The Rand West City Local Municipality suspects sabotage, after sewage spilt into the land surrounding its sewage treatment plant in Randfontein on Wednesday.

A Randfontein resident said he saw a “big river of sewage” next to the treatment plant.

“The sewage went to the field where cattle graze,” the man, who asked not to be named, said.

Quizzed about what happened, Rand West City mayoral spokesperson Tshidiso Tlharipe said a team found rocks, old carpets, sand and other objects had been thrown into the manhole.

“The unblocking and cleaning will continue first thing tomorrow [Thursday] morning. We suspect sabotage,” Tlharipe said.

Last November, the municipality admitted to the SA Human Rights Commission that its waste water treatment works was not fully operational‚ resulting in untreated sewage leaving the plant and polluting the community's water source.

The commission was assured that the plant was being refurbished.