It is usual in the treatment of water for human consumption to resort to different chemicals at the different treatment stages, as well as during the disinfection processes throughout the distribution systems.

Chemicals to be used in the treatment of water for human consumption must have a suitable quality so that they do not compromise the quality of the water after it has been treated.

Technical specifications regarding the quality of chemicals are established in European standards (refer to table) along with the proper testing methods for their characterisation.

Technical specification standards regarding the quality of a few chemicals used in the treatment of water for human consumption

Product	Standard
Aluminium Sulphate	NP EN 878 - Chemicals used for treatment of water intended for human consumption – Aluminium sulphate
Sodium Hypochlorite	NP EN 901- Chemicals used for treatment of water intended for human consumption – Sodium Hypochlorite
Lime	NP EN 12518 - Chemicals used for treatment of water intended for human consumption – Lime

EPAL's Central Laboratory has developed, implemented, and validated a series of testing methods for the characterisation of the following chemicals:

Aluminium Sulphate

• Aluminium in aluminium sulphate (internal method)
• Iron in aluminium sulphate (NP EN 1302)
• Insoluble matter in aluminium sulphate (NP EN 1302)
• Determining As, Cd, Cr, Ni, Pb, Sb and Se in aluminium sulphate by means of inductively coupled plasma mass spectrometry (internal method)

Sodium Hypochlorite

• Active chlorine in sodium hypochlorite (EN 901)
• Determining Cd, Ni, Pb, Sb and Se in sodium hypochlorite by means of inductively coupled plasma mass spectrometry (internal method)
• Determining As in sodium hypochlorite by means of atomic absorption spectrometry with hydride generation (internal method)
• Determining sodium bromate and chlorate in sodium hypochlorite by means of ion chromatography (internal method)

Hydrated Lime

• Calcium hydroxide in hydrated lime (internal method)
• Calcium carbonate in hydrated lime (internal method)
• Humidity in hydrated lime (internal method)
• Water insoluble substances in hydrated lime (internal method)
• Determining SiO₂, Al₂O₃, Fe₂O₃ and MnO₂ in hydrated lime by means of inductively coupled plasma optical emission spectrometry (internal method)