Sewage sludge is an intensive kind of biomass waste, a collection infrastructure is in place, that suitable for utilization. Anaerobic digestion is a technique that can reduce the solids in sewage sludge and recover energy from it. However, due to the long fermentation time, it is necessary to install a huge digestion tank as part of this process. In this study, we investigated a method to speed up anaerobic treatment of sewage sludge using a combined hyper thermal solubilization and membrane separation system. We developed a prototype membrane separation type solubilization tank by installing a microfiltration membrane module in a solubilization tank. The temperature of the membrane separation solubilization tank was set at 70°C, was operated at a hydraulic retention time of 2.5 d, and excess sludge was used as a substrate. The total solids and suspended solids in the excess sludge were reduced at rates that reached 40% and 50%, respectively. This volume reduction rate was the same as achieved by conventional mesophilic anaerobic digestion. In addition, the biogas yield was 0.3 m~3/kg_(VS-added). These results suggested that the membrane separation and solubilization process could, at 70°C, greatly reduce the processing time of conventional anaerobic digestion.
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