The following processes are commonly used, either individually or in combination, for municipal drinking water treatment:
• Pre-chlorination. Chlorine is added to the water as it enters the plant, killing microorganisms such as bacteria, protozoa, and viruses, and preventing the growth of algae during the upcoming processes.
• Aeration. Bringing air into contact with water for the purpose of exchanging certain components is called aeration. Oxygenation is one of the purposes of aeration. Others are removal of volatile organic substances, hydrogen sulfide, and ammonia. Used along with pre-chlorination, aeration also removes dissolved iron and manganese.
• Coagulation. Coagulation removes dirt and other particles suspended in water. Alum and other chemicals are added to water to form tiny sticky particles called "floc" which attract the dirt particles. The combined weight of the dirt and the floc becomes heavy enough to sink to the bottom. Coagulant aids also known as polyelectrolytes improve coagulation for thicker floc formation.
• Sedimentation. Sedimentation is designed for the removal of suspended solids trapped in the floc. The heavy particles settle to the bottom and the clear water flows out of the basin and moves on to filtration.
• Filtration. Filtration removes left-over floc. The water passes through filters – usually made of layers of sand, gravel, and charcoal – that help remove even the smallest particles. As water filters through the sand, the remaining particles of suspended matter are trapped in the sand bed.
• Disinfection. Chlorine is added or some other disinfection method is used to kill any remaining bacteria or microorganisms that may remain in the water. Water is placed in a closed tank or reservoir in order for disinfection to take place. The water then flows through pipes to homes and businesses in the community.
If you have more questions about the quality of your residential drinking water, call the professionals at HELP Plumbing, Heating, Cooling and Electric at (513) 333-HELP (4357) or visit our website at http://333help.com.