Bioremediation of Crude Oil Polluted Soil Using a Blend of NPK Fertilizer and Periwinkle Shell Ash

Abstract

Analysis on the bioremediation of crude oil polluted soil using a blend of NPK (15-15-15) fertilizer and Periwinkle Shell Ash (PSA) is presented. The analysis involves using 7-batch bioreactors under aerobic conditions with each bioreactor containing 2 kg of soil sample and spiked with 200 ml of crude oil except for the control experiment, and were properly mixed and periodically tilled during the experimentation period of 90 days. The substrate concentration was analyzed as Total Petroleum Hydrocarbon (TPH) while the microbial concentrations Total Heterotrophic Bacteria (THB) and Hydrogen Utilizing Bacteria (HUB) was also analyzed, including the soil pH, during the period. Soil parameters (nitrogen, organic compound, phosphorus and potassium) were also measured at the beginning and at the end of the experiments. The results showed that THB increased with time from 6.0 × 105 cfu/g to 3.02 × 108 cfu/g for the control experiment, to 3.3 × 108 cfu/g for sample with 100 g NPK, to 3.95 × 108 cfu/g for sample with 100 g NPK and 200 g PSA during the period. HUB also increased from 2.74 × 104 cfu/g to 4.45 × 107 cfu/g for the sample during the same period. TPH values reduced from 58,200 mg/kg to 34,591 mg/kg for the control and to 18,045 mg/kg been the lowest for sample with 100 g NPK and 500 g PSA during the same period. pH values varied from 5.7 – 8.8 for all sample during the experimentation. Also nitrogen increased from 0.42% to 0.91%, organic carbon from 1.65% to 1.78%, organic matter from 2.58% to 3.20% phosphorus from 26.8% - 31.57%, and potassium from 0.35% - 0.46%.

Keywords — Bioreactors, Biodegradation, Monod growth kinetics, substrate concentration, Total

Heterotrophic Bacteria