The Bioremediation of Refinery Wastewater Using Inorganic Fertilizer

Abstract

This study investigated the treatment of refinery wastewater using inorganic fertilizer. The biological method of treatment using the process of bioremediation was used. Inorganic fertilizer (NPK 15:15:15) was used to biostimulate the microorganisms present in the wastewater. Five samples of the refinery wastewater with equal pollution load were treated with different amounts of fertilizer (5, 10, 20, 30, and 40 g/l). Biochemical oxygen demand (BOD), pH, dissolved oxygen (DO) and total hydrocarbon content (THC) of the wastewater were monitored for a period of 35 days. From the results obtained, the BOD was observed to have dropped from 68.71 to 30.23 m/l; 68.71 to 23.92 mg/l; 68.71 to 22.11 mg/l and then 68.71 to 21.86 mg/l for the 5, 10, 20, 30, and 40 g/l of the refinery samples, respectively. Similar decreases were also observed for the other physiochemical parameters, except for the pH and DO, which increased with time. It was observed that the 40 g/l sample was more effective in the 35 days of the study and these results met the Federal Environmental Protection Agency (FEPA) standard for BOD, which is within the range of 30–35 mg/l. Hence, the method of bioremediation using fertilizer in the treatment of refinery wastewater can be applied on a large scale treatment.