Impact of Applying Electrocoagulation Pre-treatment Step on Grey Water Treatment by Submerged Membrane Bioreactor

摘要

Chemical coagulation is widely used for enhancing the performance of various waterand wastewater treatment systems, including membrane filtration processes such assubmerged membrane bioreactor (SMBR) units. However, the addition of chemicalsto the wastewater may result in production of undesirable chemical by-products orincrease the volume of sludge in the bioreactor. Alternatively, applyingelectrocoagulation (EC) technique has been shown to be a promising and novelapproach in SMBR applications. In this study, the impact of applying EC step wasinvestigated as a pretreatment stage for grey water treatment by SMBR system. Themain objective of the present study was to investigate the performance of theintegrated process of EC-SMBR under different voltage gradients. The performanceof the integrated process of (EC-SMBR) was compared with the operation of a SMBRsystem operated alone. The comparison was achieved in two sequential operationalphases in which two different voltage gradients were applied in the EC step. In bothphases, aluminium electrodes were used. The results indicated that the EC unit cancontribute in improving the SMBR performance if an adequate voltage gradient wasapplied in EC step. The improvement was observed clearly in Phase II when a voltagegradient of 1.26 V/cm was applied. Applying a low level of voltage gradient of 0.64V/cm (Phase I) in EC step did not exhibit a significant improvement in pollutantremovals.