What is Poly Aluminium Chloride (PAC) and How is it Used in Water Treatment?

PAC is a pre-hydrolysed aluminium coagulant. On dosing it releases polymeric aluminium species that neutralise charge on colloids so pin-floc can form in the flash mix.

Compared with straight alum, many plants see faster floc and a lower dose for the same turbidity — but jar tests on your own composite still decide.

Powder PAC is typically 28–30% Al₂O₃; liquid PAC is often 10–18% Al₂O₃. Powder stores easier; liquid suits automated dosing skids.

PAC usually works across a wider pH window than alum (roughly 6.5–8.5), so you may spend less on lime or caustic just to keep coagulation alive.

Municipal plants use PAC for raw-water clarification ahead of filters when turbidity spikes in monsoon.

Textile, paper and dye-house ETPs dose PAC in primary clarifiers before biological or tertiary stages.

On reactive-dye colour, PAC often beats alum when CPCB colour limits are the pain point — again, prove it on a jar test.

Pools and recreational systems sometimes use a PAC shock dose for cloudy water alongside normal disinfection.

Typical ETP product dose sits somewhere between 50–300 mg/L; start from jar tests, not a catalogue number.

Keep powder dry and off the floor — PAC cakes hard in monsoon sheds. Liquid belongs in HDPE, out of direct sun.

Read every COA for Al₂O₃, basicity and iron. High iron can stain paper or textile process water.

Ask for bag sizes you can actually handle (25/50 kg or jumbo), batch COA samples before PO, and a clear RFQ reply SLA — not a public list price.

Drashti Chemicals stocks related industrial chemicals from Vadsar with batch COA, MSDS and GST invoicing (24AGLPC6288M1ZX). We are a supplier/stockist — share grade and quantity for a documented bulk quote. No public list prices.