Performance evaluation of Industrial Effluent Treatment Systems (IETSS) an insight for biotechnology advances in agro-based wastewater treatment

Abstract

Seven Industrial Effluent Treatment Systems (IETSs, IETS1-IETS7) were evaluated to identify the most effective biological treatment for palm oil mill effluent (POME) and their compliance to the prevailing national discharge standard. Two main groups of IETSs were selected, comprising the conventional secondary biological treatment (G1) and biotechnologically advanced tertiary treatment processes (G2). G1 IETSs treated POME with an organic content equivalent to raw domestic sewage from a population of 175,799 to 480,558 persons (PE) while G2 IETSs in the range of 136,986 to 406,392 PE. Removal efficiency of aggregate organic constituents in terms of the biochemical oxygen demand (BOD), chemical oxygen demand (COD) and oil & grease (OG) as well as the physical properties in terms of the suspended solids (SS) and volatile suspended solids (VSS) in the IETSs was evaluated. Results indicated that the most efficient system was IETS6 with BOD, COD and OG removal of 99.7%, 98% and 99.6% respectively. It comprises the open-top anaerobic tank digesters, lagoon system and a polishing plant (extended aeration, coupled with fixed packing in activated sludge aeration tank), with large amount of biological agent. The biological treatment efficiency of POME for IETSs was described. All IETSs showed compliance to the national discharge standard except IETS1.