Sludge Stabilization of Vermifilter Andanalysis of Influence Factors

Under different operating modes, this paper studies on the sludge stabilization effect and of vermifilter in different medium, and analyzed efficiency factors of the sludge stability in filter. The results showed that after the treatment of vermifilter, the average sludge VSS/SS was smaller than 50%, the average VFA was 30-40%, and the average organism decomposition rate was up to 48-65%, so the system's whole effect was perfect. Filter medium was one of the most important factors which affect the function of sludge stabilization. Compared to silica sands, earthworms' sludge digestion efficiency in ceramic pellets was higher, and the system's whole effect was better. It was mostly due to the damage to earthworms caused by filter medium. The most suitable temperature for earthworms' sludge digestion efficiency was 23-28degC, and the whole effect was the best at the same condition. Since hydraulic overloading was somehow negative to earthworms' normal activities and its sludge digestion efficiency, it should be less than 6.00 m/d.