Coagulant for Alkaline Waste Activated Sludge

[ch81pc]

I am currently working on a project to chemically treat WAS to increase its dewaterabilty. The end result being a very alkaline sludge of around 12 pH units. We currently use Ciba Zetag 87 polymer but I would be interested to hear of any other polymer solutions that would give better performance at such a high pH. Thanks

Paul

 

[oxilume]

Paul,

First, what are your goals;
(1) Dewater sludge to reduce transportation and disposal costs?
(2) Reduce chemical costs?
(3) Produce a Class A biosolid?

Second,
A.Contact a water treatment chemical company and request that the sales person visit you; several excellent companies are:
(1) Nalco Oneda
(2) Betz
(3) Chemtreat
(4) Drew Industrial (Division of Ashland Chemical)

B. Have the salesperson conduct a jar study.

C. Have the salesperson submit a proposal with a ROI.

Sincerely,

Todd Foret
toddforet@usa.net

 

[ch81pc]

Thanks for the contact details Todd,

The primary goal of the project is to reduced transport/disposal costs, secondary to that is the production of a class A biosolid. Additional benifits include the reduction in the polymer demand (saving of ~3kg active ton-1 dry solids)of the sludge so I guess you could say that all three goals are met. Do you have any experience with the new crosslinked polyacrylamide polys? Thanks

Paul

 

[ischgl99]

WAS does not dewater well under the best conditions and a pH of 12 isn't helping things, few polymers work well at that level. What are you using to chemically treat it and where at? What kinds equipment are you using and the results?

If you are using a sodium based product, that will decrease your dewaterability and usually increase the amount of polymer needed. Alum also will have a negative effect on dewatering. Are you using lime in the sludge before dewatering to increase the pH for your class A requirements? If so, that kills polymers very quickly.



Mike Bensema

http://www.dutchmenservices.com

 

[oxilume]

Paul,

If your primary goal is to reduce transportation and disposal costs then you need to dry the sludge to "bone dry."

I can send you information on a cost-efficient mobile sludge dryer.

Sincerely,

Todd Foret
toddforet@usa.net