Method of treating an organic sludge, especially paint sludge
AssigneeParkner GmbH
InventorsOtto Stuckmann, Peter Hombach, Wolfgang Ruger, Karl Grosse, Wolfgang Leiner, Winfried Schmidt, Reinhard Diekmann
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Abstract
A paint sludge is subjected to aerobic biodegradation with increased dry content of the resulting sludge and the latter is then subjected to anaerobic biological degradation. The effluent from the two biostages are sterilized by ozonization, UV-irradiation or peroxide addition. The sludge from the anaerobic biostage can be dried to an inert granulate and drying vapors are recycled to the aerobic biostage. The sterile liquid is returned to the wash water circulation of the painting plant.
Claims9
A method of treating paint sludge from a painting plant in which a wash water is recirculated between a spray booth and a settling basin and a paint sludge is formed in said settling basin, said method comprising the steps of:
- (a) subjecting said sludge withdrawn from said settling basin to aerobic degradation in a first biostage to decompose low molecular weight organic compounds and produce a first biostage sludge of greater dry substance content than the sludge from said basin and a first biostage clarifier effluent;
- (b) biologically degrading said first biostage sludge under anaerobic conditions in a second biostage to decompose high molecular weight organic compounds and produce a second biostage sludge with increased dry substance content over said first biostage sludge and a second biostage clarifier effluent;
- (c) drying said second biostage sludge with the production of vapors to produce a dry product;
- (d) condensing said vapors to form a condensate;
- (e) recirculating said condensate to said first biostage;
- (f) sterilizing said first biostage effluent and said second biostage effluent to produce a sterile effluent;
- and
- (g) recirculating said sterile effluent to said wash water.
The method defined in claim wherein said second biostage sludge has a dry substance content of 40 to 60% by weight.
Dependencies are inferred from the claim text.