Recovering and Recycling Coagulated Sludge

I would be interested in this but i don't think you would be able to recover it.

1. Try dissolving them in the same acid their anions are made off. I can't say that it will definitely work, but you can always experiment around.
2. Impossible.

Spteng,

Recovery and reuse of settled coagulated sludge is possible if the suspended solid or insoluble organics content is feeble. Such a sludge which is having active coagulant is worth recycling for second time use along with mild dosing of fresh coagulant.

The other option to reuse effectively the primary sludge in liquid form from primary clarifier's to recycle in flash mixer along with reduced dosage of fresh coagulant. This calls for a flash mixer of larger capacities around 10000 liters and above and very slow flow rate to have maximum retention time in flash mixer. This method has the advantage of activated primary sludge formation, which will drastically reduce sludge generation and reuse scope of available un reacted coagulant in the primary treated effluent.

This strategy had been successfully applied to minimize coagulant dosing and sludge generation.

You can eliminate the tedious separation process of coagulant and flock matter, if your intention is to reduce coagulant and primary sludge generation.

* The other part of your question thermolysis, like you I await for a useful information from other posts.

Dear all, thank you for the reply.

I have found several papers on recovery of alum sludge is possible by using acidicfication, alkalization, ion-exchange, membrane techniques.

However, all these are for alum sludge recovery. Do you think the same methods can be applied for polyaluminium chloride (PAC) sludge recovery also?

I personally feel that, it should be fine as the coagulat treated effluent/sludge also contain Al(OH)3 flocs, no matter the coagulant used is PAC or alum? Do you agree with me on this statement?

Thank you.