Water Quality Managements Developments: Nutrients and Bacteria

WQ Management DevelopmentsWQ Management Developments

Nutrients, BacteriaNutrients, Bacteria

Jim Davenport

Monitoring & Assessment Section

Water Quality Planning Division

Office of Water

Texas Commission on Environmental Quality

[email protected] tel. 512/239-4585

February 22, 2011

Nutrient Criteria: NationalNutrient Criteria: National

�EPA 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: FloridaEPA Nutrient Criteria: Florida

� Lawsuit from Florida Wildlife Fed. & others in 2008

� EPA promulgated criteria for Florida lakes & streams in Dec 2010 – in effect Mar 2012

� EPA estuary criteria – propose in Nov 2011

� New countersuits – Florida cities, Ag Comm., etc.

� Lakes TP: 0.01-0.05 mg/L TN: 0.51-1.27 mg/L

� Streams TP: 0.06-0.49 mg/L TN: 0.67-1.87 mg/L

� Potential long term costs?

- Regulated groups: $3 - $8 billion per year

- EPA: $135 - $206 million per year

Why Are Nutrient Criteria Difficult?Why Are Nutrient Criteria Difficult?

� Lack of clear “use-based” thresholds, for uses such as recreation & aesthetics, aquatic life propagation, drinking water sources

� Responses to nutrients are highly variable –e.g., effect of TN,TP on Chl a

� No consensus on how to derive criteria

� Independent criteria, or “weight-of evidence”?

� Insufficiencies in historical monitoring data

� Initial EPA guidance criteria were problematic

� High concern about regulatory impacts

TCEQ Nutrient Criteria: DevelopmentTCEQ Nutrient Criteria: Development

�Submitted plans to EPA in 2001, 2006

�Reservoirs, then streams & estuaries

�Convened advisory workgroup

�Separate criteria for each reservoir

�Set on historical conditions

�Adopted for 75 reservoirs – 6/30/10

�Based on Chlorophyll a

(suspended algae)

�New permitting procedures for nutrients

Nutrient Criteria: ExamplesNutrient Criteria: Examples

Reservoir Chl a (µg/L)

Stand-alone

TP (mg/L)

Not adopted

Transparency (meters)

Not adopted

Eagle Mtn 25.4 0.07 0.80

Cedar Creek 30.4 0.07 0.80

Livingston 23.0 0.16 0.67

Lewisville 18.5 0.06 0.60

[Houston –

not adopted]

[12.4] 0.18 0.28

Travis 3.7 0.03 3.13

2010 Nutrient Implementation Procedures2010 Nutrient Implementation Procedures

� In 2010 Standards Implementation Procedures

� Applied to increases in domestic discharges

� Sets framework for nutrient (TP) effluent limits

� Reservoirs – predict effects on “main pool”

� Relate TP to reservoir chlorophyll a criteria

� Streams 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 StreamsNutrient 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 FactorNutrient Screening: Example of Local Factor

� Factor: Instream dilution in streams

Concern level Percent effluent in dry weather

Low < 10 %

Moderate 10 to < 25 %

High > 25 %

Nutrient Criteria: The Road AheadNutrient Criteria: The Road Ahead

� Reconvene nutrient advisory committee

� Review data and academic research; and

survey 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 indices

� Consider 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. 605 168

Adopted 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 Effluent Bacteria: Houston TMDL Studies

Minor municipal facilities(114 data points)

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

0 5 10 15 20

residual chlorine (mg/L)

E.

co

li (

log

of

#/1

00 m

l)

E. coli log

Single samplemaximum log (2.6)

Geometric mean log(2.1)

SummarySummary

� National 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 criteria

� Numerous UAA reviews of individual small streams

is continuing

� Questions?

Bacteria Requirements

Bacteria Limits

in TPDES Domestic Permits

Agreement with EPA

� Interim: bacteria limits in certain permits

� Bacteria limits in all permit actions issued after 1/1/10.

� Permits issued under interim agreement may see frequency adjustment in next permit

Implementation

� Next permit action

� New

� Renewal

� Amendment

� No compliance schedule

� Recommend evaluating now

Bacteria Limits� Standard

� E coli

� 126 avg

� 394 max

� Enterococci

� 35 avg

� 89 max

Measurement FrequenciesFlow Chlorine Ultraviolet Natural

>10 5/wk Daily Daily

5—10 3/wk Daily 5/wk

1—5 1/wk Daily 3/wk

0.5—1.0 2/mo Daily 1/wk

0.1—0.5 1/mo 5/wk 2/mo

<0.1 1/qtr 5/wk 1/mo

Continued Need for Chlorine Testing

� Retain

� 4.0 mg maximum

� 0.1 mg dechlor

� Regular check between bacteria samples

Chlorine Contact Chambers

�Recommend evaluating now

� If undersized or short-circuiting, violating current regulations

� 21-day retention time

� Recommend evaluating

� Capacities

� Sample Locations

� Wildlife impacts (birds, nutria, etc)

� Compliance schedule for new construction

Pond Systems

Laboratory Issues

� In-house testing without NELAC

� Contract lab must be NELAC certified

� Proximity to plant

� Increased workload

Sample Holding Times

� Standard Methods

� Holding time – 6 hours

� Set-up time – 2 hours

� Travel 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 advanced

nutrient removal is innovative and

nonconforming technology and is subject to

217.10(b)(2) of this title (relating to

Innovative and Nonconforming

Technology).” - 217.163

Results

� Wide variety of removal processes yielding eco-regionally dependent results

� Problems-

� Variability of ego-regional conditions in Texas

� One treatment process with several different performance reports

Design Criteria Changes

� Engineer’s report must include detailed design calculations correlating the proposed removal process with the anticipated effluent concentration.

� Process

� TP/TN Influent Characteristics

� TP/TN Effluent Characteristics

Desired Ranges

� Total Nitrogen < 8 mg/L

� Total 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 still considered on case-by-case basis in each permit

Contact Info

� Louis C. Herrin, III, P.E.

� [email protected]

� 512.239.4552

Compiled Surveys from Vendors of Membranes

� Huber, Koch, Kruger, Kubota, Siemens, Zenon

Results of Survey, Literature and Other State Regulations

Concerns

� 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)

Applicability

� Submerged

� Low-pressure, vacuum or gravity

� Ultrafiltration or microfiltration

� 217.8(b)(2) Approval of Nonconforming and Innovative Technologies

� May require pilot study and/or 2 year performance bond


� 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)Expected Performance

Membranes

Hollow fiber or Flat plate

Nominal Pore Size

Microfiltration 0.10 – 0.40 microns

Ultrafiltration 0.02 to 0.10 microns

Common Membrane materials

Pretreatment

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


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 gfd

Operational 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 psi

Operational Range of MLSS Concentration

Bio Reactor 4,000 - 10,000 mg/l

Membrane Tank 4,000 – 12,000 mg/l

Operational control parameters

SRT 10 – 25 days


Operation

Amount of air used per square foot of membrane

0.01 – 0.04 SCFM / SF

Method of Integrity Testing : In-line Turbidity <=1.0 NTU

Hollow Fiber Pressure Decay Testing

Surface Wasting to Foam Control

Run in full manual mode or backup PLC

Aeration

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 DO

Nutrient Removal

deoxygenate recycle

recycle 300 – 600 percent


Redundancy

N+1, trains, units or storage. Show calculations

Peak Flow

Peak Ratio of 2.5 requires Equalization, off-line storage or reserve membrane capacity

RAS rate

200 – 400 percent of influent

Warranty

5 year on Membranes

May require a 2 year performance bond


� Engineering Report Required

� Common range of values

� Justification for using parameters outside the common range

� May be required to provide 2 year performance bond

217.157 Membrane Bioreactors

Treatment Systems (MBR)