Patent ID: 6808636
Filing Date: 2004-10-26
Classification: C02F

Abstract:
A method for reducing sludge viscosity of a sewage sludge having a solids concentration of at least ten percent by weight, being sewage sludge that, prior to use of the method, is so viscous as to be non-pumpable, the method comprising:(a) increasing the pH of the sludge to the range of 9.5 to 11.5; (b) maintaining the sludge at the pH of (a) and at a temperature of 10Â° C. to 37Â° C. for a period of at least one day; (c) incubating the sludge by maintaining the resultant sludge at a temperature in the range of 4Â° C. to 100Â° C. for a period of time of at least one hour; (d) subjecting the sludge to such physical shearing or disintegration as to transform the sludge front being non-pumpable to being pumpable; (e) subsequently discharging the sludge; and carrying out the step (d) no later than simultaneously with the step (c).