Chlorination of drinking water which contains natural organic matter will result in formation of disinfectants byproducts such as Trihalomethanes (THMs). Since chlorination by-products are classified as potential carcinogenic by EPA, it is essential to provide treatment mechanisms. THMs have the highest concentration of chlorination byproducts in drinking water and chloroform is the most abundant with a maximum contaminant level (MCL) of 0.070 mg/L. Several physical and chemical removal methods are used to treat chloroform which are expensive and could generate secondary pollutants. Biofiltration is one of the most proven technologies for VOC control as it is environment–friendly, cost effective and releases fewer byproducts.  In this study, an integrated technology was proposed by taking chloroform (CF) alone and then mixtures of CF and dichlorobromomethane (DCBM) as a model THMs. The integrated technology consists of nitrogen stripping followed by anaerobic Bio-trickling Filter (BTF) or air stripping followed by aerobic BTF. Initially, two independent trains of aerobic and anaerobic BTFs with similar chloroform (5 ppmv) concentrations were investigated. In the anaerobic BTF, a co-metabolite and surfactant were utilized to enhance the biodegradation process. Upon the addition of Ethanol (co-metabolite) and Tomadol 25 - 7 (surfactant), the performance of the anaerobic reactor improved from an initial 49% to over 64% removal efficiency. Alternatively, the aerobic BTF was investigated under acidic environment to enhance fungi growth. The average removal efficiency under this acidic condition was 80%.<br/>Further studies were conducted with mixtures of CF and DCBM in two independent aerobic BTFs. One BTF with cometabolite and the other one with bio surfactant were investigated in removing the stripped THMs. Ethanol and surfactin (bio surfactant obtained from supernatant of  B. subtilis) were used as co metabolite and bio surfactant, respectively.  Adding co metabolite resulted in removal efficiencies of 72% for CF and 74% for DCBM. Whereas at the same loading rate condition, the use of surfactin showed a better removal efficiency of 85% and 79% for CF and CBM, respectively.  The study further investigated the microbial diversity within both BTFs in order to understand the dominant microbes which were responsible for the BTFs performance.

Comparative study in treating stripped off mixtures of trihalomethanes (THMs) in biotrickling filters (BTFs)

254th National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.