# Presentation: 678098

## The Stage 1 Disinfectants/Disinfection Byproducts Rule

## Background

**Improve protection against risks from**
**Known DBPs**
**Unknown DBPs**
**Balance risks and benefits of**
**SWTR**
**IESTWR and LT1ESWTR**
**Pb & Cu Rule**
**Total Coliform Rule**

## General

**§141.2 Definitions**
**Enhanced coagulation**
**Enhanced softening**
**GAC 10**
**Haloacetic acids (five) (HAA5)**
**Maximum residual disinfectant level (MRDL)**
**Maximum residual disinfectant level Goal (MRDLG)**
**Subpart H systems**
**SUVA**
**Total Organic Carbon (TOC)**

**Notes:**
There are several important definitions found in the rule language. These include the following.

## MCLGs and MCLs

## MCLGs and MCLs (cont.)

## MCLGs and MCLs (cont.)

## MRDLGs and MRDLs

## § 141.130 General requirements

**Applicability**
**CWSs and NTNCWSs that add chemical disinfectants or deliver disinfected water**
**TNCWSs that add chlorine dioxide**
**Compliance dates**
**Subpart H serving 10,000 or more**
**3 years ****	****	****	****	****December 2001**
**All other systems**
**5 years****	****	****	****	****December 2003**
**Qualified personnel**

## § 141.132 Monitoring—DBPs

**Subpart H**
****** ****500-9,999**
**Subpart H**
**< 500**
**Ground Water**
**< 10,000**

**1/plant/qtr**
**1/plant/year**
**mo. warmest**
**water temp.**
**1/plant/year**
**mo. warmest**
**water temp.**

**Max. RT**
**Max. RT**
**Max. RT**

****** ****50% of MCLs**
**TOC ******** 4.0 mg/L**
**No reduced**
**monitoring**
****** ****50% of MCLs **
**(2 years)**
**or**
****** ****25% of MCLs**
**(1 year)**

**1/plant/year**
**mo. warmest**
**water temp.**
**1/plant/year**
**mo. warmest**
**water temp.**
**1/plant/3 years**
**mo. warmest**
**water temp.**

**System Type**

**Frequency**

**Location**

**Conditions**

**Frequency**

**Routine—TTHMs and HAA5**

**Reduced**

## § 141.132 Monitoring – DBP

**Chlorite (only for plants with chlorine dioxide)**
**Routine**
**Daily**
**At entrance to distribution**
**Monthly**
**Near 1st customer**
**Average residence time**
**Maximum residence time**
**Additional**
**If daily sample > MCL, monitor the following day**
**Reduced **
**1 three-sample set/quarter if no sample > MCL for 1 year**
**Revert to routine if any sample > MCL**

## § 141.132 Monitoring – DBP

** ****Bromate (only for plants with ozone)**
**Routine**
**1 sample/month/plant at entrance**
**Reduced**
**If average source water bromide is < 0.05 mg/L**
**1 sample/quarter/plant at entrance**

## § 141.132 Monitoring – Disinfectant Residuals

**Chlorine and chloramines**
**Routine**
**Same point and time as coliform**
**Subpart H systems may use results of monitoring under provisions of SWTR**
**Reduced**
**No reductions**

## § 141.132 Monitoring – Disinfectant Residuals

**Chlorine dioxide**
**Routine**
**Daily monitoring **
**at entrance to distribution system**
**Additional monitoring**
**When any daily sample > MRDL**
**Reduced**
**No reductions**

## § 141.132 Monitoring – Monitoring Plans

**Each system must develop and implement a monitoring plan**
**Available 30 days after compliance date**
**Subpart H systems > 3,300 must submit with first report**
**Plan must include:**
**Locations and schedules**
**Compliance calculation methodology**
**Entire distribution system (for consecutive systems)**

## § 141.133 Compliance – DBP

**TTHM and HAA5**
**Systems monitoring quarterly**
**Based on running annual arithmetic average**
**Computed quarterly**
**Of quarterly arithmetic averages**
**Systems monitoring less frequently**
**Compliance based on average of samples**
**If average > MCL, increase monitoring to quarterly**
**Systems on reduced monitoring**
**When annual average > MCL**
**Revert to routine**
**No violation**

## § 141.133 Compliance – DBP

**Bromate**
**Running annual arithmetic average,**
**Computed quarterly**
**of monthly samples (or averages)**
**Chlorite**
**Arithmetic average of **_**each**_** 3-sample set**

## § 141.133 Compliance – Disinfectant Residuals

**Chlorine and chloramines**
**Running annual arithmetic average**
**computed quarterly, of all samples**
**If a system switches disinfectants the results of both must be used for compliance calculations**
**Chlorine dioxide**
**Acute violations based on samples collected on consecutive days**
**Entrance sample > MCL and 1 or more distribution sample(s) > MCL**
**Nonacute violations based on consecutive daily samples at entrance (2 samples > MCL and all distribution samples < MCL)**

## § 141.135 Treatment Technique For DBPP

**Designed to**
**reduce production of known and unknown DBPs**
**Applicability**
**Subpart H systems using conventional treatment**
**Requirements**
**Meet one of the alternative compliance criteria or**
**Achieve required TOC removals or**
**Get waiver from State**

## § 141.135 Treatment Technique For DBPP

**Conventional plants monitor for**
**TOC ****	****	****	****	****(Raw and Finished)**
**Alkalinity ****	****	****	****(Raw)**
**SUVA (optional)****	****	****(Raw and Finished)**
**UV****254**
**DOC**
**Mg Hardness (optional)****	****(Raw and Finished)**
**	****	****(Softening systems only)**

## § 141.135 Treatment Technique For DBPP

**To achieve compliance systems must do one of the following**
**Meet one or more alternative compliance criteria         ****	****	**
**Achieve Step 1 TOC removal requirements**
**Establish and achieve Step 2 TOC removal requirements **
**Obtain a State waiver of the requirements**

**Notes:**
Steps 1 and 2 are “enhanced coagulation and enhanced softening” requirements.

EPA expects very few systems will need to go through the Step 2 procedure.  Fewer yet will go through Step 2 and achieve a State waiver for having TOC that is not amenable to enhanced coagulation.

## § 141.135 Treatment Technique For DBPP

**Alternative Compliance Criteria **
**1.  Source water TOC < 2.0 mg/L (annual average) **
**2.  Treated water TOC < 2.0 mg/L (annual average**
**3.  Source water SUVA ******** 2.0 L/mg-m (annual average)**
**4.  Treated water SUVA ******** 2.0 L/mg-m (annual average)**
**5.  Source water TOC < 4.0 mg/L, alkalinity > 60 mg/L and**
**TTHM/HAA5 ******** 50% of MCLs; or,**
**clear and irrevocable financial commitment to technologies that limit TTHM/HAA5 to ******** 50% of MCL**
**technologies operational within 6 1/2 years**
**6.  TTHM ******** 50% of MCLs and using ****only chlorine**

## § 141.135 Treatment Technique For DBPP

**Additional alternative compliance criteria for ****softening systems **
**1.  Treated water alkalinity < 60 mg/L**
**2.  Removal of 10 mg/L Mg hardness**

**Notes:**
If a system meets any one of these criteria, it does not have to implement enhanced coagulation/enhanced softening.
The clear and irrevocable financial commitment is addressed in the guidance manual. In general, decision must be made by compliance date and completed by 78 months.
Technologies include membranes, GAC, ozone, chlorine dioxide.

## § 141.135 Treatment Technique For DBPP

**Enhanced coagulation and ****enhanced softening**
**Step 1: Required removal of TOC**

**Notes:**
If a system does not meet any of the previous criteria, it must do enhanced coagulation to meet the TOC removal targets in this table (also referred to as the “3X3 matrix.”
The Technologies Working Group and FACA committee examined data from recent studies to develop the removal percentages. The 3X3 matrix reflects the best judgment of the group based on available data of what removal was achievable (Consensus of stakeholders across the board).
The data showed that it was more difficult to remove TOC in high alkalinity, low TOC waters.  The ease of TOC removal is directly related to increased TOC in the raw water and decreased raw water alkalinity.
Thus, systems with high alkalinity and low TOC have lower removal targets than lower alkalinity/high TOC waters.  For example, systems with alkalinity above 120 mg/L and TOC of 3.0 mg/L are required to remove 15% of the TOC.
Systems with alkalinity of 30 mg/L and TOC of 9.0 mg/L are required to remove 50% TOC.
Systems doing enhanced softening need to meet the removals in the far right column.  EPA believes that softening systems will be able to meet either these removal requirements or one of the alternative compliance criteria.

## § 141.133 Compliance – DBP Precursors

**For each of 12 months**
**Determine actual TOC % removal **
**Determine required TOC % removal **
**Divide actual by required **
**Add 12 results together **
**Divide by 12**
**Result must be ******** 1.00**
**System may assign monthly value of 1.0 for any month one of the alternative compliance criteria is met**

## § 141.133 Compliance – DBP Precursors

**Compliance Calculations**

- Month
- Jan.
- Feb.
- Mar.
- Apr.
- May
- Jun.
- Jul.
- Aug.
- Sep.
- Oct.
- Nov.
- Dec.

- _A_
- Treated TOC
- (mg/L)
- 4.6
- 4.0
- 4.4

- _B_
- Source TOC
- (mg/L)
- 8.2
- 6.1
- 6.2

- _C_
- % removed
- (1-A/B) x 100
- 44
- 34
- 29

- _D_
- Source Water
- Alkalinity (mg/L)
- 70
- 75
- 85

- _E_
- Required TOC
- Removal (%)
- 40
- 35
- 35

- _F_
- C/E
- 1.10
- 0.94
- 1.03
- 1.07
- 0.98
- 1.24
- 1.10
- 1.07
- 1.02
- 1.10
- 0.98
- 0.83

**If average is******** 1.0, **
**the PWS is ****in compliance**

**       ******** ****(F) ****= 12.48**
** ****12.48/12= 1.04        **

## SIMULTANEOUS COMPLIANCE ISSUES

**SWTR and LT1ESWTR**
**TOTAL COLIFORM RULE**
**LEAD and COPPER RULE**

## SWTR and LT1ESWTR

**Microbial inactivation**
**Contact time**
**Concentration**
**Disinfectant type**
**pH**
**Particulate removal**
**Improved with enhanced coagulation/softening**
**Not necessarily true**

## Total Coliform Rule

**Changing secondary disinfectant to chloramine**
**Nitrification**
**Ammonia --- Nitrifying bacteria**
**Nitrite----Nitrate **
**Loss of chlorine residual**
**HPC**
**Regrowth**
**Coliform**
**Recommendations**
**Higher residuals**
**Higher chlorine:ammonia ratios**
**Periodic switch to free chlorine**
**More frequent turn-over in storage**

## Total Coliform Rule

**Change to ozone as primary disinfectant**
**Production of AOC**
**Regrowth**
**Recommendation**
**Biologically active filters**
**2 minutes EBCT may remove up to 90% of AOC**

## Lead and Copper Rule

**Enhanced coagulation****	**
**pH**
**Alkalinity**
**Changes in chloride and sulfate concentrations**
**NOM**
**Corrosion**
**Addition of polyphosphate and/or orthophosphate (Pb/Cu Rule)**
**Regrowth**
**Slight turbidity increase**

## Operational Issues

**Corrosion of treatment facility**
**Staff training**
**Waste residuals**
**Volume**
**Dewatering****	**
**Tastes and odors**