Sludge thickening performance of mesh filtration process

Abstract

Small-scale wastewater treatment facilities play an important role in improving the aquatic environment in many countries. Although sludge treatment is essential for overall wastewater treatment, it is difficult for small-scale facilities to use mechanical equipment or other facilities. As the first step of the sludge treatment, it is important to develop a convenient sludge thickening process for small-scale facilities. In this work, we examined the sludge thickening performance of a mesh filtration system: the mesh opening sizes of 100-500 microm, and the sludge (3,000-9,000 mg-SS/L) was obtained from a domestic wastewater treatment facility. The filtration was carried out only under the hydraulic pressure between the water level and the effluent port connected to the mesh filter module. The sludge reduction rates were in the range of 85-95% for 6-7 h; the initial filtration rate was very high, but the rate decreased with a decrease in hydraulic pressure due to the reduction of the water level in the vessel. In addition, the effluents (passed through the mesh) contained very low SS and could be directly discharged into the environment.

Enhanced Biological Phosphorus Removal for Liquid Dairy Manure

“…This is because the settlement of waste activated sludge is relatively slow and gas emitted from activated sludge during thickening process may adversely affect sludge settling (Lang, 2005). On the other hand, comparing to other thickening methods, gravity thickening is more economical and easy to operate, although usually the effluent suspended solid is relatively high (Park et al, 2004).…”

“…In other instances, Park et al (2004) utilized mesh filtration with pore sizes of 100 to 500 μm for thickening and achieved a 85-95% of sludge volume reduction, despite that thickening was very fast in the beginning, and slowed down as solids clogged the surface of mesh. In order to minimize P release during sludge thickening, pre-aeration and a combination of linear screen and belt press were introduced by Pitman et al (1991).…”