Remediation of simulated oil contaminated sites using shells of clams and oyster - Total petroleum hydrocarbons of simulated oil contaminated sites, before and after remediation

Abstract

Aquatic contaminated sites due to oil spillage were simulated using five crude oil samples (Usan crude, Ogbele condensate, Ogbele crude, Abo crude and Kokori crude oil) in a water body at constant volume and temperature. The Total Petroleum Hydrocarbon (TPH) of the five contaminated sites were determined before and after remediation using Gas Chromatographic analyses. The TPH of the five contaminated samples before remediation were: 977, 817, 1029, 1131, 1209 mg/L respectively. Powdery oyster and clam shells of different particle sizes (60 µm, 30 µm and 10 µm) were used as adsorbents to remediate each of these contaminated samples through bioremediation. The same percentage reduction of TPH were obtained for four samples(contaminated with Usan crude, Ogbele condensate, Ogbele crude, Abo crude)after remediation with 10 µm powdery oyster shell (POS) and 10 µm powdery clam shell (PCS) respectively; The values obtained were: 99.9 %, 99.88 %, 99.90 % and 99.90 % respectively, thereby leaving a TPH of 1 mg/L for each of the four samples after remediation. Adsorbents with the smallest particle size of 10µm gave the best result with the highest percentage reduction of Total Petroleum Hydrocarbon (TPH) for the five contaminated samples. Samples contaminated with Kokori oil were more resistant to adsorption due to suspected higher molecular weight hydrocarbons that are non-biodegradable, hence the percentage reduction of Total Petroleum Hydrocarbon were 57.82% and 68.32% after remediation with 10 µm powdery oyster and clam shell respectively, thereby making clam shell a better adsorbent. The effectiveness of the adsorbents is directly proportional to their surface area which is a function of the particle size. The smaller the particle size of the adsorbents the larger the surface area. Total Petroleum hydrocarbons in aquatic environment can lead to the death of aquatic lives in addition to making the water unfit for domestic and industrial uses.

Keywords: Biodegradation, adsorption, adsorbents, contamination, hydrocarbons, spillage, simulation, bioremediation.