In the processes for treating municipal sewage and storm water containing
biosolids to discharge standards, biosolids, even after dewatering,
contain typically about 80% water bound in the dead cells of the
biosolids, which gives biosolids a negative heating value. It can be
incinerated only at the expense of purchased fuel. Biosolids are heated
to a temperature at which their cell structure is destroyed and,
preferably, at which carbon dioxide is split off to lower the oxygen
content of the biosolids. The resulting char is not hydrophilic, and it
can be efficiently dewatered and/or dried and is a viable renewable fuel.
This renewable fuel can be supplemented by also charging conventional
biomass (yard and crop waste, etc.) in the same or in parallel
facilities. Similarly, non-renewable hydrophilic fuels can be so
processed in conjunction with the processing of biosolids to further
augment the energy supply.