Settlement

• Water is either pulled out of the ground or taken from above ground surfaces, such as lakes or rivers. The first step in the filtration process is the removal of large objects, such as tree limbs and rocks. This is achieved by setting up grates that catch the material and keep it from moving any further. A second set of grates have smaller openings and catch smaller material, such as small rocks, leaves and twigs. After the larger objects are removed the water is sent to a holding area where sand and other material can settle to the bottom and out of the water.
  
  

Suspended Solids

• Once settled, the water is sent to a processing plant. There are some particles still in the water in the form of suspended solids. This means that they won't settle on their own because they are suspended between water molecules. There are a couple of ways these solids can be handled. One is to use a sand filtration to capture the particles as the water is run through the sand filters. Also, coagulants can be added to the water to remove the charge of the ions in the suspended solids. This allows them to join into larger particles and settle.
  
  

Disinfection

• After the suspended solids are removed, there is sometimes another settling, and then the water is disinfected to kill bacteria that might still be in it. The water then is transferred to holding tanks until the disinfectant dissipates.