Improved processing waste water - by combining wash water contg. active washing cpds. with rinsing water, filtering and processing by flotation for re-use

摘要

In processing and reuse of waste water, esp. contg. active washing cpds. and of rinsing water from cleaning of articles, esp. vehicles, the used wash water and the used rinsing water are fed together, as waste water, to a container, part of the waste water is filtered to recover (part of) the needed wash water, so that active washing cpds. in the waste water are reused, and part of the waste water is processed by flotation to recover (part of) the needed rinsing water. Fresh water pref. demineralised, is added to the rinsing water in at least one rinsing stage. The part of the waste water reused as wash water is filtered in a multi-layer filter, esp. with layers of differing granulation pref. a layer of coarse hydroanthracite and/or a layer of finer quartz sand. A pressure redn. flotation is used, and metal salts or a flocculating agent is added to the part of the waste water to be fed to the flotation. At least part of the flotation sludge is recycled to a pptn. stage. The part of the waste water to be fed to the flotation is (partly) exposed to a tension discharge. Waste water which is not to be reused may be processed by flotation. ADVANTAGE - The process is simplified, and the amt. of active washing cpds. to be added is reduced. Metal salts are not added and the water can be recycled for a longer time, reducing the amt. of fresh water needed and the amt. of waste water