (Q / Ra)]/0.77AAOLOL = [(300 mg/L / 140) x (500 gallons/day / 0.25 = [(300 mg/L / 140) x (500 gallons/day / 0.25

gallons/ftgallons/ft22--day)]/0.77 day)]/0.77 AAOLOL = (2.14 x 2000 ft= (2.14 x 2000 ft22)/0.77)/0.77AAOLOL = 6114 ft= 6114 ft22

Required area: Required area: 5558 ft5558 ft2*2*

*more than 2.5 times as large as calculated with hydraulic *more than 2.5 times as large as calculated with hydraulic loadingloading

QuestionQuestion

What would the life What would the life expectancy be for a expectancy be for a

system operating at both system operating at both maximum flows and maximum flows and

waste strengths?waste strengths?

Physical Treatment: SeparationPhysical Treatment: Separation

Stokes law in action Stokes law in action SettlingSettling

FloatationFloatationDiscrete particle Discrete particle settlingsettlingFlocculent Flocculent development development Hindered particle Hindered particle settlingsettlingParticle compressionParticle compression

Particle

Upward Forces

Downward Forces

FlowTurbulence

Gravity

Buoyancy

Sludge Profile at outlet. L-R Ft 1,2,3,4,5

Compression

Hindered

Flocculent

Flocculent

Clear Zone

Scum

All systems will do one or All systems will do one or more of three things which more of three things which

may influence physical may influence physical treatmenttreatment

BulkingBulkingSloughingSloughingEmulsificationEmulsification

Resulting in FlocculentResulting in Flocculent

BulkingBulkingWhat is bulking?What is bulking?What is the impact on a system What is the impact on a system

that has bulked?that has bulked?Reduction in the solids contained in a Reduction in the solids contained in a

treatment tank treatment tank Can resettle Can resettle

Naturally occurring bulkingNaturally occurring bulkingBlack in colorBlack in color Naturally occurring bulkingNaturally occurring bulking

Emulsification Emulsification What is emulsification?What is emulsification?

Discrete particles in suspensionDiscrete particles in suspensionLoss of stratificationLoss of stratification

CausesCausesTemperatureTemperature

•• Example: FOG emulsified by high temperatureExample: FOG emulsified by high temperatureChemical EmulsificationChemical Emulsification

•• Brownish or yellow in colorBrownish or yellow in color•• Fabric softeners and wax releasing agentsFabric softeners and wax releasing agents

EffectsEffectsHomogeneous mass of solids that is not contained in Homogeneous mass of solids that is not contained in the septic tankthe septic tankWill not settled back outWill not settled back out

Healthy septic tank

• Scum and sludge normal• Some carryover to second compartment• Limited flocculent in clear zone

Chemical emulsification near completion

• Homogeneous mixture• No clear zone• Solids carryover definite

Solids carryover from this chemically Solids carryover from this chemically upset systemupset system

Statistics –• Estimated 150 gpd• Family of 2 adults• 1000 gallon septic tank• System less than 3

years old• Excessive liquid fabric softener was used

• Other chemicals likely

After drying, this remaining material was fibrous in nature showing a definite texture.

Chemical EmulsificationChemical Emulsification Recoverable TrenchRecoverable Trench

Facilitate sludge Facilitate sludge removalremovalClean out pipe at Clean out pipe at bottom of trenchbottom of trenchClean out & Clean out & Inspection port at Inspection port at ends connected to the ends connected to the clean out pipe clean out pipe

SloughingSloughingWhat is sloughing?What is sloughing?

Loss of accumulated organic material / biological growth Loss of accumulated organic material / biological growth from surfacesfrom surfaces

Where does it occur?Where does it occur?Media, trickling filters, pipe interiorsMedia, trickling filters, pipe interiors

When does sloughing occur?When does sloughing occur?When gas develops between organic /biological growth When gas develops between organic /biological growth and surface it is attached toand surface it is attached toGas causes solids to loose grip on surface and solids Gas causes solids to loose grip on surface and solids become unattached and mobile.become unattached and mobile.Scouring velocity passing through a pipe.Scouring velocity passing through a pipe.

What impact does sloughing have on a system?What impact does sloughing have on a system?Naturally occurringNaturally occurringAdvanced treatment system designs usually account for Advanced treatment system designs usually account for thisthisSludge return pumps in trickling filtersSludge return pumps in trickling filtersLargely responsible for orifice cloggingLargely responsible for orifice clogging

ATU Working Properly ATU Working Properly –– sloughing should sloughing should happen according to designhappen according to design

Outletend

Sloughing in a pipe carrying Sloughing in a pipe carrying sewage/effluentsewage/effluent

FLOCCULENTFLOCCULENTWhat is flocculent?What is flocculent?

Neutrally buoyant organic material Neutrally buoyant organic material aggregating togetheraggregating togetherOften composed of fibrous materialsOften composed of fibrous materialsCan be sparse or denseCan be sparse or dense

Where is flocculent present?Where is flocculent present?Primary, recirculation, processing, Primary, recirculation, processing, and clarifier tanks or compartmentsand clarifier tanks or compartments

Heavy flocculent

Treatment TrainsTreatment Trains““Treatment trainTreatment train”” refers to the series of refers to the series of components functioning together in a components functioning together in a wastewater treatment system to remove wastewater treatment system to remove contaminants from wastewater. contaminants from wastewater. Order and specific component selection Order and specific component selection importantimportantMust understand:Must understand:

How each component operatesHow each component operatesHow the train functions as a wholeHow the train functions as a wholeThe limitations of each component within the The limitations of each component within the traintrainThe treatment processes occurringThe treatment processes occurring

Flow Equalization TanksFlow Equalization Tanks

Makes the flow introduced to the treatment Makes the flow introduced to the treatment system more consistent. system more consistent. Flow equalization is important ifFlow equalization is important if

The average flow is The average flow is ≥≥ 70% of the design 70% of the design capacitycapacityWater use habits or facility operations are Water use habits or facility operations are variablevariable-- Example church only open on Sun.Example church only open on Sun.

Frequent peaks exceed system capacityFrequent peaks exceed system capacity•• Wash day: cleaning serviceWash day: cleaning service

Flow Equalization/Surge TankFlow Equalization/Surge Tank

Moderates flow from Moderates flow from facilityfacilityDetermine peak/surge Determine peak/surge to be moderatedto be moderated

DailyDailyWeeklyWeekly

Improves treatment Improves treatment by ALL by ALL DOWNSTREAM DOWNSTREAM componentscomponentsUp stream sized for Up stream sized for peakpeak

TimeTime--Dosed / Pumping SystemsDosed / Pumping Systems Diversity of Flows from a Supermarket

Separation of BusinessesSeparation of Businesses

Strip Mall Strip Mall Multiple storesMultiple storesDifferent sourcesDifferent sources

Initial tank for each Initial tank for each facilityfacilityRental contract tied to Rental contract tied to wastewater quality & wastewater quality & quantityquantity

Flexibility Flexibility -- Spacing & Elevation Spacing & Elevation of Componentsof Components

Water TightnessWater Tightness

Critical for treatmentCritical for treatmentWater entering Water entering Water exitingWater exiting

Hydraulic overloading Hydraulic overloading flushes systemflushes system

Partially treated Partially treated wastewater exitswastewater exitsSolids carryoverSolids carryoverDilutes microbial Dilutes microbial populationpopulation

Operation and MaintenanceOperation and Maintenance

Defined activitiesDefined activitiesDesigner specifiedDesigner specified

O&M activitiesO&M activitiesTroubleshootingTroubleshooting

Data contained in reportsData contained in reportsMechanism in place to Mechanism in place to ensure they are occurringensure they are occurringLack of O&M leads to Lack of O&M leads to malfunction malfunction

O&M requirements O&M requirements MUSTMUST be included in plansbe included in plans

Accessibility for MaintenanceAccessibility for Maintenance

Manufacturers Manufacturers guidanceguidanceRisers to surfaceRisers to surfaceAppropriate size Appropriate size openings openings Appropriate depthAppropriate depthConnections to Connections to componentscomponents

All Systems NEED O&MAll Systems NEED O&MO&M Frequency is a function of:O&M Frequency is a function of:

RegulationsRegulationsSite conditionsSite conditions

•• Risk associated with soil typeRisk associated with soil type•• Dispersal method (surface requires more O&M because of Dispersal method (surface requires more O&M because of

greater risk) greater risk)

Wastewater loading to the environmentWastewater loading to the environment•• Watershed loading rate (subdivision on small lotsWatershed loading rate (subdivision on small lots-- greater greater

loadload——higher risk)higher risk)

Technology Technology –– system complexitysystem complexity•• Manufacturer recommendationsManufacturer recommendations

Wastewater source or useWastewater source or use•• Operating at >70% of design requires more O&MOperating at >70% of design requires more O&M

Monitoring FrequencyMonitoring FrequencyWho sets the monitoring Who sets the monitoring frequency?frequency?State requirements!State requirements!Local regulators! Local regulators! What factors?What factors?

Residential systemsResidential systemsCommercial systemsCommercial systemsSite conditionsSite conditionsWastewater loading to the Wastewater loading to the areaareaHuman and Environmental Human and Environmental risk factorsrisk factorsTechnology usedTechnology used

Operational DataOperational DataAll commercial systems All commercial systems must record flowmust record flowFlow recordingFlow recording

Flow meter Flow meter –– high quality high quality effluenteffluentElapse time meterElapse time meterCycle counterCycle counterPotable water meterPotable water meter

Amber alarm Amber alarm Add to flow equalization Add to flow equalization tank to water level in tanktank to water level in tank

Communication with Communication with ownerowner

System UpgradesSystem UpgradesA good business will growA good business will growHow will we deal with the How will we deal with the extra wastewater?extra wastewater?Centralized sewers have Centralized sewers have a set/accepted schedule a set/accepted schedule Performance based Performance based systems can be required systems can be required to upgrade treatment to upgrade treatment system system –– tied to food tied to food permitpermitFlexibility is key to future Flexibility is key to future system upgradessystem upgradesWaste minimizationWaste minimization

SummarySummary

Wastewater characteristicsWastewater characteristicsManaging common processes of Managing common processes of flocculation, bulking and sloughing flocculation, bulking and sloughing Building treatment trains for a site specific Building treatment trains for a site specific facility incorporating sustainability & facility incorporating sustainability & recovery featuresrecovery featuresOwner responsibility and good data are Owner responsibility and good data are essential to working through essential to working through design/loading challengesdesign/loading challenges