Strange things in our region's sewers

04 January 2017

London’s sewer system is famous for its “fatberg”, a massive ball of congealed waste about the size of a double-decker bus that had to be removed from the network below the city.

It was discovered about three years ago and was formed when residents continually poured waste, such as used cooking oil, grease and wipes, down their sinks and toilets.

It may surprise people to know that Wannon Water also has to deal with a large number of foreign objects in its sewerage network. Balls of waste are regularly removed from screens at reclamation plants in Portland, Hamilton, Port Fairy and Warrnambool.

Plastics and other materials can also affect the use of biosolids as organic soil conditioners. Biosolids are produced from the stabilised sludge at these large sewage treatment plants as well as at smaller facilities in Camperdown, Cobden, Coleraine, Dunkeld, Heywood, Mortlake, Peterborough, Port Campbell, Simpson, Terang and Timboon.

The biosolids are dried and stabilised for several years before the nutrient-rich material is applied on farms. Any contamination of the sludge can create environmental problems and impact the useable nature of the biosolids.

Wannon Water Branch Manager Operations, Wayne Murdoch, said a large amount of the material came from so-called “flushable” toilet wipes which did not readily break down and was likely to block pipes.

“These products do not disintegrate like toilet paper when they are flushed, meaning the screens at our plants have to be cleaned each week. This takes up to two hours each time,” Mr Murdoch said.

“The conveyors and augers, which aid in the removal of coarse solids from the sewage, are also periodically blocked by these wipes, requiring one or two operators to clean out the mess. This can take between one and four hours depending on the entanglement.

“Across Australia, it’s costing the community millions of dollars every year to deal with the issues these products cause in the sewerage system, not to mention the potential for long-term impacts on the environment,” Mr Murdoch said.

Other foreign objects that have been found at Wannon Water reclamation plants over the years have included mobile phones, dummies, reading glasses, toys and golf balls.

 We have had requests from a person who accidentally dropped their wedding ring down the toilet and from someone who dropped four $50 notes down their toilet, both asking if we could find them,” Mr Murdoch said.

“Unfortunately, this is an impossible task with millions of litres of sewage entering our plants each day.”

Wannon Water also urges people not to dispose of products such as cotton buds, nappies, paints, oils, vegetable scraps, Band Aids, pills, sanitary pads and tampons via the sewerage system.