Application Of Biologically Activated Carbon For Treatment Of Sulfide Laden Groundwater PDF Download

Small-system water purveyors must overcome many challenges to provide an adequate and safe water supply to its consuming public. This dissertation reports on research related to the application of biologically activated carbon (BAC) media filters for the treatment of well water to remove disinfection by-product (DBP) precursor matter, measured as dissolved organic carbon (DOC), at two treatment plants serving a small community water system. Four research questions were investigated individually in discrete, yet interconnected studies at two water treatment facilities processing groundwater that contained hydrogen-sulfide (~1.2 mg/L) and dissolved organic carbon (~2.0 mg/L). The first study revealed that BAC filters operated at the pilot-scale removed 50% of DOC regardless of carbon type or loading rate. A second study showed that GAC media replacement frequency, when transitioned from adsorption mode to biological-mode, would extend media change-out from 4 times per year to once to once every 2.5 years of service, providing a total savings of $40,000 per facility per operational year. A third investigation used genetic sequencing and quantitative polymerase chain reaction (qPCR) techniques using universal primers to identify the microbial communities within GAC filters operating in biological mode. Both sulfur-reducing and sulfur-oxidizing bacteria were identified as the predominant groups colonizing the GAC contactors. Genotyping of the different carbon types showed similar community composition; however, differences in the phylogenetic diversity of the samples were evident. A fourth study demonstrated that tray aerators could be integrated into a BAC process to decrease total trihalomethane DBPs entering the water distribution system.