Enhanced treatment and evaluation alternatives of waste anaerobic sludge – the effluent of the anaerobic sludge digesters from municipal waste water treatment plants

In this study, four different treatment methods were conducted for enhanced treatment and reusability of the waste anaerobic sludge. Thermal-alkaline hydrolysis pretreatment method was used for enhancing the solubility and biodegradability of the waste anaerobic sludge and the methane yield. Carbonization process is used for biochar production from waste anaerobic sludge after that, fuel and adsorbent qualities of the biochars were determined. And finally sulphate reducing bacteria were used to reduce the solid concentration of waste anaerobic sludge. According to the results, optimum process parameters are as follows: at boiling temperature and pH 12 with a holding time of 6 hours for thermal alkaline pretreatment; holding 2 hours at 700 oC with ZnCl2 activation for carbonization process and starting pH of 5 and 2500 mg/L SO4 concentration for solid removal by SRB.