Treatment of waste gas containing monomethylamine in a biofilter enriched with Pseudomonas mendocina R.A. Pandey * , R. Gangane, S.N. Mudliar, A.S. Rajvaidya National Environmental Engineering Research Institute, Nehru Marg, Nagpur-440 020, India Accepted 11 January 2005 Available online 25 May 2005 Abstract Waste gas containing monomethylamine (MMA) was treated in a biofilter packed with compost along with wood chips and enriched with Pseudomonas mendocina. The biofilter could remove MMA to the extent of more than 99% at a loading of 42.36 g m À3 h À1 with an empty bed retention time of 12 s. At optimal operating conditions, the moisture content in the biofilter was maintained at around 45%. The biodegradative products of MMA were ammonia, nitrite, and nitrate. Ó 2005 Elsevier Ltd. All rights reserved. 1. Introduction Industrial emissions with malodors cause consider- able nuisance, as odor regulations are most difficult to enforce due to the difficulty in defining standards. Most of the odors encountered by human olfactory sense are not pure but complex mixtures of different molecules, many of which are at concentrations far below the levels detectable by commercially available measuring stan- dard instruments that simulate the sensation of smell. Monomethylamine (MMA) is an obnoxious odorant generated in the MMA manufacturing industry, domes- tic wastewater treatment plants, solid waste disposal sites of urban domestic origin, and several types of industries. MMA is used in tanning, organic synthesis, dyeing of acetate textiles, and paint removers; as an intermediate for accelerators, dyes, pharmaceuticals, insecticides, fungicides, and surface active agents; and as a fuel additive, polymerization inhibitor, photo- graphic developer, and rocket propellant (Neill et al., 1978; Beer, 1967). The use of MMA in such activities also generates waste gas streams containing the odorant. The volatilization of cattle waste also produces ammo- nia and MMA. In a sewage treatment plant, 60– 80 ppm of ammonia and 0.15–0.26 ppm of organic amines have been observed in the vent gas of the night-soil dumping pit (Devinny et al., 1999). In a muni- cipal waste incineration unit, concentrations of 5.37 ppm of methylamine and 26 ppm of trimethyl amine were detected (Environmental Protection Agency, 1988). MMA has been detected in various European riv- ers, in swamps, and soil. It has also been found to be naturally occurring in a variety of foods. MMA has a threshold odor concentration of 3.35 ppm at normal conditions with an odor index of 940,000 at 20 °C(Ver- schueren, 1983). MMA is of environmental concern since it is toxic to living beings. Inhalation of MMA may be harmful and its vapors are extremely irritating; its contact causes irritation to skin and eyes. Contact with liquid may cause frostbite (Bluden et al., 1982). Thus, waste gases containing MMA require proper treatment prior to their emission into the atmosphere. Various physico-chemical methods, viz. adsorption, combustion, acid/alkali scrubbing, and chemical oxida- tion have been used for removal of malodorous com- pounds from contaminated air (USEPA Design manual, 1985). Activated carbon adsorption and ozona- tion processes have been reported for treatment of waste 0956-053X/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.wasman.2005.01.024 * Corresponding author. Tel.: +91 712 2240097; fax: +91 712 2249900. E-mail address: rapandey@hotmail.com (R.A. Pandey). www.elsevier.com/locate/wasman Waste Management 26 (2006) 233–244