Two=stage activated-sludge treatment of waste water - with conditions favouring optional-anaerobic microorganisms in first stage

摘要

Activated-sludge treatment of waste water is carried out in a plant comprising 1st-stage activating tanks, an intermediate clarifier, 2nd-stage activating tanks, and a final clarifier. The waste water is fed into a high-throughput 1st-stage activating tanks and then into the intermediate clarifier. The sludge from the intermediate clarifier is recycled to the 1st-stage tanks and/or withdrawn for processing. The 2nd-stage activating tanks and then to the final clarifier. The sludge from the final clarifier is recycled to the 2nd-stage tanks and/or withdrawn for processing. The improvement lies in the fact that the 1st-stage tanks are equipped to work with optional-anaerobic microorganisms which can be switched over from oxidative degradation to substrate-bound phosphorylation or incomplete oxidn., and the O2 content in the 1st-stage tanks is such that the optional-anaerobic microorganisms function by substrate-bound phosphorylation while obligatory-anaerobic microorganisms are suppressed and aerobic respiration is prevented. The process gives improved degradation of difficult-to-degrade substances (esp. carbon cpds.) with low energy consumption.