DATA SHEET: 6162/1 02.03

Fire Fighting FoamDisposal Recommendations

Angus Fire foam concentrates are specially formulated for minimal environmental impact.However, as with all foams, they are capable of impacting on the environment under certainconditions. Measures should therefore be adopted to dispose of foams responsibly in accordancewith relevant liquid waste disposal regulations.

Foam-Water SolutionFoam-water solution is generally discharged under eithercontrolled conditions (eg. training exercises, foam systemcommissioning and maintenance tests) or uncontrolledconditions (eg. manual fire fighting and vapour suppressionoperations, foam system activation).

Foam-water solution should be contained and disposed of inan environmentally responsible manner. It should not bediluted and dispersed into watercourses, soils, or foul waterdrains without the prior consent of the local environmentalauthority.

There are a variety of containment measures that may beemployed, ranging from temporary arrangements topermanent engineered systems. The relevant enforcingauthority should be consulted for practical advice on the mostappropriate containment measures for a particular site anddischarge scenario.

Once the foam-water solution has been contained, the mostcommon method of disposal is to treat it biologically in awastewater treatment plant (WWTP).

A WWTP should be contacted prior to discharge. In most casesit will require a Material Safety Data Sheet for the foamconcentrate (contains information on composition, BOD,aquatic toxicity), an estimate of the total volume of foam-watersolution to be discharged, and the anticipated timing of thedischarge.

A WWTP may require foam-water solution to be diluted inadvance. The US National Fire Protection Association (NFPA)recommends that the concentration of any foam-water solutionin the total volume of WWTP influent should not exceed 1700parts per million (ppm). For example, foam-water solutioncould be discharged at the rate of 7 gallons per minute (gpm)to a 6 million gallon per day WWTP. The difficulties of meteringsuch a low rate of discharge can be overcome by diluting thefoam-water solution by 10 or 20 to 1, permitting dischargerates of 70 or 140 gpm respectively.

At discharge concentrations greater than 100 ppm foam-watersolution may cause aesthetic and operational problems atWWTPs by foaming in activated sludge aeration basins. Thismay be prevented or controlled by the use of defoaming agents.Angus Fire recommends various defoaming agents. Theenvironmental properties of any defoaming agent should betaken into consideration prior to use.

Foam-water solution pre-treated in oil/water separators mayemulsify with hydrocarbon fuels and so carry them over intothe water stream. Synthetic detergent based foams have agreater tendency to emulsify than natural protein-basedfoams.

Foam-water solution generally exhibits low toxicity to bacteriain WWTPs. Natural protein-based foams exhibit lower toxicitythan synthetic detergent based foams. Foam-water solutionhas a higher BOD than liquids that are usually treated inWWTPs, however, and so microbial oxygen uptake may beinhibited if excessive quantities are discharged.

Foam ConcentrateFoam concentrate may need to be disposed of in the event ofa spillage or if it is judged unsuitable for use as a result ofbeing diluted or contaminated by foreign materials. It shouldbe taken to an approved disposal site by a licensed wastedisposal contractor for disposal by controlled release to aWWTP, incineration, or liquid landfill.

Further InformationLow/Non Hazardous Products with Potential for PollutingWater, B. McGlashan, UK Environment Agency, Fire Prevention,May 1995.

Foam and the Environment: A Delicate Balance, NFPA Journal,May/June 1995.

A Review of Fire Fighting Foams to Identify Priorities for EQSDevelopment, UK Environment Agency, 1994.

Pollution Prevention Measures for the Control of Spillagesand Fire Fighting Run-Off, UK Environment Agency, 1994.

The Control of Fire-Water Run-Off from CIMAH sites to PreventEnvironmental Damage (Guidance Note EH 70), Health andSafety Executive, 1995.

The right is reserved to vary or modify any specification without prior notice. © Angus Fire

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e-mail: general.enquiries@kiddeuk.co.ukwebsite address: www.angusfire.co.uk

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