These are higher molecular weight compounds and come in a variety of anionic and cationic charges. Polymers are most often used to increase the viscosity of water or to encourage flocculation of particles present in water such as general industrial wastewater and all kinds of municipal wastewater and sewage. Polymers cause suspended particles in wastewater to aggregate, forming a floc and make fine solids in treated water adhere to one another until they become big enough to settle out or be captured by filters to make sewage sludge which can be filtered or removed more easily.

Polymers are used extensively for a wide variety of industrial processes involving paper making, petrochemical extraction, Sugar manufacturing, electroplating, textiles, oilfields, food processing, pharmaceutical, leather, breweries, wineries, slaughterhouses and to treat water from mineral mining processes, including production of coal (coal washing), Ore washing, lead, titanium, gold, zinc, iron, sand, phosphoric acid, silver, nickel, copper, steel, gravel, alumina uranium as well as potash processing.