Integrated treatment of submerged membrane and adsorption using dried Aphanothece sp for removing cadmium from synthetic wastewater

Abstract

Water pollution from the discharge of wastewater containing toxic heavy metals such as cadmium (Cd) to the natural water bodies is one of the biggest problem affecting humanity. Different technologies such as sorption, membrane filtration etc. have been used to remove heavy metal from the polluted water. In this work, the effects of operational parameters on the ability of the submerged membrane adsorption hybrid system (SMAHS) to remove Cd2+ from synthetic wastewater using dried Aphanothece sp A15 as a suspended biosorbent was evaluated. This biomass originates from a cyanobacterium was cultivated in a photobioreactor system enriched with 15 % of CO2. The operational parameters investigated were filtration flux, biomass dosage, frequency of replacing biosorbent, and initial metal concentration. Of the various parameters, the filtration flux and the initial concentration of Cd were the most influential parameters concerning biosorption efficiency in this study. More than 95 % removal of Cd was achieved with initial Cd concentration of 4.89 mg/L at a filtration flux of 20 L/m2.h. The highest biosorption capacity (112.89 mg/g) was obtained with a flux of 60 L/m2.h.The biosorbent became saturated after 20 h of operation without biosorbent replacement. This suggests that the dried biomass of Aphanothece sp A15 has the potential to be implemented in the industrial wastewater treatment plant using SMAHS processes integrated within the CO2 bio-sequestration unit. Therefore, cadmium removal from wastewater can be coupled with the reduction of CO2 emissions from flue gas.