PROCEDURE FOR RECYCLING HEAT FROM WASTEWATER IN A CLEANING PLANT AND CLEANING PLANT FOR THE PERFORMANCE OF THE PROCEDURE

摘要

A purifying plant for waste water comprises at least two receptacles (1, 2, 3, 4) in which waste water is successively treated, and a heat exchanger (10) connected to the plant outlet (9) for recovering heat from the purified water. There are provided conduits (14, 16) and valve means (13, 15) by means of which at least one (3, 4) of the receptacles can be isolated such that inflowing waste water by-passes that receptacle. A conduit (18, 20) from said receptacle and pump means (17, 19) in the conduit serve for recirculating water from the receptacle, when isolated from the throughflow of water, back to the throughflowing water flow upstream of the heat exchanger. When said means are operated according to the method described, the flow rate of water through the heat exchanger can be maintained substantially constant irrespective of fluctuations in the inflow rate of waste water to the plant, and the water temperature at the heat exchanger inlet can be maintained substantially constant.