Deodorization of livestock odors utilizing photoinduced hydrophilicity and decompodition on TiO_2

点击翻译按钮获取中文摘要

Recently, there has been the livestock field near home zone from a suburban agriculture, which causes a lot of complaints for livestock odors from the neighborhood. Thus, the technology of deodorant for livestock odor is required. We have designed a deodorant system for the odors from the windowless pig house or the closed compost facility utilizing photoinduced hydrophilicity and decomposition on TiO_2 surfaces. The system involves two steps, one step is the treatment by microbial cells cultivated naturally on the biofilter and continuous step is photocatalytic treatment.First, we have selected "photocatalytic filter" as a photocatalytic material which can enough adsorb and decomposed ammonia gas and can easily wash out nitrate generated from ammonia oxidation. Next, the systems having two layers of biofilters (SKOV Co. Denmark) and one layer of photocatalytic filter were constructed in an actual windowless pig house and a closed compost facility, and were evaluated for the deodorant effect. For example, the concentration of ammonia gas in the closed compost facility was 70-120 vppm, and it changed less 10 vppm after passing through biofilters of two layers, and finally it decreased by less 2 vppm after passing through photocatalytic filter of one layer. The bad odors even with low concentration such as sulfur compounds (H_2S, SO_2) and organic acids (propionic acid, n-, iso-valeric acid) can be also removed by passing through both filters. Furthermore, a photocatalytic filter with high durability was prepared by coating stainless steel with TiO_2 film, and evaluated far the removing effect of ammonia gas. The prepared photocatalytic filter had almost same photocatalytic activity as the current filter.