Comparison of the Effect of Fresh and Dry Lemon Grass (Cymbopogon citratus) Granules on Biodegradation of Petroleum Hydrocarbons

This work compared the result of the effect of lemongrass granules as a local raw material in the treatment of crude oil polluted soils when it is in a fresh or dry condition. The comparison of the usage in fresh or dry state is aimed at identifying the most effective among the two conditions that will give the best result in biodegradation of petroleum hydrocarbons. The soil samples were obtained with hand soil auger and analyzed in the laboratory using standard methods. Soil sample C represented the soil treated with fresh lemongrass while soil sample E was treated with dry lemongrass. Poultry droppings were added to them as nutrients while the experiment was monitored for 28days. The determined parameters were total petroleum hydrocarbon, pH, total nitrogen and phosphorous and hydrocarbon utilizing bacteria. The results show that the soils samples were Clay soils and total petroleum hydrocarbon decreased by 77% and 24 % for soil sample C and E respectively. The soil pH values were 6.51 and 6.10 for soil sample C and E. Also total nitrogen was 0.11% and 0.355% for soil sample C and E. The concentration of phosphorous in soil sample C and E were 0.24 and 1.26% respectively. The hydrocarbon utilizing bacteria count increased from 3.65×103 cfu/g to 5.41×103 cfu/g in soil sample C but decreased to 2.10×103 cfu/g in soil sample E. Comparison of the two process showed a significant decrease in concentration of total petroleum hydrocarbon using fresh lemongrass granules to dry lemongrass granules. This implies that the use of fresh lemon grass is more effective compared to that of dry lemon grass granules. This is because the use of fresh lemongrass granules enhanced rapid growth of microorganism, therefore a significant result on biodegradation of petroleum hydrocarbon was achieved. This confirmed the use of fresh lemongrass granules as a better method compared to dry lemon grass granules in the treatment of soils contaminated with petroleum hydrocarbons.