new approaches to developing local limits

New Approachesto

Developing Local Limits

Industrial & Hazardous WasteCommittee Meeting

July 18, 2001

byRichard W. von Langen, P.E.

New Approachesto

Developing Local Limits

New Approaches to Developing Local LimitsNew Approaches to Developing Local Limits

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I&HW CommitteeI&HW CommitteeJuly 18, 2001July 18, 2001

Sampling Data

• Where?

• What?

• When?

– Residential, Commercial, Industrial, Treatment Plant, Collection System

– POC, Conservative, Non-Conservative, O&G, VOC, TDS, pH

– 1-2 Weeks, Monthly, Quarterly, Weekends, Wet Season, Dry Season


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Characterizing the Waste andHow Low Can You Go ?

• Metals

• CN, O&G, VOC

• BOD, TSS

• Representative Sampling

• Liquids Versus Sludge

– Ag, As, Cd, Cr, Cu, Hg, Ni, Pb, Zn

– Grab Samples? CN in residential WW ?

– Flow Proportional, Process Water Meters


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Now… What do I do with the Data?

• Mass Balances

• The “< MDL” Dilemma

• Variable

• When There Isn’t Enough?

– Collection System, Headworks, Plant

– Should the value be used? Assign it a O or =, 50%, or 2/3 of the MDL?

– O to > Avg + 2 SD; SD > 20%, NDs

– Less than 5 (10, 21?) data points


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Limiting Criteria

• Collection System & Primary Treatment

• Worker Health & Safety

• Biological Treatment Inhibition

• Effluent Limit

• Sludge Disposal

• Air Emissions

– Physical Inhibition or Corrosion

– Airborne, pH related

– EPA Guidance, Plant Data?

– Stream, CTR, Ocean Discharge Limit, Title 22, No Limit

– 503, Fed HW, State-TTLC, STLC

– Odor, VOC


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Mass BalancesHeadworks data are the fulcrum point for mass balances

Industrial Waste Residential Commercial

EffluentSludge

Headworks


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Headworks Mass Balance

IW + RES + COM = Headworks

• Effect of Collection System Operations• Lots of NDs• One or Two NDs• No Commercial Samples• Headworks Data Versus Plant Removal• EPA-Within 10-15%


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Plant Mass Balance

Sludge

Sludge Treatment

HeadworksSecondary Treatment

PrimaryTreatment

Disinfection Effluent

• Chemical Addition• Consumption• Different disposal options• No prim/sec sludge data• Return flows• NDs


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American Canyon WWTP Flow Diagram

IndustrialFlow

TreatmentTrain 1

Surface WaterDischarge*

ChlorineDisinfection

UVDisinfection

Reuse asRecycled

Water

Domestic/Commercial

Flow

(Winter)

Sludge HoldingBasin

Landfill LandApplication

Dewatered Sludge

Sludge

Sludge

TreatmentTrains 2, 3, 4

* Instantaneous concentration limits and rolling 12-month mass limits


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VCWD WWTP

Sludge

Sludge Treatment

HeadworksSecondaryTreatment

PrimaryTreatment

PercolationPonds

Discharge

TertiaryTreatment

Recycle


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Example - Aluminum

1.8 X 2.4 = 36#

50#

39#

E - 6#

S - 33#

R - 2.65 x 2.22 = 49#

I - 0.82 x 0.18 = 1#

C- ?


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Raw Data - Aluminum (mg/L) Residential

#1 #2 #32.9 4.5 2.0

4.7 2.4 2.2

1.6 1.6 4.1

2.3 2.0 2.8

4.1 1.7 3.1

2.8 1.4 3.5

1.7 2.6

Avg – 2.66 SD – 1.01 % SD – 38 Med – 2.4


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Raw Data - Aluminum (mg/L) Headworks

2.3 Avg – 1.81.8 SD – .351.5 % SD – 201.6 Med – 1.81.91.81.42.41.5


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Aluminum Local Limit • WDR

• POTW Flow

• POTW % Removal

• MAHL

• Existing Influent

• Uncontrolled Influent

• MAIHL

• Uniform IU Conc. Without Safety Factor

– 1.0 mg/L

– 2.4 MGD

– 84

– 128 lb/day

– 36-50 lbs/day

– 35-49 lbs/day

– 93-79 lbs/day

– 63-53 mg/L


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Example - Cadmium

R - NDC - ?I - 0.00154#

E - NDS - 0.0021#

ND


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Raw Data - Cadmium mg/LIndustrial Contribution

#1 #2 #36 days – ND 4 days – ND 6 days – ND

1 day – 0.004 2 days – 0.001 Same process as #2

Residential – ND Headworks – ND Plant Inf/Eff – ND

MDL=0.001


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Cadmium Local Limit

40 CFR 503 39 mg/Kg CdPOTW % Removal 70%MAHL 0.05787 lb/dayIndustry ContributoryAllocation

0.3 mg/L


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Example - Silver

R - <DL mg/LC - ?I - 0.00054#

E - ND mg/LS - 0.013#

Headworks<DL


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Limiting Criteria for Silver

• Process Inhibition

• Pass Through

• Sludge Criteria

– No EPA Criteria

– CTR?, Effluent Limit, WDR, Title 22

– No 503 Requirement, Federal HW? California HW - TTLC, STLC?


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Mass Balance - Chloride mg/L

R - 44.6C - ?I - 115

Cl2

E - 49S - ?

Headworks44 mg/L


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TDS Local LimitsLimiting Criteria - Water Source + 400 mg/L

Approach:– Compute controlled and uncontrolled concentrations of TDS– Subtract (average, highest, lowest?) source water

concentration– Compute MAHL using 400 mg/L and WWTP influent flow– Subtract uncontrolled mass using (average, highest, lowest,

upper quartile, average + 1 SD) uncontrolled sources concentration

– Subtract safety factor– Allocate MAIHL to all Industrial Users


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Sensitivity Analysis

• NDs

• Variable Data

• Expansion Factor

• Allocation Method• TDS

– Calculate LL at different ND values; adjust headworks concentration to match mass balance

– Eliminate outliers; use geometric mean or median to calculate LL

– Vary; compare to Residential, Commercial, and Industrial Waste contributions

– Total versus contributory IU flows– Vary concentrations of source water,

and uncontrolled sources

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