The stage 2 d dbpr and lt2eswtr where are we going
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The Stage 2 D/DBPR and LT2ESWTR--Where are We Going. J. Alan Roberson, P.E. Director of Regulatory Affairs AWWA-Washington, DC. Outline. Overview of the M/DBP Cluster Overview of IESWTR and Stage 1 D/DBPR Preliminary ICR Data Analysis Where the LT2ESWTR and Stage 2 D/DBPR May Be Going.

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The stage 2 d dbpr and lt2eswtr where are we going

The Stage 2 D/DBPR and LT2ESWTR--Where are We Going

J. Alan Roberson, P.E.

Director of Regulatory Affairs

AWWA-Washington, DC


Outline
Outline

  • Overview of the M/DBP Cluster

  • Overview of IESWTR and Stage 1 D/DBPR

  • Preliminary ICR Data Analysis

  • Where the LT2ESWTR and Stage 2 D/DBPR May Be Going


Microbial disinfection by products m dbp cluster
Microbial/Disinfection By-Products (M/DBP) Cluster

  • Balancing of acute microbial risks with chronic chemical risk a unique regulatory challenge

  • EPA used negotiative processes instead of traditional proposal and public comment

    • ‘92 & ‘93 negotiated rulemaking (Reg-Neg) led to ‘94 proposals for ICR, Stage 1 D/DBPR , & IESWTR

      • ICR data would be used for selection of IESWTR option

        • ICR delayed due to multiple problems

        • ICR monitoring started in July, 1997 instead of October, 1994

    • Led to ‘97 Federal Advisory Committee (FACA)


1997 federal advisory committee faca process
1997 Federal Advisory Committee (FACA) Process

  • Looked at components of ‘94 proposals

    • What can we use to meet statutory deadlines?

  • FACA met through March-July, 1997

    • Agreement in Principle signed in July, 1997

  • Notice of Data Availability published in Federal Register on March 31, 1998

    • IESWTR focused on new turbidity standards

      • Profiling/benchmarking provisions

    • Minor changes to Stage 1 D/DBPR


The first regulations in the m dbp cluster
The First Regulations in the M/DBP Cluster

  • Stage 1 D/DBPR & IESWTR published in the Federal Register on Dec. 16, 1998

    • New MCLs and treatment techniques

    • Optimizing existing treatment rather than major shifts to alternative technologies

    • Costs not insignificant--$1 Billion/year

    • Compliance in 2001 & 2003

  • LT1ESWTR for systems <10,000 people

    • Final in 2000 and compliance in 2003


Stage 1 d dbpr
Stage 1 D/DBPR

  • Lowers existing MCL for TTHM from 0.10 mg/l (100 ug/l) to 0.080 mg/l (80 ug/l)

    • Applies to all systems (except for transients)

      • Phased compliance for small systems

  • Establishes new MCLs

    • HAA5--0.060 mg/l (60 ug/l)

      • MCAA, DCAA, TCAA, MBAA, DBAA

    • Chlorite--1.0 mg/l

    • Bromate--0.010 mg/l (10 ug/l)


Stage 1 d dbpr cont
Stage 1 D/DBPR (cont.)

  • Establishes Maximum Residual Disinfectants Levels (MRDLs) for common disinfectants

    • Chlorine & chloramine--4.0 mg/l (as Cl2)

    • Chlorine Dioxide--0.8 mg/l (as ClO2)

      • Daily monitoring for chlorine dioxide & transients

    • MRDLs can be exceeded for short periods

  • Enhanced coagulation and softening treatment technique for TOC removal

    • Step 1 matrix & Step 2 process (with “outs”)


Ieswtr
IESWTR

  • Surface water systems serving >10,000 people

  • 2 logs Cryptosporidium removal credit for conventional treatment

  • Lowered combined filter turbidity

    • From <0.5 NTU to <0.3 NTU 95% of the time

    • From <5 NTU to <1 NTU as a maximum

      • Monitor treatment processes carefully

    • Compliance still based on 4-hr. intervals


Ieswtr cont
IESWTR (cont.)

  • Individual filter turbidimeters

    • Readings every fifteen minutes

  • Exceptions reported to state when:

    • >1.0 NTU for any 2 15-min. readings or >0.5 NTU for any 2 readings after 1st 4 hours

      • Develop filter profile within 7 days

    • Self-assessment for >1.0 NTU for 2 15-min. readings at any time in 3 consecutive months

    • Comprehensive Performance Evaluation for >1.0 NTU in 2 consecutive months


Ieswtr cont1
IESWTR (cont.)

  • Profiling & Benchmarking

    • TTHM >0.064 mg/l or HAA5>0.048 mg/l

      • Develop profile-daily inactivation for one year based on daily measurements of operational data

    • Calculate benchmark & consult with State

      • Lowest monthly average inactivation

  • Cover new finished water reservoirs

  • Sanitary survey requirements


Information collection rule
Information Collection Rule

  • DBP and microbial monitoring data to be used for the Stage 2 D/DBPR & LT2ESWTR

  • 18 months of data from the systems serving >100,000 people--296 utilities--501 plants

    • July, 1997 to December, 1998

    • Data is currently being analyzed

      • A lot more work than initially thought

  • Bench- and pilot-scale treatment studies for systems with high levels of DBP precursors


Icr data analysis tools
ICR Data Analysis Tools

  • ICRFED--the very large Federal database for all monitoring & engineering data

  • Auxiliary databases developed for more relevant data (Access-based)

    • Available on CD from EPA

  • Stage 1 baseline & Stage 2 options

    • Surface Water Analytical Tool (SWAT)

      • Results extrapolated for medium & small systems

    • Expert panel for large groundwater systems


Auxiliary database relationships

Aux 1 - Primary Auxiliary Database

Utility and Plant Level Data

Sampling Results Data

Treatment Operation Data

Auxiliary Database Relationships

Query

Tool

Aux 2

CT & Disinfectant Decay

Aux 4

Sludge Production .

Aux 6

Distribution System DBPs

Aux 8

Model Interface/ Database

Aux 3

Enhanced Coagulation

Aux 5

Washwater Return


Surface water analysis tool data process overview

Model Outputs

Model Inputs

Aux1

Graphical User Interface (GUI)

SWAT/ Model

Aux8

Selection Criteria

Surface Water Analysis Tool Data Process Overview



Historical comparison of tthm cumul freq distributions
Historical Comparison of TTHM Cumul. Freq. Distributions Levels

  • AWWARF Survey 1984-86

    • 727 utilities

  • NOMS--1976-77

    • 450 utilities

  • NORS--1975

    • 490 utilities

  • ICR--three quarters of data

    • 469 plants; 1002 quarterly averages







Microbial monitoring
Microbial Monitoring Levels

  • Source water monitoring

    • Giardia, Cryptosporidium, viruses, & coliforms

      • Virus monitoring “out”

  • Finished water monitoring

    • Giardia & Cryptosporidium monitoring based on triggers in source water monitoring

      • Not many plants monitored finished water

        • Handful of detects in finished water


Microbial monitoring cont
Microbial Monitoring (cont.) Levels

  • Cryptosporidium results (total)

    • 93% non-detects

      • Higher detections in flowing streams versus reservoirs

      • Supplemental survey results--higher detectsions

  • Giardia results (total)

    • 82 % non-detects

    • Similar higher detections in flowing streams

  • Virus results--77% non-detects


Cryptosporidium results percentage non detects 18 months icr data
Cryptosporidium LevelsResultsPercentage Non-Detects--18 Months ICR Data


Stage 2 d dbpr lt2eswtr
Stage 2 D/DBPR & LT2ESWTR Levels

  • Part of the ‘92-’93 Reg-Neg agreement

    • EPA committed to meeting their deadlines

  • How far do we need to go beyond the Stage 1 D/DBPR & IESWTR?

  • Negotiations April, 1999-July, 2000

    • New health effects data & ICR data will be a key part of the negotiations

    • Proposal in early 2001

    • Final in May, 2002


The possible future for the stage 2 d dbpr lt2eswtr
The Possible Future for the Stage 2 D/DBPR & LT2ESWTR Levels

  • Major changes to the Stage 1 rules

    • Single Maximums

    • Cryptosporidium inactivation requirement

      • Inactivation based on additional monitoring?

      • 1 log additional for systems on flowing streams

  • Minor changes to the Stage 1 rules

    • Shaving peak DBP levels

    • Distribution systems??

      • States requirement for cross-connection controls


Potential stage 2 d dbpr lt2eswtr options
Potential Stage 2 D/DBPR & LT2ESWTR Options Levels

  • DBP options

    • 80/60 annual average of the maximum

      • Similar to location running annual average

    • Single max.--80/60 & 40/30 as MCLs and 120/90 as an Action Level (combinations?)

    • Bromate at either 10 ppb or 5 ppb

  • Cryptosporidium inactivation

    • 0, 0.5 log, and 2.0 log requirement

    • Ultraviolet (UV) light treatment on and off


The revised matrix 41 swat runs
The Revised Matrix-- Levels41 SWAT Runs


Comparison of raa lraa and aam from icr tthm data cl2 plants
Comparison of RAA, LRAA Levelsand AAM from ICR TTHM Data--Cl2 Plants


Comparison of raa lraa and aam from icr tthm data clm plants
Comparison of RAA, LRAA Levelsand AAM from ICR TTHM Data--CLM Plants


Raa equivalencies based on icr plant data
RAA Equivalencies LevelsBased on ICR plant data


80 60 raa equivalencies based on icr plant data
80/60 RAA Equivalencies LevelsBased on ICR plant data


Elements of potential microbial framework
Elements of Potential Microbial Framework Levels

  • Treatment Characterization

  • Characterize source water

    • Determine whether additional Cryptosporidium monitoring is necessary

    • Monitoring criteria for estimating mean Cryptosporidium concentrations in source water

  • Criteria for classifying potential exposure

    • Using mean Cryptosporidium concentration and treatment characterization for plant

  • Criteria for mitigating potential exposure

    • Based on watershed and/or treatment control measures


Treatment characterization
Treatment Characterization Levels

  • Characterize existing treatment

  • Compare to toolbox

  • Determine if adequate and whether further action is necessary. (see toolbox)


Characterize source water determine if cryptosporidium monitoring is needed
Characterize Source Water - Determine if LevelsCryptosporidium monitoring is needed

  • Use one or more of following: fecal coliform, E.coli , Total coliform, turbidity, as indicator(s) of challenged watershed, and/or watershed characteristics (a watershed index)

    • If indicator(s) (possibly a mean value) is below a critical level, system would be below Crypto occurrence level of concern

  • Acceptable misclassification rates a major issue


The stage 2 d dbpr and lt2eswtr where are we going

Vulnerability Index Levels

Correct

Incorrect of Concern

Protective


Characterize source water monitoring criteria for estimating means
Characterize Source Water - Monitoring Criteria for Estimating Means

  • Suggested conditions: 24 monthly samples (2 years)), at least 10L/sample, 40% mean recovery, 50% CV, approximately $500./sample)

  • Concerns: high costs (utilities and states), method is not approved, interpretation of results, high burden on small systems, does not measure infective Crypto, not necessarily capturing peak events

  • Benefits: most direct way of determining relative levels of Crypto in the sourcewater


Characterize source water monitoring criteria for estimating means1
Characterize Source Water - Monitoring Criteria for Estimating Means

  • Plants that must monitor would monitor monthly for Cryptosporidium in source water at intake of each plant

    • Method 1623 (or equivalent) by approved labs

  • At the end of 2 years, systems would calculate

    • option 1: mean value

    • option 2: highest running annual mean

  • Systems would use mean concentration of each plant to classify potential exposure


The stage 2 d dbpr and lt2eswtr where are we going

Classifying Potential Categories Estimating MeansDistinguish relative amounts of Cryptosporidium in source water

Plant Highest Running Action to Reduce

Category Annual Mean Exposure

A < 0.01/L No Action

B > 0.01/L to < 0.1/L No Action/“Toolbox ”

C >0.1/L to < 1.0/L “Toolbox”

D >1.0/L “Toolbox ”


Treatment toolbox options
Treatment Toolbox Options Estimating Means

Challenges = (1) assigning category shift values and

(2) implementation transaction costs for utilities and States





Conclusions
Conclusions Estimating Means

  • EPA is going to propose a rule in early 2001

    • FACA will have to scramble to complete their negotiations by July, 2000

  • Most everyone has some concern about high single DBP values

  • Most everyone has some concern about systems “vulnerable” to microbial contamination