Design of Anaerobic Digester
1. Design a high rate two-stage anaerobic digester for the treatment of sludge using the following data: Population = 7000, sludge produced = 0.09 kg/capita/day, volatile solids in the raw sludge = 70%, Moisture content of raw sludge = 96%, Specific gravity of raw sludge solids = 1.2, volatile solids reduction during digestion = 60%, Moisture content of digested sludge = 92 %, and specific gravity of digested sludge solids = 1.6. Check for volatile solids loading.
2. An anaerobic treatment process is used to treat a flow of 600 m3/d with an influent soluble COD concentration of 5000 mg/L. The net biomass yield is 0.04 g VSS/g COD removed and 95% soluble COD removal occurs at a temperature of 30oC. Assuming the gas contains 65% methane, calculate the total gas flow in m3/d. What is the energy value of the gas produced in kJ/d (Heat value of methane is 50.1 kJ/g at 30oC)
