Disintegration as a key-step in sewage sludge treatment

Abstract

Fields of application of the mechanical sewage sludge disintegration are presented. Various methods of mechanical cell disintegration are described and the obtained results are compared. All methods are able to break up the flocs, but only some of them provide enough energy for the disruption of micro-organisms. The possible improvement of the anaerobic degradation process using raw sludge, excess sludge and digested sludge is shown. Excesssludge proves to be the most suitable. The use of disintegrated sludge as a carbon source for the denitrification is explained as a second field of application. External carbon sources can be substituted and the amount of sewage sludge to be disposed of is reduced at the same time. Foamingin digesters caused by filamentous micro-organisms can be reduced by disintegration of these sludges. Adsorbed gas bubbles are released and the settling properties of the sludge are improved. Another field of application is the solution of organic components of the sludge solids. The increased concentration of nitrogen and phosphorous in the supernatant causes recovery processes to be operated at a higher cost efficiency. A comparison of effort and advantages shows that disintegration is especially useful if there are problems in the sludge treatment process of the WTP.