Optimisation of static magnetic field (SMF) on physical properties of biomass using central composite design experiment

Abstract

One of the principle issues for the biomass is the poor settleability that therefore influences the effluent quality. Batch tests were led to appraise the optimal conditions for improving the settleability of the biomass under static magnetic field (SMF). A four-factor central composite design (CCD) was executed to investigate the main and interaction effects of the factors while response surface methodology (RSM) was used for process optimization. Four independent factors, viz. SMF (15.0 – 88.0 mT), exposure time (0.5 – 48.0 h), biomass concentration (2000 – 4000 mg/L) and agitation speed (200 – 400 rpm) were applied and quadratic model was worked to anticipate the reactions. Analysis of variance (ANOVA) was utilized to assess the significance of the autonomous factors. At the optimum conditions of 88.0 mT SMF, 16.5 h exposure time, 2800 mg/L biomass concentration and 300 rpm agitation speed, the turbidity removal, aggregation and settling velocity achieved its highest predictions of 92%, 99% and 0.011 cm/s, respectively. The analysis demonstrated that the applied SMF could enhance the settling property of the biomass through the enhancement of its aggregation ability. These suggesting that the SMF is dependable in accelerating the biomass settleability, subsequently potential to improve the performance efficiency in treating wastewater.