Industrial Process & Water Treatment

Both are aluminium coagulants. Poly aluminium chloride (PAC) is partly pre-neutralised, so it consumes less alkalinity, lowers pH less and works over a wider pH range than aluminium sulphate (alum). It often forms flocs faster and performs better in cold water. Alum remains widely used for drinking water and effluent where pH is controlled. The right coagulant and dose for a particular water are found by jar testing.

All three are sodium hydroxide. Lye is a ready-made solution, delivered by tanker or in IBCs and dosed directly by pump, which suits large continuous users with storage tanks. Flakes and prills are solids of about 98% NaOH that are easier to store and move in bags; prills are free-flowing beads that produce less dust. Dissolving solid caustic releases a lot of heat, so always add it slowly to water, never water to caustic.

Sodium hypochlorite is a liquid that is easy to dose by pump but loses strength in storage, especially in warm conditions. Calcium hypochlorite is a solid with about 65-70% available chlorine and keeps better, so it suits pools and emergency disinfection. Stable bleaching powder (chlorinated lime) carries roughly 32-35% available chlorine and leaves a lime residue, but it is widely used in India for drinking water disinfection and sanitation.

Both are salts of the same chelating agent and bind metal ions such as calcium, magnesium and iron. Disodium EDTA gives a mildly acidic solution, about pH 4-5.5, and is the usual choice in cosmetics, pharma and laboratory work. Tetrasodium EDTA gives a strongly alkaline solution, about pH 10.5-11.5, and suits detergents, soaps, textile processing and peroxide bleaching. EDTA acid itself is poorly soluble in water and is mainly used to make the salts.

Peracetic acid is a fast-acting oxidising sanitiser that works at low temperatures and breaks down into acetic acid, water and oxygen, without forming chlorinated by-products. It is widely used for CIP and surface sanitising in dairy, beverage and food plants and for wastewater disinfection. Hydrogen peroxide on its own is a slower disinfectant and is used mainly for bleaching and oxidation. Peracetic acid is corrosive and strongly oxidising, so it needs compatible containers and protective equipment.

Liquid acids, caustic lye, hydrogen peroxide and hypochlorite are supplied in 20-50 L carboys and jerry cans, 200 L HDPE drums or 1,000 L IBC tanks, and in tanker loads for bulk users. Every pack carries product, batch and hazard labelling, and the manufacturer's COA and SDS travel with each batch. Pack type, lead time and terms are confirmed in writing in the quotation.