KENYA WATER INDUSTRY ASSOCIATION
Wastewater is now seen as a potential resource and its use , or recycling after suitable treatment , can provide economic and financial benefits .
Wastewater can be used within the business itself or between several businesses through ‘ industrial symbiosis ’. Industrial water consumption is responsible for 22 % of global water use ( UN-Water , 2012 ). In 2009 in Europe and North America , water consumption by industries was 50 % as compared to 4-12 % in developing countries ( WWAP , 2009 ). It is expected that in rapidly industrialising countries , this proportion could increase by a factor of five in the next 10-20 years . Therefore , there is a strong incentive to use wastewater in-house and locally , based on cost savings alone .
Businesses can directly use some wastewater , providing it is fit for purpose . For instance , using process water for cooling or heating , or rainwater from roof collection or concrete aprons for toilet flushing , irrigation or vehicle washing .
sterdam , is comparable to that of a small city with a population of 45,000 . About half of the wastewater originates from passengers and businesses at the airport , 25 % is discharged by aircraft and catering , and the remaining volume is produced by other aviation-related businesses . The on-site wastewater treatment plant biologically purifies water to a quality fit for discharge into local waterways .
WASTEWATER AND INDUSTRY
Societal and environmental pressures over recent years have led to a growing movement for industry to reduce its wastewater and to treat it before discharge .
Examples :
• An industrial ecosystem . In Kalundborg , Denmark , the by-products of one enterprise are used as a resource by other enterprises , in a closed cycle . The Asnæs Power Station receives 700,000 m 3 of cooling water from Statoil each year , which it treats and then uses as boiler feed water . It also uses about 200,000 m 3 of Statoil ’ s treated wastewater for cleaning each year . The savings to local water resources are considerable : nearly 3,000,000 m 3 of groundwater and 1,000,000 m 3 of surface water per year . 7
• Reclaiming water from mining . The Witbank coalfields are located around Emalahleni , a small city in
7 Domenech and Davies ( 2011 ), “ Structure and morphology of industrial symbiosis networks : The case of Kalundborg ”, Procedia - Social and Behavioral Sciences , vol 10 , 2011 , pages 79-89 : http :// www . sciencedirect . com / science / article / pii / S1877042811000127
16 Africa Water , Sanitation & Hygiene • March - April 2017