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:

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Mercury Control
Jason Graham
Posted: Tuesday, November 29, 2011 2:09 PM
Joined: 2/17/2011
Posts: 7

Hi Everyone,


I am trying to learn more about programs used by other utilities to help control mercury from a pretreatment standpoint.  For example, does your entity have the following programs in place?


1)  Amalgam separator program with local dentists?  Inspection process?

2)  Programs for photo finishers to remove Hg prior to the collection system?  Inspection process?

3)  Program that investigates and identifies all potential and real sources of Hg from all non-domestic sources including schools?  Inspection process?

4)  Other programs or lessons learned?


Thank You!


Posted: Monday, December 31, 2012 11:03 AM
Joined: 12/31/2012
Posts: 2

I was an industrial waste engineer for City of Toronto. We did a joint study on dental practices with Environment Canada. There are 2000 dentists in the City. We amended the City by-law to demand that all dentists install and maintain amalgam traps. The month after the deadline was imposed there was 40-80% reduction in influent mercury at 4 Toronto STPs. The remainder is probably legacy mercury from dental and other uses sitting in sewers - with specific gravity of 11-12 it doesn't like to move in sewer systems. Piles of amalgam can be seen in dental plumbing systems if no amalgam trap is in place.


Plumbing and maintenance of the traps are key issues; You just can't buy a trap and install it willy-nilly or fail to maintain it.


In my opinion 90%+ of all mercury entering an STP may be from dentists.