A fluid treating method for treating fluid to reduce the concentration of undesirable metal constituents contained therein is disclosed. The method utilizes a bed of metal particulate matter. The metal particulate matter comprises copper. Preferably, the metal particulate also contains zinc and can be in the form of an alloy. The fluid treated is often water, preferably, drinking water. Among the metals that may be effected by the present method are aluminum, arsenic, barium, cadmium, chromium, copper, gold, iron, lead, mercury, selenium and silver.

Method for treating fluids

A method for treating fluid to remove hydrogen sulfide and sulfur dioxide is disclosed. The method includes passing fluid containing the hydrogen sulfide and/or sulfur dioxide through a bed of metal particulate matter. The metal particulate matter is preferably chosen from metals having favorable redox potentials relative to the redox potentials of these undesirable constituents so as to establish conditions for spontaneous oxidation and reduction reactions between the undesirable constituents and the metal particles.

Method of treating fluids

A process and apparatus for the chemical-mechanical treatment and purification of ground and surface waters and effluents of various types employs adding materials for coagulation, flocculation, precipitation, sedimentation and altering the pH value. The process comprises separate process stages carried out successively as follows: (1) a first initial process stage wherein certain additives are admixed to the raw water by stirring; (2) a second initial process stage wherein contact sludge is admixed by stirring; (3) a third initial process stage wherein a flocculent aid and possibly also at least some of the other materials added in the first stage are admixed by stirring with high energy input; and alternatively (4) a fourth initial process stage for the formation of course flocs and completion of reaction of the previously added materials and formation of settleable particles and conglomerations of particles together with adsorbed and attached and occluded raw water components with moderate movement. After the initial process stages a further stage occurs wherein flocs and reaction products and raw water components are separated from the clarified water with separate removal of the separated solids and the clarified water. The separation of flocs and reaction products and raw water components from the clarified water in the further zone is accomplished by inclined sedimentation means and at least a part of the sludge is concentrated to a solids concentration of at least 1% weight/volume after drying with at least a part of the concentrated sludge being returned as contact sludge in the second initial process stage.

Process and apparatus for the chemical-mechanical treatment and purification of ground waters, surface waters and effluents

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 84 and 106 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

A lime-treatment method is disclosed to neutralize acidic waters containing heavy metals and sulphate and precipitate the metals as hydroxides along with calcium sulphate solids which are called sludge. The method comprises neutralizing the water in two reactors, the pH of the first reactor being increased to 4-4.5 using a predetermined amount of recycled sludge to precipitate only ferric hydroxides whereas other metal hydroxides coming from the recycled sludge are dissolved, the pH of the second reactor being increased to 9-10 using a mixture of lime and a small amount of the sludge recycled to the first reactor; feeding the ferric hydroxides precipitated in the first reactor to the second reactor to act as nuclei in the second reactor to promote crystallization; and introducing air into the second reactor to oxidize ferrous iron to less soluble ferric iron which results in formation of a more stable sludge compared to ferrous sludge.

Lime neutralization process for treating acidic waters

Ferrous iron-containing acid waste waters are neutralized to form a dense, compact, and easily settleable sludge. Ferrous to ferric iron ratios are adjusted prior to neutralization by catalytic oxidation to conform approximately to that of magnetite; 1Fe to 2Fe . Neutralization of the acid waste and precipitation of a mixed valence iron oxide is accomplished using a finely divided limestone slurry as the preferred neutralizing agent.

Edward A Mihok

Papers

Neutralization of ferrous iron-containing acid wastes