Police and Yarra Valley Water are seeking public help in identifying the person who dumped hundreds of litres of liquid latex into a manhole in Dallas.
The incident caused sewage to spill into a nearby creek and onto a public reserve.
The damage was caused on September 28 and resulted in the entire sewer pipe being removed and water quality disrupted for up to five weeks.
Yarra Valley Water managing director Pat McCafferty said the dumping was highly unusual and liquid latex had no place being in a sewer.
“The substance was incredibly difficult to work with, turning into solid rubber as soon as it made contact with the air and expanding on contact with liquid,” he said.
“It would not dissolve and was impossible to cut. Our crew said it was expanding before their eyes … we were unable to even get our camera into the sewer to assess the damage.”
The solid rubber mass stretched more than two metres and left Yarra Valley Water with a $600,000 clean-up bill.
The blockage caused the sewer to discharge into Merlynston Creek and onto Jack Roper Reserve.
It took Yarra Valley Water crews five weeks to restore the water quality to normal.
For three weeks the affected area had to be bypassed by the sewage system to prevent further spills. Nine manholes along Berger Dallas, and Maffra streets, Coolaroo, required cleaning; 65 metres of pipe had to be replaced and 20 staff worked on the clean-up.
Anyone who has noticed suspicious behaviour in the area, particularly around manholes or drains, is asked to contact Crimestoppers on 1800 333 000.
