Treatment
Further information: Sewage treatment, Agricultural wastewater treatment, and Industrial wastewater treatmentThere are numerous processes that can be used to clean up wastewaters depending on the type and extent of contamination. Most wastewater is treated in industrial-scale wastewater treatment plants (WWTPs) which may include physical, chemical and biological treatment processes. However, the use of septic tanks and other On-Site Sewage Facilities (OSSF) is widespread in rural areas, serving up to one quarter of the homes in the U.S. The most important aerobic treatment system is the activated sludge process, based on the maintenance and recirculation of a complex biomass composed by micro-organisms able to absorb and adsorb the organic matter carried in the wastewater. Anaerobic processes are widely applied in the treatment of industrial wastewaters and biological sludge. Some wastewater may be highly treated and reused as reclaimed water. For some wastewaters ecological approaches using reed bed systems such as constructed wetlands may be appropriate. Modern systems include tertiary treatment by micro filtration or synthetic membranes. After membrane filtration, the treated wastewater is indistinguishable from waters of natural origin of drinking quality. Nitrates can be removed from wastewater by microbial denitrification, for which a small amount of methanol is typically added to provide the bacteria with a source of carbon. Ozone Wastewater Treatment is also growing in popularity, and requires the use of an ozone generator, which decontaminates the water as Ozone bubbles percolate through the tank.
Disposal of wastewaters from an industrial plant is a difficult and costly problem. Most petroleum refineries, chemical and petrochemical plants have onsite facilities to treat their wastewaters so that the pollutant concentrations in the treated wastewater comply with the local and/or national regulations regarding disposal of wastewaters into community treatment plants or into rivers, lakes or oceans. Other Industrial processes that produce a lot of waste-waters such as paper and pulp production has created environmental concern leading to development of processes to recycle water use within plants before they have to be cleaned and disposed of.
Read more about this topic: Wastewater
Famous quotes containing the word treatment:
“To me, nothing can be more important than giving children books, It’s better to be giving books to children than drug treatment to them when they’re 15 years old. Did it ever occur to anyone that if you put nice libraries in public schools you wouldn’t have to put them in prisons?”
—Fran Lebowitz (20th century)
“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)
“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)