Abstract: The invention relates to a process for the recovery of heat and chemicals from a mixture of ashes and spent liquor by carrying out the final concentrating (2) of the liquor, and its feeding (8) into the soda recovery unit (5), under pressure and at a temperature higher than the atmospheric boiling point of the liquor. According to the invention, the ashes (1) are not mixed with the waste liquor (7) until after the final concentrating (2) of the liquor, and the mixture is further expansion evaporated (4) before the thus concentrated pressurized liquor is fed into the soda recovery unit (5).

Abstract: In a combustion process, liquid or gaseous residues having little or no calorific value are supplied to a flame in the main combustion chamber in addition to the fuel gas and the air for combustion. Stabilization of the flame and hence a reduction in the emission of nitrogen oxides is achieved by preheating the fuel gas and introducing it into the main combustion chamber at a temperature above its ignition temperature.

Abstract: A process for incinerating fluid waste, which comprises introducing a high heating value fluid waste and an oxidant having at least about 28% oxygen concentration into an oxygen/fuel burner to engender a flame and providing additional oxidant annularly around the flame.

Abstract: Device making it possible to effect the injection of sludge originating, in particular, from sewage-purification stations, into the combustion chamber of an incinerator, in particular of a household-refuse incinerator, characterized in that it comprises at least one injector (10) of small diameter, traversing the thermal-projection means of the combustion chamber and fed, at a constant rate for all of the injectors, via a distribution chamber (12), each injector consisting of a tube (18) having a cylindrical shape and comprising a conical nozzle (20), on the combustion chamber side, with the large diameter situated on the side of the outlet of the sludge from the injector, and in that each injector is thermally regulated in order to obtain a linear temperature gradient along the whole length of the injector, causing the formation in the injector, as the injection progresses, of a cylindrical element of sludge having a predetermined diameter and a surface crust in the zone close to the combustion chamber.

Abstract: For melting an inorganic fiber which is mixed with an organic substance, the inorganic fiber material and organic substance are heated in a furnace to a temperature sufficient for the organic material to combust, and sufficient oxygen enriched gas is fed to the furnace that the combustion of the organic substance produces sufficient heat to melt the inorganic material. The oxygen enriched gas is preferably oxygen enriched air having an oxygen content of at least 40% by volume. It should be fed in sufficient quantity to heat material having an adiabatic temperature of at least 850.degree. C., and preferably 1200.degree. C. which permits the melted inorganic material to freely flow out of the furnace. The oxygen enriched gas is preferably fed to a location adjacent a boundary layer between the melted material and unmelted material on the top thereof.

Abstract: Medical waste material is sealed in a nonflammable and long infrared radiation pervious film bag. The bag is subjected to long infrared radiation by an apparatus for a sufficient period of time at sterilizing temperature levels. Any smoke and odor generated during sterilization is treated.

Abstract: The present invention is directed to processes and apparatus in which supercritical fluids are used as viscosity reduction diluents for liquid fuels or waste materials which are then spray atomized into a combustion chamber. The addition of supercritical fluid to the liquid fuel and/or waste material allows viscous petroleum fractions and other liquids such as viscous waste materials that are too viscous to be atomized (or to be atomized well) to now be atomized by this invention by achieving viscosity reduction and allowing the fuel to produce a combustible spray and improved combustion efficiency. Moreover, the present invention also allows liquid fuels that have suitable viscosities to be better utilized as a fuel by achieving further viscosity reduction that improves atomization still further by reducing droplet size which enhances evaporation of the fuel from the droplets.

Abstract: In a process for the production of clinkers from sludges containing heavy metals, especially electroplating sludges, river and/or harbor sludges, in which the sludges are mixed with clay, especially brickyard clay, and optionally lean materials and fluxing materials and then are burned to clinkers especially at temperatures between 750.degree. and 1150.degree. C., zeolites are admixed with the sludges and the clay before the burning.

Abstract: A burner apparatus provides on-site destruction of waste liquids such as liquid anti-freeze, waste motor oil, and the like independently of the liquid concentration thereof. The apparatus comprises a storage tank for waste liquid including a reservoir and a level sensor for sensing the level of the waste liquid in the reservoir, and a burner unit energized responsive to the level sensor when the level of waste liquid exceeds a predetermined value. The burner unit includes first and second chambers connected together by a flame port provided between the chambers at the bottom of the chambers. An atomizing injector injects waste liquid from the storage tank, in an atomized form, into a flame produced by a first burner located at the top of the first chamber so that combustion products that are produced fall towards the bottom of the first chamber and pass through the flame port into the second chamber. A second burner burns combustion products exiting from the flame port into the second chamber.

Abstract: A method of drying black liquor to a dry solids content of about 100% in which water is evaporated from the black liquor by direct heat exchange contact with hot smelt from a recovery furnace in which the dried black liquor is burned.

Abstract: A method and apparatus are provided for reacting waste matter in a flame using fuel such as a flammable gas and oxygen. The apparatus includes a substantially cylindrical burner comprising a burner base and a removably attachable base extension having a diameter greater than that of the base. The base and the base extension each have aligned central nozzles extending their entire lengths for ejecting waste matter to be reacted, and aligned fuel nozzles radially spaced from each of the central nozzles for ejecting fuel to be ignited. The perimeter of the burner base extension is notched to provide channel-shaped peripheral oxygen nozzles. A substantially cylindrical cooling jacket surrounding the burner is adapted to receive oxygen which passes through the space defined by the outer surface of the burner base and the inner surface of the cooling jacket, then through the peripheral oxygen nozzles of the base extension.

Abstract: A process for controlling the temperature and flame front in a liquid waste incinerator comprising: dispersing fluid wastes into the flame of at least one oxygen/fuel burner to incinerate the waste in and around the flame, wherein flame energy is regulated by adjusting the fuel to the low heating value waste ratio to control the flame front and temperature in said incinerator. The flue gas resulting from burning the waste may be used to heat, possibly concentrate partially and/or evaporate (if liquid is present) the fluid waste prior to dispersing it into the flame.

Abstract: Toxic wastes are destroyed by contact thereof with a steam plasma jet and immediately thereafter with an oxidizing medium followed by washing of the resultant gaseous product with an alkaline medium. An apparatus for carrying out this method is in the form of a tubular assembly adapted to be received on a plasmatron in axial alignment therewith.

Abstract: The invention relates to a process for obtaining a substantially homogenous temperature profile along the length of an incinerator during the incineration of halogenated waste containing materials comprising:(a) providing a mixture containing an aqueous solution and halogenated waste having a preselected heating value;(b) introducing said mixture into the incinerator in the presence of oxidant to engender a flame; and(c) spraying an aqueous solution into or around the flame.

Abstract: A method is described for environmentally sound usage of combustible hazardous waste in an operating rotary kiln. The method is particularly adapted for disposal of solid hazardous wastes, optionally in the form of a blended waste homogenate, packaged in sealable containers. The containers are used as fuel modules and charged into a rotary kiln cylinder where kiln gas temperatures range from about 950.degree. to about 1200.degree. C. to achieve high destruction and removal efficiencies.

Abstract: Method for disposal of oily refinery sludges containing a hydrocarbon component, a solids component comprising sediments such as sand, silt, rust or scale, and water in an operating rotary kiln comprising a heated, rotating cylinder containing in-process mineral matter comprising analyzing the oily refinery sludge to determine its composition, drying the oily refinery sludge to a bulk granular material having an energy content of at least about 4,000 BTU per pound, and charging the dried bulk granular material to the rotary kiln and burning the bulk granular material therein.

Abstract: A method and apparatus for cleansing contaminated soil (11), the apparatus includes an extraction vessel (12) into which contaminated soil (11) is delivered together with a solvent. A slurry is produced which is delivered to a settler (18) which produces a settler underflow and contaminated solvent. The settler (18) underflow is delivered to a drier (23). The contaminated solvent passes through a filter (20) which produces a filter cake also delivered to the drier (23). The contaminated solvent passes through a distillation column (28) and is subsequently delivered to a plasma gun (35) whereat the contaminants are oxidized.

Abstract: A process for the destruction of waste including the steps of passing an organic waste into a chamber, pumping an inert gas into the chamber until the pressure within the chamber is at least 10,000 p.s.i., heating the chamber to a temperature in excess of 300.degree. F., dissociating the organic waste into its gaseous constituents, and passing the gaseous constituents from the chamber. The chamber is filled with an inert gas so as to displace oxygen from the chamber. The pressurized gaseous constituents are delivered to a turbine so as to actuate the turbine and to generate electricity therefrom. The gaseous constituents pass from the turbine into a boiler. An oxygen-containing gas is mixed with the gaseous constituents within the boiler so as to produce pressurized steam. This pressurized steam is passed to a turbine so as to produce electricity. The inert gas is argon.

Abstract: A method for regulating the feed and/or combustion conditions of concentrated waste liquors of varying chemnical and physical properties, for their burning in a soda recovery unit, by determining the maximum expansion upon heating of a dry matter particle of the liquor to be fed into the soda recovery unit, and by regulating the feed and/or combustion conditions on the basis of the expansion thus determined. The measure used for the expansion is the ratio of the lignin present in the concentrated liquor to any one or several of the acids present in the concentrated liquor, such as aliphatic acids.

Abstract: The distance between the combustion nozzle and the pump of a waste oil heater can be significantly increased by using a positive displacement pump which is proximate to the reservoir and remote from the nozzle, contary to the usual positioning of oil delivery pumps. The pump, which is not pressure regulated, thus pushes oil to the nozzle at a constant flow rate regardless of oil pressure at the nozzle.

Abstract: A method is described for environmentally sound usage of combustible hazardous waste in an operating rotary kiln. The method is particularly adapted for disposal of solid hazardous wastes, optionally in the form of a blended waste homogenate, packaged in sealable containers. The containers are used as fuel modules and charged into a rotary kiln cylinder where kiln gas temperatures range from about 950.degree. to about 1200.degree. C. to achieve high destruction and removal efficiencies.

Abstract: A waste treatment system conditions waste materials for combustion by uniformly drying them to a predetermined moisture level and subsequently incinerating the dried materials in a burner which effects complete combustion of even high moisture content fuels. The system includes the burner, a dryer assembly, and a system of fans which clarifies vapors withdrawn from the dryer and which returns at least part of these vapors to the burner. The system mixes exhaust gasses from the burner and recycled vapors returned by the fans to produce gasses of a suitable temperature for drying the materials. The waste materials and the gasses are then introduced into the dryer, which is designed to use the gasses to dry the material uniformly to the predetermined moisture level without burning them prematurely. The dried materials are then conveyed to the burner, where they are burned to produce more exhaust gasses for drying additional materials. The residual ash in the burners is nontoxic and is suitable for burying.

Abstract: A pressurized combustion of slurries of low-cost, unbeneficiated solid fuels in the presence of steam and alkali in which sulfur oxide emissions are inherently low, emissions of nitrogen oxides controlled by the injection of a scavenging agent and emissions of particulates prevented by condensing steam on and around them. The combustion has applications to steam boilers, combined cycles and gas turbines, including steam injected (STIG) and intercooled steam injected (ISTIG) versions. Turbine blade and nozzle erosion and deposits are avoided by the effective wet separation of ash particles before reheating and expansion.

Abstract: An apparatus for the preheating of liquid waste having a heated sealed container, a liquid waste tank, a jacket positioned around the sealed container so as to form a heat exchange region between the interior of the jacket and the exterior of the sealed container, and an injector for transmitting a heated liquid waste from the tank into the interior of the sealed container. An inert gas container is connected to the waste tank so as to pass argon gas for displacing the oxygen from the interior of the liquid waste tank. An insulating layer is formed around the exterior of the sealed container and the waste tank. Suitable conduits connect the waste tank with the heat exchange region of the sealed container. A storage vessel is in valved relationship with the liquid waste tank. Suitable pumping is provided so as to transmit the liquid waste into the heat exchange region and back to the liquid waste tank.

Abstract: Apparatus is provided for controlling the burning of a volatile waste liquid together with a conventional fuel in a boiler in the form of a free-standing module which contains a flow-control valve for the waste liquid. This system includes a means for monitoring the position to the fuel-control valve for the conventional fuel and a separate means for monitoring the position of a controlled valve for feeding of the volatile liquid. The two monitoring means are coupled and comparisons are made of the relative valve positions indicated thereby. The process controller used for such comparison contols a valve which stops the flow of volatile liquid to the burner in the event that more than a predetermined discrepancy occurs between the indicated valve positions. Said controller may also be employed to correct the valve position. Other features include a reverse purge pumping system which is actuated upon shutdown of volatile fuel flow.

Abstract: A method for endothermically dissociating contaminated acid wherein high velocity oxidant causes a recirculation flow within a combustion zone and combusts with fuel to release heat and wherein the heat is efficiently applied by the internal recirculation to the acid for endothermic dissociation of the acid.

Abstract: This invention provides a method and apparatus for recycling paper pulp sludge. Paper pulp sludge is incinerated in a rotary kiln, typically a rotary cement kiln, asphalt dryer, or fluidized bed incinerator. Paper pulp sludge is fed continuously into said rotary kiln while temperatures are maintained in the range of approximately 800.degree. to 3500.degree. F. During incineration, mixing catalysts (typicaly casein or soy protein) and wood pulp fibers are burned, while moisture is evaporated. The resulting incinerated product consists essentially of carbonate particles which are collected for subsequent use. Typically, but not exclusively, later use of the resulting product could be as mineral filler binding agents in the manufacture of construction products such as concrete, asphalt and others; or in gravel-based construction operations; or in earthen-fill constructions operations; or in other ways.

Abstract: A system for disposing of sludge by using the sludge as a primary source of fuel for its disposition by combustion thereof in which a mass of liquified sludge is processed to reduce the solids to a predetermined size for use as the fuel and concurrently separating a substantial portion of the contained liquid, delivering the processed solids and liquids to a combustor for converting the solids to ash and converting the liquids to vapor, introducing ambient air to the combustor to support combustion of the solids while employing a portion of the ambient air to the combustor for removing the vapor at a temperature below the temperature at which the solids are reduced to ash, utilizing a portion of the vapor removed from the combustor to initiate vaporization of the liquid in the mass of liquified sludge being processed initially, using a part of the removed vapor to enter into a heat exchange relationship with the ambient air prior to its being admitted to the combustor, and releasing excess vapor to the ambien

Abstract: An apparatus and method for recovering constituents and/or heat energy from a fluidized bed combustion process utilizes a single vessel which combines a combustor for fluidized bed combustion of a chemical mixture fed therein and a heat exchange section. Characteristics of the fluidized bed are controlled by withdrawing an appropriate portion of the larger, unburned constituent particles from the bottom of the combustor, and smaller constituent particles are withdrawn by becoming entrained within the gases of combustion and being transported to the heat exchange section. The smaller particles are separated from the gases without the use of a cyclone separator and accumulate as another fluidized bed in the heat exchange section where heat is adsorbed from the particles for recovery purposes and to cool the particles. A portion of the cooled particles is then recirculated to the combustor by, for example, pneumatic transport methods for controlling the operating temperature of the combustion process.

Abstract: A method for thermal treatment of human waste has the steps of feeding a predetermined small quantity of human waste into an indirectly heated flash chamber, instantaneously evaporating the human waste with a large capacity of heat in the flash chamber, and decomposing the human waste into a small gaseous water vapor and a residue of human waste.

Abstract: In a combustion air supply system, particularly a secondary air supply system for a recovery furnace, the secondary air inlet ports are divided into two arrays in such a manner that the combustion air coming in through the inlet ports of the first array is directed in part to contact and in part to by-pass a central region in the outer surface of a carbonization layer. The combustion air coming in through the inlet ports of the second array is directed to by-pass the combustion air coming in through the inlet ports of the first array thereabove. The first and second arrays are located on the opposite walls of the combustion chamber, preferably on the front and rear walls. The recovery furnace further comprises a primary air supply zone for blowing combustion air onto the sides of the carbonization layer and a tertiary air supply zone above a waste liquor inlet.

Abstract: The present invention relates to neutralization of liquid waste products containing different organohalides. A method of combustion neutralization of liquid waste products resides in that a mixture of the liquid waste products with an alkali reagent is prepared and introduced in the form of a sprayed flow into a high-temperature stream of the fuel combustion products, sprayed water being introduced between the stream of fuel combustion products and the path of the sprayed mixture. The consumption during combustion neutralization is no less than 1.2 kg per kg of the above mixture of waste products with the alkali reagent and no more than 2.5 kg per kg of the fuel being used.

Abstract: In a method and a plant for the combustion of special waste, a combustion chamber is connected downstream of a tubular revolving furnace which receives waste to be burnt. A part of the special refuse, particularly gaseous and liquid refuse is introduced into the combustion chamber and is burnt therein by a burner. A revolving tube of the revolving furnace opens into a lower conically downwardly tapering area of the combustion chamber which is constructed as an upright tube. The flue gases produced in the tubular revolving furnace flow from the bottom of the top of the combustion chamber together with the flue gases produced in the combustion chamber. Secondary air is also introduced into the combustion chamber so that there is ensured an extremely good, complete burning up of the waste to the end of the combustion chamber. Due to the fact that part of the special waste is burnt-out in the combustion chamber, the dimensions of the tubular revolving furnace can be reduced.

Abstract: A method for combusting wet waste wherein heat released by the combustion of combustibles from dry waste is recirculated by operation of high velocity oxidant in order to dry wet waste.

Abstract: This Hazardous Waste Reclamation process pyrolyzes hazardous waste such as PCB (polychloro-biphenyl) in a closed system in a molten alloy, containing some aluminum, at a minimum of 800 degrees C. to form activated carbon that is recovered from the circulating exit gas stream and an impure alloy ingot containing unreacted metals and metal salts that are saleable to a metal processor as a high grade ore. The composition of the alloy may be varied to assure maximum reaction to nontoxic alloy salts that remain in the ingot.

Abstract: A fuels conversion which consumes energy and produces an aqueous waste is combined with a pressurized wet combustion which charges the waste, converting its combustible contaminants to energy returned to the conversion, concurrently purifying the waste for use or disposal. The heating value of the contaminants may be supplemented by an extraneous fuel, using the waste as slurrying medium, so that the combination is made energy self-sufficient. Transfer of heat may be by direct contact between hot combustion products and fuel being converted. Other processes which produce aqueous waste and consume energy may similarly be combined with the wet combustion.

Abstract: The present invention relates to combustion devices such as incineration furnaces and the like, and in particular, relates to combustion devices which include a combustion gas cooling device by means of which slag, combustion by-products and the like are rapidly cooled and thereby converted to nonadhering fly ash. By converting slag to nonadhering fly ash, the accumulation of slag in downstream exhaust processing equipment is diminished, and hence, the necessity of halting the operation of the combustion apparatus in order to remove the accumulated slag is eliminated, thereby improving the efficiency of operations.

Abstract: Method and apparatus for treating waste materials to produce aggregates wherein pellets comprised of a mixture of solids, liquid wastes and clay are dried by hot air in a dryer. The pellets are then fed to the pyrolysis zone of a rotary kiln wherein they are heated by hot gas from an oxidation zone of the kiln to drive off most of the volatile gases. Remaining volatile gases and the fixed carbon in the waste are oxidized in the oxidation zone, and the silicates in the clay are vitrified in a vitrification zone of the kiln to produce aggregates which are crushed and screened. Volatile gases given off from the pyrolysis zone are mixed with exhaust gases from the dryer to feed the burner for the vitrification zone and to supply oxygen to the oxidation zone.

Abstract: A method and system for detoxification of waste materials, comprising incineration of the waste materials followed by additional contaminant reduction steps. The waste material is separated into solid and liquid portions that are fed separately into a combustion chamber wherein they are exposed to a plasma arc torch to affect combustion, producing a gaseous emissions stream and an obsidian residue. The gaseous emissions stream passes through an emissions control unit to eliminate acid gases, metals, and particulates, producing a cleansed exhaust gas and an emissions residue. The emissions residue is passed through an electroplating unit to reclaim metals. The obsidian residue is pulverized and then treated by a chemical process, or passed through the electroplating unit, to reduce the concentration of unbound barium contained therein, producing an inert obsidian residue that is free of toxic levels of all contaminants.

Abstract: An apparatus and method for recovering constituents and/or heat energy from a fluidized bed combustion process utilizes a single vessel which combines a combustor for fluidized bed combustion of a chemical mixture fed therein and a heat exchange section. Characteristics of the fluidized bed are controlled by withdrawing an appropriate portion of the larger, unburned constituent particles from the bottom of the combustor, and smaller constituent particles are withdrawn by becoming entrained within the gases of combustion and being transported to the heat exchange section. The smaller particles are separated from the gases without the use of a cyclone separator and accumulate as another fluidized bed in the heat exchange section where heat is adsorbed from the particles for recovery purposes and to cool the particles. A portion of the cooled particles is then recirculated to the combustor by, for example, pneumatic transport methods for controlling the operating temperature of the combustion process.

Abstract: A method for the destruction of chemical stable waste by pyrolysis whereby heat is applied to the waste using at least one plasma torch formed of non-transferred arc plasma type. The waste generated inside a duct having an end orifice flows upward passing the orifice and toward the nozzle of the plasma torch, wherein the axis of the nozzle of the plasma torch and the axis of the orifice are substantially collinear. Gaseous and/or liquid waste products resulting from the heating step are subjected to expansion and combustion in the combustion chamber whereby gaseous products resulting from combustion and expansion are quenched and then washed.

Abstract: It has been found that trace concentrations of organic materials, including toxic organic compounds, oxidize slowly. Safe and reliable incineration of toxic organic compounds at low concentration is provided by injecting a clean fuel such as H.sub.2, CH.sub.4, or CO into the incinerator combustion chamber to promote rapid oxidation of the toxic organic compounds. It is believed that the clean fuel added to the combustion effluents raises the total concentration of fuel and organic materials above the second oxidation threshold so that the toxic organic compounds are rapidly destroyed.

Abstract: A method is described for environmentally sound usage of combustible hazardous waste in an operating rotary kiln. The method is particularly adapted for disposal of solid hazardous wastes, optionally in the form of a blended waste homogenate, packaged in sealable containers. The containers are used as fuel modules and charged into a rotary kiln cylinder where kiln gas temperatures range from about 950.degree. to about 1200.degree. C. to achieve high destruction and removal efficiencies.

Abstract: A method for the thermal decomposition of a fluid toxic substance contained in a gas comprises a cylindrical main combustion chamber and a secondary combustion chamber arranged thereabove. An inlet opening leads into the main combustion chamber at an angle to introduce a stream of the gas containing the toxic substance into the main combustion chamber with an angular momentum, a burner is arranged to direct a flame into the main combustion chamber above the inlet opening for subjecting the gas containing the toxic substance to combustion, and an annular gas stream retaining device is arranged above the burner.

Abstract: A method is described for environmentally sound usage of combustible hazardous waste in an operating rotary kiln. The method is particularly adapted for disposal of solid hazardous wastes, optionally in the form of a blended waste homoenate, packaged in sealable containers. The containers are used as fuel modules and charged into a rotary kiln cylinder where kiln gas temperatures range from about 950.degree. to about 1200.degree. C. to achieve high destruction and removal efficiencies.

Abstract: Coherent radiation is used to provide the energy, excite and sustain of plasma in which solid waste materials are reduced to a slag-like material from which has been removed the more harmful constituents. The effluvia of the plasma reduction process is scrubbed to remove particulates and the gas is processed by additional heating to eliminate products of incomplete combustion and/or chemically convert harmful constituents. The remaining gas is then safely exhausted into the atmosphere. The solid waste material may be the ash by-product of prior incineration.

Abstract: A method and apparatus for the incineration of waste materials contained within metal containers is disclosed wherein the metal containers containing the waste materials are fed through a shredder to form a mixture of waste materials and metal shreds. This mixture is then fed, in a controlled manner, to a primary combustion chamber wherein the waste materials and metal shreds are incincerated to produce ash, deconiannated metal sheds and combustion gases.

Abstract: Crude oil sludges and other relatively heavy hydrocarbon liquid sludges are mixed with diatomaceous earth or perlite to form a friable and flowable solids mixture which is conveyed to a combustion unit, such as rotary kiln, calciner or lift pipe type combustor, wherein combustion of the hydrocarbons is carried out to provide gaseous combustion products and a substantially hydrocarbon free solids mixture. The solids discharged from the combustion unit may be recycled for use in the mixing process to reduce the sludge to a friable material for introduction to the combustion unit and excess solids may be discharged for disposal.

Abstract: A method for carrying out combustion in a combustion zone using oxygen or oxygen-enriched air as the oxidant wherein atomized liquid is provided to the combustion zone separate from oxidant and combustible vapors, causing it to be distributed throughout the combustion zone and then, especially after its vaporization, uniformly provided to the combustion reaction with consequent uniform temperature moderation, and resulting in reduced NO.sub.x generation and reduced refractory damage.

Abstract: A system is described for producing small uniform pellets of predetermined size which are substantially free of fines from mechanically dewatered sewage sludge and a means for controlling odor from the production of said pellets. The system includes a process and apparatus for mixing the dewatered sludge with previously dried recycled particles of said sludge. Drying the mixture in a thermal drier, separating a substantial portion of the dried solids from the drier off-gas. Clarifying said separated solids to separate the pellets of predetermined size, oversized pellets, and undersized pellets and particles, mechanically crushing the oversized pellets and admixing the crushed oversized pellets with the undersized pellets and particles and recycling said mixture for mixture with incoming dewatered sludge to the drier. The off-gas from the mechanical separation process is then passed through a condenser to remove some of the water therein, and is routed to an afterburner wherein it is burned.