Utilization of Biomass and Its Environmental Impact in Lake Kasumigaura Basin from the Viewpoint of Nutrient Flow and Greenhouse Gas Emissions

Abstract

In this paper, we focus on the risks to human health that may be directly and indirectly caused by food production. A typical example is the inappropriateness of the material balance of nitrogen and phosphorous in the Lake Kasumigaura Basin. Agricultural production and fishery activities prosper in the basin. Nitrogen and phosphorous overflow into the lake due to the industrial wastes as well as from other sources of water pollution such as household and manufacture wastewater even though they must be processed and treated following strict regulations on wastewater effluents into the lake set by the Prefectural Government. The water of Lake Kasumigaura is used for drinking even though inorganic nitrogen and phosphorous cause sudden growth of toxic Microcystis. Furthermore, underground water is contaminated with nitrogen nutrients and the contaminated water is hazardous especially if taken by children. Another example of contamination is the emissions of Greenhouse Gases (GHG) such as methane and dinitrogen monoxide due to improper or insufficient treatment of biomass wastes in the basin. In this paper, the material balance of nitrogen and phosphorous in the basin is shown and the potential of the biomass resources in the lake estimated. Feasibility and effectiveness of composting and methane fermentation technologies are analyzed from their impacts on GHG emissions in the basin and the flow of nutrients into the lake.