The hydraulic retention time (HRT) control upon palm oil mill effluent (POME) treatment by bio-CSTR 1 m3.

The influence of hydraulic retention time (HRT) on treating domestic wastewater of Palm Oil Mill Effluent (POME) was investigated in the pilot plant bio-continuous stirred tank reactor (Bio-CSTR) 1 m³. The bio-CSTR was operated at mesophilic condition and under two HRT conditions (33.3 days and 100 days) aimed to evaluate biogas productivity and operational stability. The pilot plant system was started with cow manure in the beginning, and its combination of POME, cow manure, and urea-DAP as micro nutrition in the first week. Afterward feeding of fresh POME was set between pH 5.4 and 5.5 by mixed it with overflow and further adjusted it with commercial ash soda. The performance observation shows that at shorter HRT, the organic compound was not consumed optimally. This was indicated by low pH 5.1 at the bio CSTR system and the amount biogas produced reached 54.3 L. In addition, it was needed more amount of ash soda to adjust the feeding. Setting by extending the HRT was gradually increased the pH so that needed less ash soda to adjust the pH. The biogas produced was increased 11.3 times higher than that of biogas at short HRT. The effectiveness of POME usage was got by the more organic compound was decomposed that indicated by lower COD analyzed at overflow. [ABSTRACT FROM AUTHOR]