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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

  • 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)
    • 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”)
  • 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



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


Graphical User Interface (GUI)

SWAT/ Model


Selection Criteria

Surface Water Analysis Tool Data Process Overview
historical comparison of tthm cumul freq distributions
Historical Comparison of TTHM Cumul. Freq. Distributions
  • 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
  • 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.)
  • 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
stage 2 d dbpr lt2eswtr
  • 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
  • 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
  • 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
elements of potential microbial framework
Elements of Potential Microbial Framework
  • 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
  • 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 Cryptosporidium 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

Vulnerability Index


Incorrect of Concern


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

Classifying Potential CategoriesDistinguish 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

Challenges = (1) assigning category shift values and

(2) implementation transaction costs for utilities and States

  • 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