Air Products and Chemicals, Inc.

Charles S Block

Michael S Chen

Sun-Nan Hong

Olaf J Noichl

Wastewater containing phosphorus values and BOD is initially admixed with recycled sludge containing activated biomass under anaerobic conditions, then contacted with oxygen-containing gas, followed by separation of a dense sludge layer from the mixed liquor. A portion of the sludge layer, containing the activated biomass, is held under non-aeration conditions for sufficient time to reduce any nitrates and/or nitrites contained therein, before admixture of the recycled sludge with the wastewater influent.

Treatment of wastewater containing phosphorus compounds

A wastewater treatment system of the activated sludge type is disclosed having an aeration basin provided with staggered partitions and of a particular geometrical design and mode of operation whereby more efficient purification of the wastewater may be achieved in a system of a given size.

Activated sludge system with staggered partition basin

A wastewater treatment system of the activated sludge type is disclosed in which variable degrees of effective staging of the mixed liquor are achieved in an oxygenated aeration basin without the use of walls or partitions to physically divide the mixed liquor into separate liquid stages.

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Allentown, PA, United States of America

Charles S Block