Leachate spill at Wolumla tip after heavy rains

Bega Valley Shire Council alerted the Environment Protection Authority on May 5 that leachate dams at the tip at Wolumla had overflowed after two significant rain events, with EPA officers attending the site the following day to collect samples.

BVSC waste services manager Alan Gundrill said "due diligence was followed" with all customers downstream of the CWF informed, as well as the NSW EPA.

"We took immediate action with daily monitoring of water quality at all of our regulated sampling locations on and around the site," Mr Gundrill said.

"Independent testing shows that leachate is highly diluted as a result of the heavy rainfall. Concentrations of heavy metals, pollutants and synthetic organic compounds are either absent or better than relevant standards required for land use and irrigation."

Opponents of the development a decade ago regularly raised the spectre of potential leachate spill into nearby Wolumla Creek, a feeder creek of the Bega River and therefore the district's drinking supplies.

It's not the first time leachate spills have been reported at the site.

The council was fined $15,000 by the EPA for "sediment-laden stormwater" spilling from the tip's collection ponds into Wolumla Creek in November 2016.

Then in October 2017, it was estimated between 5-10,000 litres of leachate spilled on to the surrounding grassy area after the end of a conveyance pipeline was removed from the dam.

An EPA spokesperson told the Bega District News that following the most recent incident, water samples from each of the discharging basins was collected on May 6, with results likely available within two or three weeks.

"The Central Waste Facility is designed to contain stormwater generated in a 1-in-25 year 24-hour storm event. Any leachate that occurs in a storm event above this is likely to be highly diluted," the EPA spokesperson said.

The EPA said it would be "carefully reviewing" the CWF's operational capacity to manage, collect and treat leachate "to ensure that it meets the standards prescribed by the environment protection licence".

Mr Gundrill said, in the short term, leachate is now being carted from the CWF dams to the Merimbula sewage treatment plant.

"Additionally, we are capitalising on periods of dry weather by irrigating the leachate within the confines of the landfill cell to encourage evaporation," he added.

"In the long term, our aim is to develop a leachate treatment plant at the Central Waste Facility to significantly reduce dependency on leachate dams. "