Water reclamation for industrial and potable reuse

摘要

In this paper an industrial and a potable reuse application is apresented．The first one describes the reclamation of refinery/petrochemical effiuents for reuse as boiler make-up water，an bjective that is met by the employment of an advanced multi-barrier system，which includes ultrafiltration and reverse osmosis．The plant has been in operation for fifteen months and shows excellent performance，e．g．the level of silica，one of the most crucial parameters，is reduced from approximately 100 mg/l in the raw water to 6 μg/lin the boiler make-up water．The second case described involves the reuse of secondary municipal effiuent as potable water．There are several indirect potable reuse applications(e．g．in California)，but Windhoek has the world's only direct potable reuse system．Due to its limited water resources and severe droughts in the past，the city of Windhoek depends on the reclamation of secondary effiuent．The potable water is reclaimed in the New Goreangab Water Reclamation plant (NGWRP，21，000 m3/d)，an advanced multi-barrier system with ultrafiltration as a final barrier．This system provides several barriers for each crucial parameter(e．g．protozoa such as cryptosporidia and giardia)．Hence all the requested clean water standards have been met safely(e．g．trihalomethanes：11 μg/l；requested 20μg/l)．As cost calculations show．both reuse applications are viable．Furthermore，they are essential in order to safe the water supply．