Lọc sinh học bao gồm một chiếc giường đất hoặc phân ủ bên dưới là một mạng lưới các ống đục lỗ. Dòng chảy không khí bị ô nhiễm thông qua đường ống và ra khỏi các lỗ ở hai bên của đường ống do đó được phân phối khắp giường. Lọc sinh học hoạt động bằng cách cung cấp một môi trường mà vi sinh vật phát triển mạnh. Các chất hữu cơ cung cấp các muối và các nguyên tố vi lượng cho vi khuẩn, và VOC cung cấp nguồn thức ăn. Hành động này là một sự. | 15 Control of VOC and HAP by Biofiltration INTRODUCTION A biofilter consists of a bed of soil or compost beneath which is a network of perforated pipe. Contaminated air flows through the pipe and out the many holes in the sides of the pipe thereby being distributed throughout the bed. A biofilter works by providing an environment in which microorganisms thrive. The organic substrate provides the salts and trace elements for the bacteria and the VOC provides the food source. This action is an adaptation of biogdegradation in which the air cleanses itself naturally. The microorganisms are the same that degrade organic wastes in nature and in wastewater treatment plants. These microorganisms in a moist environment oxidize organic compounds to CO2 and water. The soil or compost beds provide a network of fine pores with large surface areas. In soils the pores are smaller and less permeable than in compost. Therefore soil requires larger areas for biofiltration. Biofiltration is a relatively new technology in the . used for effectively controlling Volatile Organic Compound VOC emissions organic and inorganic air tonics and odor from gaseous streams. This technology has been used in Europe for many years and is considered to be a Best Available Control Technology BACT for treating contaminated gaseous streams. Biofilters function efficiently and economically for removing low concentrations less than 1000 to 1500 ppm as methane of VOCs air tonics and odor. Biofiltration offers many potential advantages over existing control technologies such as low installation and operation costs low maintenance requirements long life for the biofilter and environmentally safe operation. Also many of the existing control technologies cannot be economically applied to dilute gas stream treatment. Biofilters are effective systems for removing pollutants from gaseous streams. The percent removals possible vary in the literature. For odorous compounds 98 to 99 removal has been .
