Application of microwaves for sewage sludge conditioning

The article focuses on the effect of microwave treatment on the dewaterability of sewage sludge. The specific resistance to filtration, capillary suction time, and dry matter content in centrifuged sludge cake were measured. The quality of sludge liquor obtained after microwave processing was also analysed. It was found out that microwaves improve sludge dewaterability. The quantitative improvement depends on sludge type—better effect of microwave processing were observed in the primary sludge compared to mixed or digested sludges. If microwave treatment is followed by polyelectrolyte conditioning, the effects are considerably better than while these conditioning methods are used separately. Microwave conditioning increased burden of organic matter (BOD5, COD) in the sludge liquor.