An experimental pilot scale study was conducted to compare the effectiveness of two agriculture waste (wheat straw and rice husk) in increasing the performance of anaerobic sludge digester. Molasses + Wheat straw and Molasses + rice husk were applied and evaluated. Two pilot units were operated in parallel erected for this reason in El Berka wastewater treatment plant in El Sallam district, Cairo, Egypt. The experiment consists of two stages. In the first stage molasses + rice husk and molasses + wheat straw were added to thickened sludge at mixing rates 5%, 10%,15% and 20% by weight. In the second stage, the optimum mixing ratio 15% of molasses+ wheat straw was added to thickened sludge and compared with another pilot digester filled with thickened sludge only. Characteristics of thickened sludge such as Temperature, pH, COD, TS, VSS, total alkalinity, volume of methane and CBOD/NBOD ratio were monitored and evaluated. The most efficient material based on COD, BOD and VSS destruction percent was 15% mixing rate (7.5% molasses + 7.5 % wheat straw). |
