The word polymer simply means “many parts,” which covers a broad range of compounds including styrofoam and DNA. Polymers are long-chain molecules with repeating parts. For wastewater treatment, polymer pertains to polyelectrolytes, which are polymers with molecular chains that produce an electric charge when dissolved.Cationic polymers produce a positive charge while anionic polymers produce a negative charge. These long chain molecules attract particles of an opposite charge while offering many sites for attachment. In some cases, both positively and negatively charged polymers are used in a scheme called dual polymer flocculation, where the polymers are introduced in sequence. There are
