Decentralized and separated waste water treatment system (DSWWTS) is a new proposed system that consists of a non-flushing toilet (composting toilet) which converts excreta into fertilizer and some compositional units such as slant soil treatment system for grey water including wastewater from kitchen, bath and cleaning. According to environmental assessment, the pollution loads such as BOD, T-N and T-P were estimated to be significantly reduced comparing with conventional sewage system or GAPPEI-JOUKASOU system. Life Cycle Assessment (LCA) method was also used to assess the energy consumption as environmental load in terms of construction stage to operation stage. As a result, the energy required for DSWWTS was estimated to be smaller than those for two conventional systems.

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  Biological removal of hydrogen sulfide in biogas, which was produced from an anaerobic digester treating cattle manure with a HRT of 25 days, was carried out by adding a low amount of air to the headspace of the digester (approximately 1% of oxygen concentration in the digester). The concentration of hydrogen sulfide was successfully reduced from 3,500 ppm to a low level of 1,100 ppm after air adding. A microbial mat with an elemental sulfur content of 90% per g-TS was developed in the headspace of the digester as a result of the sulfide oxidation. Cloning analysis revealed that close-relatives of Halothiobacillus neapolitanus and Sulfurimonas sp., both known as sulfide oxidizer, were predominant in the mat and might be responsible for the sulfide oxidation and for the elemental sulfur accumulation under microaerophilic environment. A microbial sulfide oxidation activity test demonstrated that the wetness of the mat is important to the microbial sulfide oxidation activity. These results suggest that an appropriate design for microbial habitat in a digester is one of the important factors for the biological hydrogen sulfide removal.

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  In order to accurately evaluate effectiveness of introducing District Heating and Cooling (DHC) systems using wastewater heat, Trunk Sewer Model and DHC Plant Model were developed. Applying these models and life cycle analyses to hypothetical areas which have various heat load characteristics, it was found that a large amount of CO₂ reduction at a low CO₂ reduction cost are achieved when DHC systems are introduced in some office buildings, hotels and hospitals. Furthermore, the results of the model simulation in Tokyo 23 wards show that the potential of CO₂ reduction by utilization of wastewater heat is about 140 thousand tons of CO₂ by introducing 320 DHC systems, and its average cost is about 16,800 JPY per ton of CO₂.

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  This study was carried out in aiming for utilization of nonferrous metal slag as fine aggregate for asphalt mixture. The nonferrous metal slag, which is produced in the process to refine copper or ferronickel, was used at the experiment. Several examinations were executed to evaluate the environment safety and the quality of the slag and the characteristics of asphalt mixture with the slag. As the results, it was clarified that the quality of the slag satisfied the standard of fine aggregate of the asphalt mixture and the mutual-rubbing reformation of slag is effective for the asphalt mixture.
  Furthermore, it was confirmed that the asphalt mixture is satisfied performance as the surface material fully at the field test. In particularly, there was a slag that the content of several toxic substances exceeded its standard of the environment safety, but it was confirmed that does not affect the environment by the soil quality examinations at the field test.

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In 2004 natural spawning of chum salmon (Oncorhynchus keta) was observed in the Sho River, in the western part of Toyama Prefecture, because the salmon trap installed at the lower reaches of the river had been destroyed. Investigation of their spawning-related habitat and emerged salmon fry showed that the spawning sites clearly coincided with the upwelling (or spring) area located at the base of the Sho River alluvial fan. Upwelling water provided various types of riverine environmental components such as side pools, secondary channels, and these water areas derived from upwelling maintained a higher water temperature than other water areas. These properties contributed significantly to both salmon reproduction as well as environmental diversity and biodiversity.

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The purpose of the present study is to evaluate quantitatively CO₂ emission from micro pile method using pre-cast concrete member. This paper describes CO₂ emission by using typical models of L-shaped retaining wall and box culvert, which often employ pre-cast concrete member. Additionally, the authors estimated CO₂ emission of an actual pre-cast box culvert for micro pile construction as comparing with cast-in-place concrete. As these results, the micro pile method with pre-cast concrete indicated higher effectiveness of CO₂ emission reduction than normal construction.

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