Solidification/Stabilization

The north and south tar ponds, located in downtown Sydney, N.S., are tidal estuaries, which flow into Sydney Harbour.  They contain approximately 700,000 tonnes of sludge contaminated with PCBs, PAHs, semi-volatiles, metals (lead, mercury, arsenic, cadmium, etc.) petroleum hydrocarbons, BTEX, HNCs and dioxins/furans.

Government’s “cleanup” plan now underway, referred to as Solidification and Stabilization consists of mixing over 100,000 tonnes of dry cement powder into the 700,000 tonnes of toxic waste insitu – all of this contamination will be left in place and buried under one million tonnes of imported topsoil, fill and grading materials.  We call that a COVERUP as not one molecule of contamination will be cleaned up.

This process of mixing binders, in this case cement powder only, with contaminated waste is call Solidification and Stabilization (SS) and concerns have been raised regarding its long term efficacy and its effectiveness on organic sediments.  The problem is that the tar ponds sediment is high in organics.

The Sydney Tar Ponds Agency states on their website that Solidification and Stabilization treatment is a means of creating a structurally enhanced, low permeable concrete mass that immobilizes contaminants.

Will this mixing of cement powder with tar ponds sludge turn into a concrete mass?

Nowhere close to concrete.  The unconfined compressive strength (UCS) of sidewalk concrete is about 3500 pounds per square inch (PSI).  The minimum UCS requirement for the toxic waste in the tar ponds following SS is a mere 25 psi,  and some areas have already failed to meet that minimum requirement.

The final product is not a “concrete mass” but is more like a crumbly toxic soil.  Excavators have easily dug out channels through this SS’d material and piled up this toxic soil on site.  Pictures of this excavated material can be seen under the heading above “Tar Ponds flood during SS” (Dec. 27, 2010 photo).  These piles have been sprayed with green odour suppressant foam to limit the off-gassing of volatile organic contaminants from this excavated SS’d hazardous waste.  Unfortunately this foam does little to suppress these noxious fumes which affect the surrounding community.

June 14, 2010 Read the latest comments on SS by Drs. Lee and Jones-Lee

http://www.tarpondscleanup.info/uploads/SS/STP_SSRemObjectives.pdf

Lee, G. F., and Jones-Lee, A., “Comments on the Adequacy of the Sydney Tar Ponds Agency SS Remediation Objectives,” Report of G. Fred Lee & Associates, El Macero, CA, June 14 (2010).  Excerpt follows:

“… the STPA approach will fail to provide reliable protection of public health and environmental quality….”

——————————————————————————

The tar ponds “clean-up” will not work

By Elizabeth May on 24 March 2010 – 10:17am

CBC News announced today that the clean up of the tar ponds has begun. The country’s worst toxic waste site will be completely remediated by the mid-1990s.

Sorry.  Wrong press release.  That was the one from 1986 announcing the first failed clean-up.  The incinerator that didn’t work.

On March 23, 2010, the most recent failed clean up has begun.  This time the plan is to bury the 700,000 tons of toxic waste, tons of polyaromatic hydrocarbons (PAHs) including hot spots of PCBs, in concrete.  The contaminated site consists of one hundred acres, and it is not really ponds, rather it is an estuary.  So the water flow is supposed to be diverted and the sediments de-watered as the concrete is stirred in.   There will be no clean up of contaminated backyards or basements (with high levels of arsenic and lead). Only those areas inside the fence on the lands destroyed by coke-ovens and steel mills will be the focus of a $400 million clean up that will fail.

As I write this, I know there will be howls of protest from the true believers in this solution.   “This is,” as the project manager said on CBC today, “an effective method. It’s used worldwide; it’s proven what it does.”

The federal and provincial governments have chosen to ignore all the evidence that it is nothing of the kind.

The first problem was that in the course of the $62 million Joint Action Group (JAG) process, the citizens of Sydney said they did not want this approach. They opted for a real clean-up in which the sediments would be removed and actually cleaned, removing PCBs.  That technology exists.  It was developed for use in cleaning soils contaminated in Alberta Tar Sands operations.

Many technologies were studied in the 10-year JAG process. Whenever they tried bench-scale testing of adding cement to the tar ponds sediments, it didn’t work.  Instead of hardening with time, the tests showed it weakened.

There was a joint Federal-Provincial Environmental Assessment Panel in the spring and summer of 2006.  The Sydney Tar Ponds Agency pitched its bury-in-concrete solution.  It is a technology called “solidification and stabilization.”  Experts came to testify. The most knowledgeable was Dr. G. Fred Lee — the man who actually wrote the U.S. EPA specifications for how to use S/S technology.

Dr. Lee explained why it could not work.  Solidification and stabilization only work in waste sites where the sediments are capable of binding to concrete and hardening.  The tar ponds sediments are about 50% coal.  In chemical terms, that is high organic content. There is not an example anywhere in the world of using S/S technology on sediments with high organic content such as in the tar ponds.

The Federal Provincial Panel Report agreed.  “The Panel is not convinced that the solidification/stabilization technology is proven for use in the Tar Ponds context — that is to be applied to organic contaminants in organically rich sediments in an estuary with potential groundwater and seawater influx.”

The Panel made many recommendations.  No money should go to the STPA until it could prove the technology could work.  Every move of the STPA should be monitored.  None of the recommendations were followed.  In fact, I doubt either the federal or provincial ministers even read the report.

I had hoped that when the New Democrats won the provincial election in June 2009, they would implement the panel’s recommendations.  Not a chance. Within days of the election, the Dexter government signed the same deal drafted by the previous Conservative government.

The waste of money ($80 million on the first failed incinerator, $62 million on the JAG process and now $400 million) should be enough to make every Canadian livid.  But it is the health impacts that make me want to weep. Ignored is the on-going grim reality of health problems from living in neighbourhoods contaminated with toxic waste, soon to be worsened as the toxic volatile organics move from the drying sediments, cross the street (the tar ponds are surrounded with residential areas) and start making people sick. The human health impact of the tar ponds continues to be ignored; it is that that should make us join the people of Sydney in demanding a real clean up.

But the people of Sydney are tired.  And after more than two decades of failed clean ups and false hopes, they are too exhausted to scream in protest.   The polluters walk away.  The contracts are issued.  And nothing will be cleaned up.

(For details, check my book, co-authored with Maude Barlow, FrederickStreet: Life and Death on Canada’s Love Canal or go towww.safecleanup.com)

——————————————————————————

Plans for the tar ponds cover-up no longer include an incineration component.  All PCB-impacted sludge will now be left in the tar ponds while Stabilization and Solidification is conducted on a total of 700,000 tonnes of hazardous waste.  (April 16, 2010)

Questions abound over plan to firm up the tar ponds

Weekend Feedback – Marlene Kane
Cape Breton Post
Sat., May 21, 2005

Early in March I asked Frank Potter of Sydney Tar Pond Agency why stabilization-and-solidification (S/S) was chosen for the majority of the tar ponds sediment when it has limited success on soils with high concentrations of organic contaminants. Parker Donham submitted my question and Potter’s response, two months later, to the Post for publication (Weekend Feedback: Structural Stability the Main Aim, April 30).

My question came almost verbatim from a Joint Action Group government document called Considering Technologies Fact Book. Knowing that the tar ponds contains high concentrations of organic contaminants, I wondered why this method was chosen when it had only limited success, according to government’s own document.

Several technologies showed “much promise for efficient and effective remediation of the Sydney tar ponds sediments” during the 2001-02 technology demonstration program. Some showed suitability and feasibility in producing commercial fuels from much of the tar ponds sediments, while others significantly reduced PAH and PCB levels in the sediment. Unfortunately, government selected none of these technologies.

During the demonstration process, the sediment was not actually stabilized, and long-term immobility of some organic compounds was not proved. This may be problematic because the tar ponds contains high concentrations of organic compounds.

The technology track record states that while S/S was successful commercially on materials with high inorganic impacts, it had less experience on organics. S/S did show “some indirect benefits in terms of improving sediment handling capabilities but its suitability and feasibility depend on further definition of specific remedial action objectives.”

According to the government’s plan for remediating the tar ponds, 120,000 tonnes of PCB-contaminated sediments will be excavated, dewatered and incinerated in a temporary incinerator less than two kilometres from Cape Breton University, and much closer than that to many residences. This technology was chosen despite the fact there were no PCB incineration test burns of tar ponds sludge during the demonstration.

Emissions from incinerating PCB sediments from the tar ponds have not been measured and the resulting ash from that process has not been tested, yet STPA vows it is safe. The plan is to construct an incineration facility first and then conduct a test burn.

Next, depending on which government report you refer to, either the top one to two metres (unspecified tonnage) or all of the remaining contaminated material (580,000 tonnes) in the tar ponds will be solidified and stabilized in place using a cement-like additive. Bearing in mind that the addition of solidifying agents like Portland cement can almost double the volume of contaminated material, it presents quite a vision.

Instead of getting rid of the tar ponds once and for all, the government plan is to increase the volume by 40 per cent. This material will then be capped, likely using fill, layers of drainage material, and topsoil.

During the technology demonstration, complications were experienced within drummed samples of tar ponds sludge when methane gas was generated from the decomposition of sewage organics. This pressure forced some of the drums to become deformed, which required all to be vented to atmosphere. How will this methane gas and the pressure it creates affect the outcome of the S/S process and the surface cap?

If indeed only the top one to two metres of sediment is to be treated with S/S, how will the added weight of the top processed material affect the sludge underneath? Would the weight force the bottom material to move in one direction or another? Will methane be generated in the lower sediments, and if so how will it be vented so as not to damage the solidified sediments and the cap?

Potter writes: “The purpose of S/S is normally twofold: 1) to improve the structural stability of the material and 2) to reduce the leaching characteristics of the material to acceptable criteria.” However, he goes to say: “The tar ponds sediments meet the leachate criteria even before the application of the S/S technology.”

So the main objective of S/S then becomes improving the structural stability of the sludge and increasing the bearing capacity to allow a stable working surface for final grading and future use. The technology demonstration reported that the S/S process improved the handleability of the sediment, while its bearing capacity was relatively low. Will this processed sediment, with its low bearing capacity, be able to achieve the main objective?

Potter says the tar ponds sediments tend to have low leachability characteristics, meeting the leachate criteria even before the application of the S/S technology. However, the technology demonstration report states that while the samples used in this demonstration “represent a range of the type of sediments that exist, it is not conclusive that all the sediments in the ponds will behave the same.” In addition, it is noted that all sediment samples used during the demonstration came from the South Pond; none came from the North Pond.

The only way to ensure all the contaminated soil mixes with the binding material (Portland cement) is to excavate the sludge and then mix it above ground, which is how it was dealt with during the demonstration and how it was proposed to be dealt with for full-scale treatment (the big “cleanup”).

However, this is not what government plans to do. It plans to conduct the S/S process in place, leaving the sludge in the tar ponds while an attempt is made to mix it with Portland cement powder. How will that affect the outcome and how effective has in-situ S/S treatments proved to be in other full-scale, 580,000 tonne projects?

The fact that Potter says the project expects “to gain experience from the S/S work that will be undertaken on the cooling pond” doesn’t inspire a lot of confidence. It seems there are more questions than answers.

Why did government waste millions of dollars and several years conducting a technology demonstration and then disregard the results? Area residents clearly chose removal and destruction technologies as the most acceptable options during the JAG, workbook sessions. Why ask their opinion and then ignore their chosen option?

It’s a sad day when after 20 years of studies and millions upon millions of wasted taxpayers’ dollars, the best government can come up with is to add some cement to the tar ponds, increasing the volume, and have our children and their children’s children monitor it and maintain it indefinitely.

Marlene Kane, a volunteer advocate on
environmental issues, lives in Sydney.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: