Sludge providing an environmental mindset for the future

Last week we heard from Chief Executive David Ryan and Acting GM Strategy, Engagement and Innovation Sandra Ricci about our new Environment, and Customer and Community Corporatestrategies.

One of the teams helping us work towards our environmental goals of net zero emissions and becoming a climate-ready business is the Research team, and one of the projects they’re working on is measuring and quantifying greenhouse gas (GHG) emissions from sludge lagoons, and ultimately mitigation of those emissions.

Sludge drying lagoons are an important part of treating and stabilising our wastewater treatment plant sludge, but the downside is they release methane and nitrous oxide into the air and how much they release is hard to quantify.

To reach net zero emissions and be climate-ready we need to know how much GHG we’re producing.

Lead Scientist Environment Wastewater Ben van den Akker said the project, co-funded by our business and partnering with Melbourne Water and Hunter Water is addressing a common problem faced by the water industry.

“In Australia, approximately half of the wastewater treatment plants use sludge lagoons that can take months or even years to dry, as an alternative to energy intensive mechanical drying,” Ben said.

“Sludge lagoons are not a recognised source of greenhouse gas emissions because sludge is often digested up stream to produce methane for onsite power generation. This digested sludge still has potential to release emissions during lagoon drying.

“The Research team is using biochemical and microbiological analysis to ultimately quantify methane and nitrous oxide emissions.”

University of Queensland PhD candidate Sarah Aucote said innovative mitigation strategies will reduce the impact of this new source of GHG emissions on the environment and help us understand how we can reduce the contribution of sludge lagoon systems to our carbon footprint at wastewater treatment plants.

“We’re investigating the use of alternate water caps containing nitrate and nitrite to mitigate the methane emissions,” Sarah said.

“This new data will inform the best way to reduce or offset those emissions.

“Instead of waiting a decade and dealing with it, we're being proactive in knowing what GHG we’re contributing and making informed choices to mitigate its effects to achieve sustainable wastewater treatment.”

This important research is contributing to our success as a business reducing greenhouse gas emissions and transforming the way wastewater is treated in our business.

Bolivar Wastewater Treatment Plant sludge lagoon

Dora Creek sludge lagoon

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