Effect of Waste Tea Leaves and Waste Frying Oil on the Bioremediation of Petroleum Polluted Soil

Abstract

Petroleum hydrocarbons when released in to soil cause serious effects on plants, animals and humans. Accumulation of PHCs, especially the polycyclic aromatic hydrocarbons (PAHs) in the tissues of living organisms causes mutation or death of the organism. For the protection of living organisms, these pollutants must be removed or detoxified from the environment. Bioremediation of the PHC polluted sites is promising strategy, it is cost effective and safe for the environment. In the present work a polluted sandy soil was bioremediated by using the effect of certain additives such as waste frying oil (WFO), waste tea leaves, NP fertilizer and combination of these materials; on the microbial counts of this soil and on the biodegradation of the oil. It must be noted that no previous research work was carried out using WFO and waste tea leaves (T) for enhancing the biodegradation of PHCs. The results obtained show that higher counts of THB were 18.08 × 107 and 17.21 × 107 CFU/gm soil in presence of WFO and waste tea leaves respectively. As for THB the higher counts were recorded in the presence of WFO and WFO + T although no significant variations were obtained. These results indicate that the main factor for increasing total counts of bacteria is presence of WFO and sometimes the presence of (T). As for the effects of the different treatments on the biodegradation (Loss %) of the pollutant, the results show that after 60 days of treatments, WFO +NP succeeded to remove the higher amount of oil (47.0%), followed by WFO alone, although statistically no significant variations between the results were observed. Again it can be seen that the main factor is the presence of WFO. The above results lead to the conclusion that the application of WFO and /or “T” may represent promising, cost - effective and safe strategy that can be used under emergency conditions. Polycyclic aromatic hydrocarbons (PAHs) at the beginning and at the end of 60 days treatments were identified and quantified by using HPLC analysis technique. The results show that this pollutant contained 13 PAH individuals of the 16 US EPA priority PAHs. The total of these PAHs are 129.7 mg/kg soil, with pyrene the dominant (92.3 mg/kg soil). Results of the biodegradation of total PAHs show that the higher loss (%) was 79.9% in presence of WFO alone, followed by 40.8% in the absence of any treatments. In presence of WFO alone of different PAH individuals were completely degraded (100%), of the 7PAHs 3 PAHs were known to be carcinogenic compounds. Mixing the WFO with T+NP resulted in the complete degradation of 5 PAH individuals, of which two only are