Carbon sink or swim: biochar win-win-win?

Carbon sink or swim: biochar win-win-win?

Explore potential value and gaps to realise upcycling of biosolids into biochar as a win-win-win for environment, economy and community.


Carbon sinks are critical in a sustainable and regenerative future world (more than greenhouse gas emission abatement alone). Utilisation of capital markets and pyrolysis/gasification technology is anticipated to provide a strong demand signal for carbon drawdown by relevant industries like water utilities. The level of demand and benefits both locally and nationally is uncertain but promising where co-processing of biosolids (emissions reduction / avoided decomposition) with waste vegetation (atmospheric carbon removal) could realise both commodity value and carbon credit value whilst addressing traditional problems of value/unit of biosolids material and emerging issues of contaminants of concern.

Many Australian water utilities are committed to developing circular economies and action towards the Paris Agreement for a 1.5 degree world. Emerging contaminants of concern, such as PFAS and microplastics, are threatening existing biosolids reuse application to land, with further treatment technologies likely required to optimise utilisation and avoid disposal to landfill at environmental and financial cost.

Biochar is one of six key Negative Emissions Technologies (NETs) identified by the IPCC (2018) for atmospheric CO2 Removal critically required to meet Net Zero 2050. Despite major potential value commercially and environmentally, application of the biochar product worldwide is in its infancy. Biochar is also emerging as an input in wastewater treatment to adsorb contaminants of concern such as antibiotic resistant genes and pharmaceuticals prior to reuse of treated effluent. It is also possible that biochar could be an input during the secondary wastewater treatment process acting as a ‘sponge’ for ammonia to avoid nitrous oxide emissions during nitrification/denitrification and enhance energy recovery from biomass. Not all biochar is created equal. An understanding of the quality and value of the biochar produced from various Australian water industry biosolids is essential to reduce uncertainty and inform decision making regarding thermal treatment processes.

Hence the objectives of this project are:

  1. Identify and extrapolate biosolids-derived biochar opportunities more broadly to inform industry biosolids treatment decisions in the context of a net-zero emission circular economy water utility.
  2. Prove pyrolysis/gasification technology at pilot scale in Australia with capability to deliver a valuable biochar product from sewage biosolids assessing energy neutrality, product quality/safety and process by-products/residuals.

WaterRA Contact

Dr Arash Zamyadi

Amount being sought


Due Date

29th Oct, 2021