What are the process steps present in a typical water treatment plant?
Although each facility is different and will have its own process, the steps you would typically see at a water treatment plant are outlined below.
- Screening: To protect plant equipment and aid in efficient plant operation. Both coarse and fine screening can be used to remove materials such as leaves, twigs, rags, paper, and other debris that could obstruct water flow.
- Aeration and/or Prechlorination: Water is aerated by passing over a series of steps to take in oxygen from the air. This can help expel organic or soluble gases as well as provide for oxidation of iron and manganese for removal later on in the process. Prechlorination with chlorine gas or bleach which also aids oxidation of iron and manganese as well as provide bacteria and odor control.
- Coagulation (Fast Mix Zone): The addition of a chemical coagulant which is designed to remove fine particles through charge neutralization. Chemical coagulant usually impart a positive or cationic charge to the very fine particles which are negatively charged for charge neutralization. The coagulant is added in a fast mix zone to allow for the coagulant to contact as many of the fine solid particles as possible to form a visually small solid in the water called “pin” floc.
- Flocculation (Slow Mix Zone Flocculators): As Pin Floc grows larger, the water enters a slow mix zone which is usually paddle type flocculators which turn very slowly allowing particle size to grow. At this point, a chemical flocculant or settling aide can beaded to assist in forming a very large particle size for settling purposes in the next step of the process (Sedimentation).
- Sedimentation (Settling): This part of the process provides a long retention time for settling of solids to the bottom of a tank or a piece of equipment called a clarifier. The settled solids accumulating/ compacting on the bottom of the tank or clarifier is referred to as sludge.
- Filtration: The clear portion of the water on the top of the tank now flows to a filter which most of the time is composed of sand for removal of any fine particles which did not settle in the Sedimentation area.
- Disinfection (Chlorination): This part of the process is to remove any pathogenic micro-organisms from the water making it safe for human consumption and use. Chlorine is the most common chemical used for disinfection which can be in a gas form or bleach as well as chlorine dioxide.
If you operate a water treatment plant and want to know how Aries Chemical can benefit your water treatment process, please give us a call at (315) 346-1489 or send us a note.