Pretreatment Headworks Analysis

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Pretreatment Headworks Analysis

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Title: Pretreatment Headworks Analysis

1

2007 HEADWORKS ANALYSIS WORKSHOP
2
Todays Presentation

Objectives of Pretreatment Program
Purpose of Headworks Analysis
Introduce TYPICALVILLE
Discuss the Long/Short Term Monitoring Plan
(L/STMP)
Develop Removal Rates from L/STMP data
Determine Maximum Allowable Headworks Loading
(MAHL)

3
Todays Presentation (cont,)

Evaluate Uncontrollable Load to the POTW
Determine Maximum Allowable Industrial Loading
(MAIL)
Allocation Table (AT)
Headworks Addendum for Sludge Loading(HASL)

4
TYPICALVILLE
NPDES Permit Limits
WWTP
Aeration Basin Clarifier Disinfection Digester
Water Quality Standards
Land Application Standards
5
Objectives of the Pretreatment Program- 40 CFR
403.2

1) Protect the Waters of the State (the stream)
2) Protect the POTWs Microorganisms WWTP
3) Protect the Land/ Groundwater (Sludge)
4) Protect Worker Health and Safety

6
Headworks Analysis What is it Good for?

Tool to help POTW meet the objectives of 40 CFR
403.2
Summarizes Operating Conditions at the POTW
Summarizes Ability of POTW to remove Pollutants
of Concern (POCs)
Calculates
Maximum Allowable Headworks Loading (MAHL)
Maximum Allowable Industrial Loading (MAIL)

7
Three Limiting HWA Criteria or Basis for MAHL

1) Pass Through Criteria-
a) NPDES
b) NC-Water Quality Standards
2) Biological Processes Inhibition-
a) Activated Sludge Inhibition
b) Nitrification Inhibition
c) Anaerobic Digester Inhibition
3) Sludge Criteria- 503 Regulations
a) Ceiling concentration
b) Cumulative loading

8
HWA -Limiting CriteriaPass Through
Bar Screen
Clarifier
Aeration Basin
Aeration Basin
Grit Removal
Filter
Digester
Sludge
Chlorine/ UV Disinfect
1a
River Styx
9
Pass Through for Lead- based on NPDES Permit Limit
Commercial
SIUs
NPDES Permit
NPDES Permit Limit 0.05mg/l
WWTP
10 MGD 75 RR
Limits
0.2 mg/l (16.7 s/day) Influent
Water Quality Standards
Residential
Land Application Standards
10
Three Limiting HWA Criteria or Basis for MAHL

1) Pass Through Criteria-
a) NPDES
b) NC-Water Quality Standards
2) Biological Processes Inhibition-
a) Activated Sludge Inhibition
b) Nitrification Inhibition
c) Anaerobic Digester Inhibition
3) Sludge Criteria- 503 Regulations
a) Ceiling concentration
b) Cumulative loading

11
HWA -Limiting CriteriaBiological Process
Inhibition
2a and 2b
Bar Screen
Clarifier
Aeration Basin
Aeration Basin
Grit Removal
Filter
2c
Digester
Sludge
Chlorine/ UV Disinfect
River Styx
12
Inhibition Loading for Lead- based on Activated
Sludge Inhibition
Commercial
SIUs
WWTP
10 MGD Activated Sludge
0.5 mg/l (41.7 s/ day) Influent
Water Quality Standards
Land Application Standards
13
Three Limiting HWA Criteria or Basis for MAHL

1) Pass Through Criteria-
a) NPDES
b) NC-Water Quality Standards
2) Biological Processes Inhibition-
a) Activated Sludge Inhibition
b) Nitrification Inhibition
c) Anaerobic Digester Inhibition
3) Sludge Criteria- 503 Regulations
a) Ceiling concentration
b) Cumulative loading

14
HWA -Limiting CriteriaSludge 503 Regulations
Bar Screen
Clarifier
Aeration Basin
Aeration Basin
Grit Removal
Filter
3a 3b
Digester
Sludge
Chlorine/ UV Disinfect
River Styx
15
Sludge Loading for Lead- based on Cumulative
Sludge Loading
Commercial
SIUs
WWTP
10MGD
75 RR
0.125 mg/l (10.4 s/ day) Influent

Given
267 lbs/acre std. from permit
122 acres permitted
3.5 solids
0.001 MGD flow to disposal

Water Quality Standards
Land Application Standards
16
Compare Allowable Loads

Pass Through Loading
NPDES 16.7 s/day
Inhibition Loading
Activated sludge inhibition 41.7 s/day
Sludge Loading
Cumulative sludge loading 10.4 s/day
Use the most limiting criteria to protect the
plant!

17
What does this number mean?

All things being equal
The POTW can safely treat 10.4 s/day of Lead
Greater than 10.4 s/day may cause violation of
the cumulative sludge loading criteria.
The POTW has 10.4 s/day of lead allocation to
distribute to its users.

18
Example Allocation

Lead

19
Three Limiting HWA Criteria or Basis for MAHL

1) Pass Through Criteria-
a) NPDES
b) NC-Water Quality Standards
2) Biological Processes Inhibition-
a) Activated Sludge Inhibition
b) Nitrification Inhibition
c) Anaerobic Digester Inhibition
3) Sludge Criteria- 503 Regulations
a) Ceiling concentration
b) Cumulative loading

20
HWA -Limiting Criteria
2a and 2b
Bar Screen
Clarifier
Aeration Basin
Aeration Basin
Grit Removal
Filter
2c
3a 3b
Digester
Sludge
Chlorine/ UV Disinfect
1a
River Styx
21
Preparing Your HWA

Where do I begin?
How long will it take to prepare a HWA?
Where can I find the answers to common questions?

22
Preparing Your HWA

Where do I begin?
Long or Short Term Monitoring sampling.
How long will it take to prepare a HWA? Anywhere
from 2 weeks to 2 months.
Where can I find the answers to common questions?
Comprehensive Guide or contact the PERCS Unit.

The Key To A Headworks Analysis

24
Longterm Monitoring Plan

Division approved LTMP has
proper sampling locations
proper pollutants of concern
proper detection levels
Typically, your LTMP will say to monitor monthly
for 12 months to provide adequate sampling data
for the HWA
Or use at least three years of quarterly sampling

25
Longterm Monitoring Plan

Use your DMR data plus your LTMP data
Flow
BOD
TSS
NH3
Other parameters you may sample more often for
your NPDES permit metals, cyanide

26
Short-term Monitoring Plan Modified Programs

Frequency
Four sets of quarterly samples
Use your DMR data plus your STMP data

for Pollutants of Concern in your Publicly Owned
Treatment Works

28
Town of Oz WWTP
Gold Brick Metal Finishing
Flying Monkey Kitchen
NPDES Permit Limits
WWTP
Aeration Basin Clarifier Disinfection Digester
Water Quality Standards
Land Application Standards
29
OZ- WWTP
Bar Screen
Clarifier
Aeration Basin
Aeration Basin
Grit Removal
Filter
Sludge
Chlorine Disinfect
River Styx
30
What Do I Need To Calculate POTW Removal Rates?

Long/Short Term Monitoring Data
DMR Data for BOD and TSS, etc.
Removal Rate Equations
Default Removal Rates/Literature RRs
Literature RRs found in Appendix 5-D

31
Calculating Removal Rates

POTW Removal Rate Calculation
RR (CI- CE)/ CI 100
RR Removal Rate Percentage
CI Concentration Influent, mg/L
CE Concentration Effluent, mg/L

32
Removal Rate - Spreadsheet
33
Removal Rate - Answers
34
Removal Rates- Spread Sheet Continued for Cadmium
35
Cadmium - RR Continued Use 1/2 Detection
36
When Do I Use Literature RRs?

When more than 50 of the data collected is below
the detection level
When you have a small data set or a
misrepresentative data set
Any Questions? Call the Pretreatment Unit or
Consult The Comprehensive Guidance for
Pretreatment Programs in North Carolina, Chapter
5, Section 5-D, page 1

37
Cadmium - RR Continued Answers
38
Calculate Removal Rates For Each POC

Average influent/effluent for all POCs, mg/L
All summarized data must be sent to DENR-
not lab sheets
Calculate the Removal Rate for all POCs
Document the basis for your Removal Rate

39
Removal Rates Summary Page
Review DWQ Removal Rates Spreadsheet!!
40

41
Calculate Pass Through Using EitherNPDES Permit
Limit or NC Water Quality Standards
PROTECTING THE STREAM
42
HWA -Limiting CriteriaPass Through
Bar Screen
Clarifier
Aeration Basin
Aeration Basin
Grit Removal
Filter
Digester
Sludge
Chlorine/ UV Disinfect
1a
River Styx
43
What Do I Need To Calculate Pass Through?

Current NPDES Permit
Which parameters are limited?
New NPDES limits expected/drafted?
NC Water Quality Standards Table
All parameters not limited in your NPDES
Pass Through Equations
Removal Rates
Average POTW Flow (NOT Permitted flow)

44
Calculating Pass Through

NPDES Limit Calculation
LNPDES(8.34)(CNPDES)(QPOTW)
(1-RRPOTW)
LNPDES Allowable Headworks Loading based on
NPDES
Limit in lbs/day
CNPDES NPDES Permit Limit, mg/L
QPOTW Average POTW Effluent Flow, MGD
RRPOTW Removal Rate Across the POTW, as a decimal

45
Calculating Pass Through For BOD

NPDES Limit Calculation
LNPDES_BOD( 8.34 )( )(
) ________
( 1-
)
CNPDES_BOD NPDES Permit Limit, mg/L1
QPOTW Average POTW Flow, MGD2
RRPOTW_BOD Removal Rate Across the POTW,
decimal3
1) TAB 2 - REF. ANSWERS - NPDES Permit
2) TAB 2 - REF. ANSWERS - General Info
3) TAB 2 - REF. ANSWERS - Removal Rate Summary

lbs./day
46
Pass Through for BOD

NPDES Limit Calculation
LNPDES (8.34)(CNPDES_BOD)(QPOTW)
(1-RRPOTW_BOD)
CNPDES_BOD 30 mg/L
QPOTW 2.206 MGD
RRPOTW_BOD 0.954

47
Pass Through- BOD Answer

LNPDES (8.34)(30)(2.206)
(1- 0.954)
11,999 lbs./day BOD
allowed to meet the NDPES Permit Limit of 30 mg/L

48
What If I Calculate A Different Removal Rate?

For Example
What if your POTW
removal rate 98?
What if your POTW
removal rate 94?
How much difference does it make?

49
If Your RR were 98?

LNPDES_BOD_98 (8.34)(30)(2.206)
(1-0.98)
(using 98Removal Rate)
27,597 lbs./day

50
If Your RR were 94?

LNPDES_BOD_94 (8.34)(30)(2.206)
(1-0.94)
(using 94Removal Rate)
9,199 lbs./day

51

52
What about the Concentrations?
Lbs/day / (MGD 8.34) mg/l
53
What about the Concentrations?
Lbs/day / (MGD 8.34) mg/l
54
What about Design?

The engineers who designed your WWTP designed it
to be able to treat a specific target or design
influent value for selected parameters and still
meet your NPDES limit.
LDesign
(8.34)(Design Influent, mg/l)(Design flow, MGD)
Use average Design values, not max or peak

55
Where are my Design values?

OM Manual
Plans and Specs
Engineers Calculations
What about
Upgrades
Expansions
New design parameters

56
BOD Design MAHL

Town of Oz Design BOD _______ mg/l1
Town of Oz Design Flow _______ MGD1
(8.34) ( _____ mg/l) ( ______ MGD)
________ lbs/day
Tab 2- References and Answers OM Manual

57
BOD Design MAHL

Town of Oz Design BOD 200 mg/l
Town of Oz Design Flow 5.0 MGD
(8.34) (200 mg/l) (5 MGD)
8,340 lbs/day

58
What about the Concentrations?
When does the influent concentration become too
high?
59
287 mg/l or 200 mg/l ?Whats the Big Deal?

All NC POTWs must evaluate the Design Load for
any applicable parameters and compare to the
Pass-through Load, in both mg/l and lbs./day
Pass-through less than Design, use Pass-through
as MAHL
May be able to use Design if underloaded.
Contact PERCS to discuss.
Design less than Pass-through,use Design as MAHL
Remember thats all MAHL you will ever have.
Not happy?

Show HWA Spreadsheet!
60
287 mg/l or 200 mg/l ?Whats the Big Deal?

Sometimes a WWTF can actually treat wastewater
better than the design criteria set by the
engineer.
An MAHL Design Criteria may be approved with
Design Multiplier
Historic Data Design Load?
NC Professional Engineer provides new Stamped
Design Calculations
Other Compelling Argument?
More specific guidance on web-site soon!

Show HWA Spreadsheet!
61
Calculating WQ Pass Through

NC Water Quality Standard Calculation
LWQS(8.34)(CWQS)(QPOTW QSTR)
(1-RRPOTW)
LWQS Allowable Headworks Loading based on
WQS,lbs/day
CWQS Water Quality Standard, mg/L
QPOTW Average POTW Flow, MGD
QSTR Receiving Stream 7Q10 Flow, MGD
RRPOTW Removal Rate Across the POTW, as a
decimal
except phenols in WS streams-use 30Q2 Flow,
MGD- Call DWQ for assistance
Human Health Carcinogens use Average
Flow, MGD - Call DWQ for assistance

62
Calculating WQ Pass Through For Cadmium

NC Water Quality Standard Calculation
LWQS_Cd (8.34)( )(
) ________
( 1-
)
CWQS_Cd Water Quality Standard, mg/L1
QPOTW Average POTW Effluent Flow, MGD2
QSTR Receiving Stream 7Q10 Flow, MGD3
RRPOTW_Cd Removal Rate Across the POTW, as a
decimal4
1) Blue Sheet - COMP GUIDE 94 - Water Quality
Standards Appendix 5-E
23) TAB 2 - REF. ANSWERS -General Info
4) TAB 2 - REF. ANSWERS - Removal Rate Summary

lbs./day
63
WQ Pass Through For Cadmium

NC Water Quality Standard Calculation
LWQS(8.34)(CWQS)(QPOTW QSTR_7Q10)
(1-RRPOTW)
CWQS 0.002 mg/L (Aquatic Life Standard- Class
C)
QPOTW_AVG 2.206 MGD
QSTR_7Q10 58.17 MGD (to covert CFS to MGD, by
1.55)
RRPOTW 0.67

64
WQ Pass Through Cd- Answer

LWQS_Cd (8.34)(0.002)(58.172.206)
(1- 0.67)
3.0517 lbs./ day Cadmium
allowed to meet the NC WQS
of 0.002 mg/L, Aquatic Life Class-C

65
What If Your 7Q10 Flow Equaled Zero?

LWQS_Cd(8.34)(0.002)(02.206)
(0.33)
0.1115 lbs./ day
of Cadmium to Meet NC WQS if your 7Q10 were Zero

66
Action Levels

Action Level Parameters in NC are
Cu, Fe, Ag, Zn, and Chlorides
Do not calculate Water Quality Standard Pass
Through for Action Level Parameters, UNLESS
The POTW is failing Toxicity and an Action Level
Pollutant is the cause for failing.

Review HWA.AT Spreadsheet!!
67

(Interference)

68
Calculate Biological Inhibition By
Evaluating Activated Sludge Inhibition
Nitrification Inhibition Anaerobic Digester
Inhibition
PROTECTING THE POTW's MICROORGANISMS
69
HWA -Limiting CriteriaBiological Process
Inhibition
2a and 2b
Bar Screen
Clarifier
Aeration Basin
Aeration Basin
Grit Removal
Filter
2c
Digester
Sludge
Chlorine/ UV Disinfect
River Styx
70
What Do I Need To Calculate Biological
Inhibition?

A Basic understanding of the microorganisms
active at your WWTP
Wastewater Biological Treatment Units-
Activated Sludge, Aeration Basin, etc.
Trickling Filter
Carbonaceous Vs. Nitrogenous/Nitrification
Sludge Biological Treatment Units-
Anaerobic Digester
Inhibition Formulas
LTMP/STMP data from basins and Digesters
Note No literature Biological Inhibition
Criteria for BOD, TSS, Mo, Se, Phenol, or several
other parameters

71
Activated Sludge/ Nitrification Inhibition

L2INH (8.34)(C2INH)(QPOTW)
(1-RR1)
L2INH Secondary Inhibition, lbs./day
C2INH 2 Inhibition Criteria, mg/L
QPOTW_AVGAverage POTW Flow, MGD
RR1 Primary Removal Rate, as
a decimal

Aeration Basin
No primary clarifiers? No problem! Divide by 1
72
Activated Sludge/ Nitrification Inhibition for
Cadmium

L2INH_Cr (8.34)( )( )
_____
( )
C2INH_Cd 2 Inhibition Criteria, mg/L1
QPOTW_AVGAverage POTW Flow, MGD2
RR1_Cd Primary Removal Rate, as a decimal3
1) Pink Sheet - COMP GUIDE 94 TAB - Appendix 5-D,
table 3.2 and 3.4
2 3) TAB 2 - REF. ANSWERS - General Info
note OZ WWTP does not have primary clarifiers

lbs./day
73
Activated Sludge/ Nitrification Inhibition for
Cadmium

L2INH_Cd (8.34)(C2INH_Cd)(QPOTW)
(1-RR1_Cd)
C2INH_Cd 1.0 mg/L Activated Sludge
C2INH_Cd 5.2 mg/L Nitrification
QPOTW 2.206 MGD
1-RR1_Cd 1
RR1_Cd 0 , because OZ doesnt have Primary
Clarifiers

Which Inhibition value do I use?
74
Which Inhibition Value Do I Use? Activated Sludge
or Nitrification

Activated Sludge Inhibition
All POTWs must evaluate for Activated Sludge
Inhibition
Nitrification Inhibition
Only POTWs who have
an Ammonia limit
and/or
Nitrogenous Bacteria

75
Which Inhibition Value Do I Use, Activated Sludge
or Nitrification?

Look at the OZ NPDES Permit1
Do they have a limit?
Look at the LTMP Data2
Does the data suggest the WWTP Nitrifies?
Ask the ORC
Does your POTW Nitrify?
1) TAB 2 - REF. ANSWERS - NPDES Permit
2) TAB 2 - REF. ANSWERS - Removal Rates Summary
Page

76
Activated Sludge/ Nitrification Inhibition for
Cadmium

L2INH_Cd (8.34)( )( )
_____
( 1- )
C2INH_Cd 2 Inhibition Criteria, mg/L1
QPOTW_AVGAverage POTW Flow, MGD2
RR1_Cd Primary Removal Rate, as a decimal3
1) Pink Sheet - COMP GUIDE 94 TAB - Appendix 5-D
table 3.2 and 3.4
2 3) TAB 2 - REF. ANSWERS - General Info
note OZ WWTP does not have primary clarifiers

lbs./day
77
Activated Sludge/ Nitrification Inhibition for
Cadmium- Answer

L2INH_Cd (8.34)(1.0)(2.206)
(1-0)
Use the most limiting Criteria- in this case use
Activated Sludge Inhibition Criteria at 1.0 mg/L
18.3980 lbs./day
of Cd to Meet Literature Wastewater
Inhibition Criteria for Activated Sludge
Inhibition

78
Site Specific Inhibition Criteria

What if Site Specific cadmium values are
greater than Literature Values?
For Example What if ...
LTMP Aeration Basin Sampling 1.25 mg/L
Can the POTW use this number for Biological
Inhibition Criteria instead of 1.0 mg/L found in
the
Literature Inhibition Criteria for Activated
Sludge ?

79
Site Specific Inhibition Criteria

The LTMP data suggests that the WWTP is
acclimated to higher levels of Cadmium than
traditional literature values Questions for the
ORC
Does the 1.25 mg/l of Cd upset the plant?
Were there NPDES or Toxicity violations?
Were any effluent parameters (usually BOD, TSS
NH3) elevated above normal for no other apparent
reason?
Was there Foaming?
Was there fluctuations in the DO?
Did the Bugs Die?
If No, then the POTW may reevaluate the
Biological Activated Sludge Criteria using
1.25mg/L
(this gives the POTW 22.9976 lbs./day of Cd for
meeting the Site Specific Biological Inhibition
Criteria)

80
Anaerobic Digester Inhibition

LSLINH (8.34)(CSLINH)(QDIG)
(RR)
LSLINH Sludge Inhibition, lbs./day
CSLINH Anaerobic Digester Inhibition Criteria,
mg/L
QDIGAverage POTW Flow to Digester, MGD
RR Removal Rate across the POTW, as a decimal

Review HWA.AT Spreadsheet!!

Anaerobic
Digester

Note Town of OZ WWTP- Doesnt Have an Anaerobic
Digester
81

Land Application Residuals

82
Calculate Sludge Criteria-503 Regulations By
EvaluatingCeiling ConcentrationCumulative
Loading
PROTECTING THE LAND AND GROUND WATER
83
HWA -Limiting CriteriaSludge 503 Regulations
Bar Screen
Clarifier
Aeration Basin
Aeration Basin
Grit Removal
Filter
3a 3b
Digester
Sludge
Chlorine/ UV Disinfect
River Styx
84
Sludge Criteria

What do I need to determine the sludge Criteria?
Copy of your current Sludge Permit
Copy of your current Annual Sludge Report
Sludge Formulas

85
Ceiling Concentration

LSLCEIL(8.34)(CCEIL)( Solids/100)(QDISP)
(RRPOTW)
LSLCEIL Ceiling Concentration
Allowable Headworks, lbs./ day
CCEIL Sludge Ceiling Standard/Limit, mg/kg
Solids Percent Solids to Disposal
QDISP Sludge Flow to Disposal, MGD
RRPOTW POTW RR, as a decimal

86
Ceiling Concentration For Cadmium

LSLCEIL_Cd(8.34)( )( /100)(
) ______
( )
CCEIL_Cd Sludge Ceiling Standard/Limit, mg/kg1
Solids Percent Solids to Disposal2
QDISP Sludge Flow to Disposal, MGD3
RRPOTW_Cd POTW RR, as a decimal4
1) TAB 2 REF. ANSWERS -Sludge Permit Limits Page
2 3) TAB 2 REF. ANSWERS - General Info
4) TAB 2 - REF. ANSWERS - Removal Rates Summary

lbs./day
87
Ceiling Concentration for Cadmium

LSLCEIl_Cd(8.34)(CCEIl_Cd)( Solids/100)(QDISP)
(RRPOTW_Cd)
CCEIL_Cd 85 mg/kg
Solids 3.59 Solids
QDISP 0.005MGD
RRPOTW_Cd 0.67

88
Ceiling Concentration for Cadmium- Answer

LSLCEIL_Cd(8.34)(85)( 3.59/100)(0.005)
(0.67)
0.1899 lbs./day Cadmium
allowed in order to meet the Ceiling
Concentration Standard/Limit for Land Application

89
Cumulative Loading

LSLCUM (CAR)(SA)
(SL)(RRPOTW)(365 days/year)
LSLCUM Cumulative Application, lbs./day
CAR Cumulative Application Limit, lbs./acre
SA Site Area, in acres
SL Site Life
RRPOTWRemoval Rate, as a decimal

90
Cumulative Loading For Cadmium

LSLCUM_Cd ( )(
) ___________
( )( ) (365
days/year)
CAR_Cd Cumulative Application Limit, lbs./acre1
SA Site Area, in acres2
SL Site Life3
RRPOTW_CdRemoval Rate, as a decimal4
1) TAB 2 - REF. ANSWERS - Sludge Permit Limits
Page
2) TAB 3 - REF. ANSWERS - Sludge Permit Cover
Page
3 4) TAB 2 - REF. ANSWERS - General
Info,-Removal Rate Summary

lbs./day
91
Cumulative Loading for Cadmium

LSLCUM_Cd (CAR_Cd)(SA)
(SL)(RRPOTW_Cd)(365 days/year)
CAR_Cd 34 lbs./acre
SA 122, in acres
SL 400 years
RRPOTW_Cd 0.67

92
Cumulative Loading for Cadmium Answer

LSLCUM_Cd (34)(122)
(400)(0.67)(365)
0.0424 lbs./day Cadmium
allowed in order to meet the Cumulative Sludge
Limit for Land Application

93
Compare Sludge Values for Cd

Ceiling Loading
0.1899 lbs./day
Use 0.0424 lbs./day in the MAHL comparison
because Cumulative Loading is more limiting

Cumulative Loading
0.0424 lbs./day

Vs
Vs
94
Sludge Loading Comparison
BOD TSS, Ammonia, and Cyanide do not have
established sludge criteria.
Review HWA.AT Spreadsheet!!
95
Notice To Composters!
The previous example was for land applied
sludge. If you compost your sludge or create a
high quality sludge for distribution to the
public you must replace the ceiling limits with
the more stringent monthly average concentration
limits (40 CFR 503.13). Please note the
Molybdenum ceiling concentration will still apply
as it is the most restrictive criteria.
Review HWA.AT Spreadsheet!!
96

Determines the Amount of Pollutant the POTW can
Treat Based on the Most Restrictive Criteria

97
MAHL Comparison Of The Three Criteria- Choose
Most Limiting
Review HWA.AT Spreadsheet!
98

Determines the Amount of Uncontrollable Flow and
Pollutants to the POTW

99
What Is Uncontrollable Load?

Everything that contributes to the POTW not
covered in an SIU Permit
Residential
Non-Residential, but not SIU
Some Examples
Commercial
Hospitals, Funeral Homes
Doctors, Dentists
Car Repair/Wash Centers
Inflow/Infiltration
ALL Non-SIUs

100
Uncontrollable Flow Determination

Uncontrollable Flow Calculation
Q UNC_Flow (Q POTW_Flow-S QSIU_Flow)
QUNC_Flow Uncontrollable Flow
QPOTW_Flow Average POTW Flow
S QSIU_Flow Sum of the Average SIU Flow

101
Uncontrollable Flow Determination

Uncontrollable Flow Calculation
Q UNC_Flow ( - S
) _________
Q POTW_Flow Average POTW Flow1
QSIU_Flow1 Average SIU 1 Flow2
QSIU_Flow2 Average SIU 2 Flow3
1) Tab 2 - REF. ANSWERS - General Info
2 3) Tab 2 - REF. ANSWERS - SIU Data Summary

MGD
102
Uncontrollable Flow Determination

Q UNC_Flow (Q POTW_Flow-SQSIU_Flow)
Q POTW_Flow __________
QSIU_Flow1 __________
QSIU_Flow2 __________
QUNC_Flow _____ - (____________)
__________ of Uncontrollable Flow
to the POTW

103
Uncontrollable Flow Determination- Answer

Q UNC_Flow (Q POTW_Flow-SQSIU_Flow)
Q POTW_Flow 2.206 MGD
QSIU_Flow1 0.187 MGD
QSIU_Flow2 0.15 MGD
QUNC_Flow 2.206-(0.1870.15)
1.869 MGD of Uncontrollable Flow
to the POTW

104
Uncontrollable Pollutant Load may be determined
in two ways

1)Mass Balance Method
Sum of all SIU contributions for each POC
Subtract this amount from the total WWTP Influent

2)Sampling Method
Sample for uncontrollable pollutants per LTMP

105
What Do I Need In Order To Evaluate The
Uncontrollable Load To The POTW- Using The Mass
Balance Method?

POTW Influent Data
Flow data (actually from effluent)
Pollutant data
SIU Effluent Data
Flow data
Pollutant data

106
Uncontrollable Pollutant Load- Using the Mass
Balance Method
107
Uncontrollable Pollutant Load- Mass Balance
Method for BOD

LUNCMB_BOD
(8.34)(QPOTW)(CINF)-S(8.34)(QSIUn)(CSIUn
)
QPOTWAverage POTW Flow, MGD1
CINF_BOD Average Influent BOD, mg/L2
QSIUn_Flow Average SIUn Flow, MGD3
CSIUn_BOD Average SIUn BOD, mg/L4
1 -4) TAB 2 - REF. ANSWERS -General Info,-
Removal Rate Summary,
SIU Data Summary, SIU Data Summary

108
Uncontrollable Pollutant Load- Mass Balance
Method for BOD

LUNCMB_BOD (8.34)(QPOTW)(CINF)-S(8.34)(QSIUn)(C
SIUn)
QPOTW_Flow _______ MGD
CINF_BOD _______ mg/L
QSIU1_Flow _______MGD
CSIU1_BOD _______mg/L
QSIU2_Flow _______MGD
CSIU2_BOD _______mg/L

109
Uncontrollable Pollutant Load- Mass Balance
Method for BOD

LUNCMB_BOD (8.34)(QPOTW)(CINF)-S(8.34)(QSIUn)(C
SIUn)
QPOTW_Flow 2.206 MGD
CINF_BOD 195 mg/L
QSIU1_Flow 0.187 MGD
CSIU1_BOD 75 mg/L
QSIU2_Flow 0.15 MGD
CSIU2_BOD 311 mg/L

110
Uncontrollable Pollutant Load- Mass Balance
Method for BOD

STEP ONE Solve for SIU BOD Load
SIU1 (8.34)(QSIU1)(CSIU1_BOD)1
SIU1 (8.34)(_____)(_________)1 _______
lbs./day
SIU2 (8.34)(QSIU2)(CSIU2_BOD)2
SIU2 (8.34)(_____)(_________)2 _______
lbs./day
TOTAL SIU CONTRIBUTION
_____________ __________ __________
1 2) TAB 2 - REF. ANSWERS - SIU Data Summary

111
Uncontrollable Pollutant Load- Mass Balance
Method for BOD

STEP ONE Solve for SIU BOD Load
SIU1 (8.34)(QSIU1)(CSIU1_BOD)1
SIU1 (8.34)(0.187 MGD)(75 mg/l)1 117 lbs./day
SIU2 (8.34)(QSIU2)(CSIU2_BOD)2
SIU2 (8.34)(0.150 MGD)(311 mg/l)2 389
lbs./day
TOTAL SIU CONTRIBUTION
117 lbs/day 389 lbs/day 506 lbs/day
1 2) TAB 2 - REF. ANSWERS - SIU Data Summary

112
Uncontrollable Pollutant Load- Mass Balance
Method for BOD

STEP TWO
Solve for Influent BOD to the POTW
POTW Influent BOD (8.34)(QPOTW)(CINF)
POTW_INF_BOD (8.34)(2.206)(195) 3588 lbs./day

113
Uncontrollable Pollutant Load Mass Balance - BOD
Answer

STEP THREE
Solve for Uncontrollable BOD Load
LUNCMB_BOD (3588) - (506)
3082 lbs./day
of Uncontrollable BOD to the POTW

114
Uncontrollable Pollutant Load Confirm Mass
Balance Answer

BACK CALCULATE FOR EQUIVILANT
BOD IN mg/L
POTW_Uncontrollable Uncon_BOD in lbs./day
(8.34)(QUNC)
Back Calculate to see if this number makes sense

115
Uncontrollable Pollutant Load Confirm Mass
Balance Answer

BACK CALCULATE FOR EQUIVILANT
BOD IN mg/L
POTW_INF_BOD 3082
(8.34)(1.869)
198 mg/L of BOD from Uncontrollable
Sources

116
What Do I need to Calculate Uncontrollable Load
- Using the Sampling Method?

SIU Effluent data
Flow data
POTW Influent data
Flow data (actually from effluent)
DENR Approved Sampling Location
for Uncontrollable Determination!!

117
Uncontrollable Pollutant Load- Sampling Method

LUNCs (8.34)(CUNC)(Uncontrollable Flow)

LUNCS Uncontrollable Loading Sampling,
lbs/day CUNC Uncontrollable Pollutant
Concentrations Uncontrollable Flow from previous
Calculations
118
Uncontrollable Pollutant Load- Sampling Method
for BOD

LUNC_BOD
(8.34)(_ CUNC_BOD mg/l)(Uncontrollable Flow MGD)
(8.34)(_______mg/l)(_________MGD)
CUNC_BOD Uncontrollable BOD as sampled, mg/L1
TAB 2 - REF. ANSWERS -General Info
Uncontrollable Flow from previous calculations

119
Uncontrollable Pollutant Load- Sampling Method
for BOD

LUNC_BOD
(8.34)(CUNC_BOD)(Uncontrollable Flow)
CUNC_BOD 350 mg/L1
Uncontrollable Flow 1.869 MGD
1)As sampled in LTMP. See TAB 2 - REF. ANSWERS
- General Info

120
Uncontrollable Pollutant Load Sampling Method -
BOD Answer

LUNC_BOD
(8.34)(350)(1.869)
5456 lbs./day
or 350 mg/l (as sampled in LTMP)
Do I use 350 mg/l or 198 mg/l as my
Uncontrollable Load?

121
Uncontrollable Pollutant Load Confirm Sampling
Method Results

Which number makes sense? What is a typical
Uncontrollable value for BOD?
Should I use the Mass Balance Method number of
198 mg/L
or
the Sampling Method number of 350 mg/L
or
the literature value of 220 mg/l?
Wastewater Engineering, Metcalf Eddy, 3rd
Edition.

122
Mass Balance Vs. Sampling Method Comparison

Mass Balance Sampling Literature
198 mg/L 350 mg/L
220 mg/L
3082 lbs./day 5456 lbs./day
3429 lbs./day
use 3082 lbs./day (198 mg/L) as Uncontrollable
Load because
1) the average Influent BOD is only 3587 lbs./day
2) 198 mg/L of BOD makes more sense then 350 mg/L
Most of the influent is from uncontrollable
sources

or
or
123
Uncontrollable Sampling Troubleshooting

Sample location not really uncontrollable, i.e.
1 house and 27 restaurants
new subdivision (low flow toilets, no sewer
leaks)
No commercial and/or non-SIU
Inaccurate sample collection
May need 1 sampling point or a larger data set
Flow may be too low
BOD will degrade in the collection system

124
Uncontrollable Mass Balance Troubleshooting

Inaccurate flow or pollutant data
in particular- SIU flow data
Limited data set
Widely variable detection levels
Inflow and Infiltration
Degradation of the pollutant in the collection
system
Conservative/non conservative pollutant

Review SIU Uncontrollable and HWA.AT Spreadsheets
125

Determines the Amount of MAHL
Available to your Industries

126
Maximum Allowable Industrial Loading (MAIL)

MAIL MAHL- LUNC
MAIL Maximum Allowable Industrial Loading,
lbs./day
MAHL Maximum Allowable Headworks Loading,
lbs./day1
LUNC Uncontrollable Loading, lbs./day2
1 2) See the next slide for this information.

127
MAHL And Uncontrollable BOD Values Revisited

MAHL BOD 8,340 lbs./day
from Design Criteria
as determined earlier
minus
Uncontrollable BOD 3082 lbs./day
from the Mass Balance Method
as determined earlier
MAIL __________________

128
Maximum Allowable Industrial Loading for BOD

MAIL_BOD MAHL_BOD- LUNC_BOD
MAHL_BOD 8,340 lbs./day
LUNC_BOD 3,082 lbs./day
MAIL_BOD(8,340- 3082)
5,258 lbs./day
of BOD Available to SIUs (MAIL)

129
Maximum Allowable Industrial Loading (MAIL)For
Each POC
Review HWA.AT Spreadsheet!!
130

Allocating The MAIL To Your Industries

131
Sample AT- For Cadmium
See the next slide for this information
132
Maximum Allowable Industrial Loading (MAIL)For
Each POC
133
Over Allocated For Cadmium!
134
What Do I Do When Im Over Allocated?

Does this over allocation make sense?
Are you violating MAHL Criteria based on
1) NPDES/NC Water Quality Standards
2) Biological Inhibition
3) Sludge Criteria
If NO, then Reevaluate the MAHL

135
What Do I Do When Im Over Allocated?

Generally-
Are the Uncontrollable values appropriate?
Is the Removal Rate correct?
Specifically
Is Inhibition Limiting?
If yes Can you use site specific Inhibition
Criteria?
Is Sludge Limiting?
If yes, Can you perform the HASL Worksheet?
Can you lower SIU limits (pollutant or flow)?

136
What Do I Do When Im Over Allocated? EXAMPLE- Cd

For OZ Cadmium is limited by the Cumulative
Sludge Criteria
Is OZ violating their Land Application Program?1
Can we use the HASL?
1)TAB 2 - REF ANSWERS - Sludge Permit- Land
Application Summary

137

Headworks Addendum for Sludge Loading
(Updated January 2004)

138
HASL Worksheet

Re-evaluates MAHL for Sludge Criteria by taking
into consideration
Historical WWTF Performance Data,
Historical Sludge Report Data, and
Applicable Sludge Criteria.

Only applicable for pollutants over allocated
based on sludge criteria!
Only applicable for pollutants over allocated
based on sludge criteria!
139
HASL Worksheet

Three Steps to completing HASL
Cumulative Sludge Criteria (lb/acre) Check
Cumulative Sludge Criteria. If available land is
over 80 of criteria, you can not use HASL
worksheet to alleviate over-allocation due to
sludge standards.
Sludge Ceiling Criteria (mg/dry kg) Calculate
of Ceiling Concentration Limit based on maximum
concentration from sludge report. If ceiling
concentration is over 80 of criteria, you can
not use HASL worksheet to alleviate
over-allocation due to sludge standards.
Recalculate Sludge MAHL Using historical WWTF
influent and the of Ceiling Concentration
Limit, recalculate a new sludge MAHL.

140
What Do I Need For A HASL?

Copy of your current Sludge Permit
Copy of the current Annual Sludge Report
Historic WWTF Influent Data
HASL Worksheet and Calculations

141
HASL Step 1 - CadmiumCumulative Criteria

Check each POC to assure that the available land
does not exceed 80 of the Cumulative Loading
Rate.

For the Pretreatment World the most heavily
loaded field is the field with the highest
cumulative lbs/acre for that pollutant.
142
HASL Step 1 - CadmiumCumulative Criteria
For the Pretreatment World the most heavily
loaded field is the field with the highest
cumulative lbs/acre for that pollutant.

TAB 2 - REF. ANSWERS Annual Field Summary Form
TAB 2 - REF. ANSWERS -Land Application Permit

143
HASL Step 1 - CadmiumCumulative Criteria -
Answer
0.37 is much less then 80 Looks good for
Cadmium so far!!!
144
HASL Step 2 - Cadmium Sludge Ceiling Criteria
2. Calculate the of Ceiling Concentration
of Ceiling Concentration Limit

TAB 2 - REF. ANSWERS - Annual Residual Sampling
Summary Form
TAB 2 - REF. ANSWERS - Land Application Permit

145
HASL Step 2 - CadmiumSludge Ceiling Criteria -
Answer
2. Calculate the of Ceiling Concentration
3.6 is much less then 80 So can use HASL to
resolve over allocation for Cadmium!!!
146
HASL Step 3 - Cadmium Recalculate Sludge MAHL
A new Sludge MAHL is calculated using historical
WWTF influent and the of Ceiling Concentration
Limit.
147
HASL Step 3 - Cadmium Recalculate Sludge MAHL
Part 1
1. Calculate the Average Influent Loading

TAB 2 - REF. ANSWERS Removal Rates Summary
TAB 2 - REF. ANSWERS General Info.

148
HASL Step 3 - Cadmium Recalculate Sludge MAHL
Part 1 - Answer
1. Calculate the Average Influent Loading
149
HASL Step 3 - Cadmium Recalculate Sludge
MAHL Part 2

Calculate a new Sludge MAHL based on Historical
Influent Data and the Sludge Ceiling Limit is
calculated.

All values previously calculated

150
HASL Step 3 - Cadmium Sludge Ceiling Criteria
- Part 2 - Answer
151
Now What?

If there are sludge violations you can not use
the HASL Worksheet! Call DWQ!
If HASL indicates Flags, then you must do a
Metals Management plan - call DWQ!
If HASL is applicable, then input an x in the
appropriate cell of the HWA spreadsheet (MAIL
Calcs) to
Include the Sludge Ceiling MAHL from the HASL
worksheet in the HWA spreadsheet (Sludge Loading
Calcs)
Ignore the Cumulative Sludge MAHL values in the
HWA Spreadsheet
Select the Sludge Ceiling MAHL from the HASL
worksheet as the minimum sludge loading criteria
in the HWA Spreadsheet.

Review HWA HASL Spreadsheet!!
152
NEW AT For Cadmium- Using HASL MAHL in HWA
153
Over Allocated?- NO!

Do This For All POCs
A complete copy of the OZ HWA
can be found in the TAB 2 REF. ANSWERS - Final
HWA and AT Class Example
Any Questions?-Please Call

154
HWA FLOW CHART
Pass Thru
Removal Rates
MAIL
Inhibition
Sludge
Reduce SIU Limits?
Yes
5 years or major change to WWTP or new NPDES
permit
Finished
155
What To Submit to NCDENR?