Safe & effective disposal of foam
Published: 01 April, 2006
Foam manufacturers have developed fluorosurfactant-free foams (FSFF) that have no long term detrimental environmental impact. There are numerous areas of application for this type of product, in particular with the European fire and rescue services.
However, the main issues relate to foams containing fluorosurfactants. AFFF foam, for example, is found in the vast majority of portable foam extinguishers because of its high performance versus fluorosurfactant free foams. When used correctly this type of foam is extremely efficient and cost-effective. It only becomes an environmental problem if it finds its way into groundwater.
The Ground Water Regulations 1998 descibe specific groups of substances which fall into two lists, List I and List II. Those detailed in List I include organohalogen compounds and should be prevented from entering groundwater. All Aqueous Film Forming Foam (AFFF) formulations contain fluorosurfactants which are organohalogens and fall within List I of the Regulations. Any substance that is found to be Persistent, Bioaccumulative or Toxic (PBT) must be prevented from entering groundwater. All fluorosurfactants are known to be environmentally very persistent (vP) with a halflife of the order of a decade or more. Some fluorosurfactant breakdownproducts, for example, PFOS, also bioaccumlate and are toxic. The lithium salt of PFOS is even an insecticide!
There is an interesting piece of data which came from a survey in 2002 undertaken by the extinguisher trade associations FETA and IFEDA into the use of portable extinguishers in six European countries. It was found that only 1,188 foam extinguishers had been discharged for the purpose of extinguishing an actual fire at reported incidents.
Of the foam extinguishers discharged in 2002, 516 (43%) were in the UK. The most common size of foam extinguisher used commercially contains 6 litre of foam.
Given these statistics, only 3,096 litres of foam were used in anger in the UK, with a total 7,128 litres in all the European countries surveyed. Only 430 litres of 6% foam concentrate, i.e., less than half of a 1 tonne IBC, would have been used.
So why would this very small and insignificant amount of foam cause such concern?
A report by the Fire Industry Council in 1999 entitled ‘Competitive Analysis UK Fire Protection Industry’. An estimated 12 million extinguishers were under service that year in the UK of which 2.2 million were foam extinguishers. This would equate to approximately 13.2 million litres of foam with an additional 1.6 million litres annually from new foam extinguishers sold in the UK.
The concern is now quite clear. If, in 1999, only 3,096 litres of foam (516 units) from portable extinguishers were used on actual fires, what then happens to the estimated 14.8 million litres being discharged during servicing from 2000 onwards?
of the water company and they would unwittingly become responsible for the contamination. Clearly, the responsibility lies with the fire engineering industry as it is they who create the waste.
Sustainable best practice
Safe disposal of firefighting foam and, in some cases, foam concentrates has never raised more questions than it does currently. From the well documented withdrawal by 3M from fluorosurfactant manufacture using perfluorooctanyl sulphonate (PFOS) chemistry in May 2000 to the present day, dealing with foam as a waste product has assumed an importance for many groups and organisations as a fundermental environmental issue for the fire engineering industry.
Using a patented and tested system, a new UK company, Foamclean Limited, removes the chemicals from the solution that make a firefighting foam an effective extinguishing agent. The process removes the environmentally damaging fluorosurfactants and other agents, rendering the treated solution harmless and clean.
This is achieved through the Perfluoro Filtration Extraction Cleaning and Treatment process known as perfFECTTM. This is a patented process for cleaning fluorinated solutions such as AFFF foam. The process works by passing the solution through a carefully designed carbon matrix to extract the fluorosurfactants, rendering the treated foam solution free of contaminants.
The carbon matrix employed in this process eventually becomes saturated with the fluorosurfactants and other agents such as glycol. The organohalogen substance is locked into the carbon matrix which is then incinerated to destroy the contaminants.