Abstract: Methods and systems are provided for drying wet biosolids to produce a class A biosolids. Generally described, the method of treating biosolids includes drying a wet biosolids in an indirect dryer to produce a partially dried biosolids and drying the partially dried biosolids in a direct dryer in series with and downstream of the indirect dryer to produce a class A biosolids. The indirect dryer and direct dryer may be operated at an average temperature of greater than about 100° C. and may have a total combined residence time of less than about 60 minutes. Also provided are systems for drying wet biosolids including an indirect biosolids dryer and a direct biosolids dryer in series. The methods and systems are particularly effective at reducing the moisture content of the biosolids from greater than 85% to less than 10% by weight.

Abstract: A method and apparatus for cleaning the interior of a container or one or more objects suspended therein comprising generating a fluid vapor column by forming an air column having a direction of air flow. The air column is passed through a heating means, so as to heat the air, and then the cleaning fluid is injected into the air column against the direction of air flow. The fluid vapor column is then brought into contact with the interior of the container so that the vapor condenses on the interior of the container or on objects suspended therein.

Abstract: A method is disclosed for drying particulate material, particularly alumina, which comprises the steps of subjecting a first portion of a wet particulate material feed to pre-drying to produce at least partially dried particular material and moisture, heating the at least partially dried particulate material to a temperature higher than the temperature of the pre-drying to produce hot particulate material, water vapour and products of combustion, passing the water vapour and products of combustion to the pre-drier, mixing the hot particulate material with a second portion of the wet particulate material feed to cool the hot particulate material and further cooling the cooled particulate material and subsequent separation to produce a low temperature particular material product.

Abstract: A process is provided for drying raw material that comprises solids and a substantial amount of moisture. The process in its basic form involves the steps of forming the raw material into pellets by extrusion under pressure through a forming die into pellets with the solids compacted into a cohesively secured mass and then drying the pellets thus formed to reduce the moisture to a desired percentage. Raw material that has an excessive amount of moisture such that they cannot be extruded are first mixed with a dry material to reduce the moisture content to the point where they can be extruded.