WEF Discussions — Now on LinkedIn!

WEF is pleased to announce the creation of free LinkedIn groups associated with its technical discussion forum topics. Through these LinkedIn groups, members will be able to view and participate in discussions, as well as communicate with one another via direct messages. Share your experiences and knowledge, ask questions and respond to other discussions as frequently as you like!

You must have a LinkedIn profile to join a LinkedIn group; you can create your profile here. If you already have a LinkedIn profile, all you need to do is submit a request to join one or all of the following groups:

Water Environment Federation (Main) | Biosolids | Collection Systems | Nutrients | Stormwater 
Utility Management | Water Reuse | Water for Jobs | Watershed Management | Laboratory Practices 

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Cold Water Treatment using Poly Aluminum Chloride
Tom Cleveland
Posted: Monday, January 10, 2011 2:24 PM
Joined: 9/7/2010
Posts: 1


This is Tom Cleveland, Plants & Engineering Manager, Decatur Utilities in Decatur Alabama.  We own and operate a 68-MGD conventional surface water treatment plant which uses the Tennessee River as a source.  Our treatment processes are: coagulation, flocculation, sedimentation, filtration, and disinfection with chlorine gas.  The chemicals we use are: Sodium Permanganate (20%), pre-chlorine, poly-aluminum chloride (PACl), fluoride, post-lime, post-chlorine, and poly-orthophosphate.  On January 2, 2011 following a rain event which dropped ~5 inches of rain in 2 days, we had an elevated raw water turbidity of ~70-80 NTU.  We were feeding ~30-40 mg/L of PACl at the beginning and during the first few hours of the increased raw turbidity event.  We ended up "loosing" all of our 40 filters due to high filtered turbidities (~0.3 NTU) and high settled water turbidities (~16.0 NTU).  We eventually solved our problem by increasing our coagulant (PACl) dosage rate anywhere from 85 to 105 mg/L. 


Do you know of any water plant that has had to feed PACl at that high of a dosage rate?  Also, do you have as ideas as to what might create such a high coagulant demand with a raw water turbidity of only ~70 NTU?  Are there any resources or technical advice available to us as WEF members?  If so, please contact me via phone or e-mail.”


Thank you.


Tom Cleveland, p.E.

Plants & Engineering Manager

Decatur Utilities

(256) 301-4605Office

(256) 654-1630 Cell

(256) 552-1484 Fax