|Budget Amount *help
¥1,900,000 (Direct Cost : ¥1,900,000)
Fiscal Year 1994 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1993 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1992 : ¥700,000 (Direct Cost : ¥700,000)
The treatment system whereby a humus-filled reactor is added to the usual activated-sludge process produces almost no odor characteristic of the sewage treatment plant, and displays different characteristics compared to the traditional activated-sludge process.
In this research, mainly repeated analyzes and studies of the operation log of the Water Purifying Center in Yamanouchi, Nagano Prefecture, as well as indoor experiments, were carried out, and the fllowing design factors were descovered.
1)The required ventilation air volume per BOD removed is sufficient at only around half of the usual activated-sludge process.
2)More satisfactory effluent is obtained when the MLDO is 0.4mg/1 or less.
3)The aeration tanks prefer anaerobic and anoxic dual-phase operation, and also interrupted operation, and slso interrupted operation ; the consequent denitrification and phosphate removal rates are around 65-85%.
4)The amount of sludge produced is approximately half compared to the extended method, and the sludge can be dewatered without the application of chemicals.
5)As the sludge has a tendency not to settle well, when running at more than 5000mg/1 MLSS,the settlement duration must be taken into consideration.
The biology of the activated-sludge of this study does not contain the large protozoa usually found in activated sludge, and is comprised mainly of microscopic, highly active microbes.It is thought that the presence of these microbes is the cause for such characteristics as a high level of activity (and thus efficient purification) even under anoxic conditions, a low sludge production rate, and a good dewatering quality. A decrease in the amount of aeration leads to a reduction in cost of the activated sludge process, and is an important advantage for operation and maintenance.