South Africa: Power Cuts Lead to Sewage Spills

Sewage plants in South Africa’s northern Gauteng Province poured millions of litres of untreated waste into three rivers between the capital, Pretoria, and the commercial centre of Johannesburg earlier this month.

National power utility Eskom cut electricity to the treatment plants, which were then unable to process the waste water before it was released into the rivers.
Eskom cut the electricity as part of a national programme aimed at helping it cope with excessive demand for power. In recent months, the utility has systematically turned off electricity to large parts of the country because it has been unable to meet the demand for power.

[…]

Water bearing raw waste streams into the sewage plants and is treated without stopping its flow into nearby rivers. “There is no tap that you can close,” explained the engineer.

Some chemicals are used in the treatment process; but most viruses and tapeworm eggs are eliminated by pumping oxygen into the water — hence the importance of maintaining electricity to plants. The oxygen allows air-breathing bacteria to break down organic waste products.

Eskom apologised for the power interruptions, but said they were necessary because unseasonable cold and rainy weather had caused coal supplies to become wet and increased demand for power just as the utility was embarking on summer maintenance.

allAfrica