Response surface optimization and effects of agricultural wastes on total petroleum hydrocarbon degradation

This study was carried out to investigate the effects of Goat manure (GM) and Palm oil mill effluent (POME) on total petroleum hydrocarbons (TPHs) degradation. Microbial respiration rates (CO2 evolution) were investigated. TPHs degradation rate constants were estimated using the first-order kinetics model. Scanning electron microscope (SEM) and infrared spectroscopy (FT-IR) were used to investigate the surface morphologies and functional groups in GM and POME. The CO2 evolution rates in TPH contaminated soil treated with GM (TPHCS-GM), TPH contaminated soil treated with POME (TPHCS-POME), and the untreated TPH contaminated soil (UTPHCS) were 497 mg/g, 440 mg/g, and 296 mg/g, respectively. TPHCS-GM showed higher TPH degradation rate with corresponding lower half-lives. Results from the physiochemical characterization indicated that GM performed better in restoring the scarce nutrient in the TPH contaminated soil. 58% and 39% of TPH were degraded at pH 8 and 4 in TPHCS-GM and TPHCS-POME, respectively. The response surface optimization process indicated the accuracy of the quadratic model (R2 value of 0.9891) in predicting TPH degradation (76.59%) with optimum independence variables of initial TPH concentration (300 g/L) and pH (6). The results obtained from this work showed the positive prospects of GM and POME as organic nutrients in TPH contaminated soil.

Source: Beni Suef University Journal of Basic and Applied Sciences - July 11, 2018 Category: Science Source Type: research