In the processes for treating municipal sewage and storm water containing biosolids to discharge standards, biosolids, even after dewatering, contain typically about 80% water bound in the dead cells of the biosolids, which gives biosolids a negative heating value. It can be incinerated only at the expense of purchased fuel. Biosolids are heated to a temperature at which their cell structure is destroyed and, preferably, at which carbon dioxide is split off to lower the oxygen content of the biosolids. The resulting char is not hydrophilic, and it can be efficiently dewatered and/or dried and is a viable renewable fuel. This renewable fuel can be supplemented by also charging conventional biomass (yard and crop waste, etc.) in the same or in parallel facilities. Similarly, non-renewable hydrophilic fuels can be so processed in conjunction with the processing of biosolids to further augment the energy supply.

Slurry dewatering and conversion of biosolids to a renewable fuel

An organic or inorganic feed compound can be treated in two or more zones to progressively oxidize the compound. The first zone oxidizes the compound to an intermediate product which includes a first intermediate compound which is intermediate the feed compound and end product. The second zone further oxidizes the intermediate product to an end product or a second intermediate compound which is intermediate the first intermediate compound and an end product. One or both zones may operate catalytically and/or at supercritical conditions for water to oxidize the compounds.

Method and apparatus for multiple-stage and recycle wet oxidation

A high pressure and high temperature reactor (10), comprising a pressure vessel (22) and a reaction chamber (12) enclosed within the pressure vessel forming an annular space (24) providing thermal insulation of reaction chamber (12); a feeding tube (30) ending in the vicinity of the top chamber (12) end; an effluent output (34) at the bottom vessel (22) end; a quench tube (36) and further supplimental tubes for introducing first and second constituents in the reaction zone, an inert fluid inlet adaptable to introduce fluid to the annulus (24). The reaction chamber is made of titanium or covered with a liner material comprising titanium, noble metals or platinum. The reactor is especially designed for oxidation of aqueous waste liquids under supercritical water conditions.

Turbulent flow cold-wall reactor

A reactor enclosed in a pressure vessel in a manner that the walls of the pressure vessel are thermally insulated and chemically isolated from the harsh environment of the reaction zone in the reactor. This allows the pressure vessel to handle the high pressures involved, since it is maintained at a reasonably low temperature range. Simultaneously, it allows the reactor to handle the high temperatures involved, since the pressure differentials around it are only minimal.

Reactor for supercritical water oxidation of waste

A wastewater treatment system and method for substantially reducing or eliminating total suspended solids (TSS), biological organic discharge or biochemical oxygen demand (BOD), and fats, oils and greases (FOG) contaminants. The system includes at least one mixing chamber for mixing wastewater with at least one dewatering agent or chemical and air to form an aerated mixture and at least one tank having a plurality of compartments for facilitating flotation, settling and removal of contaminants from the aerated mixture as it flows through the tank. Preferably, the system includes first and second mixing chambers and first and second tanks arranged in series with each of the tanks including drag lines for removing floating and settled contaminants.

Wastewater treatment system and method

A two-stage wet oxidation process for COD removal from high strength wastewater is disclosed. The wastewater stream is treated in a first stage subcritical wet oxidation zone at temperatures between about 250° and 374° C. to remove a substantial portion of the COD. Subsequently, all or a portion of the first stage oxidized waste stream is treated in a second stage supercritical wet oxidation zone at temperatures of 374° to about 600° C. to remove any remaining COD content. Both stages of wet oxidation treatment are carried out at essentially the same system pressure.

Two-stage subcritical-supercritical wet oxidation

A process and system for the destruction of compounds having a carbon-hetero atom bond. The process includes wet oxidation at elevated temperature and pressure of an aqueous mixture of at least one compound having a carbon-hetero atom bond to substantially destroy the carbon-hetero atom bond of the at least one compound. The resulting oxidized material may be further treated in an advanced oxidation process to destroy any residual carbon-hetero atom bonds remaining.

Wet oxidation process and system

A wet oxidation process is used to control the concentration of reduced sulfur compounds from a viscose process. The wet oxidation process oxidizes the reduced sulfur compounds to convert such reduced sulfur compounds to an alkali sulfate and/or thiosulfate species. The alkali sulfate stream is recycled to the viscose process. Oxidation is performed under elevated temperature and pressure conditions such that the offgas has an oxygen concentration of between about 2% to 18% and the alkali sulfate stream has a pH of about 2 to 10.

System and method of wet oxidation of a viscose process stream

A two-stage wet oxidation process for COD removal from high strength wastewater is disclosed in which the wastewater stream (10) is treated in a first stage subcritical wet oxidation zone (20) at temperatures between about 250o and 374oC to remove a substantial portion of the COD, and, subsequently, all or a portion of the first stage oxidized waste stream is treated in a second stage supercritical wet oxidation zone (28) at temperatures of 374o to about 600oC to remove any remaining COD content. Both stages of wet oxidation treatment are carried out at essentially the same system pressure.

William M. Copa

Papers

Two-stage subcritical-supercritical wet oxidation

Wet oxidation process and system

System and method of wet oxidation of a viscose process stream

Two-stage wet oxidation process for treating wastewater