Water Quality Managements Developments: Nutrients and Bacteria
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Water Quality Managements Developments: Nutrients and Bacteria



SETAWWA February 22, 2011

SETAWWA February 22, 2011
Jim Davenport, Louis Herrin III



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Water Quality Managements Developments: Nutrients and Bacteria Water Quality Managements Developments: Nutrients and Bacteria Presentation Transcript

  • WQ Management Developments Nutrients, BacteriaJim DavenportMonitoring & Assessment SectionWater Quality Planning DivisionOffice of WaterTexas Commission on Environmental Qualityjdavenpo@tceq.state.tx.us tel. 512/239-4585February 22, 2011
  • Nutrient Criteria: NationalEPA and numerical nutrient criteria:- 1998 mandate: states to have criteria by 2004- Allowed state development plans and schedules- Established stringent national guidance criteria ○ Calculated from historical instream data ○ Separate for lakes, streams, reservoirs ○ Pooled for large, aggregate ecoregions ○ Criteria = 75th percentile of unimpacted sites- Urged by EPA Inspector General, Aug 2009- Lawsuits: Florida (Wisconsin, Kansas)
  • EPA Nutrient Criteria: FloridaLawsuit from Florida Wildlife Fed. & others in 2008EPA promulgated criteria for Florida lakes & streams in Dec 2010 – in effect Mar 2012EPA estuary criteria – propose in Nov 2011New countersuits – Florida cities, Ag Comm., etc.Lakes TP: 0.01-0.05 mg/L TN: 0.51-1.27 mg/LStreams TP: 0.06-0.49 mg/L TN: 0.67-1.87 mg/LPotential long term costs?- Regulated groups: $3 - $8 billion per year- EPA: $135 - $206 million per year
  • Why Are Nutrient Criteria Difficult?Lack of clear “use-based” thresholds, for uses such as recreation & aesthetics, aquatic life propagation, drinking water sourcesResponses to nutrients are highly variable – e.g., effect of TN,TP on Chl aNo consensus on how to derive criteriaIndependent criteria, or “weight-of evidence”?Insufficiencies in historical monitoring dataInitial EPA guidance criteria were problematicHigh concern about regulatory impacts
  • TCEQ Nutrient Criteria: DevelopmentSubmitted plans to EPA in 2001, 2006Reservoirs, then streams & estuariesConvened advisory workgroupSeparate criteria for each reservoirSet on historical conditionsAdopted for 75 reservoirs – 6/30/10Based on Chlorophyll a (suspended algae)New permitting procedures for nutrients
  • Nutrient Criteria: Examples Reservoir Chl a (µg/L) TP (mg/L) Transparency Stand-alone Not adopted (meters) Not adoptedEagle Mtn 25.4 0.07 0.80Cedar Creek 30.4 0.07 0.80Livingston 23.0 0.16 0.67Lewisville 18.5 0.06 0.60[Houston – [12.4] 0.18 0.28not adopted]Travis 3.7 0.03 3.13
  • 2010 Nutrient Implementation ProceduresIn 2010 Standards Implementation ProceduresApplied to increases in domestic dischargesSets framework for nutrient (TP) effluent limitsReservoirs – predict effects on “main pool”Relate TP to reservoir chlorophyll a criteriaStreams and reservoirs – assess local impacts:- Apply site-specific screening factors- Level of concern – low, moderate, or high- Assess “weight-of-evidence”
  • Nutrient Screening: Local Factors for Streams- Size of discharge- Instream dilution- Sensitivity to attached vegetation – type of bottom- Sensitivity to attached vegetation – depth- Sensitivity to nutrient enrichment – clarity- Sensitivity to aquatic vegetation – observations- Sensitivity to aquatic vegetation – sunlight, tree shading- Streamflow sustainability- Impoundments and pools- Consistency with other permits- Listed as a nutrient concern in WQ inventory?
  • Nutrient Screening: Example of Local FactorFactor: Instream dilution in streamsConcern level Percent effluent in dry weatherLow < 10 %Moderate 10 to < 25 %High > 25 %
  • Nutrient Criteria: The Road AheadReconvene nutrient advisory committeeReview data and academic research; andsurvey criteria development state-by-state(joint project with U. of Houston Clear Lake)Continue special stream surveys (> 100 so far)Develop criteria options for streams & estuaries:(1) Historical levels at reference sites(2) Relate TP,TN to D.O., algae, biological indicesConsider in part for next standards revisions
  • Revised Recreational Standards (6/30/10)< Previously: Almost all water bodies primary contact< 303 water bodies not meeting bacteria criteria (2010)< Expand recreational categories< Implement new use-attainability analyses< Require bacteria limits in discharge permits - in addition to chlorination (11/4/09)
  • Recreation Uses Indicator Bacteria Geometric Mean Criteria (colonies/100 ml) E. coli (FW) Enterococci (SW)Previous Standards: Contact recreation 126 35 Noncontact rec. 605 168Adopted Standards: (6/30/2010) Primary contact 126 35 Secondary contact 1 630 175 Secondary contact 2 1030 -- Noncontact rec. 2060 350
  • Recreational Use-Attainability▸ Uses other than primary contact may be appropriate for some water bodies▸ TCEQ has new recreational UAA procedures▸ Surveys include physical & flow characteristics, + observed evidence of recreation▸ Local input (interviews) important▸ Initiated 124 recreational UAAs▸ Involves major coordination effort and public participation
  • Effluent Bacteria: Houston TMDL Studies Minor municipal facilities (114 data points) 5 4.5E. coli (log of #/100 ml) 4 3.5 E. coli log 3 2.5 Single sample 2 maximum log (2.6) 1.5 1 Geometric mean log 0.5 (2.1) 0 0 5 10 15 20 residual chlorine (mg/L)
  • SummaryNational interest in nutrient criteria is increasing, partly in response to new EPA criteria for Florida.TCEQ adopted criteria (Chl a) for 75 reservoirs, but EPA has not yet approved them.TCEQ is developing draft criteria with multiple options for streams and rivers, and for estuaries.TCEQ has adopted expanded recreational categories and criteriaNumerous UAA reviews of individual small streams is continuingQuestions?
  • BacteriaRequirements Bacteria Limitsin TPDES Domestic Permits
  • Agreement with EPAInterim: bacteria limits in certainpermitsBacteria limits in all permit actionsissued after 1/1/10.Permits issued under interimagreement may see frequencyadjustment in next permit
  • ImplementationNext permit action New Renewal AmendmentNo compliance scheduleRecommend evaluating now
  • Bacteria LimitsStandard E coli 126 avg 394 max Enterococci 35 avg 89 max
  • Measurement Frequencies Flow Chlorine Ultraviolet Natural >10 5/wk Daily Daily 5—10 3/wk Daily 5/wk 1—5 1/wk Daily 3/wk0.5—1.0 2/mo Daily 1/wk0.1—0.5 1/mo 5/wk 2/mo <0.1 1/qtr 5/wk 1/mo
  • Continued Need for Chlorine TestingRetain 4.0 mg maximum 0.1 mg dechlorRegular checkbetween bacteriasamples
  • Chlorine Contact Chambers Recommend evaluating now If undersized or short- circuiting, violating current regulations
  • Pond Systems21-day retention timeRecommend evaluating Capacities Sample Locations Wildlife impacts (birds, nutria, etc)Compliance schedule for newconstruction
  • Laboratory IssuesIn-house testingwithout NELACContract lab must beNELAC certifiedProximity to plantIncreased workload
  • Sample Holding TimesStandard Methods Holding time – 6 hours Set-up time – 2 hoursTravel time issues
  • Reporting Units Colony Forming Units CFU Most Probable Number MPN Both Acceptable!
  • Nutrient Removal Chapter 217:Design Criteria for Wastewater Systems
  • Current Regulations“A facility design that proposes advancednutrient removal is innovative andnonconforming technology and is subject to217.10(b)(2) of this title (relating toInnovative and NonconformingTechnology).” - 217.163
  • ResultsWide variety of removal processes yieldingeco-regionally dependent resultsProblems- Variability of ego-regional conditions in Texas One treatment process with several different performance reports
  • Design Criteria ChangesEngineer’s report must include detaileddesign calculations correlating theproposed removal process with theanticipated effluent concentration. Process TP/TN Influent Characteristics TP/TN Effluent Characteristics
  • Desired RangesTotal Nitrogen < 8 mg/LTotal Phosphorous Chemical Addition: 0.1 - 0.5 mg/L Membrane Filtration: 0.1 - 0.5 mg/L BNR: 0.2 - 0.3 mg/L
  • Specific effluent standards are stillconsidered on case-by-case basis in eachpermit
  • Contact InfoLouis C. Herrin, III, P.E.louis.herrin@tceq.texas.gov512.239.4552
  • Membrane Bioreactors (MBR)Compiled Surveys from Vendors of Membranes Huber, Koch, Kruger, Kubota, Siemens, ZenonResults of Survey, Literature and Other State RegulationsConcerns Prevention of Fouling Adequate aeration at high MLSS concentrations Achievable rate of flow through membranes Adequate pretreatment i.e. fine screening Hydraulics Ensure Integrity Foam Control Warranty Nutrient Removal
  • Membrane Bioreactors (MBR) ApplicabilitySubmergedLow-pressure, vacuum or gravityUltrafiltration or microfiltration217.8(b)(2) Approval of Nonconforming and InnovativeTechnologies May require pilot study and/or 2 year performance bond
  • Membrane Bioreactors (MBR) Expected Performance CBOD5 5 mg/l TSS 1 mg/l Ammonia 1 mg/l Total Nitrogen (w/pre-anoxic zone) 10 mg/l Total Nitrogen (w/pre-anoxic and post-anoxic zone) 3 mg/l Total Phosphorus (with chemical addition) 0.2 mg/l Total Phosphorus (with Bio-P removal) 0.5 mg/l Turbidity 0.2 NTU Bacteria up to 6 log removal (99.9999%) Viruses up to 3 log removal (99.9999%)If proposed design is for higher quality effluent, Pilot Study or Data from Similar Facility
  • Membrane Bioreactors (MBR)Membranes Hollow fiber or Flat plate Nominal Pore Size Microfiltration 0.10 – 0.40 microns Ultrafiltration 0.02 to 0.10 microns Common Membrane materialsPretreatment Fine Screen - perforated plate or drum Hollow fiber 1.0 - 2.0 mm Flat plate 2.0 - 3.0 mm No Bypass Primary clarifier Evaluated for > 1 MGD Grit Removal excessive I/I Oil and Grease Removal 50 mg/l
  • Membrane Bioreactors (MBR)Operation Average Daily Net flux rate @ 20 C 12 to 20 gfd Peak Daily Net flux rate @ 20 C 20 gfd Two Hour Peak Daily Net flux rate @ 20 C 24 gfdOperational Range for TMP Maximum Operational TMP Hollow Fiber 2.0 – 10.0 psi Max 12.0 psi Flat Plate 0.3 - 1.5 psi Max 3.0 psiOperational Range of MLSS Concentration Bio Reactor 4,000 - 10,000 mg/l Membrane Tank 4,000 – 12,000 mg/lOperational control parameters SRT 10 – 25 days
  • Membrane Bioreactors (MBR)OperationAmount of air used per square foot of membrane 0.01 – 0.04 SCFM / SFMethod of Integrity Testing : In-line Turbidity <=1.0 NTUHollow Fiber Pressure Decay TestingSurface Wasting to Foam ControlRun in full manual mode or backup PLCAeration alpha value of 0.5 or lower anoxic 0.5 mg/l DO aerobic 1.5 – 3.0 mg/l DO membrane 2.0 - 8.0 mg/l DONutrient Removal deoxygenate recycle recycle 300 – 600 percent
  • Membrane Bioreactors (MBR)Redundancy N+1, trains, units or storage. Show calculationsPeak Flow Peak Ratio of 2.5 requires Equalization, off-line storage or reserve membrane capacityRAS rate 200 – 400 percent of influentWarranty 5 year on Membranes May require a 2 year performance bond
  • 217.157 Membrane Bioreactors Treatment Systems (MBR)Engineering Report RequiredCommon range of valuesJustification for using parameters outside the commonrangeMay be required to provide 2 year performance bond