Predicting methanol and glycerol concentrations in microbial treated wastewater discharged from a biodiesel fuel production process using near infrared spectroscopy

摘要

Microbiological treatment of wastewater discharged from purification processes of biodiesel fuel (BDF) produced from waste edible oil with alkaline catalyst was carried out in a 3 L jar-fermentor. Wastewater treatment was started by the addition of the seed culture of Rhodotorula mucilaginosa HCU-1 to the medium prepared from oil-removed wastewater. Methanol and glycerol concentrations in the wastewater were predicted simultaneously using near infrared (NIR) spectroscopy. The wastewater containing the microorganism cells in a 1 mm light path length cuvette was placed in an NIR spectrophotometer and the absorbance at wavelengths between 400 nm and 2500 nm was measured at 2 nm intervals. Simple or multiple linear regression analysis was used to obtain calibration equations relating to the NIR spectral data and the content of a calibration sample set (n=66) obtained by the conventional methods. The wavelengths at 2264nm, and 2274nm and 2256nm were selected to make calibration equations for methanol and glycerol, respectively. Prediction of methanol and glycerol contents (n=45) was successfully carried out using NIR spectroscopy with r{sub}2 = 0.996 and SEP=0.637gL{sup}(-1) and r{sup}2 = 0.996 and SEP=0.31 g L{sup}(-1), respectively.