Removal of Hydrogen Sulfide Produced in a Municipal WWTP Using a Biotrickling Filter with Polypropylene Rings as the Packing Material and Microbial Community Analysis

Abstract

Under transient conditions, a biotrickling filter was developed to treat gaseous H2S produced from the fine-grid reservoir of a municipal wastewater treatment plant (WWTP) with AAO excess sludge as the inoculum and polypropylene rings as the packing material. The start-up process and steady-state operation of the biotrickling filter were studied. With an empty bed retention time of 14 s, an ambient temperature of 7.8-32.5℃, and an inlet concentration of 2.02-319.19 mg·m-3, an average removal efficiency of 91.8% was achieved with a maximum H2S elimination capacity of 78.37 g·(m3·h)-1. Over a 247-day period, the pressure drop across the biotrickling filter was maintained at 96 Pa·m-1. Microbial analysis using high-throughput sequencing technology showed a variation in the microbial community during the experiment; the Shannon index dropped from 4.99 to 3.75, and the functional genera Pseudomonas and Thiobacillus were identified as good performers in the biotrickling filter system. These results indicate that the application of AAO excess sludge as an inoculum for biotrickling filters is feasible for effective H2S removal. A steady pressure drop was achieved using polypropylene rings as the packing material. The diversity of the microbial community showed a downward trend when exposed to H2S, but the elimination capacity could be increased.