Date of Award
Master of Engineering (ME)
Civil, Environmental & Architectural Engineering
R Scott. Summers
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
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.
Yang, Nathan, "Evaluation of Adsorptive and Biological Mode Dbp Removal in Activated Carbon Filters" (2017). Civil Engineering Graduate Theses & Dissertations. 174.