Characterization and treatment of sludge from the petroleum industry

Abstract

Samples of sludge from the petroleum industry were collected and characterized for their pollution characteristics. The solids concentration, pH, temperature, biochemical oxygen demand, chemical oxygen demand, dissolved oxygen, phosphate, nitrogen, conductivity, calcium, magnesium, sodium, potassium, iron, manganese, lead and chromium were determined. The analysis revealed that the mean value of total solids (TS) content, total suspended solids (TSS) and total volatile solids (TVS) were 1987, 1050 and 937 mg/l respectively. The dissolved oxygen (DO) content was 3.7 mg/l. The biological oxygen demand (BOD) and chemical oxygen demand (COD) were 518 and 1345 mg/l, respectively. The total nitrogen and phosphorus contents were 3.4 and 2.3 mg/l respectively. The total bacteria counts were 7.4 x 10⁸/100 ml. All these values exceed those of the standard as set by World Health Organisation (WHO) for potable water. This shows that the sludge has high pollution potentials and so need treatment before disposal. The COD:BOD ratio was 2.60 which indicated that the sludge can undergo biodegradation and suggests that biological method could be used in effecting treatment to the sludge. The high conductivity also indicated that the sludge can be treated by physicochemical method of coagulation and flocculation.

Keywords: Petroleum sludge, pollution characteristics, eutrophication, biodegradation, aerobic treatment,physicochemical method