Treatment of polluted river water with a photocatalytic slurry reactor using low-pressure mercury lamps coupled with a membrane

摘要

A novel configuration of a photocatalytic slurry reactor using low-pressure mercury lamps coupled with membrane filtration was proposed,and treatment of polluted river water with a pilot plant of this system was investigated.Both COD and NH_4~+-N in the river water were simultaneously removed.Under the conditions of a hydraulic retention time of 3.0 h,influent COD strength of 50-80 mg L~(-1)and NH_4~+-N of 2-6 mg L~(-1),80 COD and 50 NH_4~+-N were achieved,respectively.The reactor was found to own a higher UV utilization effectiveness than most reported photocatalytic reactors.Intermittent backwash was effective to retard the membrane fouling and enable stable membrane operation for more than 1 month.An adhered catalyst,algae and fungi in the river water were the main contaminants of the membrane,but the membrane permeability could be almost recovered through sequential rinsing by tap water and a sodium hypochlorite solution.After continuous operation for over 1 month,the photocatalytic activity of catalysts was found elevated,which likely resulted from adsorption of hydroxyl-rich alcohols onto the catalyst surfaces.