Composition, Production, and Treatment of Sewage Sludge

Abstract

Sewage treatment ultimately culminates in the concentration of the solid phase. Sludge are separated mainly in primary or secondary decanters. Even in biological treatment, where biological degradation of organic matter actually occurs, there is the separation of excess sludge concentrated in the bottom of the secondary settlers of activated sludge systems or biological filters. In fact, the production of sludge is an important differential in the choice of the treatment system. While purely aerobic systems such as activated sludge or high-rate biological filters can produce 0.6-0.8 kgSS/kgBOD applied, sludge production in an upflow anaerobic sludge blanket (UASB) reactor is only about 0.2 kgSS/kgCOD applied. Even the mixed anaerobic/aerobic system leads to less sludge production than that of an exclusively aerobic system. This advantage is very important nowadays, especially since, besides reducing the treatment needs, the difficulties with the final disposal of the sludge are usually very large.

Dynamic Characteristics Analysis of Metallurgical Waste Heat Radiative Drying of Thin Layers of Sewage Sludge

“…The most critical step in wastewater sludge treatment is sludge drying, which can be commonly categorized into mechanical drying, natural drying, and thermal drying methods. Mechanical drying involves using mechanical equipment such as centrifugation, filtration, or evaporation to reduce the moisture content of the sludge [11]. Natural drying refers to methods where moisture is allowed to evaporate naturally or gravity is utilized to separate water, with sludge drying beds being a typical example, where sludge is spread over sand beds until it dries [12].…”