Developments in odour control and waste gas treatment biotechnology: a review

Waste and wastewater treatment processes produce odours, which can cause a nuisance to adjacent populations and contribute significantly to atmospheri c pollution. Sulphurous compounds are responsible for acid rain and mist; m any organic compounds of industrial origin contribute to airborne public he alth concerns, as well as environmental problems. Waste gases from industry have traditionally been treated using physicochemical processes, such as s crubbing, adsorption, condensation, and oxidation, however, biological trea tment of waste gases has gained support as an effective and economical opti on in the past few decades. One emergent technique for biological waste gas treatment is the use of existing activated sludge plants as bioscrubbers, thus treating the foul air generated by other process units of the wastewat er treatment system on site, with no requirement for additional units or fo r interruption of wastewater treatment. Limited data are available regardin g the performance of activated sludge diffusion of odorous air in spite of numerous positive reports from full-scale applications in North America. Th is review argues that the information available is insufficient fur precise process design and optimization, and simultaneous activated sludge treatme nt of wastewater and airborne odours could be adopted worldwide. (C) 2001 E lsevier Science Inc. All rights reserved.