Room temperature granulated fly ash on a fixed bed as sorbent for organic contaminants from wastewater

The removal of colour, turbidity and C.O.D. from the polluted waters containing organic contaminants, like humic acids and sodium ligninsulphonates was experimented: the results suggest an 'ecofriendly' technology for the polluting industries producing both: those producing fly ashes (i.e. coal thermal plants) and organic contaminated wastewaters. The process was developed in a fixed bed with use of by using a granulated fly ash as sorbent, a clear advantage in comparison to the use of fly ashes in the form of a slurry. Granulation was carried out by mixing a silico-aluminous coal fly ash with 10 % (w/w) of hydrated lime and water; curing of the granules was at room temperature. The process allowed the obtainment of granules with tailored porosity and good durability in water. Last, but not least, the exhausted bed can be regenerated by thermal treatment, and repeatedly used. The granulated fly ash has yet a sorption capacity at about the same extent in comparison with the original product.