Abstract: A method for processing sewage eliminates chemical "treatment", or, the addition of chemicals that are as harmful or more so to the environment as raw sewage. The method of processing sewage disintegrates the generally solid components of sewage into a highly de-moisturized powder via alternative processes of either (i) a freeze-drying process, or (ii) a combination centrifugal separation and an evacuated "bake-out" process, both which substantially drive out the vaporizable components of the sewage. In consequence, there are no resultant effluent and/or exhausting vapors from this method which would impact the environment.

Abstract: A method for treating a mechanical pulp plant effluent waste stream by freezing the effluent stream and separating frozen product. The frozen product contains between about 50 to 150 ppm chemical oxygen demand (COD), and may be reclaimed.

Abstract: Soap is separated from spent, cellulosic pulping liquor by strenuously percolating a gaseous, aliphatic hydrocarbon through a quantity of liquor volume under such temperature and pressure conditions that an equilibrious strata of liquid phase hydrocarbon is sustained on the surface of the liquor. Following strenuous combination and agitation, the gas-liquor mixture is allowed to settle so that the entrained, gaseous hydrocarbon and coagulated soap floc gravimetrically rises to the liquor surface and stratifies with the soap layer between the residual liquor solution and a liquid phase layer of hydrocarbon. Thereafter, the liquid hydrocarbon and soap layer are decanted away from the residual liquor solution and depressurized to vaporize the hydrocarbon leaving a reservoir of isolated soap.

Abstract: A method for reducing the clay content of a colloidal clay-water mixture which comprises combining the mixture with air at superatmospheric pressure and thereafter expelling the mixture in the form of small droplets at atmospheric pressure at a temperature below 32.degree. F. to form synthetic snow. Thereafter synthetic snow can be melted to recover water containing reduced mineral content. The invention is particularly applicable to sludge associated with the hot water extraction method for recovering bitumen from tar sands.

Abstract: A process is described for purifying liquids by cryogenic sublimation. This process involves solidifying the liquid by reducing the temperature and pressure to below the triple point. Purification is then carried out by direct transformation from the solid to the vapor phase. Because of increased differentials in vapor pressures at the low temperature at which the procedure is carried out, this purification process is highly efficient and is also particularly suitable for liquids that are susceptible to decomposition with ordinary purification procedures requiring elevated temperatures. The procedure is also advantageous in separating azeotropes, structurally similar compounds, as well as treating flammable, hydroscopic, corrosive and fuming compounds.

Abstract: Pulping liquor borne solids are concentrated within an aqueous solution by a successive plurality of freezing steps wherein a discrete quantity of the solution is crystallized in each step by freezing. The water crystals from each freezing step are subsequently separated from the remaining liquid solution by screening and applying axial pressure to the crystalline mass. Greater efficiencies may be obtained in some cases by mixing or reslurrying a pressed, crystalline mass and pressing a second time. Another auxiliary separation step comprises a quiescent thaw of the crystalline mass from the first two press steps to permit additional dissolved solids to be drained away from the purified water ice.