Treatment
Spent backwash water is either discharged without treatment to a sanitary sewer system or is treated and recycled within the plant. Historically, backwash water was discharged directly to surface water supplies; however, direct discharge is now highly regulated through NPDES discharge permits and is often discouraged. Used backwash water contains high concentrations of particulate material. Typical treatment processes include coagulation, flocculation and sedimentation. High molecular weight synthetic organic polymers are sometimes added to facilitate the formation of settleable floc. Failure of a backwash treatment process and reintroduction of the resulting poor quality water into the main water purification plant flow stream can cause overall process upsets and result in the production of poor quality treated drinking water.
Read more about this topic: Backwashing (water Treatment)
Famous quotes containing the word treatment:
“I will use treatment to help the sick according to my ability and judgment, but never with a view to injury and wrongdoing. Neither will I administer a poison to anybody when asked to do so, nor will I suggest such a course. Similarly, I will not give to a woman a pessary to cause abortion. I will keep pure and holy both my life and my art.”
—Hippocrates (c. 460–c. 370 B.C.)
“Our treatment of both older people and children reflects the value we place on independence and autonomy. We do our best to make our children independent from birth. We leave them all alone in rooms with the lights out and tell them, “Go to sleep by yourselves.” And the old people we respect most are the ones who will fight for their independence, who would sooner starve to death than ask for help.”
—Margaret Mead (1901–1978)
“James’s great gift, of course, was his ability to tell a plot in shimmering detail with such delicacy of treatment and such fine aloofness—that is, reluctance to engage in any direct grappling with what, in the play or story, had actually “taken place”Mthat his listeners often did not, in the end, know what had, to put it in another way, “gone on.””
—James Thurber (1894–1961)