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1999-2009 RERA Preface |
21. Hybrid
Lagoon Performance
To prevent eutrophication of Lake Biwa, Shiga Prefecture has imposed regulations stipulating that wastewater from cattle (or hog) breeding shall contain less than 45 mg/liter T-N and 15 mg/liter T-P. On the basis of the results of tests to evaluate hybrid lagoon automatic control facilities, conducted within the Shiga Prefecture? Breeding Stock Grounds, hybrid lagoon facilities were adopted for use as high-level treatment facilities by the? West Okayama Hog Breeding Union (3,000 head of hogs) of Omi Hachiman City, and was constructed in May 1985. The concentration of impurities in the drainage water treated by these facilities is higher than the design values, at l0, 000 mg/liter BOD, 5,000 mg/liter T-N and 1,000 mg/liter T-P. Nevertheless, high-level processing without dilution was possible as planned, with the discharged water quality better than 20 mg/liter BOD, 20 mg/liter T-N and 10 mg/liter T-P. The cost of processing waste water using these facilities is roughly JPY 65 per month per hog (cf. Photo 21 ref. mat. 373-379) Survey conducted April 23, 1986, weather fair, temperature +17C, water temperature 14C Table
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MLSS 5.400mg/l. MLVSS4.260mg/l. SV-30 99% |