Articles published in trade and business publications are an excellent way of gaining publicity and developing new leads. Here’s one I wrote for Sonic Environmental Solutions Inc., for publication in Site Remediation News.

SOUND NEW METHOD FOR REMEDIATING CONTAMINATED SOILS

In Vancouver, British Columbia, an environmental company has built and successfully deployed the first practical, industrial-scale sonic generator for remediating polychlorinated biphenyl (PCB) contaminated soils.

In March 2004, engineers from Sonic Environmental Solutions Inc. (Sonic) loaded 250 kilograms of PCB-contaminated soil into a tank where it was slurried with a low cost solvent. They then powered up an array of electromagnets surrounding a 2,500 kg steel rod attached to a reaction chamber and pumped the slurry through the chamber.

Within seconds, the vibrating bar blasted the soil and solvent mixture with enough energy to shake the PCB molecules loose from the soil, liberating the PCB into the solvent. Then a reagent added to the solvent destroyed the PCB, converting it to ordinary table salt and leaving behind a low-grade fuel mixture, suitable for use as an industrial fuel.

The soil was cleaned of any residual solvent ready for re-use on the site or elsewhere.

That was the first demonstration of Sonic’s PCB Sonoprocess and it was a huge success.

A $40 Billion Problem

There are over 200 types of PCBs, and the very thermal stability, non-conductivity and resistance to breakdown that made them so attractive to business and industry also makes them a highly persistent environmental contaminant.

Health and environmental agencies believe all PCBs are toxic to some degree. Many cause cancers in lab animals and likely in people, too. They are known to cause nerve and liver damage, skin and reproductive problems and may also trigger autoimmune responses. Even worse, PCBs were almost always contaminated by furans and dioxins during manufacture – two chemicals that are much more toxic than the PCBs themselves.

Since PCBs were manufactured in such quantity for so long – more than 1.4 billion pounds over about 40 years – and were so useful in so many ways, they have literally spread around the world, to virtually every factory of any size, large military bases and any other facilities using PCB oils in heat exchangers, electric transformers and other industrial uses.

Through accidental spills and subsequent seepage, PCBs have found their way into many water, soil and sediment systems (in fact, because of the volatility of some PCBs, you can even find traces of them in Arctic ice). In soils, PCBs adsorb tightly to soil particles and persist for many years.

The U.S. Environmental Protection Agency estimates there are at least 55 million tonnes of PCB contaminated earth in more than 500 sites designated as priority sites for cleanup. There are thousands of other sites – “brownfields” – that need to be remediated before they can be redeveloped.

In Canada there are an estimated five million tonnes of similarly contaminated soil tagged for urgent cleanup, plus many more less-critical sites.

“Environmental assessment studies indicate that the value of the worldwide market for remediating PCB-contaminated soils may be as high as $40 billion,” says Adam R. Sumel, President and CEO of Sonic Environmental Solutions Inc.

New Solution for a New Century

As we entered this century, the engineers and management were examining a new technology, developed in the 1990s as a process for mixing and grinding ores.
Unlike previous attempts to use sound energy on an industrial-scale, this process had no difficulty producing levels of energy that would destroy most normal industrial machinery.

“Although we liked it for its mining applications,” says Mr. Sumel, “we saw it had even more commercial promise in soil remediation – especially as a transportable unit. In 2002 we acquired the technology and began working flat out to perfect what we call our PCB Sonoprocess.”

Following their successful demonstration in 2004 of a complete pilot scale process, Sonic received confirmation of compliance with the Hazardous Waste Regulations in B.C. and also satisfied the emission requirements of the GVRD – some of the most stringent air quality requirements in North America.

Sonic demonstrated that it could successfully remediate a soil contaminated to levels of 500 ppm to below 2 ppm, easily meeting the requirements for commercial and residential land use accepted by regulators.

How PCB Sonoprocess Works

Conventional methods for generating high intensity sound require a lot of costly energy. But Sonic’s PCB Sonoprocess uses the principles of sonic resonance to create industrial strength low frequency sound.

In the process, electromagnets vibrate a large, 2.5 tonne steel bar at low frequencies (100-500 Hz). The bar is attached to a special reaction chambers. As the bar vibrates at its natural, or resonant, frequency, the electromagnets produce an intensity in the reaction chamber at least 10 times more powerful than conventional industrial mixing systems.

Within seconds, these powerful waves can cause the complete deagglomeration of PCB from the soil, literally shaking the PCB molecules loose from the soil particles and helping to suspend them in the solvent.

Fast, Effective – and Portable

In situ remediation is usually complicated and expensive, or very slow.
Incineration is also problematic: besides the expense and risks of transporting soil to one of the few approved PCB soil incinerators in North America (there are fewer than 20), incineration destroys the soil. That means it can’t be resold for other uses, and that new soil has to be imported to the remediated site.

The PCB Sonoprocess has a capacity of 30 to 90 tonnes of soil per day, and can remove contamination to below 2 ppm, rendering the soil and the site completely safe for redevelopment, including for human habitation.

The process consumes very little energy – far less than incineration – and can be at least partially self-sustaining by using the spent solvent as low-grade fuel.
Best of all, says Mr. Sumel, “PCB Sonoprocess has a modular transportable design, which means it can be taken right to the contaminated site. Why transport the soil, when you can more easily transport the technology?”

Looking Ahead

Sonic has recently completed construction and testing of their first full scale, commercial transportable facility, and has deployed the plant at a contracted clean up site in Delta, B.C., where it is being commissioned.

The company is working on developing alliances with major environmental engineering firms in the U.S., to ensure its technology complies with the different environmental regulations there.

The company also showcased its technology at the WASTEC 2004 trade show in Japan last November, where demand for environmentally friendly solutions is growing quickly.

“We have already received follow-up interest from some of the multi-billion dollar companies we met there,” says Mr. Sumel. “We also expect potential partners and clients we met at WASTEC to visit our facilities here, soon, as a prelude to launching our technology in Japan, and in other countries in Europe and South America.”

SIDEBAR #1: What were PCBs used for?

According to the US Environmental Protection Agency, PCBs were used in capacitors, transformers  and hydraulic fluids, such as those for

  • gas transmission turbines
  • flame retardants inks and adhesives
  • microencapsulation of dyes
  • paints, plasticizers and pesticide extenders
  • slide-mounting mediums for microscopes
  • surface coatings, wire insulators, and metal coatings.

All told, some 1,400,000,000 pounds of PCBs were manufactured in the U.S., although none were made in Canada. They’ve been barred from use in Canada and the USA since the mid-1970s, but a grandfather provision allowed existing equipment using PCBs to remain in use.

SIDEBAR #2: A primer in resonant frequency

If you give a playground swing a small push (input), it swings back and forth, but doesn’t go far with each swing (low amplitude). If it hits you, even with somebody sitting on it, it doesn’t do so with much force.

But if you keep giving the swing small pushes, it begins to swing higher and higher – its amplitude grows. The bottom of the swing moves through a greater distance, but in the same time (frequency) as with the initial small push. That frequency is its natural frequency, sometimes called ‘resonant’ frequency.

As the amplitude of the swing grows, so does the force of the person sitting in it – enough in some cases to knock you off your feet or remove some teeth.

From a steady input of small pushes resonant frequency delivers big resultant forces. If you’ve ever seen film of the Tacoma Narrows bridge being destroyed by a steadily blowing wind (November 1940), then you have some idea of the energy resonant frequencies can produce.

Note: You’ll find it very easy to get the swing to move with its natural frequency, but very hard to get it to move faster. And as soon as you stop pushing harder and faster, the swing returns to its natural frequency.

*You can see a short clip of the bridge in motion here:

http://www.enm.bris.ac.uk/research/nonlinear/tacoma/tacnarr.mpg

Advertisements