PROCESSES FOR DEWATERING DIGESTED SEWAGE SLUDGE

摘要

The invention provides processes for dewatering digested sewage sludge which can give floc excellent in aggregation, filterability and the clarity of separated liquid with reduction in the amount of flocculant used and which brings about lowering in the water content of dehydrated cake. The invention relates to a process for dewatering digested sewage sludge which is characterized by adding a cationic polymer flocculant containing a polymer which contains cations in an amount of 4.0meq/g or above and exhibits a 0.5% salt viscosity of less than 40mPa s to digested sewage sludge and then dewatering the resulting sludge with a belt press or filter press; and a process for dewatering digested sewage sludge which is characterized by subjecting digested sewage sludge to centrifugal dehydration without an inorganic flocculant either while or after adding a cationic polymer flocculant containing a polymer which contains cations in an amount of 4.0meq/g or above and exhibits a 0.5% salt viscosity of 40mPa s or above to the sludge.