How Chemtura's treatment system works
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May 17, 2012  |  Vote 0    0

How Chemtura's treatment system works

Elmira Independent

Gail Martin, Independent Editor

Elmira’s contaminated groundwater goes through a series of treatment steps at Chemtura, before eventually being discharged at the Canagagigue Creek.

The Elmira Independent recently went on a lengthy tour of Chemtura’s $4 million treatment system, in response to recent concerns raised by both the Chemtura Public Advisory Committee and Woolwich Township council, on whether Chemtura will be able to clean up Elmira’s contaminated groundwater by 2028.

According to Jozef Olejarz, plant manager at Chemtura, and Jeff Merriman, an environmental engineer at the company, the answer is unequivocably “yes.”

“We don’t have different goals, we have identical goals,” said Olejarz. “We want to clean up the groundwater.”

There are three main contaminants in Elmira’s municipal aquifer, two of which come from historic practices at Chemtura — NDMA and chlorobenzene. The third, ammonia, comes from a second source — Yara, a fertilizer company that is no longer operating in Elmira.

The recent CPAC resolution, which was also endorsed by Woolwich council, speaks to the need to do more in removal of source contamination, to speed up the process of reclaiming Elmira’s groundwater.

According to Merriman, that request doesn’t seem to make sense.

“There are no more ongoing sources of these contaminants on our site now,” said Merriman.

Historical waste pits on the site were excavated in the late 1980s, and eventually sent to the hazardous waste landfill in Corunna, said Merriman. He noted that the contamination that is already in the groundwater underneath Chemtura is being contained by its on-site collection wells, “so none of it is getting off site.”

Contaminated groundwater under Chemtura’s property is contained by the company’s pump-and-treat system. The intent of the onsite wells is to contain any contaminated groundwater onsite, preventing it from leaving the Chemtura property. All pumped water then goes through the treatment system, before being released to the Canagagigue.

Merriman said that he is certain the onsite contaminants are contained by two things — the levels of well water in monitoring wells on the edge of the property — which are higher than monitoring wells on site — and the fact that the contaminants Chemtura tests for are lower in concentration than they are on site.

The off-site collection treatment system brings groundwater from Elmira, via two pumping wells — one located on Howard Avenue near the water tower, and one between Midas Muffler and McDonald’s — to the chemical plant for treatment, before it, too, is discharged to the Canagagigue Creek, eventually making it to the Grand River, the source of Elmira’s drinking water.

Chemtura voluntarily tests the treated water three times a week, with once-a-month testing mandated by the Ministry of the Environment.

The end product, according to Merriman, is an improvement on the water that is already in the Canagagigue, upstream of the property.

“There’s less ammonia (in the treated water) than the creek has now,” said Merriman.

There are several stages in the treatment process for the contaminated groundwater.

Both the onsite and offsite groundwater is treated with a 30,000 W ultraviolet light, which removes the NDMA.

When the nine-reactor system for the onsite groundwater originally came online, the contaminated water had to go through all nine reactors to remove all traces of NDMA. Now, it only uses two.

It’s a similar tale for the offsite system, which originally used six reactors, and now only needs two.

“This is a success story here,” said Merriman.

Chlorobenzene is removed by an activated carbon filter, which Merriman likened to a huge Brita filter.

The off-site water is also treated through a biological process involving ammonia-loving bacteria that eat the ammonia, removing it as a contaminant, through both aerobic (oxygen-rich) and anaerobic (oxygen deprived) cycles.

After the ammonia is removed, the water goes through a final sand filter, to remove remaining contaminants, and to clarify the water.

When the ammonia treatment system first came online in August 2008, the company enjoyed a great deal of success with the system, said Merriman.

“It ran like a Swiss watch,” said Merriman. “ It worked very well.”

The system was pumped close to or at its target rate for the first full two years of operation, said Merriman.

However, towards the end of 2010, they started noticing problems with the system.

The bacteria in the ammonia treatment system would not settle at the bottom of the clarifier tank — and would rise to the top of the tank. This posed a problem, since there was potential for the bacteria to overflow the tank into the next system — the sand filter — and clog it up.

Pumping rates had to be reduced, by almost half.

Merriman said Chemtura has been actively working on the solution, and has finally narrowed down the source of the problem — trace contaminants of aniline, carboxin and benzothiazole (historical contaminants found on the Chemtura site) were making through the activated carbon filter into the biological system.

Essentially, the bacteria were getting sick.

Merriman said that he believes the problem is solved, and the treatment system will be able to pump at its previous high rates within the next few months.

In the meantime, however, the lower pumping rate just reduces the speed at which the cleanup takes place — and isn’t allowing the contamination to spread further.

“It means we’ll not clean it up at the rate we need to,” said Merriman, who pointed out that the initial pumping rate was higher than the target rate. “However, I’m certain we’ll get back to the target rates soon.”

Merriman and Olejarz both believe that the company will be able to meet its obligation of cleaning up Elmira’s contaminated groundwater by the 2028 deadline.

Merriman said that the pump-and-treat system the company is using is a dynamic system — pumping wells can be moved to new locations, as contaminant plumes of NDMA and chlorobenzene move from one location to another, to make the pumping more effective.

This fall, the company will be undertaking its five-year review of the treatment system, to determine if there are ways to optimize the effectiveness of the system.

“If things aren’t working as they ought to be, we can look at the location of the wells,” said Merriman. “(The study) will give us all a much better picture of what the long-term cleanup looks like.”

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