Abstract:
The study of oleophilic fertilizer aimed to supply essential nutrient -nitrogen (N) andphosphorus (P) in order to stimulate hydrocarbon-degrading bacteria (RBC 109) in bioremediationof crude oil contaminated in seawater. The experiments were divided into 2 parts: firstly, study onthe composition of the oleophilic fertilizers which are urea, lecithin, 2-Butoxy-1-Ethanol, water andoleic acid as formula 1, stearic acid was used in stead of oleic acid as formula 2. The solubility ofnitrogen and phosphorus from both fertilizers formulas in seawater, suitability of microbial growthand degradation of contaminated hydrocarbon were designed to choose a proper effective fertilizer.The second study focused on the effective ratio of the fertilizer to hydrocarbon degradation, whichare 0.5, 1 .O, 2.0 and 4.0 (vlv) of crude oil.Bacteria RBC 109 can grow in seawater with range of salinity 0-30 ppt. and in 1.0 %(vlv) contaminated crude oil. The result of the studied fertilizer shown that the suitable componentof the first fonnula are 217 gA oleic acid, 232 gll 2-Butoxy-1-Ethanol, 65 g/l urea and 382 glllecithin and the second formula comprise of 55 gll stearic acid, 523 mlll2-Butoxy-1-Ethanol, 65 g/lurea and 382 gll lecithin. The essential nutrient concentration in both fonnulas of the oleophilicfertilizer are 32.5 gll nitrogen and 3.25 gll phosphorus. It was found that the first fonnula (oleicacid) shows higher immobilization efficiency in the crude oil than the second formula (stearic acid)in term of nitrogen and phosphorus dissolved to seawater. However the solubility of these nutrientsdid not effect on microbial growth rate. Nevertheless the second fonnula of fertilizer affect to higherdegradation rate of hydrocarbon than the first formula (the degradation rate of hydrocarbon ofthe first fonnula is 10.8% at 120 hours of experiment and the degradation rate of hydrocarbon ofthe second formula is 29.1% at 120 hours of experiment). It was found that the suitable suppliesratio of the oleophilic fertilizer per crude oil is 1 :1 (vlv).