Adding pretreatment to an existing water treatment plant can provide significant process advantages when a plant is faced with challenging influent and stringent effluent water quality regulations. Removing excessive suspended solids early in the treatment scheme reduces the solids loading on subsequent processes, effectively sharing the load among all unit processes.
This distribution of treatment processes often allows components to operate more efficiently than otherwise would have been expected. In the later filter polishing step, longer filter runs between backwashes result in significantly reduced backwash waste and time offline for the process. Without proper pretreatment, water plant operators often scramble in an effort to provide proper chemical feed rates and to avoid process upsets. As such, operators can sometimes be forced to shut down the water plant if it is unable to produce acceptable effluent quality water.