Australia’s first biosolids gasification facility

Logan Water has pioneered an Australian first; a facility which transforms human waste, or biosolids, into renewable energy and a sustainable product called biochar.

The facility was recently awarded the National Infrastructure Project Innovation Award (Metro) at the Ozwater’23 Gala Dinner, recognising the work of the Logan Water Partnership including Logan Water, Downer, WSP in Australia, Stantec, and Australian Renewable Energy Agency (ARENA).

Biochar recently featured in a short ABC documentary, with a starring role by Johanna Johnson, the Queensland Young Water Professional of the Year for 2022. You can watch the documentary here.

The biosolids gasification facility destroys chemicals in biosolids like persistent organic pollutants, and micro and nano-plastics. It will reduce carbon emissions by about 6,000 tonnes a year.

The innovation solves the age-old question of what to do with biosolids by identifying a role for it in the circular economy. In this economy, the community takes part by creating a nutrient-rich ‘resource’ which is processed to significantly reduce its volume and enhance its quality and marketability.

Logan Water will no longer pay contractors about $1.8M a year to truck 34,000 tonnes of biosolids from Loganholme Wastewater Treatment Plant (WWTP) 300km to the Darling Downs agricultural area for disposal. Operational cost savings and carbon credits will return almost $1M a year to the City of Logan, and a new revenue stream is being created from biochar sales.

Biochar contains nutrients like those found in commercial slow-release fertilisers; making it great for healthy soil and plants. Biochar can also be added to soil, asphalt, concrete and bricks to sequester carbon for thousands of years.

Innovative design and delivery

The biosolids gasification facility design adapts existing technologies including gasification approaches developed for the Queensland agricultural industry, and biosolids drying methods from Europe.

The design features dewatering of biosolids in centrifuges to 20% dry, drying it in belt dryers to 90% dry and then treating it in a gasifier at 650oC to create a pelletised, charcoal-like product.

The facility captures and reuses its own heat energy to dry the biosolids, while a 1MW solar array provides additional energy.

The team worked with local and global partners to deliver the facility. However, with COVID-19 border closures in place, international personnel were unable to visit our work site to assemble and test equipment. The team improvised by using tools like augmented reality software to manage design and quality management discussions, and shipped large items fully assembled like 34-tonne dryers.

The $28M project was opened in April 2022. It was funded by Council with a $6.2M grant from the Australian Renewable Energy Agency (ARENA).

A sustainable outcome

This project will leave a legacy for the City of Logan and the Australian water industry by:

• advancing the achievement of the United Nations Sustainable Development Goals
• encouraging water businesses to take a more sustainable approach to managing the 2.3M tonnes of dewatered biosolids produced each year in Australia (AWA, 2019)
• developing new legislation with the Queensland Department of Environment and Science to guide the production and use of biochar
• reducing energy use for City of Logan operations, and increasing use of clean energy
• helping Council to meet its target of carbon neutral operations by the end of 2022
• reducing operating costs for Council, enabling funds to be redirected to other services
• sequestering carbon and supporting the economy by providing biochar to industry.