Date of Award

Spring 1-1-2017

Document Type

Thesis

Degree Name

Master of Engineering (ME)

Department

Civil, Environmental & Architectural Engineering

First Advisor

R Scott. Summers

Second Advisor

Christopher Corwin

Third Advisor

Chad Seidel

Abstract

Small drinking water systems face unique compliance challenges with regards to

many water quality parameters, including disinfection-by-product (DBP) levels in the

distribution system. Filtration with granular activated carbon (GAC) can be an effective

technology for the removal of total organic carbon (TOC) and DBPs.

The objectives of this thesis were to develop and evaluate the use of GAC in the

distribution system to meet DBP regulations under both adsorptive and biological modes.

It was hypothesized that a post-treatment reactor strategically located in the distribution

system will offer small systems a cost-effective alternative to controlling total

trihalomethanes (TTHMs), sum of five haloacetic acids (HAA5s) and other unregulated

DBPs. A total of six adsorptive rapid small scale column tests (RSSCTs) and three pilot

scale biofilters were operated to investigate the effects of GAC type, source water

quality, temperature and empty bed contact time (EBCT) on the adsorption and

biodegradation of TOC and DBPs in treated drinking water.

Experimental results show that adsorption with bituminous GAC is an effective

treatment strategy for the removal of TOC and TTHMs through at least 6,000 bed

volumes (42 days at 10min EBCT) and often longer depending on influent conditions.

Pore surface diffusion model (PSDM) analysis indicated that the presence of both natural

organic matter (NOM) and co-solutes are important to consider when analyzing THM

breakthrough, with THM adsorbability being the most important factor in determining breakthrough order (TCM ->DCBM -> DBCM ->TBM) and influent concentration

determining localized breakthrough. Experimental HAA adsorption results were

nonsystematic.

In biofiltration pilot runs, DCAA and TCAA made up >85% of HAA5.

Experimental DCAA removal between 83%-97% was reported at all EBCTS (5, 10 and

20min) for the duration of the pilot runs. TCAA removal ranged between 50%-78% at 5

minute EBCT, 80%-96% at 10 minute EBCT and 93%-98% at 20 minute EBCT. No

THM biodegradation was observed. HAA reduction and reformation results indicated

that biofiltration is an effective treatment for the reduction in HAA5 both immediately

after biofiltration as well as at the end of the distribution system, across many ranges of

chlorinated influent bromide and TOC conditions.

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