Abstract
This paper investigated the effects of parameters, like inoculum size (15, 10 and 5% of the working volume of the reactor), gas velocities (0.0027, 0.00342 and 0.0068 m/s), bed heights (0.3, 0.6 and 0.9 m), static bed heights (4.85 and 2.43 cm), sizes of solid media particles (12, 4 mm), and the height to diameter ratio (H/D: 0.25 and 0.5) onto COD reduction process for electroplating effluent (initial COD values: 1140 ppm) using Pseudomonas aeruginosa and Pseudomonas putida. The authors derived simple mathematical correlations representing the entire COD reduction process. The correlation between the inoculum volume and gas velocities was in the form of an equation Y = ax(2) + bx + c, as deduced from nonlinear regressions. The correlations were validated, and percentage errors were found out to infer the effects of all parameters in the COD reduction process. The maximum COD reduction was achieved to 28.30 ppm (97.52%), in a batch mode, at 10% inoculum size, 0.0027 m/s low gas velocity and a static bed height of 2.43 cm.