Phil Brandhuber PhDHDR

Rengao Song PhDLWC

Sources and Fate of Chromium in Drinking Water Systems

CA – NV Section Fall Conference October 2, 2013

Today’s Presentation

WaterRF 4449 Project- Tailored Collaboration with Louisville Water Corporation

(LWC)

LWC Case Study- Motivation for much of the Tailored Collaboration

WRF 4449 Project Objectives

Measure chromium sources and sinks - Treatment plants - Distribution systems

Bench level evaluation of reduction coagulation filtration (RCF) process- Multiple source waters- Ferrous/ferric blends

Develop chromium control approaches - Develop specific chromium control strategies for

participating utilities

Project Team

Sponsoring Utility

- Louisville Water Company

Participating Utilities

- Madison Water Utility

- Tulsa Municipal Utility Authority

- City of Norman, OK

- San Jose Water Company

Investigators

- PI => Phil Brandhuber PhD (HDR)

- Co-PI => Rengao Song PhD (LWC)

Research Manager

- Mary Smith

Chromium isn’t Unique to California(!)

Location of participating utilities

Reference USEPA

Characteristics of Participating Utilities

Utility Water source Infrastructure Treatment Type Anticipated

CrVI LevelsLouisville

Water

Company, KY

Ohio River 2 WTPs Conventional softening, river

bank filtration, chloramine

residual

Low

City of

Norman, OK

Lake

Thunderbird,

Garber-Wellington

Aquifer

1 WTP

36 wells

SW: Conventional softening

GW: Arsenic treatment for 3

wells, no treatment for the rest.

Chlorine residual.

Elevated

City of Tulsa,

OK

Lake Oologah,

Lake Eucha,

Lake Spavinaw

2 WTPs Conventional with GAC

Chlorine residual.

Low

San Jose Water

Company , CA

Groundwater

Surface water,

Purchased water

2 WTPs

100 wells

Chloramine or chlorine residual. Elevated

City of

Madison, WI

Groundwater 23 wells Chlorine residual; fluoride

addition

Elevated

Low : < 1 ppb

Elevated: ≥ 1 ppb

Chromium Mass Balance in Water System

Factors Influencing Speciation in System

Differences Between Plant and Distribution System

Raw

Water

Treatment

ChemicalDistributed

Water

Waste

Short time periods

Many chemicals

Large changes to equilibrium

Plant sampling

Distributed

WaterRaw Water

Long time periods

Large surface areas

Moving to equilibrium

Distribution system sampling

What Factors May Impact Cr Fate or Speciation?

Treatment Plant Distribution System

Oxidants

Treatment

Chemicals

Treatment

Processes

Treatment

Residuals

Disinfectant

Residual

Water Age System

Materials

Ozone

Chlorine

Chloramine

Permanganate

Chlorine

dioxide

Ferric Chloride

Ferric sulfate

Lime

Alum

Conventional

Softening

NF/RO

membrane

Ozone

generation

Chlorine

dioxide

generation

Filter

Backwash

Membrane

Concentrate

Sludges

Recycle water

Chlorine

Chloramine

With and

without

boosting

EPDS

ART

MRT

Ductile iron

Cast iron

AC

PVC

Plan for Source and Sinks Sampling

Similar approach as

McNeill and McLean

Repeat quarterly

over 1 year period

Plant sampling

- LWC

- Tulsa

DS sampling

- Norman

- Madison

- San Jose

RCF Bench Testing

Take advantage of range of water qualities available

from participating utilities

Perform jar tests

- Ferric/ferrous mixes

- Aeration requirements

- Presence of oxidants

- Performance predictions

Chromium Control Plan

“Top level” assessment of

Cr(VI) treatment impact

Assess (desk top)

- Technology

- Approach

- Cost

Insights into treatment

approach for distributed

source systems

Two water treatment plants:- 180 MGD Crescent Hill WTP: Conventional treatment using

Ohio River as source water

- 60 MGD B. E. Payne WTP: River Bank Filtration (RBF) of Ohio River water with conventional treatment and lime softening

- Both plants use chloramines as secondary disinfectant

Not concerned about Cr(VI) until release of EWGReport in 2010

Case Study - Louisville Water Company

B. E. Payne Plant Treatment Process

Sample Date Jan, 2011 April, 2011 July, 2011

Source RBF/River Blended 100% RBF 100% RBF

Location of lime

addition

Prior to softening

basin

Prior to softening

basinHead of plant

Raw (RBF) <0.02 <0.02 <0.02

After lime

addition0.14 0.27 0.03

After chlorine

addition0.19 0.35 0.09

Finished 0.22 0.35 0.04

Distribution

system0.27 0.35 0.04

BEP Cr(VI) Sampling

Cr(VI) in ug/L

Jar Test Cr(VI) Increase Related to Lime Addition

0

0.05

0.1

0.15

0.2

0.25

RBF RBF + 200# Lime

RBF + 400# Lime

RBF + 600# Lime

RBF + 600# Lime +3 ppm Cl2

BEP Finished

Cr(

VI)

(u

g/L

)

# per million gallons treated

Jar TestAdd a Ferrous Reductant to the System

Sample

Cr(VI) under anoxic

conditions

(DO<1ppm),

ug/L

Cr(VI) under oxic

conditions,

ug/L

RBF <0.02 <0.02

RBF+600# Lime 0.14 0.12

RBF+600# Lime

+20# FeCl2<0.02 <0.02

RBF+600# Lime

+40# FeCl2<0.02 <0.02

RBF+600# Lime

+60# FeCl2<0.02 <0.02

# per million gallons treated

SampleCr(VI) (ug/L)

0.1 ug/L Cr(VI) Spike 10 ug/L Cr(VI) Spike

Ohio River 0.07 0.07

Ohio River + spike 0.18 10

Ferric/Ferrous (0#/100#) <0.02 0.03

Ferric/Ferrous (30#/70#) <0.02 0.03

Ferric/Ferrous (50#/50#) <0.02 <0.02

Ferric/Ferrous (70#/30#) <0.02 0.02

Ferric/Ferrous (100#/0#) 0.14 9

# per million gallons treated

Jar TestFeasibility of a Ferric/Ferrous Blend

Full Scale TestImpact of Ferrous Addition on Cr(VI) Concentration

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

RBF After Lime Addition (550#)

Basin 1 - With Ferrous Addition

(1 ppm)

Basin 2 - Without Ferrous Addition

Cr(

VI)

(u

g/L

)

ND

# per million gallons treated

Full ScaleImpact of ‘Background’ and ‘Added’ Ferrous

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

Lime applied at softening basin

Lime applied at head of plant Lime + 0.5 ppm FeCl2 applied at head of plant

Cr(

VI)

(u

g/L

)

Conclusions

WaterRF 4449 Project- Get better handle on sources and fate of Cr

LWC Case Study- Potential for Cr(VI) from contamination

• Relevance to 10 ppb MCL

- May be simple was to implement ferrous reduction

Yes, it did rain a lot in Colorado