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Effectiveness of biosurfactant for the removal of trihalomethanes by biotrickling filter
Citation:
Mezgebe, B., G. Sorial, D. Wendell, AND E. Sahle-Demessie. Effectiveness of biosurfactant for the removal of trihalomethanes by biotrickling filter. Engineering Reports. John Wiley & Sons, Ltd., Indianapolis, IN, 1(1):e12031, (2019). https://doi.org/10.1002/eng2.12031
Impact/Purpose:
Trihalomethanes (THM) are a group of chemicals that are formed along with other disinfection byproducts when chlorine or other disinfectants used to control microbial contaminants in drinking water react with naturally occurring organic and inorganic matter in water. Chronic exposure of THMS cause adverse health effects to human including cardiac irregularities, loss of a fetus, low birth weight and pre-term delivery. THM levels tend to increase with pH, temperature, time, and the concentration of "precursors" present. We have developed air stripping method for removing THM from chlorinated drinking water and treat the gas phase using a biological process. This technology is a low-cost and practical approach that is applicable for small water treatment plants. Precursors are a natural organic material which is present in all surface water and reacts with chlorine to form THM's.
Description:
In this study, the biodegradation of a mixture of two trihalomethane (THM) compounds, chloroform (CF) and dichlorobromomethane (DCBM), was evaluated using two laboratory‐scale biotrickling filters (BTFs). The two BTFs, hereby designated as “BTF‐A” and “BTF‐B,” were run parallel and used ethanol as co‐metabolite at different loading rates (LRs), and a lipopeptide‐type biosurfactant that was generated by the gram‐positive bacteria, Surfactin, respectively. The results using BTF‐A showed that adding ethanol at a higher rate of 4.59 g/(m3 h) resulted in removal efficiencies of 85% and 87% for CF and DCBM, respectively. Conversely, for the same LR, the use of Surfactin without ethanol (BTF‐B) showed comparable removal efficiencies of 85% and 80% for CF and DCBM, respectively. The maximum rate constant for CF and DCBM for the BTF‐A was 0.00203 s−1 and 0.0022 s−1, respectively. For the same THMs LR, similar reaction rate constants resulted for the BTF‐B. Further studies were conducted to investigate and understand the microbial diversity within both BTFs. The result indicated that for BTF with co‐metabolite, Fusarium sp. was the most dominant fungi over 98% followed by F. Solani with less than 2%. F. oxysporum and Fusarium sp. were instead the dominant fungi for the BTF with Surfactin. Before introducing the Surfactin into the BTF, the batch experiment was conducted to evaluate the effectiveness of synthetic surfactant as compared to a biosurfactant (Surfactin). In this regard, vials with Surfactin showed better performance than vials with Tomadol 25‐7 (synthetic surfactant).
URLs/Downloads:
DOI: Effectiveness of biosurfactant for the removal of trihalomethanes by biotrickling filter
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