Bioremediation of Petroleum Sludge Impacted Soils Using Agro-Waste from Moringa Seed

Abstract

The feasibility of using agricultural waste from drumstick (Moringa Oleifera Lam.) seed as organic fertilizer to remediate petroleum sludge impacted soils within an 8.5 km radius from Warri Refinery and Petrochemical Company (WRPC) in Delta State, Nigeria was studied using standard methods. The experimental set-up was monitored for 90 days at 30 days interval. The total petroleum hydrocarbon (TPH) and polycyclic aromatic hydrocarbon (PAH) contents across the 5 sampling sites(A to E) for day 1 were (293846.00, 4255.87), (123874.00, 2942.04), (97291.00, 1818.38), (87561.23, 928.22), (48063.61, 189.93) (mg/kg) as against the control (651.18, 68.06) (mg/kg) respectively. After treatment with the agro-waste from Moringa seed for 90 days, the TPH and PAH contents from sites A to E degraded to (652.58, 5.66), (520.67, 3.09), (254.32, 4.81), (68.80, 0.48) and (61.29, 1.66) (mg/kg) while the control site exhibited (50.62, 0.46) (mg/kg) respectively as detected via gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detector (GC-FID). From the Soil Quality Standards (SQSs) conducted after day 30, only the control site was free from the traces of contamination recorded at day 1. SQSs after 60 days indicated that sites D and E were no more contaminated. SQSs conducted after 90 days revealed that all the sites were free from petroleum hydrocarbon contamination. This result indicated that Moringa Oleifera seed cake (MOSC) is a suitable biostimulant for remediation of petroleum sludge impacted soils.