| abstract |
In the present invention, the concentration of oxidizing agent in fed water or an index having a correlation with the oxidizing agent concentration is measured in a path between an addition point for the oxidizing agent and a point of addition. for a sludge neutralizing agent, and the amount of an added reducing agent is set based on this measured value. In addition, the concentration of sludge neutralizing agent in the water supplied to a reverse osmosis membrane device or an index correlating with the concentration of sludge neutralizing agent is measured after the addition of the slurry neutralizer. sludge neutralizing agent, and the amount of sludge neutralizing agent added is set based on this measured value. |