Areas where livestock density per unit area is especially high, such as parts of Europe and Asian countries including Japan, are experiencing serious problems. To prevent surface and underground water pollution, a large amount of nutrient materials in livestock wastewater must be purified at some farming in Japan. The activated sludge process is reportedly cost effective for swine wastewater treatment as nitrogen and BOD removal, and increased in pig farming. But it costed for farmers and energy consume. We are now going to innovate the wastewater management system for economical and ecological aspects.
Improvement of livestock wastewater treatment system
Most swine farms in Japan use activated sludge (AS) treatment system to treat swine wastewater, which is a mixture of urine, feces, and service water; however, nitrogen can remain high after the treatment. To improve the nitrogen removal, we aim to optimize the operation condition of AS facility using the AS model, and apply anammox treatment. Constructed wetland (CW) can be used as a post treatment of AS. We also study anammox in CWs.
Energy recovery and wastewater treatment using electricity-generating bacteria
To recover energy and to purify livestock wastewater, we are studying the following topics:
- Development of anode materials for enhancing electricity generation of microbial fuel cells;
- Novel real-time biosensor using electricity-generating bacteria for monitoring biochemical oxygen demand (BOD) of wastewater;
- BOD and nitrogen removal system from wastewater using the biosensor.
GHG regulation practice
Nitrous oxide is generated on farms as an intermediate product on nitrification and denitrification, and methane is also generated from organic degradation under an anaerobic condition by microorganisms in manure or wastewater. Methane (CH4) and nitrous oxide (N2O) are emitted from livestock wastewater treatment plants as green house gas. We have demonstrated mitigation of nitrous oxide (N2O) emission from swine wastewater treatment in an aerobic bioreactor packed with carbon fibers. We also aim to quantify actual GHG emissions in domestic wastewater treatment facilities of swine waste.
- Yamashita T, Ishida M, Asakawa S, Kanamori H, Sasaki H, Ogino A, Katayose Y, Hatta T, Yokoyama H (2016) Enhanced electrical power generation using flame-oxidized stainless steel anode in microbial fuel cells and the anodic community structure. Biotechnol Biofuels doi: 10.1186/s13068-016-0480-7. eCollection 2016.
- Yokoyama H, Ishida M, Yamashita T (2016) Comparison of anodic community in microbial fuel cells with iron oxide-reducing community. J Microbiol Biotechnol 26(4): 757-62 doi: 10.4014/jmb.1510.10037
- Yamashita T, Ishida M, Ogino A, Yokoyama H (2016) Evaluation of organic matter removal and electricity generation by using integrated microbial fuel cells for wastewater treatment. Environ Technol 37(2):228-36 doi: 10.1080/09593330.2015.1066874 (Epub 2015 Jul 24)
- Yamashita T, Shiraishi M, Yamamoto-Ikemoto R, Yokoyama H, Ogino A, Osada T (2016) Swine wastewater treatment technology to reduce nitrous oxide emission by using an aerobic bioreactor packed with carbon fibres Anim Prod Sci 56(3): 330-336
- Yamashita T, Yamamoto-Ikemoto R, Yokoyama H, Kawahara H, Ogino A, Osada T (2015) Mitigation of nitrous oxide (N2O) emission from swine wastewater treatment in an aerobic bioreactor packed with carbon fibers. Anim Sci J 86(3): 358-368
- Suto R, Ishimoto C, Chikyu M, Aihara Y, Matsumoto T, Uenishi H, Yasuda T, Fukumoto Y, Waki M (2016) Anammox biofilm in activated-sludge swine wastewater treatment plants. Chemosphere (in press)
- Waki M, Yasuda T, Suzuki K, Komada M, Abe K (2015) Distribution of anammox bacteria in a free-water-surface constructed wetland with wild rice (Zizania latifolia) Ecological Engineering 81: 165-172
- Waki M, Yasuda T, Fukumoto Y, Suzuki K (2014) Effect of pH on phosphorus, copper, and zinc elution from swine wastewater activated sludge. Water Science and Technology 70(4): 593-598