Mathematical modeling of phenol degradation system using fuzzy comprehensive evaluation

New mathematical model for phenol degradation is developed that uses fuzzy comprehensive evaluation. Biodegradation of phenol by Pseudomonas putida (NICM 2174), a potential biodegradent of phenol has been investigated for its degrading potential under different conditions. In the present work, results of batch study on P. putida (NICM 2174) and its degradation activity on phenolic compounds such as phenol, o-cresol, p-cresol, p-nitrophenol and resorcinol each of concentration 0.300 g/l are considered. In the present study, the effect of glucose, yeast extract, ammonium sulphate and NaCl each at 0.5, 1.5, 2.0, 3.0 and 4 g/l on degradation of aforementioned phenolic compounds have been investigated and a fuzzy control model has been developed to predict the extent of degradation. Main aspect of this study is to establish a fuzzy relation matrix R for objective evaluation of phenol degradation. A series of membership functions for the degradation are being evaluated after investigating the growth properties of bacteria at various levels of carbon and nitrogen sources. Important element is the factor vector A, which is deduced from a survey of panel of judges (n=25). A in conjunction with R generates a multifactorial equation which can be used to calculate the extent of phenol degradation. Biomass growth contributed significantly to phenol degradation rates especially when the degradation medium was supplemented with a utilizable carbon and nitrogen sources.