Bethlehem Steel Corporation

Charles J Sterner

Daniel Kwasnoski

Kenneth R Burcaw, Jr

Russel J Horst

Stewart T Herman

Richard T Sewald, Sr

James B Pfeiffer

An industrial wastewater treatment method is described whereby heavy metals dissolved in the wastewater are precipitated as a slurry which, when allowed to settle, will form a sludge containing at least 10 weight percent solids. In the method, an aqueous suspension or solution of a neutralizing agent is introduced into a first reactor. A suspension containing particles of carrier agent is also introduced into the first reactor. A portion, if not all, of the neutralizing agent is adsorbed on the surface of the particles of the carrier, which are maintained in suspension in the first reactor. The carrier, with its adsorbed neutralizing agent, is passed to a second reactor and simultaneously the contaminated industrial wastewater is added to the second reactor. The pH of the wastewater is adjusted to a range between 8.4 and 10.6 by the neutralizing agent. Within such pH range, a substantial portion, if not all, of the heavy metals are precipitated in the form of a slurry. The mixture in the second reactor is passed to a solids separation device. The solids in the slurry settle to the bottom of the device to form a sludge which is removed therefrom. Purified water is removed as an overflow from the separation device. Optionally, a flocculant may be added to aid in settling the solids. Insoluble calcium salts may also be precipitated in the second reactor. Such insoluble salts are adsorbed on the surface of the carrier and/or the heavy metal slurry particles and become part of the sludge formed in the separation device.

Treatment of industrial wastewaters

The fouling of ammonia stills which results from the clogging, particularly of the lower plates of the stills, with sludge and precipitates is eliminated by use of combined apparatus in which a calcium compound precipitation step followed by a clarification step prior to initiation of actual distillation can be effected.

Apparatus for the distillation of weak ammonia liquor

The thermal efficiency of an ammonia still is significantly increased by the use, in conjunction with the usual countercurrent steam stripping medium, of an auxiliary inert gas stripping medium initially heated and humidified by passage through a heat exchanger together with hot still bottoms derived from the still.

Apparatus for distillation

The thermal efficiency of an ammonia still is significantly increased by the use, in conjunction with the usual countercurrent steam stripping medium, of an auxiliary inert gas stripping medium initially heated and humidified by heat exchange with hot still bottoms derived from the still.

Method and apparatus for distillation

The fouling of ammonia stills which results from the clogging, particularly of the lower plates of the stills, with sludge and precipitates is eliminated by use of a calcium compound precipitation step followed by a clarification step prior to initiation of actual distillation.

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Bethlehem, PA, United States of America

Charles J Sterner