Modeling waste gas biofiltration process for industrial use in Kenya

Abstract

Volatile Organic Compounds (VOCs) are gaseous emission contaminants which are harmful to human health and the environment. In Kenya, literature on emission and treatment of VOCs is insufficient. In this study, biofiltration was investigated as a VOCs treatment technology. A quantitative structure-activity relationship (QSAR)-based model for the biofiltration process was developed, calibrated and tested. Bioreaction parameters applicable in the design and operation of biofilters, and modeling of biodegradability of VOCs were established. An ex-situ biofiltration system was designed and set-up to investigate the capacity of biofiltration in the removal of m, p-xylene, o-xylene, 1, 3, 5-trimethylbenzene and 1, 2, 4-trimethylbenzene (XTMB). The system comprised of a compost bed biofilter and an aerobic batch reactor, which held petroleum spiked soil matrix as the source of contaminant VOCs found in petroleum off-gases. In the laboratory, the biofilter was operated periodically for 4-hours per day over 39-days. Data was collected for 22 days. Petroleum off-gases represent volatile organic compounds emitted from various industries. The VOCs mixture was pumped though the biofilter at four different flow rates that were 11.5, 14.5, 18.0 and 23.8 L/hr. Micro-organisms in the compost beds used the VOCs in the influent waste gas stream as carbon substrates, consequently degrading them and reducing their concentration in the effluent stream. Influent and effluent