摘要 |
There is provided a process capable of inexpensively producing reclaimed water having excellent quality from wastewater without using a large amount of ozone. The process for producing reclaimed water comprises: bringing ozone into contact with raw water such as treated sewage using an ozone contact column 2 or the like to enhance coagulability of a solid matter contained in the raw water; injecting a coagulant into the raw water using a coagulant-injecting pump 6 to coagulate the solid matter; and membrane-filtering the coagulated solid matter through a separation membrane 8. A residual ozone concentration in the raw water before a separation membrane is measured by a dissolved-ozone meter 5. When deterioration of quality of the raw water results in an ozone demand exceeding capacity of an ozone generator and in the residual ozone concentration lower than a given value, an amount of the coagulant to be injected is increased. |