(My third and final article on the Umgeni River for Inter Press Service).
KWAZULU-NATAL, South Africa, Oct 1 2013 (IPS) – In a few years, residents of the eThekwini municipality in the port city of Durban in South Africa could be drinking water that was once flushed down their toilets, as authorities are planning to recycle some of the municipality’s sewage and purify it to drinking quality standards.
“We’re going through a crucial water shortage, which is increased by the water demand of eThekwini,” Speedy Moodliar, the municipality’s senior manager of planning for water and sanitation, told IPS.
The municipality relies on the Umgeni river system for water. But demand on the system, which supplies drinking water to about five million people and fuels industry in the economic hubs of Durban and Pietermaritzburg, a town 66 kilometres from the coast, has outstripped supply for the past seven years.
To boost supply in future, the South African government has proposed building a dam with a capacity of 250 million cubic metres on the uMkhomazi river, the third-largest river in KwaZulu-Natal, and transferring water to the Umgeni system.
But this scheme will only be operational by 2024 at the earliest, said Moodliar. “Between now and when the uMkhomazi [project] comes online, [wastewater] re-use will be our mitigation measure.”
In dry countries like Israel, Egypt, and Australia treated wastewater is used for industry, landscaping and agriculture. But worldwide few countries put it directly into their drinking water supplies.
Singapore uses purified wastewater to meet 30 percent of its water needs, although just a small percentage goes to drinking water and the majority is used by industry. Citizens of Windhoek, the capital of South Africa’s arid northwestern neighbour Namibia, have been drinking recycled wastewater for over 40 years.
In 2011 the Beaufort West municipality, which serves close to 50,000 people, began treating its sewage for use as drinking water after a vicious drought, making it the first in South Africa to do so. According to a 2012 World Bank report “The future of water in African cities: why waste water?” few cities in Africa have functioning wastewater treatment plants and “only a small proportion of wastewater is collected, and an even smaller fraction is treated.”
eThekwini municipality plans to upgrade two of its existing, and underperforming, wastewater treatment plants – the KwaMashu and Northern treatment works, Moodliar explained.
To remove contaminants and clean the water to drinking quality standard, a three-stage system that treats effluent through ultra-filtration and reverse osmosis, as well as disinfection by ultraviolet light and chlorine would be used. The treated water would also be stored and tested before being released.
The purified water will be mixed with conventional drinking water at a ratio of 30 percent re-used water to 70 percent conventional, said Moodliar. It will feed the municipality’s northern regions, including Umhlanga, Durban North, Reservoir Hills, and KwaMashu.
Re-using wastewater in this way will add 116 megalitres of tap water to the municipality’s supply daily. This is enough to fill just more than 46 Olympic-size swimming pools. It is roughly 13 percent of the municipality’s current daily consumption, and will provide an estimated seven years of water security.
Read the full article at Inter Press Service.