With the gap between supply and demand for water expected to reach 17% by 2030, many South Africans will be required to radically change their attitudes to the way in which this precious commodity is being used and conserved, especially in the treatment of human waste.
Population growth coupled with a rise in urbanisation and increased economic activity are key contributors to the growing demand for water, while poor usage habits, the denigration of wetlands, climate change and consumer and commercial losses are factors causing the availability of this valuable resource to dwindle. With an estimated 11% of households still without sanitation services, and 26% with sanitation services which do not meet the required standard, the public health and environmental risks are enormous. In a water-scarce country like South Africa, the solution cannot be ‘flushing’. Instead, game changing new technologies which require little or no water, are required if the country is to address the sanitation challenge and the looming water gap.No more flushing
Jay Bhagwan, Executive Manager at the Water Research Commission, and representative of the Strategic Water Partner Network (SWPN), agrees with Water and Sanitation Minister Nomvula Mokanyane that, ‘It’s not all about flushing…’, and comments that universal access to sanitation does not mean that everyone must be able to flush but rather that there is universal access to a more appropriate way of treating human waste. “We need to build a culture which embraces the c of water and recognises the benefits of treating human wastes as an asset rather than a liability”, he says. Sanitation makes up about 60% of the capital costs of water services and between 30% and 40% of water is used for flushing. But while South Africa is one of few countries which returns up to 68% of water for indirect use, sludge should be viewed as a resource. The energy, nutrients and reuse thereof provide an opportunity to recover phosphates and nitrates for fertilisation, to convert sludge into biogas for power, and to recover water from flushing.Re-using waste
While there is some progress on effluent re-use within certain municipalities, the challenge of treating waste relating to sanitation remains. Current modalities for collection and removal of waste are often messy and hazardous to health whereas a flush toilet and central sewage system is viewed by society as the optimal method of disposal. In many cases this is not sustainable in the longer term. Instead, alternative thinking is required for solutions which result in less or no waste water and sewage, treat the effluent at source; result in beneficiation; delivers the same user convenience as a flush toilet; and, saves water while being environmentally safe.Dry technologies, through processes which involve dehydration, desiccation, solar treatment, combustion and the like are promising and could provide the solution which is so urgently required.