Enhanced biological phosphorus removal (EBPR) is a wastewater treatment configuration applied to activated sludge systems for the removal of phosphate.
The common element in EBPR implementations is the presence of an anaerobic tank (nitrate and oxygen are absent) prior to the aeration tank. Under these conditions a group of heterotrophic bacteria, called polyphosphate-accumulating organisms (PAO) are selectively enriched in the bacterial community within the activated sludge. These bacteria accumulate large quantities of polyphosphate within their cells and the removal of phosphorus is said to be enhanced.
Generally speaking, all bacteria contain a fraction (1-2%) of phosphorus in their biomass due to the its presence in cellular components, such as membrane phospholipids and DNA. Therefore as bacteria in a wastewater treatment plant consume nutrients in the wastewater, they grow and phosphorus is incorporated into the bacterial biomass. When PAOs grow they not only consume phosphorus for cellar components but also accumulate large quantities of polyphosphate within their cells. Thus, the phosphorus fraction of phosphorus accumulating biomass is 5-7%. This biomass is then separated from the treated water at end of the process and the phosphorus is thus removed. Thus if PAOs are selectively enriched by the EBPR configuration, considerably more phosphorus is removed, compared to the relatively poor phosphorus removal in conventional activated sludge systems.
Famous quotes containing the words enhanced, biological and/or removal:
“In what does the objective measure of value lie? In the quantum of enhanced and organized power alone, in accordance with what occurs in all occurrence, a will to increase.”
—Friedrich Nietzsche (1844–1900)
“When human beings have been fascinated by the contemplation of their own hearts, the more intricate biological pattern of the female has become a model for the artist, the mystic, and the saint. When mankind turns instead to what can be done, altered, built, invented, in the outer world, all natural properties of men, animals, or metals become handicaps to be altered rather than clues to be followed.”
—Margaret Mead (1901–1978)
“Anyone who seeks for the true causes of miracles, and strives to understand natural phenomena as an intelligent being, and not to gaze at them like a fool, is set down and denounced as an impious heretic by those, whom the masses adore as the interpreters of nature and the gods. Such persons know that, with the removal of ignorance, the wonder which forms their only available means for proving and preserving their authority would vanish also.”
—Baruch (Benedict)