| Budget Amount *help |
¥7,600,000 (Direct Cost: ¥7,600,000)
Fiscal Year 1996: ¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1995: ¥5,400,000 (Direct Cost: ¥5,400,000)
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| Research Abstract |
The objective of this study wa to propose the design and construction of urban water metabolic system which supports various water consumption with appropriate quality and quantity by an optimal use of water resource with reuse of once used water. Therefore, the following subjects of research was accomplished.
(1) Development of advanced wastewater treatment system ; The authors had proposed an anaerobic fluidized pellet bed bioreactor system as an advanced sewage wastewater treatment system. This system could be effectively nitrogenous and phosphorus compounds. In addition, by the introduction of 2nd denitrification tank and with feeding to flocculated sewage sludge, the concentration of total nitrogen and total phosphorus in the final effluent was between 0.5 and 1.0mg/l, and between 0.01 and 0.05mg/l respectively. Consequently, eutrophication potential could be greatly decreased.
(2) Natural purification system in cooperation with an advanced wastewater treatment system ; When the adv
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anced wastewater treatment process such as coagulation process was applied to the effluent from sewage treatment works, the algal growth potential (AGP) was decreased to less than 50mug CHLa/l from 120-200mugCHLa/l. Moreover, when the effluent from the coagulation process was stored in the reservoir at 40 day of retention time, the amount of algal biomass was extremely low (20-5.50mugCHLa/l) comparing the value of AGP.This result indicated that the decrease of eutrophication potential enhanced the natural purification capacity.
(3) Improvement of water quality by soil infiltration ; When the effluent from the storing reservoir was infiltrate into the soil, SS,TOC and total nitrogen could be removed physically and biologically, especially nitrogenous substances was removed above 90% by nitrification and denitrification process.
Consequently, the natural purification system combined with the advanced wastewater treatment process enabled the reuse of once used water. Moreover, the soil infiltration process enhanced the water quality. Less
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