A pilot study of a biotrickling filter for the treatment of odorous sewage air

The nuisance impact of air pollutant emissions from wastewater treatment plants (WWTPs) is a major issue of concern to Singapore and to many developing cities worldwide. Existing chemical and physical treatment methods are efficient but costly, and may generate secondary pollutants. Biotreatment, on the other hand, is a proven control technology for effectively removing hydrogen sulphide (H2S), the principal odour component of sewage air. The biotechnology is cost-effective to remove low-concentrations of biodegradable compounds from a large flow of waste gases. A pilot-scale biotrickling filter, packed with pall rings, was set up at a WWTP in Singapore to investigate its effectiveness for treatment of odorous sewage air. A series of experiments were conducted to assess the performance of the biotrickling filter under various operating scenarios. Results indicated that even at 5 second gas retention time, the biotrickling filter could remove 95% of the inlet H2S. The behaviour of the biotrickling filter under various operating scenarios are presented and discussed in this paper.