Evaluation of techniques used for parameters estimation: an application to bioremediation of grease waste

In the present work, evaluation of different conventional techniques, i.e., chemical oxygen demand (COD), biological oxygen demand, elemental analysis, Fourier transform infrared (FTIR), and gas chromatography used for estimating biodegradation of grease waste was carried out. In this order grease waste was incubated with Penicillium chrysogenum for 7-30 days and analyzed percentage of degradation. After 15 days of incubation, the percentages of reduction in COD, carbon, hydrogen, and nitrogen content of grease waste were found 28, 53.5, 12.7, and 0, respectively. Further it was analyzed by FTIR and gas chromatography-mass spectroscopy (GC-MS) and observed that bifurcated peaks of grease waste at 2,926 and 2,855 cm(-1) had reduced remarkably, which corresponds to aliphatic hydrocarbons, while new broad peaks appeared at 3,400 cm(-1) indicating addition of oxygen molecule to reduced aliphatic hydrocarbon. GC-MS study also supports the results of FTIR, COD, and elemental analysis, but quantification of the percentage of degradation was difficult and limited to volatile organic content, while COD and elemental analysis were found more accurate and more informative. The current study would be helpful in the estimation of biodegradability not only of grease waste but also of other complex nonbiodegradable compounds polluting the environment.