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 am glad you agree with me as to the treatment of the mining riots. We shall crush out the lawbreakers if the courts and juries do not fail.”
—Rutherford Birchard Hayes (1822–1893)
“The treatment of the incident of the assault upon the sailors of the Baltimore is so conciliatory and friendly that I am of the opinion that there is a good prospect that the differences growing out of that serious affair can now be adjusted upon terms satisfactory to this Government by the usual methods and without special powers from Congress.”
—Benjamin Harrison (1833–1901)
“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)