Coagulation, sometimes also referred to as charge neutralisation, is the first step in water treatment. The coagulant, positively charged, binds with the negatively charged particles (dirt in the water) and forms larger particles. The coagulants are mostly metal salts that can be in liquid or solid form.
Typical products would be: Aluminium sulfate, Polyaluminium chloride, Aluminium chlorohydrate, Polyamine blends, PolyDADmac blends or Ferric chloride/sulfate