Patent ID: 7445713

Claim:
A method for anaerobic treatment of wastewater and sludge in a plant comprising a digestive reactor coupled with a sapropel enrichment reactor, wherein a portion of digesting sludge is discontinuously evacuated and fed back into the digestive reactor, comprising the steps of: closing a gas pusher in a gas line connecting both the digestive and sapropel enrichment reactors, while a sludge pusher in a sludge line connecting both the digestive and sapropel enrichment reactors is open; operating a gas pump generating an underpressure in a gas space of the sapropel enrichment reactor while feeding digesting sludge from the digestive reactor into the sapropel enrichment reactor; closing the sludge pusher; maintaining the underpressure in the gas space of the sapropel enrichment reactor; opening the gas pusher; opening the sludge pusher to effect a reflux of sapropel concentrate from the sapropel enrichment reactor into the digesting reactor; removing a sapropel-free water fraction from the sapropel enrichment reactor; and repeating the aforementioned steps.