Institute of Livestock and Grassland Science, NARO

Air Environment Unit

The Air Environment Unit aims to develop the control technologies for environmentally harmful gas emissions from animal waste treatment and environmentally sustainable livestock production systems from a life cycle perspective.

Composting is a principal means of treating organic waste, which can convert the odoriferous and unsanitary livestock manure into the odorless and sanitary organic fertilizer. During the composting, however, substantial amounts of environmental harmful gases such as malodor and greenhouse gases are emitted, which has become a serious environmental issue. One our past study is to reduce nitrous oxide (N2O) emission that is a powerful greenhouse gas, using the bio-augmentation technique. Further study has been conducted to reduce those gases emissions from animal waste treatment.

Biological deodorization facilities, particularly biofilter, are often used in Japanese livestock farms to treat malodor containing high concentration of ammonia because of its relatively low operational costs compared with the other chemical and physical deodorization techniques. Ammonia is treated by microorganisms in the biofilter packing material. Theoretically, half of ammonia is oxidized to nitrite or nitrate by nitrifiers, the other half is absorbed into water to achieve ion balance, which resulted the nitrogen accumulation. Therefore, wastewater treatment or an exchange of the packing material is required. However, the maintenance of the biofilter is an extra burden on farmers. Our research goal is to develop technology to reduce nitrogen accumulation within the biofilter through investigation of the microbial mechanisms responsible for nitrification and denitrification.

Livestock production is a complex system, which starts from feed production in the feed crop fields and grasslands, through animal husbandry, and finally their manure is brought back to soil after appropriately treated. Accordingly, introduction of environmental technology may affect other processes in the life cycle of livestock production. Research is thus being conducted on reducing the environmental impacts of whole livestock production systems using methods such as life cycle assessment (LCA). We are also conducting research internationally for example in Southeast Asia cooperating with local research institutes aiming for environmentally sustainable development of livestock production.

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Unit Members