WATER QUALITY NEAR WASTEWATER WATER QUALITY NEAR WASTEWATER TREATMENT SYSTEMS IN ALLUVIAL TREATMENT SYSTEMS IN ALLUVIAL

AND KARST HYDROGEOLOGIC AND KARST HYDROGEOLOGIC SETTINGS, BLACK HILLS, SETTINGS, BLACK HILLS,

SOUTH DAKOTASOUTH DAKOTA

J. Foster SawyerJ. Foster SawyerSouth Dakota Geological SurveySouth Dakota Geological Survey

Fundamental ProblemsFundamental ProblemsContinuing installation of onContinuing installation of on--site wastewater treatment systems within site wastewater treatment systems within sensitive aquifer recharge areas in the Black Hills and other arsensitive aquifer recharge areas in the Black Hills and other areaseas

Need for definitive information regarding the effects of onNeed for definitive information regarding the effects of on--site site wastewater treatment systems on water quality, particularly withwastewater treatment systems on water quality, particularly withrespect to various hydrogeologic settingsrespect to various hydrogeologic settings

Limited management of existing systems, undefined contaminants, Limited management of existing systems, undefined contaminants, variable maintenance and condition, and public resistance to incvariable maintenance and condition, and public resistance to increased reased regulations and costsregulations and costs

Challenges in investigation of potential waterChallenges in investigation of potential water--quality effects from onquality effects from on--site wastewater treatment systems, particularly in karst settingsite wastewater treatment systems, particularly in karst setting

Primary goal of this study was to investigate performance of indPrimary goal of this study was to investigate performance of individual ividual onon--site wastewater treatment systems within specific hydrogeologic site wastewater treatment systems within specific hydrogeologic settings such as unconsolidated alluvial deposits and karst aquisettings such as unconsolidated alluvial deposits and karst aquifers to fers to begin to quantify the effects of these systemsbegin to quantify the effects of these systems

Approximately 9,000 Identified on-site

wastewater treatment systems in the central

Black Hills (2001)

10%-20% Failing?

Custer

Sheridan

Lake

Road

Graph showing nitrate-nitrogen concentrations from Rapid Citypublic water supply wells in the Madison aquifer (from Rahn, 2006)

Drain Field

Surfacing Effluent

Karst Aquifers

Schematic diagram showing major components of a typical on-site wastewater treatment system

Schematic cross-section showing soil treatmentzones for a typical on-site wastewater treatment system drain field

Constituents in Typical Residential Constituents in Typical Residential Wastewater (EPA, 2002)Wastewater (EPA, 2002)

Total solidsTotal solidsVolatile solidsVolatile solidsTotal suspended solidsTotal suspended solidsVolatile suspended solidsVolatile suspended solids55--day biochemical oxygen demandday biochemical oxygen demandChemical oxygen demandChemical oxygen demandTotal nitrogenTotal nitrogenAmmoniaAmmoniaNitriteNitrite-- and nitrateand nitrate--nitrogennitrogenTotal phosphorousTotal phosphorousFats, oils, and greaseFats, oils, and greaseVolatile organic compoundsVolatile organic compoundsSurfactantsSurfactantsTotal Total coliformscoliformsFecal Fecal coliformscoliforms

Waterborne Pathogens Found In Waterborne Pathogens Found In Human Waste (EPA, 2002)Human Waste (EPA, 2002)

BacteriaBacteria–– Escherichia coliEscherichia coli–– LegionellaLegionella–– LeptospiraLeptospira–– SalmonellaSalmonella–– ShigellaShigella–– VibrioVibrio choleraecholerae–– YersiniaYersinia enteroliticaenterolitica

ProtozoansProtozoans–– BalantidiumBalantidium colicoli–– CryptosporidiumCryptosporidium–– EntamoebaEntamoeba histolyticahistolytica–– GiardiaGiardia lambialambia–– NaegleriaNaegleria fowlerifowleri

VirusesViruses–– AdenovirusAdenovirus–– EnterovirusEnterovirus (67 types)(67 types)–– Hepatitis AHepatitis A–– Norwalk agentNorwalk agent–– ReovirusReovirus–– RotavirusRotavirus

MethodsMethods

•Locate appropriate study and sample locations, obtain permission from facility owners to perform research, and confirm access to springs and surface-water sampling locations

•Design monitoring well networks and install monitoring wells at selected locations in unconsolidated alluvial deposits

•Measure water levels to allow estimation of potential ground-water flow direction and interaction between surface water and ground water

MethodsMethods•Collect and analyze water samples for chemical constituents and microorganisms indicative of the influence of on-site wastewater treatment systems and municipal wastewater lagoons

•Use sample results to begin to characterize the effects of on-site wastewater treatment systems and municipal wastewater lagoons on ground-water quality

•Coordinate efforts with the TMDL project in the Spring Creek watershed involving the South Dakota Department of Environment and Natural Resources, the South Dakota School of Mines and Technology, the South Dakota Department of Game, Fish, and Parks, and the U.S. Forest Service

Study SpecificsStudy Specifics•Nine ground-water monitoring wells around residential on-site wastewater treatment systems in three different alluvial settings

•Four surface water localities just above loss zones to the Madison aquifer, two artesian springs on the flanks of the BlackHills (Madison aquifer), and eight public water supply wells in the Madison aquifer

•Five monitoring wells around the Hill City wastewater treatment facility

•Collected 128 sets of water quality samples that were analyzed for eleven parameters

Analytical ParametersAnalytical ParametersNitrateNitrate--nitrogennitrogenPhosphorusPhosphorusAmmoniaAmmoniaTotal Kjeldahl Nitrogen (TKN)Total Kjeldahl Nitrogen (TKN)ChlorideChlorideFecal ColiformFecal ColiformE. ColiE. ColiCaffeineCaffeineConductivityConductivitypHpHTemperatureTemperature

StudyArea

Residence #1

Residence #1: Significant ParametersResidence #1: Significant Parameters

R20R20--20022002--2222–– Total phosphorus........4.05 mg/LTotal phosphorus........4.05 mg/L–– E. coli...........................1.0/100 mlE. coli...........................1.0/100 ml

R20R20--20022002--2020–– NitrateNitrate--nitrogen............1.3 mg/Lnitrogen............1.3 mg/L–– Ammonia.....................0.18 mg/LAmmonia.....................0.18 mg/L–– Chloride.........................7.0 mg/LChloride.........................7.0 mg/L–– Conductivity.....................422 Conductivity.....................422 μμss

Residence #2

Residence #2: Significant ParametersResidence #2: Significant Parameters

R20R20--20022002--1010–– Total phosphorus..............10.0 mg/LTotal phosphorus..............10.0 mg/L

R20R20--20022002--1818–– E. coli.................................1.0/100 mlE. coli.................................1.0/100 ml–– NitrateNitrate--nitrogen..................1.4 mg/Lnitrogen..................1.4 mg/L

R20R20--20022002--1111–– E. coli (2)..........................1.0/100 mlE. coli (2)..........................1.0/100 ml–– Fecal coliform..................4.0/100 mlFecal coliform..................4.0/100 ml

Madison Aquifer

Karst Aquifer: Recharge PointsKarst Aquifer: Recharge PointsBear Butte CreekBear Butte Creek–– NitrateNitrate--nitrogen...................4.8 mg/Lnitrogen...................4.8 mg/L–– E. coli..............................687.0/100 mlE. coli..............................687.0/100 ml–– Fecal coliform...................470/100 mlFecal coliform...................470/100 ml–– Conductivity..........................1,237 Conductivity..........................1,237 μμss

Boxelder CreekBoxelder Creek–– E. coli..................................6.3/100 mlE. coli..................................6.3/100 ml–– Fecal coliform.....................10/100 mlFecal coliform.....................10/100 ml

Spring CreekSpring Creek–– E. coli..................................6.3/100 mlE. coli..................................6.3/100 ml–– Fecal coliform.....................10/100 mlFecal coliform.....................10/100 ml

Rapid CreekRapid Creek–– E. coli...................................3.1/100mlE. coli...................................3.1/100ml

Karst Aquifer: Discharge PointsKarst Aquifer: Discharge Points

Sturgis Well #2Sturgis Well #2–– NitrateNitrate--nitrogen...................1.2 mg/Lnitrogen...................1.2 mg/L–– Conductivity.............................601 Conductivity.............................601 μμss

Copper OaksCopper Oaks–– E. coli..................................6.3/100 mlE. coli..................................6.3/100 ml

Boulder ParkBoulder Park–– E. coli (3)............................3.1/100 mlE. coli (3)............................3.1/100 ml

City SpringCity Spring–– E. coli................................20.1/100mlE. coli................................20.1/100ml–– Fecal coliform..................110/100 mlFecal coliform..................110/100 ml

Hill City Wastewater Treatment Facility

Spring Creek

Hill City Sewage Lagoons

Hill City Wastewater Treatment FacilityHill City Wastewater Treatment Facility

R20R20--20022002--0505–– Background levels or nonBackground levels or non--detectdetect

R20R20--20022002--0404–– E. coli....................................1.0/100 mlE. coli....................................1.0/100 ml–– Total Kjeldahl nitrogen.......3.98 mg/LTotal Kjeldahl nitrogen.......3.98 mg/L–– Ammonia...............................3.09 mg/LAmmonia...............................3.09 mg/L–– Chloride....................................33 mg/LChloride....................................33 mg/L–– Conductivity...............................691 Conductivity...............................691 μμss

Hill City Wastewater Treatment FacilityHill City Wastewater Treatment FacilityR20R20--20022002--0303–– NitrateNitrate--nitrogen..........................2.0 mg/Lnitrogen..........................2.0 mg/L–– Total Kjeldahl nitrogen............5.13 mg/LTotal Kjeldahl nitrogen............5.13 mg/L–– Ammonia....................................3.59 mg/LAmmonia....................................3.59 mg/L–– Chloride.........................................86 mg/LChloride.........................................86 mg/L–– Conductivity..................................1156 Conductivity..................................1156 μμss

R20R20--20022002--1717–– NitrateNitrate--nitrogen........................10.1 mg/Lnitrogen........................10.1 mg/L–– Total Kjeldahl nitrogen............12.6 mg/LTotal Kjeldahl nitrogen............12.6 mg/L–– Ammonia....................................10.0 mg/LAmmonia....................................10.0 mg/L–– Total phosphorus.......................1.89 mg/LTotal phosphorus.......................1.89 mg/L–– Chloride.........................................89 mg/LChloride.........................................89 mg/L–– Conductivity..................................1068 Conductivity..................................1068 μμss

Hill City Wastewater Treatment FacilityHill City Wastewater Treatment Facility

R20R20--20022002--0202–– NitrateNitrate--nitrogen................<0.1 mg/Lnitrogen................<0.1 mg/L–– Total Kjeldahl nitrogen....7.16 mg/LTotal Kjeldahl nitrogen....7.16 mg/L–– Ammonia............................5.66 mg/LAmmonia............................5.66 mg/L–– Total phosphorus...............1.96 mg/LTotal phosphorus...............1.96 mg/L–– Chloride.................................84 mg/LChloride.................................84 mg/L–– Conductivity............................952 Conductivity............................952 μμss

Nitrate and Ammonia concentrations (Mg/L)

Hydraulic Conductivity AnalysisHydraulic Conductivity AnalysisUsing Darcy’s Law at the Hill City Using Darcy’s Law at the Hill City

Wastewater Treatment FacilityWastewater Treatment Facility

Q = 38,000,000 gal/yr (McLaughlin Water Engineers, Ltd., 2000)Q = 38,000,000 gal/yr (McLaughlin Water Engineers, Ltd., 2000)

Hill City Sewage Lagoons

Hydraulic Conductivity AnalysisHydraulic Conductivity Analysis

From From potentiometricpotentiometric datadata

Q = Q = K(dh/dl)AK(dh/dl)A

K = 1.0 x 10K = 1.0 x 10--77 cm/sec cm/sec →→ Q = 12,000 gal/yrQ = 12,000 gal/yrK = 1.0 x 10K = 1.0 x 10--33 cm/sec cm/sec →→ Q = 120,000,000 gal/yrQ = 120,000,000 gal/yrQ = 38,000,000 gal/yr Q = 38,000,000 gal/yr →→ K = 3.1K = 3.1 x 10x 10--44 cm/sec cm/sec

Flow net showing seepage through alluvium and fracturedPrecambrian bedrock From lagoon #2 to Spring Creekat the Hill City wastewater treatment facility

Hydraulic Conductivity AnalysisHydraulic Conductivity Analysis

From flow net informationFrom flow net information

Q = Q = KH(NKH(Nff //NNdd)b)b

K = 1.0 x 10K = 1.0 x 10--77 cm/sec cm/sec →→ Q = 10,500 gal/yrQ = 10,500 gal/yrK = 1.0 x 10K = 1.0 x 10--33 cm/sec cm/sec →→ Q = 105,000,000 gal/yrQ = 105,000,000 gal/yrQ = 38,000,000 gal/yr Q = 38,000,000 gal/yr →→ K = 3.6K = 3.6 x 10x 10--44 cm/sec cm/sec

NitrateNitrate--Nitrogen AnalysisNitrogen Analysis

Nitrogen MassNitrogen Mass--Balance ModelsBalance Models

–– HantzscheHantzsche and and FinnemoreFinnemore (1992)(1992)

–– Bauman and Schafer (1985)Bauman and Schafer (1985)

Area considered in nitrate-nitrogenmass-balance calculations

Calculation of nitrogen mass balance using the method of Hantzsche and Finnemore (1992)

31.6 mg/L

Calculation of nitrogen mass balance using the methodof Bauman and Schafer (1985)

Bauman and Schafer (1985) continued:

6.6 mg/L

Calculation of critical minimum gross acreage per developed lot using the method of Hantzsche and Finnemore (1992)

3.36 acres/dwelling unit

Graph showing resultant ground-water nitrate-nitrogenconcentration as a function of effluent quality, denitrification, and I/R

Graph showing influence of effluent quality, denitrification, and rainfall recharge on critical lot size

SummarySummaryMaximum concentrations of sampled parameters at Maximum concentrations of sampled parameters at individual onindividual on--site wastewater treatment systems:site wastewater treatment systems:

–– NitrateNitrate--nitrogen...........................4.2 mg/Lnitrogen...........................4.2 mg/L–– Ammonia....................................0.25 mg/LAmmonia....................................0.25 mg/L–– Total Total KjeldahlKjeldahl nitrogen.............0.92 mg/Lnitrogen.............0.92 mg/L–– Total phosphorus.......................10.0 mg/LTotal phosphorus.......................10.0 mg/L–– Chloride.......................................187 mg/LChloride.......................................187 mg/L–– Conductivity..............................1,070 Conductivity..............................1,070 μμs/Ls/L–– E. coli.........................................5.2/100 mlE. coli.........................................5.2/100 ml–– Fecal coliform...........................4.0/100 mlFecal coliform...........................4.0/100 ml–– CaffeineCaffeine……………………………………..…….not detected.not detected

SummarySummaryMaximum concentrations of sampled parameters from Maximum concentrations of sampled parameters from ground water and spring flow from the Madison aquifer:ground water and spring flow from the Madison aquifer:

–– NitrateNitrate--nitrogen...........................1.2 mg/Lnitrogen...........................1.2 mg/L–– Total Total KjeldahlKjeldahl nitrogen.............0.28 mg/Lnitrogen.............0.28 mg/L–– Total phosphorus.....................0.096 mg/LTotal phosphorus.....................0.096 mg/L–– Chloride.........................................18 mg/LChloride.........................................18 mg/L–– Conductivity.................................601 Conductivity.................................601 μμs/Ls/L–– E. coli..........................................6.3/100 mlE. coli..........................................6.3/100 ml–– Ammonia................................not detectedAmmonia................................not detected–– Fecal coliform.........................not detectedFecal coliform.........................not detected–– CaffeineCaffeine………………………………..……..…….not detected.not detected

SummarySummaryMaximum concentrations of sampled parameters at the Maximum concentrations of sampled parameters at the Hill City wastewater treatment facilityHill City wastewater treatment facility

–– NitrateNitrate--nitrogen.........................10.1 mg/Lnitrogen.........................10.1 mg/L–– Ammonia....................................10.0 mg/LAmmonia....................................10.0 mg/L–– Total Total KjeldahlKjeldahl nitrogen.............12.6 mg/Lnitrogen.............12.6 mg/L–– Total phosphorus.......................1.96 mg/LTotal phosphorus.......................1.96 mg/L–– Chloride.........................................89 mg/LChloride.........................................89 mg/L–– Conductivity..................................1,156 Conductivity..................................1,156 μμss–– E. coli..........................................1.0/100 mlE. coli..........................................1.0/100 ml–– Fecal coliform.........................not detected Fecal coliform.........................not detected –– CaffeineCaffeine…………...........................not detected...........................not detected

SummarySummaryCalculations of hydraulic conductivity beneath the Hill City Calculations of hydraulic conductivity beneath the Hill City sewage lagoons yielded values of approximately sewage lagoons yielded values of approximately 1.0 x 101.0 x 10--44 to 1.0 x 10to 1.0 x 10--33 cm/seccm/sec

Nitrogen massNitrogen mass--balance models applied to one study site estimated balance models applied to one study site estimated resultant average groundresultant average ground--water nitratewater nitrate--nitrogen concentrations of nitrogen concentrations of 6.6 to 31.6 mg/L6.6 to 31.6 mg/L

The critical gross acreage per developed lot was calculated as 3The critical gross acreage per developed lot was calculated as 3.36 .36 acres per dwelling unit using siteacres per dwelling unit using site--specific parameters and a specific parameters and a maximum allowable groundmaximum allowable ground--water nitratewater nitrate--nitrogen concentration nitrogen concentration of 10 mg/Lof 10 mg/L

More data is needed to accurately characterize the impacts of onMore data is needed to accurately characterize the impacts of on--site wastewater treatment systems within specific hydrogeologic site wastewater treatment systems within specific hydrogeologic settingssettings

Questions?

Protective MeasuresProtective MeasuresReducing hydraulic loads through requirements Reducing hydraulic loads through requirements for larger drain fieldsfor larger drain fields

Installation of lowInstallation of low--flow plumbing fixturesflow plumbing fixtures

Routine inspection and maintenance of onRoutine inspection and maintenance of on--site site wastewater treatment systems located in critical wastewater treatment systems located in critical recharge areasrecharge areas

Public education to increase owner awareness of Public education to increase owner awareness of proper operation and maintenanceproper operation and maintenance

Protective MeasuresProtective MeasuresIncreasing soil depth requirements below drain Increasing soil depth requirements below drain fields and remediation of existing systems with fields and remediation of existing systems with inadequate soilsinadequate soils

Increasing residential lot sizes and spacing Increasing residential lot sizes and spacing requirementsrequirements

Reducing nitrogen loadsReducing nitrogen loads

Requiring lined Requiring lined evapotranspirationevapotranspiration systems or systems or aerobic pretreatmentaerobic pretreatment

Protective MeasuresProtective Measures

Requiring greater setback distances from karst Requiring greater setback distances from karst features, springs, streams, and other surfacefeatures, springs, streams, and other surface--water water bodiesbodies

Forming community systemsForming community systems

Establishment of local ordinancesEstablishment of local ordinances

Offering incentives to upgrade or replace systems Offering incentives to upgrade or replace systems that may be deficient for a variety of reasonsthat may be deficient for a variety of reasons