Low concentration mercury removal from scrubber water

[nbuc7]

Mercury has been an on-going issue with a client of ours at a large wastewater treatment plant (120 MGD average). Multiple hearth incinerators are currently in place, with scrubber water being sent to lagoons for decanting. The decant and overflow is sent back up to the headworks of the plant, so all heavy metals (including mercury) end up running back through the wet process stream and into the plant effluent.

I've done some research to see what types of treatment technologies are available to remove mercury from the liquid phase. There is a company that uses granular carbon packed tower adsorption, however they typically use much higher mercury concentrations in the inlet stream. At the facility in question, we'd be looking to treat 2-3 MGD of scrubber water, containing approximately 20 mg/day (or 1.76 x 10^6 mg/L).

Are there any technologies floating around that any of you may know of that can remove mercury at such high flow rates and low concentrations?

Any help you can provide is much appreciated!

 

[monaco8774]

Not personally involved in this but we have some facilities in Thailand which have Mercury and Arsenic in the produced water, for these we have tailored some chemical treatments that use reagents to succesfully convert the Arsenic to an insoluble form and coagulants that actually tie the mercury to the crude side so that it can be seperated in conventional oil water seperation equipment. this is only to achieve 10PPB max mercury and 250 PPB arsenic. Inlet conditions are typically 50 PPB mercury and up to 200 PPB arsenic.

I know that Unocal did a lot of development work here as they are big in Thailand but maybe this isnt what you are looking for for your process as its pretty specific to offshore oil and gas treatment.

 

[nbuc7]

Thanks for the tip and update monaco8774, I appreciate it.

 

[pumpking]

It is worht toalking to a company called Kurion Technologies in UK who specialise in this kind of application - they manufacture such plant that you are talking about. You will have to search the web for their details as i dont have them to hand.