sewage treatment

(redirected from Primary waste treatment)
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sewage treatment

the treatment of raw sewage to make it harmless for discharge into rivers, seas and oceans. Treatment systems may involve
  1. (a) Primary treatment in which physical methods are used to remove solid matter (primary sludge) from the waste-water.
  2. (b) Secondary treatment in which biological methods, involving a range of aerobic bacteria, are used to degrade the organic matter in the waste-water. The treated sewage may then be disinfected before discharge from the sewage plant. The sludge that accumulates during both primary and secondary treatments is acted on by anaerobic bacteria in an anaerobic sludge digester. The methane produced can be used as a fuel for heating the digester, whilst the treated sludge is dried and may be used as a fertilizer.
  3. (c) Tertiary treatment in which chemical and physical methods are generally used to remove all the biochemical oxygen demand (BOD), nitrogen and phosphorus. After this treatment the water is disinfected and can be pumped direct into reservoirs. However, tertiary treatment is an expensive process, so water is often returned to the environment after secondary treatment.
References in classic literature ?
Master Pedro refused to take the money, saying, "I will not receive payment in advance or until the service has been first rendered;" and then with his right hand he gave a couple of slaps on his left shoulder, and with one spring the ape perched himself upon it, and putting his mouth to his master's ear began chattering his teeth rapidly; and having kept this up as long as one would be saying a credo, with another spring he brought himself to the ground, and the same instant Master Pedro ran in great haste and fell upon his knees before Don Quixote, and embracing his legs exclaimed, "These legs do I embrace as I would embrace the two pillars of Hercules, O illustrious reviver of knight-errantry, so long consigned to oblivion
As Dubai's primary waste treatment service company, Tadweer receives the bulk of its waste from the Dubai Municipality.