CHLORAMINES: COMMUNICATION, NITRIFICATION, AND KNOWLEDGE GAPS · Source: Krasner et al. (2013) Formation, Precursors, Control and Occurrence of Nitrosamines in Drinking Water: A review

© 2014 Water Research Foundation. ALL RIGHTS RESERVED.© 2014 Water Research Foundation. ALL RIGHTS RESERVED. No part of this presentation may be copied, reproduced, or otherwise utilized without permission.

CHLORAMINES: COMMUNICATION, NITRIFICATION, AND KNOWLEDGE GAPS

Southwest Section AWWA Annual Conference,Tulsa, Oklahoma, October 14, 2014

Frank Blaha and Kenan Ozekin, Ph.D., Water Research Foundation

© 2014 Water Research Foundation. ALL RIGHTS RESERVED.

Why This Presentation?

Chloraminationuse increasing

~1,300 utilitiesServing 68 million

concerns remain


Take-Home Messages• Nitrification

— Chemistry and biology— Number of useful approaches to preventing/recovering — Manageable

• Nitrosamines— Waters vary in ability to form nitrosamines— Pre-oxidation beneficial— Treatment chemicals a possible culprit

• Communications— Utilities a “trusted” source— Start early and be prepared— Tailor messages for different audiences— Be open, respectful, helpful, knowledgeable


About the Foundation


Foundation BackgroundResearch Cooperative

― Sponsor research

― Communicate knowledge

Volunteers and utility involvement are keyPrimarily supported by

utilitiesSome federal and

partnership money


Our Work• Primarily applied research, for use by utilities • Extensive work to identify important projects

— Extensive volunteer involvement & input• Three primary funding mechanisms• Once funded volunteers provide ongoing peer

review— Volunteers make most of the important decisions— WRF ensures the administrative issues are addressed

• Many workshops, webcasts, related activities• ~1,250 completed projects, ~250 active projects


Breakpoint Chlorination


Chloramination is not new


Increased Use of ChloramineComparison data between 2007 and 2010

Total water systems Total States

Population Served

2007 2010 % Change 2007 2010 2007 2010

Nation 944 1298 +37 36 43 54,083,661 68,397,713

Texas 282 435 +54 11,141,645 12,504,394

Florida 138 197 +43 8,914,118 10.351.719

California 45 54 +20 6,676,183 10,771,907

Li, C., Trends and Effects of Chloramine in Drinking Water. Water Conditioning & Purification 2011.


Chloramine Use in the US


WRF is Providing You Knowledge


NH3 NO2 NO3

Ammonia Nitrite Nitrate

Nitrification

Nitrosomonasbacteria(slow)

Nitrobacter bacteria(slower)


Occurrence• 1996 JAWWA Article 67 responding utilities

—63% experienced some nitrification—25% experienced severe nitrification—90% of systems with signs of had 2 mg/l or less

of total chlorine residual

• 2004 WRF Report with 56 responding utilities—48% experienced nitrification—25% experienced to or more times per summer—48% had established “nitrification plans”


Factors Promoting Nitrification

Sufficient Ammonia

Low Chlorine Residual

Long Stagnation Time

Warm Temperature

High Organic Carbon

Bacterial Hiding Places


Distribution System


Impact of Chlorite

(Zhu et al, 2010)


Chlorination & Chlorine Burn• Mixed practices- some never do, some do

annually (some states require)• Can be done in winter or prior to event

(summer/fall)• Common dose is 1.0 to 2.0 mg/L• It is effective – no nitrification during free

chlorination• Disadvantages – increase in total coliform,

increase in HPC, increase DBPs, increase T&O, nitrification will return

• Also, can increase chloramine residual up to 3.5/4.0 mg/l

Source: Skadsen, J, 2011


Summary of N-DBP Formation Pathways


Help in Managing Chloramine DBPs is Available


Managing DBPs is a Balancing Act


High-Level NDMA concerns

• UCMR2 Data – 27% of public water systems show some detection of NDMA—Max 630 nanograms/liter—Detection limit is 2 nanograms/liter—Median 4 nanograms/liter

• While low levels, concerns are real due to increased toxicity compared to THMs/HAAs –give numbers

• Solutions are real too – although some still under development


EPA Considering Nitrosamine Regulations• Toxicity

• N-nitrosamines in drinking water• Disinfection byproducts associated with chloramine disinfection• Regulation

• California 10 ng/L notification level – three N-nitrosamines• EPA considering regulation as a group

• Contaminant Candidate List 3 (2009) – five N-nitrosamines• Unregulated Contaminant Monitoring Rule 2

• Out of 6 N-nitrosamines, only NDMA commonly detected

Drinking water: 10-6 lifetime cancer risk

DBPs NDMA NDEA NDPA NPYR CHBr2Cl CHBr3 TCAA

Conc. (ng/L) 0.7 0.2 5 20 400 4000 500

This image cannot currently be displayed.

NDMA


Precursors

• A prime area of Foundation Research—Include NDBPFPs details where available—Wastewater vs. pristine water:

unacknowledged potable reuse—Treatment chemicals (polyDADMAC)—Cation exchange resins formulated using

amine groups


NDBP Prevention/Control

• Pre-oxidation – ozone, chlorine dioxide, free chlorine

• Chloraminate after filtration—Chlorine before ammonia—Elevated pH—Minimize free chlorine to ammonia ratio, but

consistent with nitrification concerns• Alternative chemicals (polyDADMAC, etc.)

for treatment or optimize those used • Corn starch, potato starch, chitosans


Phosphonium-Based polyDADMAC

• Amine to Phosphine-Based polyDADMAC Coagulant

• Outcomes— Coagulation performance comparable to amine-based

polyDADMAC— Avoids formation of nitrosated compounds— Maintains existing utility handling infrastructure

N

R R

CH3H3Cn

PCH3H3C

RR


Drinking Water Processes to Control NDMA Formation

Treatment Importance

Polymer Optimization High

Precursor Pre-oxidation High

Alternative Polymer High

Activated Carbon High

Riverbank Filtration Moderate

Modify Chloramination Protocol Moderate

Biofiltration Low/Moderate

UV Treatment Low

Anion Exchange Low

Coagulation/Softening LowSource: Krasner et al. (2013) Formation, Precursors, Control and Occurrence of Nitrosamines in Drinking Water: A review. Water Research

Polymer OptimizationReduction in polyDADMAC dosage can reduce, but not eliminate NDMA formation

Precursor Pre-oxidation • Involves risk tradeoffs

because increasing pre-oxidant exposure promotes the formation of DBPs associated with each pre-oxidant

• Ozone most effective, followed by chlorine

• UV treatment only partially effective at advanced oxidation process fluence

• Chlorine dioxide relatively ineffective

Alternative PolymerNearly all cationic polymers currently in use will contribute to nitrosamine formation because they are amine-based. Epi-DMA polymers are more potent precursors than polyDADMAC. Polyacrylamide has much less precursors than PolyDADMAC

Activated carbon• Activated carbon is more

efficient at removing NDMA precursors than TOC in limited studies

• The ability to remove precursors for other nitrosamines is limited to one study in China

Riverbank FiltrationLimited evidence shows that riverbank filtration can remove NDMA precursors

Modify Chloramination Protocol• Minimizes dichloramine, the

active inorganic chloramine for promoting nitrosamine formation

• Involves a hydraulic mixing phenomenon. Needs more pilot or full-scale testing to characterize importance

BiofiltrationBiofiltration may remove NDMA precursors, but can also increase NDMA formation by transforming some precursors into more potent forms

UV Treatment • Full-scale applications

ongoing for hazardous waste treatment and wastewater recycling applications.

• Destroys nitrosamines, but only modest destruction in nitrosamine precursors (see pre-oxidation)

• Nitrosamine formation would continue from remaining precursors within chloraminated distribution systems

Anion Exchange• Anion exchange resins can

increase nitrosamines• The ability of anion exchange

resins to remove nitrosamine precursors is unclear

Coagulation/SofteningNeither process significantly removes NDMA precursors


Examples of the Impact of Polymer Usage on Precursor Loading

0

5

10

15

20

25

30

35

40

45

50

Plant A: Nopolymer

Plant B:Polyacrylamide

Plant C:PolyDADMAC

Plant D: Polyamine

ND

MA

FP (

ng/L

)

Raw Water Treated Water-11 %-11 %

- 10%

+ 86 % + 394%


Due to Health Effects


Communication Issues

• Not the typical strength of a utility• Identify positive aspects of public

perceptions of utility information• Anti-chloramine groups and some

anecdotal tales of experiences• Provide names, websites – primarily from

AWWA publication• Discuss their tenacity and that $ available


Communication Solutions

• Communicate early, often, long, be trusted source

• Be a technical expert consistent with audience

• Open, honest• Message tailored for different groups• Start two years early• Use details AWWA guidance on

Communications


Research Agenda (Sept 2013)Year Project

FA ObjectivesPrecur

sorsTreatmen

tOther

Impacts

2012 Investigating Coagulant Aid Alternatives to PolyDADMAC X X

Nitrosamine Occurrence Survey X X X

2013

Relative Importance and Contribution of Anthropogenic and Natural Sources of Nitrosamine Precursors

X X X

Unintended Consequences of Implementing Nitrosamine Control, Phase 1-Desktop study X X X

2014

Unintended Consequences of Implementing Nitrosamine Control, Phase 2 - Cost of Implementation (WiTAF Partnership)

X X X

Formation Kinetics of Nitrosamines

Impact of Oxidation and Chloramine Application on Polymer Effectiveness and Nitrosamine Formation

X X


Research Agenda – Sept 2013 (cont'd)Year Project

FA ObjectivesPrecur

sorsTreatmen

tOther

Impacts

2015 Significance of Sampling Locations X X X

Economic Analysis: Cost of Compliance X X

2016Reactor Mixing Configuration X

Biological Treatment Approaches for the Minimization/Control of Nitrosamines X X

2017Knowledge Synthesis and Recommendation to Utilities X X X


Summary• Chloramination a valuable option• Considerable knowledge gained,

concerns remain• WRF Research should help fill

knowledge gaps on chloramine use• Key resources:

• Website• Reports & Researchers• Research managers on staff

© 2012 Water Research Foundation. ALL RIGHTS RESERVED.© 2012 Water Research Foundation. ALL RIGHTS RESERVED. No part of this presentation may be copied, reproduced, or otherwise utilized without permission.

Thank YouFrank J. Blaha, P.E.

Senior Account Manager [email protected]

Documents

CHLORAMINES: COMMUNICATION, NITRIFICATION, AND KNOWLEDGE GAPS · Source: Krasner et al. (2013) Formation, Precursors, Control and Occurrence of Nitrosamines in Drinking Water: A review