Sewage Sludge Thermal Hydrolysis Process

Abstract

In 110~190°C for 15~75min excess sludge thermal hydrolysis test, investigated the dissolution rate of the volatile suspended solids, Sludge SCOD, TCOD concentration change in composition of organic acids in the supernatant, and analysis the improvement of the anaerobic digestion performance. The results show that, with the increase of thermal hydrolysis temperature and extension of time, sludge supernatant on SCOD, VFA rising. At 190 °C, 75min conditions, SCOD, VFA reached the maximum 6674mg / L2630mg/ L; Sludge organic solids dissolved and the release of COD, etc. mainly in the first 45 min to complete, little change after 45min. When thermal hydrolysis temperature between 90~170°C, anaerobic digestion performance increase with temperature rise, When the temperature is higher than 170 °C, the sludge anaerobic digestion performance begins to decline.

Migration and transformation of heavy metals during the microwave-assisted thermal hydrolysis of sewage sludge

“…The reductions in the concentrations of TS and VS were proportional to the temperature as shown in Figure 1(a). The concentration of TS in the raw sludge decreased by 16.15% under 160°C because of the hydrolysis of organic matters, gasification of volatile substances and mineralization (Li et al 2013). Furthermore, amorphous hydroxides could be converted to oxides after microwave irradiation (Obrador et al 2001), also resulting in the reduction of TS.…”