| 摘要 |
<p>PROBLEM TO BE SOLVED: To enable stable operation by making it possible to return a part of the treated water in a treated water tank to both of a pH adjusting tank and an anaerobic wastewater treatment apparatus by a circulating pump. SOLUTION: A part of treated water is returned to the piping between a liquid supply pump 2 and an anaerobic wastewater treatment apparatus 3 (small circulating system) as circulating water. The setting of the operation method and flow rate of a circulating pump 5 is different by a circulating system and, in a large circulating system, the circulating pump 5 is stopped when the water level of a pH adjusting tank 1 is high and the water level of a treated water tank 4 is low. Herein, since a small circulating system is employed at a usual time and the circulating pump 5 is continuously operated, a freezing measure and the intermittent operation of a circulating line being the defects of the large circulating system are eliminated. Since a measure for adjusting the pH and temp. in the anaerobic wastewater treatment apparatus 3 due to trouble being the defect of the small circulating system can be taken by changing over the small circulating system to the large circulating system returning treated water to the pH adjusting tank 1 and adjusting the temp. and pH of treated water, a wastewater treatment plant can be stably operated.</p> |
