From flush to field. Biochar could turn human waste into a fertilizer goldmine
(www.anthropocenemagazine.org)
The pyrolysis process that the article refers to can turn organic material into biochar which is essentially charcoal. Organic material being anything that has carbon in it which does include sewage and critically plastics. There are studies about using biochar as reusable microplastic adsorption material but I'm not really qualified to draw any conclusions