Graduate Thesis Or Dissertation

 

Evaluation of Adsorptive and Biological Mode Dbp Removal in Activated Carbon Filters Public Deposited

https://scholar.colorado.edu/concern/graduate_thesis_or_dissertations/1831ck26k
Abstract
  • Small drinking water systems face unique compliance challenges with regards tomany water quality parameters, including disinfection-by-product (DBP) levels in thedistribution system. Filtration with granular activated carbon (GAC) can be an effectivetechnology 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 thedistribution system to meet DBP regulations under both adsorptive and biological modes.It was hypothesized that a post-treatment reactor strategically located in the distributionsystem will offer small systems a cost-effective alternative to controlling totaltrihalomethanes (TTHMs), sum of five haloacetic acids (HAA5s) and other unregulatedDBPs. A total of six adsorptive rapid small scale column tests (RSSCTs) and three pilotscale biofilters were operated to investigate the effects of GAC type, source waterquality, temperature and empty bed contact time (EBCT) on the adsorption andbiodegradation of TOC and DBPs in treated drinking water.Experimental results show that adsorption with bituminous GAC is an effectivetreatment strategy for the removal of TOC and TTHMs through at least 6,000 bedvolumes (42 days at 10min EBCT) and often longer depending on influent conditions.Pore surface diffusion model (PSDM) analysis indicated that the presence of both naturalorganic matter (NOM) and co-solutes are important to consider when analyzing THMbreakthrough, with THM adsorbability being the most important factor in determining breakthrough order (TCM ->DCBM -> DBCM ->TBM) and influent concentrationdetermining localized breakthrough. Experimental HAA adsorption results werenonsystematic.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 and20min) for the duration of the pilot runs. TCAA removal ranged between 50%-78% at 5minute EBCT, 80%-96% at 10 minute EBCT and 93%-98% at 20 minute EBCT. NoTHM biodegradation was observed. HAA reduction and reformation results indicatedthat biofiltration is an effective treatment for the reduction in HAA5 both immediatelyafter biofiltration as well as at the end of the distribution system, across many ranges ofchlorinated influent bromide and TOC conditions.
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  • 2017
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  • 2019-11-18
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