c 1997-2009 RERA
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c 1997-2009 RERA |
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All right reserved. Any Unauthorized Copying or Using Prohibited. NEW
PROCESS FOR 2nd
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METHODS
The bottom sediments sampled from the test water area in Marsh Furukawa were(muck) black without free acidity, had a putrid smell and were -500mV in oxidation-reduction potential (ORP), and 9.3 in pH value. The sediments were composed of nitrogen of 0.512% DS and phoephorus of 0.245% DS and showed an ignition residue of 23.3%. The concentration of chlorine in the sediments was 3.500 mg/l. thus indicating the properties peculiar to eutrophicated brackish lake.
In this test, the batch-type activated sludge tank located in a bathing place was used. The tank measured 4 m wide. 4 m long and 2.5 m deep, and its effective volume was 40 m3. A conceptual view of the test tank is shown in Fig.1. The controller used in this test consisted of DO, pH, ORP and water temperature measuring equipment and aeration controlling equipment. A conceptual view of the controller is shown in Fig.2.
The activated sludge produced in the above-mentioned facility was used as species sludge in this test, and acclimatization operation was carried out by adding the bottom sediments of Marsh Furukawa. The ratio of species sludge to contaminated sediment was 1:5 in volume percent. The period of acclimatization was 30 days, and acclimatization judgment was made based on DO wave characteristics and pH values. In the test, the activated sludge having nitrifying and denitrifying functions was added to the contaminated organic sludge excluding sand; then, aeration and anaerobic stirring were repeated, and the anaerobic biota of sediments was succeeded to the aerobic micro-biota, thereby transplanting the self-purifying function of the activated sludge into the sediment. The test was conducted fully automatically using programmed computers. The optimization of aeration and judgment on the succession of micro-biota were made based on DO wave characteristics, pH values and ORP values. Batch running was performed under the following conditions: aeration time + stirring time = 8 hours/cycle x 3 cycles/day. The test methods specified in the "Sediment Monitoring Methods" of the Environment Agency of Japan were used. Also, the methods of analysis specified in the Japanese Industrial Standards and the Sediment Monitoring Methods of the Environment Agency of Japan were used. |
