PSEUDOMONAS PUTIDA P67.2 AND PSEUDOMONAS FLOURESCENS P75 BASED MICROBIAL SENSORS FOR BIOCHEMICAL OXYGEN DEMAND (BOD) MEASUREMENTS IN PHENOLIC WASTEWATERS OF OIL SHALE INDUSTRY

This study evaluates applicability of microbial sensors based on Pseudomonas putida P67.2 (Ps. p.) and Pseudomonas fluorescens P75 (Ps. fl) for BOD measurements in the phenol-containing wastewaters that mimic the wastewaters from oil shale industry. Sensors are calibrated with OECD synthetic wastewater. Linear range in calibration solution for Ps. p. and Ps. fl. sensors is BOD 0-50 mg/L and 0-65 mg/L, respectively. The steady state response time for both sensors is 15-45 min. Measurements show that although Ps. fl. has better sensitivity to calibration solution, the concurrence between sensor-BOD and [BOD.sub.7] in phenol-spiked wastewater is better for Ps. p. sensor. In linear range the error is only 1.2-13%. For Ps. fl. the error in linear range is 17-55%. Preconditioning in phenol solution (BOD = 5 mg/L) increases sensor's sensitivity to phenol considerably (52%). This study demonstrates that preconditioned microbial sensors with specifically selected cultures can give better results for fast BOD determination in specific wastewaters.