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1999-2009 RERA Preface |
20.
Household Waste Water for Hybrid Lagoon Performance Record
The household wastewater treatment facilities constructed in Nabari Nursery, an organization for social welfare located in Mie Prefecture, began operation in May 1981, and has operated without incident for five years. The quality of water recently discharged from the facilities reached I mg/liter BOD, 0.6 mg/ liter T-N, and 0.15 mg/liter T-P, for a household waste water treatment efficiency exceeding 90% (6th year) Many of the lakes and marshlands in Japan today are under going contamination and eutrophication caused by the discharge of household wastewater. However, high level treatment of such unconcentrated wastes as household wastewater is difficult, and prevention of eutrophication in closed water systems represents a major problem. At present, there are no effective countermeasures. These facilities demonstrate that hybrid lagoon automatic control technology, used as an economical means of treating household wastewater, represents an effective solution to the problem of preventing eutrophication in closed water systems. The cost of high-level treatment of household waste water using these facilities is approximately JPY 20 per m3 of water treated. (Figs. 15-16, ref. 329-340) June 20, 1981, 12:00 analysis of water samples? Mie Prefecture Environment and Sanitation Corporation. Table
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