Next Hurdle: 1,2,3-Trichloropropane - CA-NV AWWA · A value of 0.1 lb GAC / 1,000 gallons has been...

Next Hurdle:

1,2,3-Trichloropropane

Kevin Berryhill

Agenda

1. Background

2. Origin of TCP

3. Regulations

4. Treatment Alternatives

5. Treatment Cost

Where Does TCP Come From?Notification Level established after

TCP’s discovery at the Burbank Superfund

site

“primary possible contaminating

activity appearing to be hazardous waste

sites

Where Has TCP Been Found?

Where Does TCP Come From?

Significant Impact on Rural Areas

Agricultural origin

Agriculture occurs in

rural areas

Rural areas have small

water systems

Small water systems have

no money

An Underreported Problem? California UCMR (2001 – 2003)

Prior to DLR=0.005 µg/L

Sample at source or entry point

<150 connections exempt

EPA UCMR 3 (2013 – 2015)

Systems > 10,000 people

800 representative PWSs

Sample at entry point

MRL = 0.03 µg/L

Private Wells

Laboratory Analytical Constraints

Detection Limit = 5 ng/L Equal to the notification level

7 times greater than the PHG

Specific California-approved analytical methods Sanitation and radiation laboratories purge and trap GC/MS

Sanitation and radiation laboratories liquid-liquid extraction GC/MS

EPA 504.1 (accuracy must be demonstrated by laboratory)

EPA 551.1 (accuracy must be demonstrated by laboratory)

USEPA methods 502.2 and 524.2 are not adequate for TCP

Why Regulate TCP?

Carcinogen Recognized as human carcinogen

by California

Classified as “likely to be” by the EPA

0.7 ppt health goal based on 1 in a million cancer risk

Known toxin

100% man-made Byproduct of chemical synthesis

Does not degrade naturally

Denser than water

“In wine there is wisdom,

in beer there is freedom,

in water there is TCP

-Benjamin Franklin

How is TCP Currently Regulated?

• Notification Level 0.005 µg/L (1999)

• PHG 0.0007 µg/L (2009)

• MCL 0.8 µg/L (mid-80s)

• MCL 0.6 µg/L (2005)

• MCL currently under review

TCP is not regulated by

the U.S. EPA

Regulatory Process

Draft MCL in 2014

45 day comment period

30 day administrative review

Effective within 5 months

Up to 6 months to sample

Treatment Alternatives

There is no “Best Available Technology” (BAT) for TCP

Look at what works for other VOCs Air stripping / packed tower aeration

Reverse osmosis (RO)

Advanced oxidation processes (AOP)

Granular activated carbon (GAC)

Air Stripping

The lower the Henry’s Law constant, the poorer the treatment performance

10 – 26% Removal

Chemical Molecular Weight

Henry’s Law

Constant

(atm-m3/mol)

Dibromochloropropane (DBCP) 236.2 0.0002

Methyl tertiary-butyl ether (MTBE) 88.0 0.0007

Tetrachloroethylene (PCE) 165.85 0.015

Trichloroethylene (TCE) 131.2 0.009

1,2,3-Trichloropropane (TCP) 147.43 0.0003

Reverse Osmosis

At least one operational RO treatment plant removing TCP

Bench-scale study (Fronk, Lykins & Carswell, 1990) Several membranes tested

39 to 85% rejection of TCP

Brine disposal issues

RO is a very expensive way to achieve incomplete removal of TCP

Advanced Oxidation

AOP is likely to be a technically viable treatment alternative

More viable for higher influent levels

HiPOx study (Dombeckand Borg, 2005)

Ozone

UVPeroxide

Potential AOP Byproducts

Tratnyek, P.G., V. Sarathy, and J.H. Fortuna. (2008) Fate and Remediation of 1,2,3-Trichloropropane. In Proceedings of the

Sixth International Conference on Remediation of Chlorinated and Recalcitrant Compounds

Biological Treatment

Natural biodegradation is insignificant

Bacterial “directed evolution” studies are in in work.

Even superbugs could require days or weeks to act.

Granular Activated Carbon (GAC)

Granular Activated Carbon

Effective for almost all organic contaminants

Reliable

Simple

All existing TCP removal plants use GAC

Existing GAC Facilities

Existing GAC treatment facilities removing TCP include:

Alhambra, CA

Burbank Operable Unit, CA

Fresno, CA

Glendale, CA

Honolulu, HI

Kaanapali, HI

Maui, HI

Oceanside, CA

San Jerardo, Salinas, CA

Tustin, CA

GAC Vessel Configuration

Carbon characteristics

Series vs. parallel

Empty bed contact time (EBCT)

Carbon Characteristics Substrate material

Coconut

Coal (anthracite, bituminous, lignite)

Peat

Adsorption properties (iodine number, molasses number, tannin value)

Gradation, uniformity

Hardness, abrasion resistance

Empty Bed Contact Time (EBCT)

Exhausted

GAC

Mass Transfer Zone

Exhausted

GAC

Mass Transfer

Zone

Unutilized

GACUnutilized GAC

Lower

EBCTHigher

EBCT

Raw

Water

Treated

Water

minuteste)Q(gal/minu

V(gal)

Series vs. Parallel?

ExhaustedGAC

Mass Transfer

Zone

Raw

Water

Treated

Water

TCP is coming out of the filter, but

This carbon still has capacity left

TCP detected

Series vs. Parallel?

Treated

Water

ExhaustedGAC

Mass Transfer

Zone

Unutilized GAC

Treated

Water

The second vessel will allow us to more

fully utilize the carbon in the first vessel

No TCP

Lead Vessel Lag Vessel

When Do You Replace Carbon?

ExhaustedGAC

Lead Vessel Lag Vessel

Detected at 5 ng/L

Already at 0.7 ng/L

PHG?

PHG < DLR

TCP slips through monitoring

Replace carbon in lead vessel based on 50% or 75% sample port in lag vessel

Carbon Usage

Usage Rate Prediction Methods Computer modeling

Bottle point adsorption isotherms

Rapid small-scale column testing (RSSCT)

Small-scale pilot or bench studies

Full-scale testing

A value of 0.1 lb GAC / 1,000 gallons has been assumed pending a site specific water quality evaluation and testing

Chemical

Molecular

Weight

Log Octanol-Water

Partition Coefficient

(Kow)

Dibromochloropropane (DBCP) 236.2 2.43

Methyl tertiary-butyl ether (MTBE) 88.0 1.13

Tetrachloroethylene (PCE) 165.85 3.14

Trichloroethylene (TCE) 131.2 2.36

1,2,3-Trichloropropane (TCP) 147.43 2.26

Bottle Point Isotherm

Multiple bottles with

different carbon weights

added

Rapid Small Scale Column Test (RSSCT)

Most practical way to estimate carbon usage

Logistics Two 55-gallon drums of water

6 weeks

Approximately $8,500 per test

Limitations Inherent assumptions in model

Snapshot in time

Neglects biological activity

Neglects GAC bed backwashing

One batch of carbon

Apply a factor of safety!

Pilot Testing

More accurate than RSSCT

Accounts for variations in raw water quality

Captures biological effects

Long-term test (Hopefully!)

Water QualityConsiderations

TCP levels may not significantly affect carbon usage rates

Background organics may be more critical

DBCP is often found in the same well

Background TOC=

250,000 ng/L

TCP =

5 ng/L

Nitrate Spikes

Source water nitrate > 22 mg/L (as NO3)

Effect similar to chromatographic peaking

Occurs following shutdowns and backwashes

Handled by: Nitrate monitoring

Flush-to-waste

GAC Site Appurtenances

Access for delivery

Washwater disposal

Initial washing

Backwashing for head

loss reduction

Aesthetic considerations

Next Steps

Recommendations for Utilities:

Explore funding sources for construction and operation of the treatment system Factor into rates

Responsible party

Grant & SRF funding once MCL is established

Measure TOC

Compile NO3 (nitrate) data

Develop accurate production data

Consider RSSCT testing

Kevin Berryhill

(559) 449-2700

kberryhill@ppeng.com