COS/Specific Substances/TBT-COS-020

Ferric and Aluminium Dosing Chemicals

COSHH & Hazardous Substances › Specific Substances › Ferric and Aluminium Dosing Chemicals

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Ferric sulphate and aluminium sulphate are coagulant chemicals used in water and wastewater treatment processes.
Both chemicals are strongly acidic solutions with pH values typically below 2, causing severe burns on contact.
Ferric sulphate solution stains skin, clothing, and surfaces permanently and causes deep chemical burns.
Aluminium sulphate dust and solution irritate the respiratory system, eyes, and skin on contact.
The COSHH Regulations 2002 require a specific assessment for all dosing chemical handling and delivery.
Chemical deliveries involve bulk tanker unloading into storage tanks, creating splash and spill risks.
Dosing systems include pumps, pipework, and injection points that may leak under pressure.
Mixing ferric or aluminium chemicals with sodium hypochlorite produces toxic chlorine gas.
Emergency eyewash and safety showers must be within 10 seconds' travel of all chemical handling areas.
Safety data sheets for each chemical must be available at the point of storage and use.

Prevent chemical burns	These highly acidic chemicals cause severe burns to skin and eyes on contact — immediate treatment is critical.
Avoid toxic reactions	Mixing with hypochlorite or other incompatible chemicals generates toxic chlorine gas that can be fatal.
Legal compliance	COSHH 2002 requires risk assessment, control measures, and training for all chemical handling activities.
Protect the environment	Spills of dosing chemicals into watercourses cause fish kills and environmental prosecution.

Don't

Read the safety data sheet before handling any ferric or aluminium dosing chemical
Wear chemical-resistant gloves, goggles, and a face shield during all handling tasks
Check that emergency eyewash and safety showers are functional before starting work
Ensure chemical bunding is intact and has sufficient capacity to contain a full tank spill
Supervise all bulk chemical deliveries and verify the correct tank before unloading begins
Flush skin and eyes immediately with water for at least 15 minutes after any contact
Store ferric and aluminium chemicals separately from hypochlorite and alkaline products
Inspect dosing pipework, valves, and pump connections regularly for leaks and corrosion
Wear RPE if working in enclosed areas where chemical vapour may accumulate
Report any spills, leaks, or equipment failures immediately to the site supervisor

DON'T handle ferric or aluminium dosing chemicals without full chemical-resistant PPE
DON'T store ferric or aluminium chemicals near sodium hypochlorite or alkaline products
DON'T allow uncontrolled spills to enter surface water drains or watercourses
DON'T use compressed air or water jets to clean chemical spills without containment
DON'T eat, drink, or smoke in chemical storage or dosing areas
DON'T attempt to repair pressurised dosing pipework without isolating the system first
DON'T transfer chemicals between containers without correct labelling on the new vessel
DON'T ignore minor leaks from dosing systems — they indicate deterioration and worsen
DON'T work in enclosed chemical stores without checking ventilation is operating
DON'T delay flushing after skin or eye contact — seconds count with acid burns

See also: COSHH Awareness | Chemical Dosing Area Safety

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