Alternative circular water sources how municipal innovations around the world are relieving water stress Author: Thembi Thulare, Business Development Manager, DuPont Water Solutions SSA
As a global water technology provider, DuPont works on a myriad of challenges in the supply of water, all with very particular local circumstances. A number of case studies were conducted to highlight some of latest technologies for the reuse of precious water. The basic premise is to use the water more than once, rather than flushing it downstream, a field we are experts in. · Serdo - Afar Region, Ethiopia – treating water with high salinity and fluoride concentrations The town of Serdo in the Afar Region of Ethiopia lies within the Great Rift Valley, which is known for underground water reservoirs that contain dangerously high levels of salinity and fluoride. The plant treats a minimum of 60 000 L of water per day. DuPont’s reverse osmosis membrane technology is used to treat contaminated borehole water by reducing the salinity and fluoride content to safe levels, at which point the clean, potable water can be used by the community. · Orange County, California – replenishing the aquif with treated wastewater California has great demands on its limited water resources which are affected heavily by cyclical rainfall. In some years there are constant droughts, in others heavy rains. The Groundwater Replenishment System (GWRS) south of Los Angeles is a 100 million gallon per day advanced water purification facility using reverse osmosis membrane technology that turns wastewater into drinking water. This is then not used directly, though it could, but injected back into the aquifer for future extraction and to hold off seawater intrusion.
This is especially important in urban areas with growing population and stricter discharge requirements, as well as where energy and CO2 savings are important. · San Francisco, California – recycling stormwater for urban power plant Until recently, excess water in the BART subway station had to be removed and treated at great cost until the loop was closed to the neighboring power plant, a major consumer of water. Our Closed Circuit Reverse Osmosis (CCRO) system in operation there helps to save 30 million gallons of drinking water per year by purifying the surplus water with advanced membrane technology. This not only saved both organizations money, but reduced the stress on precious freshwater supplies in the arid region. These are some of the way municipal leaders are creating alternate water sources for their citizens, using water repeatedly rather than letting it escape – a wise way to overcome water stress. Re-use and Recycle water is the future!
· Manila, the Philippines – dealing with great variety in source water Lake Laguna de Bay near Manila is a vital source of water for the burgeoning capital of the Philippines. There, the Putatan plant has a particular challenge: dealing with a great variety of different water qualities throughout the seasons. This requires an ultrafiltration solution that is particularly robust to ensure a safe barrier to any contaminants. Currently, 280 million liters of excellent drinking water are filtered by our membranes with a very sustainable process with superior economic and environmental performance. · Birmingham, England – retrofitting a wastewater plant with space and energy saving MABRs One of England’s larger water utilities, Severn Trent, has a full-sized wastewater treatment plant at Spernal in the Midlands. Here, as well as normal operation, new innovations are put through their paces in live processes. Like our Membrane Aerated Biofilm Reactor (MABR) – a key innovation that helps municipalities expand the capacity and efficiency of wastewater treatment plants without taking up extra space.
Thembi Thulare, Business Development Manager, DuPont Water Solutions SSA