Pilot-scale evaluation of gac adsorption using low-cost, high-performance materials for removal of pesticides and organic matter in drinking water production

摘要

To evaluate granular activated carbon (GAC) adsorption using low-cost-high-performance materials for removal of pesticides and organic matter in potable water production, a pilot-scale upgrade of the conventional treatment process was studied in the Cam Giang Water Treatment Plant, Hai Duong Province, Vietnam. The pilot system was designed to test various process schemes consisting of a series of processes, such as coagulation/flocculation, horizontal sedimentation, rapid sand filtration, and adsorption, using three types of GAC (activated carbon from bituminous coal, from bamboo, and from coconut shell). The treatment efficiencies of the individual processes and the overall treatment trains were evaluated by studying several parameters, such as turbidity, chemical oxygen dissolved, and pesticides (chlorpyrifos, diazinon, carbofuran). Results show that the two locally produced adsorbents have a similar efficiency to commercial activated carbon for adsorption. The removal efficiency was somewhat lower for both materials, but in the same order of magnitude. The removal of pesticides and organic matter with a column filled with activated carbon derived from bamboo was found the best among the two locally produced materials, approximately 30 and 23% higher than those observed for the column filled with activated carbon from coconut shells. It is concluded that bamboo-derived activated carbon can be employed on a larger scale as a low-cost-high-performance adsorbent and an alternative to commercial activated carbon in drinking water treatment.