Poly aluminium chloride (PAC) waa nooc cusub oo waxtarka sare leh ee polymer coagulant, qaadashada farsamada wax soo saarka ee horumarsan iyo walxo cayriin oo tayo leh, waxay tusinaysaa sifooyinka wasakhda hoose, miisaanka molecula sare, iyo saamaynta xinjirowga sare. Kiimikooyinka PAC waxaa loo isticmaali karaa sidii loo isticmaali jiray flocculant ama xinjirowga dhiigga, sidaa darteed inta badan waxaa loo isticmaalaa daaweynta biyaha kala duwan, sida biyaha wasakhda warshadaha, biyaha la cabbo, biyaha wasakhda magaalada, barkadaha dabaasha, iwm. Sida xirfadle soo saaraha ah ee Shiinaha, waxaan ku siin karnaa noocyada kala duwan ee kiimikooyinka PAC, soo dhawoow weydiintaada.