Comparison of the Biological H2S Removal Characteristics among Four Inorganic Packing Materials

Abstract

The applications of biological deodorizing methods have been increasing (1-4) because of their cost effectiveness and simple maintenance (2, S) compared to chemical and physical methods. Biological deodorizations are divided into two types of system. gas-solid and gas-liC!uid systems (6). Among the gas..solid systems. a packed tower deodorization system is efficient mainly because this can be constructed in a small construction area and can function sufficiently in urban a:eas. To reduce the scale of the apparatus, the selection of parldnc: m.:..terials is an important factor anJ. manj diff~ent tyPeS of packing materials suited for microt:~al growth have been actively researched. Some requirements for a good packing material are as follows: (i) high water-holding capacity, (ii) high porosity and large specific surface area, (iii) less compacting nature, (iv) low-pressure drop over a wiue range of water content, (v) small change in form in long periods of use, (vi) lightness, (vii) low cost, (viii) appropriate adsorbing ability for malodorous gases and (ix) large buffering capacity for acidic end products. Requirements (ill). (iv). (v), (vi) and (vii) are mainly related to the construction and maintenance of the biological deodorization apparatus, and (i) and (il) are related to its biological activities. The acidity or basicity of gases may be one of the factors for selecting packing materials. As organic packing materials, soil, compost and peat were sbown as good packing materials (7-14) that meet requirements (i), (ii), (vii), (viii) and (ix). Inorganic packing materials, such as perlite (15). porous ceramics (16), activated carbon fiber (17,18) and porous lava (19), are used, because they meet requirements (ill), (iv) and (v). Because comparative study of different packing materials has been rarely conducte<t under the saDIe condition (20). the evaluation of many packing materials is difficult. In this study, biologi::al H2S removal characteristics of four inorganic packing materials were evaluated under the same experimentaJ cOllditions of packing volume, Dow conditions and inoculation source. Additionally, the H2S removal characteristics were discussed in terms of pllysicocbemica1 properties and microbi:ll distribution on the packing materials.