Poly Aluminium Chloride (PAC) is now the most common coagulant in Indian water and effluent plants, but two PAC quotes can look similar and perform very differently. This guide explains what the key numbers on a PAC specification mean and how to compare grades on a like-for-like basis.
Liquid or powder?
Liquid PAC is ready to dose: it goes straight from the drum or tank to the dosing pump. It suits plants with steady consumption and storage tanks, and it avoids dissolving powder on site. The trade-off is that you are paying to transport water, so freight per kilogram of active aluminium is higher.
Powder PAC carries much more aluminium per kilogram, so it is cheaper to transport and store and keeps well in dry conditions. It has to be dissolved in a make-up tank before dosing, which adds a step for the operators.
Many plants outside the big cities choose powder for the freight saving. Large plants close to the supplier often prefer liquid for the simpler handling.
Aluminium content (Al2O3 %)
Aluminium content, quoted as % Al2O3, tells you how much active coagulant you are buying. Powder grades are typically around 28 to 30% Al2O3; liquid grades are much lower, because most of the product is water.
This is why price per kilogram alone is misleading. Compare quotes on price per kilogram of Al2O3, then confirm with a jar test, because two grades with the same aluminium content can still need different doses.
Basicity
Basicity describes how far the aluminium has been pre-neutralised (pre-hydrolysed) during manufacture. Higher-basicity PAC consumes less of the water's natural alkalinity, so it lowers pH less and generally works better in cold or low-alkalinity water. India's PAC standard, IS 15573, recognises medium- and high-basicity types.
If your raw water is soft or your effluent already has low alkalinity, ask for the basicity figure and favour a higher-basicity grade.
Standards and documents to ask for
- IS 15573 covers PAC for drinking-water treatment, in liquid and powder form. For potable water, ask whether the grade conforms to it.
- A batch test report (COA) showing Al2O3, basicity, pH of a 5% solution and insoluble matter
- The safety data sheet (SDS) and technical data sheet (TDS) for your plant records
Some powder grades also carry NSF/ANSI/CAN 60 certification for drinking-water use, which matters for plants supplying potable water.
Grades we stock
We stock liquid and powder PAC, including Vytal and AC100S powder grades and Vikram liquid grades. See the full list on our PAC supplier page, and use the jar test guide to compare them on your own water.