Qualitative Assessment of Palm Oil Mill Wastewater from Small-Scale Processing Mills in Ghana

Palm oil production in Ghana is dominated by informal small-scale mills that produces about 80% of the national production. These mills have been noted for violating environmental regulations. This research was aimed at characterizing palm oil mill wastewater produced by small-scale mills in Ghana to better understand the extent of environmental damage. Four processing mills were selected from Abura Aseibu Kwamankese District of Ghana. Wastewater samples were collected from each of the four processing mills in March 2020 (peak production season). Samples were collected in opaque plastic containers and stored under 4 °C. Parameters measured were pH, total solids, TSS, TDS, BOD5, COD, total nitrogen, phosphorus, potassium and oil and grease using standard analytical methods. The mean characteristics of the wastewater were pH (4.5 ± 0.05), total solids (3,976 ± 1,397 mg/l), TSS (3,976 ± 1,397 mg/l), TDS (358 ± 158 mg/l), BOD5 (21,877 ± 4,728 mg/l), COD (56,357 ± 3,441 mg/l), COD:BOD5 (2.6), total nitrogen (246 ± 86 mg/l), phosphorus (60 ± 16 mg/l), potassium (156 ± 24 mg/l), and oil & grease (527 ± 198 mg/l). The mean concentrations of 6 out of the 7 parameters were over 2-orders of magnitude higher than the Ghana effluent discharge standard. The pH, TDS, BOD5 and COD of the wastewater from boiling were higher than for clarification. The current practice of disposing raw wastewater into the natural environment by the small-scale processing mills is negatively affecting the environment.