Evaluating role of biosolids derived biochar in addressing nutrients and diffuse pollution from arable land

Biosolids have been well documented to be used as renewable sources of fertilisers in the form of organo-mineral fertiliser (OMF). OMF involves combining organic waste with mineral sources of fertilisers. There has also been decision support tool developed such as the Phosphate Acceptance Map to determine landbank suitability to receive biosolids. Whilst efforts are made to valorise biosolids due to ongoing pressure on landbank availability due to more stringent policies to protect the wider environment, new approaches must also be developed and adopted to address it.

This research project is therefore timely as it seeks to evaluate new approaches to convert biosolids into biochar, being far easier to store as a solid carbonaceous material whilst also potentially tackling nutrients and emerging contaminant mobility in the environment. Biochar has been demonstrated to sequester carbon in soil and increase water holding capacity, a feature very pertinent for potential flood mitigation. Biochar has high pH which further reduces heavy metal mobility. Whilst these are encouraging impacts of using biochar, a robust evaluation is needed if we were to fully exploit it as a potential avenue to utilise biosolids as a feedstock.

The aim of this project is to evaluate role of biosolids-derived biochar as suitable material for land applications to mitigate nutrients and heavy metal transport to watercourses. The specific objectives include:
1. Optimising biochar reactor operating conditions using biosolids as feedstock
2. Formulating suitable OMFs using biosolids-derived biochar
3. Characterising biosolids-derived biochar and OMFs to optimise its role for agricultural applications
4. Elucidating mechanisms on nutrients and heavy metal pathways in soil and plant uptake when OMFs are applied to soil