Is possible that the chitosan may interact with the sewage sludge via the N, O atoms resulting to flocculation. in another way, the sewage sludge may either sandwich the chitosan or be sandwiched by chitosan the result of which is flocculation. That is my opinion. we can interact more if need be. Thanks.

Many thanks for your prompt response and high quality information. I need however some papers which detail the chitosan flocculation mechanism. (This is my email if necessary: [email protected]).Regards

some quick refs: hope they help

1. F. Renault, B. Sancey, P.-M. Badot, G. Crini, Chitosan for coagulation/flocculation processes – An eco-friendly approach, European Polymer Journal, Volume 45, Issue 5, May 2009, Pages 1337-1348, ISSN 0014-3057, http://dx.doi.org/10.1016/j.eurpolymj.2008.12.027.

(http://www.sciencedirect.com/science/article/pii/S0014305708007222)

Keywords: Biopolymer; Chitosan; Coagulation; Flocculation; Wastewater treatment; Bioflocculant

2. Xiao Dan Fan et al., 2012, Advanced Materials Research, 627, 399

3. Xiao Dan Fan et al., 2012, Applied Mechanics and Materials, 253-255, 960

4. http://scialert.net/fulltext/?doi=jas.2009.2762.2769

5. http://www.omicsgroup.org/journals/the-treatment-of-shenzhen-coastal-polluted-water-by-composites-of-bio-flocculants-bacteriaalgae-2168-9652.1000120.pdf

Thank you very much Victoria for these interesting refs

A literature search on Google Scholar (http://scholar.google.com) will locate what you need. But if you want to flocculate sludge (rather than wastewater), flocculation may not be enough. For mechanical thickening or dewatering processes, an additive may produce a well-flocculating sludge (as indicated in a settling test) but the sludge flocs will be weak, and they will deflocculate under shear. So if you are testing chitosan, or any other additive, you should also test for floc strength. Any research paper that does not do this fails to give a true picture of whether the additive will work full-scale.

Try same treatment with shrim shells residues.

Because neutralization result will probably be similar.

And cost will be much lower.

Tthank you Mr steven for your precious reply, so I fully agree, however, how can I measure the strength of flocs?

Many thanks also for Denise. For my study i have used chitosan generated from crap shelle residues, it gives me a good results as flocculants in sludge conditioning.