Grantham Scholar James Bezzina is first author of a paper about removing heavy metals from sewage. Specifically the paper looks at a process where weak acid leaching of sewage sludge would be coupled to ion exchange for heavy metal ion removal.
Ion exchange removal of Cu(II), Fe(II), Pb(II) and Zn(II) from acid extracted sewage sludge – Resin screening in weak acid media is published in Water Research.
Human effluent is an good source of sustainable, phosphate rich fertiliser. However, sewage can also contain toxic heavy metals. Unfortunately, heavy metals can not only cause distress to living organisms, but can also accumulate within agricultural soils.
Currently, heavy metals are the biggest factor restricting use of sewage as fertiliser. If we can remove heavy metals, then we will be able to reuse sewage much more widely. As a result, more fertiliser would be available for agriculture.
The paper shows that MTS9301 is effective at extracting selected metal ions from all tested media. And that citrate media is effective at hindrance of metal adsorption. Further, TP214 can selectively extract copper from high complexing solutions. And C107E can selectively extract lead from lactate media.
James’ work on turning human sewage into fertiliser made the news. Read: From poop to food.