Reuse of municipal sewage (building effluent) as make-up water for cooling towers used for central air-conditioning plants in offices and other high rise buildings is a potentially excellent method of preserving large quantities of pristine waters for domestic and recreational use. This investigation was aimed at developing and evaluating a blend of conventional and modern technology for treatment of wastewater: a combination of Swirl-Flo TM Clarifier (SFC) and Ultraviolet light/Hydrogen Peroxide (UV /H20 2) process coupled with pressure sand filter and activated carbon adsorption column. The study was conducted to delineate relevant operational parameters for SFC and UV reactor. Overall Total Suspended Solids (TSS) and Chemical Oxygen Demand (COD) removal of about 82 % and 90 %, respectively was achieved in the plant. TSS removal in SFC was influenced by feed flow rate. Optimum feed flow rate in SFC was found to be 5.5-6.0 m3 /hr at PAC and Polymer dosing of 200 ppm and 2 ppm, respectively for which SS removal efficiency of 45-50 % was obtained. COD removal in SFC was 37-42 % (at the optimum flow rate), while that in UV Reactor was 18-23 % at H20 2 (50 % strength) dosing of 600-700 ppm. The quality of effluent obtained from this process was satisfactory and could be used as make-up water in cooling towers. The effluent quality was consistent and variation was much less as compared to the variation in influent wastewater.

Thesis (M.Eng.) - Asian Institute of Technology, 1997

Reuse of municipal sewage (building effluent) as make-up water for cooling towers used for central air-conditioning plants in offices and other high rise buildings is a potentially excellent method of preserving large quantities of pristine waters for domestic and recreational use. This investigation was aimed at developing and evaluating a blend of conventional and modern technology for treatment of wastewater: a combination of Swirl-Flo TM Clarifier (SFC) and Ultraviolet light/Hydrogen Peroxide (UV /H20 2) process coupled with pressure sand filter and activated carbon adsorption column. The study was conducted to delineate relevant operational parameters for SFC and UV reactor. Overall Total Suspended Solids (TSS) and Chemical Oxygen Demand (COD) removal of about 82 % and 90 %, respectively was achieved in the plant. TSS removal in SFC was influenced by feed flow rate. Optimum feed flow rate in SFC was found to be 5.5-6.0 m3 /hr at PAC and Polymer dosing of 200 ppm and 2 ppm, respectively for which SS removal efficiency of 45-50 % was obtained. COD removal in SFC was 37-42 % (at the optimum flow rate), while that in UV Reactor was 18-23 % at H20 2 (50 % strength) dosing of 600-700 ppm. The quality of effluent obtained from this process was satisfactory and could be used as make-up water in cooling towers. The effluent quality was consistent and variation was much less as compared to the variation in influent wastewater.