Equipment failure caused Central Highlands Water to pollute Yarrowee River with treated sewage

Dead fish found near a Ballarat wastewater plant were one of the signs dangerous sewage had made its way into the river. How it happened has now been revealed.

The Ballarat South Wastewater Treatment Plant, where treated sewage is released into the Yarrowee River. Picture: Central Highlands Water/YouTube

A Ballarat utility company has copped a $280,000 punishment for polluting a major river with sewage containing elevated levels of ammonia.

Central Highlands Water, which provides sewerage through the Ballarat South Wastewater Treatment Plant to about 100,000 people, must spend as many dollars in support of the Yarrowee River after equipment failure and lack of proper staff training led to pollution and fish deaths.

In February and March 2023, while the treatment plant’s normal operation was disrupted, Central Highlands Water released treated sewage into the Yarrowee.

Each day the plant treats about 19 megalitres – or 19 million litres – and releases certain treated sewage into the river.

However, because of false readings by oxygen analysers at the time, sewage with “elevated nutrient concentrations” entered the river.

High ammonia concentrations were detected downstream and dead fish were found near the plant.

Central Highlands Water self-reported the incident and brought forward upgrades to the Ballarat plant.

Dead fish were located near the Ballarat South Wastewater Treatment Plant. Picture: Central Highlands Water/YouTube

EPA South West regional manager Martha-Rose Loughnane said nevertheless, the event could have been prevented and harm reduced “had there been better training, better equipment and maintenance, and a better understanding of environmental requirements”.

By way of an enforceable undertaking with the EPA, Central Highlands Water must spent $100,000 alongside the Yarrowee Leigh Catchment Group to “benefit the community and environment”.

Enforceable undertakings are voluntary but legally binding agreements.

Central Highlands Water must also spend $160,000 on having a professional help improve its operational performance, and $20,000 on a study and industry presentation on the use and maintenance of oxygen analysers in wastewater treatment.

The enforceable undertaking is the EPA’s first in nearly 10 years.

A Central Highlands Water spokeswoman said the company had implemented remedial measures since the incident, which followed an “unprecedneted” disruption to the Ballarat South Wastewater Treatment Plant.

“CHW take this incident very seriously and have invested in a number of enhancements to the plant to reinstate normal operations, reduce future risks and improve contingency plans,” she said.

“CHW in response has invested an estimated $500,000 restoring and improving the Ballarat South Wastewater Treatment Plant, has committed to further investment of $280,000 to assure ongoing compliance and to contribute directly to the impacted community, and has brought forward $6.3 million in capital investment to upgrade the Ballarat South Wastewater Treatment Plant.”