Accelerated start-up of a semi-commercial digester tank treating palm oil mill effluent with sludge seeding for methane production

The modern closed digesters are becoming more popular for treating palm oil mill effluent (POME) and are currently being installed nationwide in Malaysia to replace the conventional open lagoons and tanks treatment system. This paper describes an accelerated start-up of the 500 m semi-commercial anaerobic digester 3 treating POME and methane gas recovery for clean development mechanism (CDM) project. Results showed that by direct seeding through the transfer of the sludge from either top or bottom of the open digester tank,the start-up period was significantly shortened. The bottom seed sludge transfer led to interesting results including a 24 day start-up period, stable pH condition (pH 6.8-7.2), high COD removal efficiency (>90%), satisfactory VFA to Alk ratio (