Abstract: A solid waste treatment system includes: a solid-liquid separator module configured to receive mixed solid and liquid waste and separating solid material from the mixed solid and liquid waste; an accumulator and macerator module configured to receive and macerate the solid material from the solid-liquid separator module; a drying module configured to receive and dry the macerated solid material from the accumulator and macerator module; and a combustion module configured to receive and combust the dried macerated solid material from the drying module.

Abstract: Provided herein is a process for improving the heating value of a cellulosic waste material. The process includes the steps of treating the cellulosic waste material with an acid solution, recovering heat produced by treating the cellulosic waste material, and filtering the treated cellulosic waste material to produce a filter cake. The disclosure also relates to a system for implementing the process.

Abstract: This invention provides a system or method that includes combustion of mixed content solid waste to produce flue gases and separation of carbon dioxide gas in the produced combustion flue gas from other gaseous constituents of the flue gas in an amount produced from the burning of plastic material contained in the mixed content solid waste. The separated carbon dioxide is sequestered in geologic formations, thereby providing environmentally sound disposal and elimination of plastic waste, in one consolidated process, free of the need for separation of plastic waste from other solid or the need to identify and separate the various forms and compositions of plastic waste material. The illustrative disposal of plastic waste hereby is generally free of emission into the atmosphere of carbon dioxide gas. The invention includes a fee-generation process applied to customers, which can quantified and generated in association with the application of the system or method.

Abstract: The pyrolysis reactor system for the conversion and analysis of organic solid waste is a dual gas-liquid separation system, allowing for the conversion of organic solid waste, as well as analysis of the conversion products. A pyrolysis reactor is provided for converting the organic solid waste into a solid product and a gas-liquid product mixture through pyrolysis. A source of carrier gas is in fluid communication with the pyrolysis reactor for degrading the organic solid waste. A first gas-liquid separator is in fluid communication with the pyrolysis reactor and receives the gas-liquid product mixture therefrom, separating a portion of gas therefrom. A second gas-liquid separator is in fluid communication with the first gas-liquid separator and receives the gas-liquid product mixture therefrom and separates the remainder of the gas therefrom. The remainder of the gas and the separated liquid are each collected separately from one another, in addition to the char.

Abstract: The present application relates to an innovative and optimized method and system for maintaining water quality in water bodies such as excavated inland structures and floating structures with bottoms comprising flexible membranes, using a simplified economic filtration system and degreasing system that requires much smaller filtration equipment than conventional centralized filtration systems and provides for consumption of significantly lower amounts of energy. The method of the invention allows activating a chemical application system, mobile suctioning device, and/or degreasing system based on information regarding turbidity, the color of the bottom of the water body, and amount of greases on the surface water layer of the water body, to adjust the water quality parameters within their limits.

Abstract: This disclosure relates to systems, devices and methods for pulping agricultural products. Features for ensiling agricultural crops, separating solids and liquids, and processing the solids and liquids for use in a variety of products and processes are disclosed. For instance, systems and methods are disclosed for pulping grass crops, making products for energy conversion processes, screening fine debris, cell bursting, using strongly alkaline chemicals in pulping processes, and using sorghum plant for producing pulp.

Abstract: Methods and apparatus for reducing the content of controlled acidic pollutants in clinker kiln emissions are disclosed. The methods and apparatus include introducing bypass dust produced during production of clinker into one or more locations between the preheater exhaust and the inlet to a dust filter including into a gas conditioning tower. Total bypass dust separated from the kiln exhaust gas may be used. The bypass dust can be separated into a fine and coarse portions. Fine or total bypass dust can be mixed with water to form a bypass dust slurry that can be introduced into the gas conditioning tower. Bypass dust can be used to reduce the content of acidic pollutants such as hydrogen chloride HCl and sulfur oxides SOx from clinker kiln emissions.

Abstract: Disclosed herein are systems and methods for the conversion of solid organic waste material, such as waste plastics, into fuel for the generation of heat and power. In addition, embodiments of the systems and methods disclosed herein relate to converting solid organic waste material into a gasified material for mixing with an oxidizing gas to allow for clean combustion of the fuel, thereby minimizing emissions of pollutants.

Abstract: The present invention relates to methods and systems for processing sewage sludge using a gasification process. The gasification process takes place at high temperatures in an oxygen-starved environment, which enables carbon-containing materials in the sewage sludge to chemically react under the preferred temperature and oxygen levels, resulting in the formation of usable products, including ash, electricity, and syngas—all of which are generally environmentally benign.

Abstract: A method and an associated apparatus for washing rock samples, which is particularly suited to the washing and preparation of rock samples obtained from oil and gas wells. In one embodiment there is provided a method of washing rock samples involving a plurality of discrete rock samples; providing a plurality of sequentially arranged discrete washers each of which is spaced from a respective washing position and configured to direct a washing flow of water towards said washing position; and automatically conveying said samples relative to said washers so that each sample moves in succession through said washing positions for sequential washing by each said washer.

Abstract: The present invention relates generally to systems and methods for drying and gasifying substances using the calorific value contained in the substances, and it more specifically relates to apparatus and methods for processing wet, pasty, sticky substances, such as municipal wastewater treatment sewage sludge, into a workable, powdered product.

Abstract: A modular cyclonic separator comprises separating tubes each including an air-guiding impeller that is fixed coaxially in an outer tube body and that is formed with spiral channels for causing an airflow, which flows radially into the separating tube, to follow a cyclonic flow pattern through a separating chamber in the separating tube, thereby separating some of solid impurities from the airflow within the separating chamber. Each separating tube is capable of connecting selectively with one or two three-port valves to form a first or second filtration module, in which the airflow passes through a fluid passage in the one three-port valve or one of the two three-port valves prior to entering the separating tube.

Abstract: Apparatus for sewage treatment, comprising: at least one tank (13), at least one inlet branch (14) to the tank (13), at least one outlet branch (15) from the tank (13), at least one microwave generator (9a) able to subject the sewage present internally of the tank (13) to at least one temperature raising treatment, at least a cooling circuit (19) of the microwave generator (9a), at least one blowing device (9b) connected to the tank (13). Blowing device (9b) is connected to an outlet (26) of the cooling circuit (19) and sending the heated gases arriving therefrom into the tank (13).

Abstract: A system and method for treating tailings from a bitumen froth treatment process such as TSRU tailings. The tailings are dewatered to at least 50 wt percent solids content, and then combusted to convert kaolin in the tailings into metakaolin. Calcined fines and heavy minerals may be recovered from the combustion products, namely from the flue gas or bottom ash or both. A trafficable deposit may be formed from the ash when mixed with tailings, such as mature fine tailings (MFT).

Abstract: A method and an apparatus for disposing wastes comprising the steps of conducting a hydrothermal decomposition reaction of the wastes, separating the products into a solid fuel and waste water, combusting the solid fuel, scrubbing the combustion gas, generating steam using the heat generated by the combustion, and purifying the waste water, exhibit a high energy-efficiency, while exhibiting a high removal rate of the pollutants generated during the combustion.

Abstract: Processes for converting organic material into renewable fuel products. A feedstock containing organic material is processed at an elevated pressure and temperature to lyse, decarboxylate, and carbonize cell structures. A portion of the processed slurry may be recirculated and mixed with cool, pressurized feedstock prior to reaching a mechanical mixing device to preheat and reduce the viscosity of the feedstock. The pressure and temperature are reduced, which may occur simultaneously to flash volatile materials, such as ammonia, out of the slurry, thereby reducing the presence of the materials in the final product and allowing recovery of the materials. The processed slurry may be treated with a halide to reduce mercury emissions in the final product. The treated slurry is mechanically and thermally dewatered resulting in a renewable fuel product in dried particulate or pelletized form that is a viable energy source having a positive heating value.

Abstract: This invention relates to a combustion system. The combustion system includes a fireplace which has a fire base, a primary combustion zone for pyrolysising and/or combusting a biomass fuel, and a secondary combustion zone for combusting gases and/or particulate matter produced from the pyrolysis and/or combustion of the biomass fuel. The combustion system also includes an exhaust flue, the exhaust flue extending to a position near to, or adjacent, the secondary combustion zone and/or the fire base. The invention may be particularly suitable for use in relation to wood burners, either by retrofitting to existing wood burners or by incorporating into new wood burners.

Abstract: Systems and processes for processing sludge and other natural waste are provided. In one example, the sludge or natural waste may be dried into a powder using high-temperature gas to absorb moisture from the sludge, causing the high-temperature gas to become an at least partially saturated gas. The at least partially saturated gas may pass through a scrubber before being heated in an air-heater and used in the moisture absorption process. The heat for the air-heater may be provided by a burner operable to burn the dried powder obtained from the sludge. The heated gas may be used to pre-heat the saturated gas and may be used to dry additional sludge.

Abstract: A method for the production of alcohol and other bioproducts hemicelluloses extracted from biomass prior to thermal conversion of the biomass to energy. The process can be integrated with the host plant process to minimize the energy loss from extracting hemicelluloses. Also disclosed is a Stepwise enzymatic break down of cellulose fibers from a pulping operation which is performed with the redeployment of equipment and vessels contained within typical existing pulp and paper manufacturing mills. The preferred feedstock is highly delignified pulp from acid or alkaline pulping process or from bleaching stage.

Abstract: A method and system for the conversion of waste into energy in a sealed system where combustion does not take place and the operating pressure prior to the inlet of the steam or power generating equipment is maintained below atmospheric pressure. Destruction of the RDF (refuse derived fuel) is accomplished by subjecting the RDF to a high temperature environment under controlled conditions in a purpose designed and built reactor. The high temperature environment, <5000° C., is achieved through the use of one or more non-transferred plasma torches for generation of plasma gas. The plasma gas exiting the torch and provides the thermal energy for the continual gasification of metallurgic coke configured as a carbon bed in the lower part of the reactor, which acts as a thermal catalyst and this provides the thermal energy for the gasification process.

Abstract: Biowaste sterilizers are described. In one implementation an exemplary system has waste transport vessels that can be intermittently heated and pressurized, for example, with steam, and are interconnected to provide multiple sterilization pathways for waste as the waste is transported. Selected sterilization pathways may depend on attributes of the waste. Sterilization factors, such as mechanical shredding, application of steam, application of pressure, maintenance of temperature, separation of liquid, etc., are integrated into the waste transport features of the system, which can be made compact to save space while processing relatively large bulk amounts of materials, such as medical wastes. The system maintains safe isolation of bio-hazardous components in the waste from the external environment. A system controller provides parameters management, smart sterilization cycle control, quality assurance, safety management, diagnostics, and reporting over a network.

Abstract: A method controls mass and heat loading of sludge feed into a fluidized bed combustor (FBC) controlled via regulation of a polymer dosage or a sludge feed rate including: continuously monitoring at least one performance characteristic of the FBC; producing an input signal characteristic; analyzing the input signal and determining a first rate of change of the characteristic; generating an output signal based on the first rate of change to control addition of polymer to the FBC; generating a second output signal to control addition of sludge feed to the FBC; and determining a transition point between the addition of polymer and addition of sludge, which transition point is an upper limit of a first rate change to maintain flow so that the value of the characteristic is maintained proximate at the upper limit.

Abstract: Process and plant for producing a refuse derived solid fuel (RDSF), including a first component having a dry fraction of a solid urban waste (MSW) in a shredded form and at least one second component in a shredded form selected from an elastomeric material and a thermoplastic material, or mixtures thereof, wherein the dry fraction of the MSW, the elastomeric polymer material and/or the thermoplastic polymer material are stored in separate containers and when required are metered and fed in subsequent layers onto a continuous conveyor which discharges into a temporary accumulating container, for example, the box body of a motor vehicle, intended to directly feed the combustion plant wherein the RDSF is burned. In this way, there is no need to premix the various fractions of the RDSF during the production stage and to maintain the resulting mixture constantly stirred in order to prevent compaction and/or separation of fractions.

Abstract: The teachings of the present disclosure provide methods and apparatus for enhanced incineration. A method for improving the performance of an incinerator may comprise separating one or more substances from a process fluid using a classifying centrifuge, ejecting a first substance from the classifying centrifuge, the first substance having characteristics optimized for incineration, incinerating the first substance, and using heat generated from the incineration of the first substance to enhance the combustion efficiency of an additional substance separated from the process fluid.

Abstract: A method controls mass and heat loading of sludge feed into a fluidized bed combustor (FBC) controlled via regulation of a polymer dosage or a sludge feed rate including: continuously monitoring at least one performance characteristic of the FBC; producing an input signal characteristic; analyzing the input signal and determining a first rate of change of the characteristic; generating an output signal based on the first rate of change to control addition of polymer to the FBC; generating a second output signal to control addition of sludge feed to the FBC; and determining a transition point between the addition of polymer and addition of sludge, which transition point is an upper limit of a first rate change to maintain flow so that the value of the characteristic is maintained proximate at the upper limit.

Abstract: The teachings of the present disclosure provide methods and apparatus for enhanced incineration. A method for improving the performance of an incinerator may comprise separating one or more substances from a process fluid using a classifying centrifuge, ejecting a first substance from the classifying centrifuge, the first substance having characteristics optimized for incineration, incinerating the first substance, and using heat generated from the incineration of the first substance to enhance the combustion efficiency of an additional substance separated from the process fluid.

Abstract: A method and apparatus for drying and reducing the particle size of malleable material. Preferred embodiments of the invention include a drying apparatus for use with a malleable material, comprising a blower, an airlock feeder, a main line which contains an accelerator, a conditioning chamber, and a dehydration chamber, a polishing line which contains an accelerator, a conditioning chamber, and a dehydration chamber, and a squid line blower for providing pressurized heated air to the apparatus. An alternative preferred embodiment of the invention comprises a method of drying and size reducing malleable material.

Abstract: Solid combustible waste materials are converted into highly efficient fuel by subjecting such materials to size reduction in suitable size-reducing equipment. The last piece of the equipment is a mill which pulverizes the waste materials into fine particles having a high surface to mass ratio and forming a highly efficient fuel when these particles are directly injected into a combustion reactor operating at high temperature.

Abstract: A garbage incinerator comprises an incinerator body having an elongated incinerating chamber, which forms an angle with a horizontal plane. A plurality of inlets are provided on the incinerator body for feeding burnable construction garbage and house refuse, respectively. A plurality of house refuse drying channels are provided in the incinerating chamber for drying the house refuse received from the inlets. A waste oil burner is provided at the bottom of the incinerating chamber. Also provided are a dust-removing device for removing dust from exhaust of the incinerator and a harmful substance detecting device.

Abstract: Process for recycling of liquid carton waste material or other similar waste material having fibrous, metal and plastics materials. The process includes introducing the waste material and a slushing liquid into a slushing apparatus and slushing of the waste material to thereby form defibrated fibrous material therein. The treated waste material is then separated into (i) a fiber suspension which includes the defibrated fibrous material, and (ii) a reject portion which includes the metal and plastics materials. The obtained fiber suspension is cleaned and the fibrous material therein is reclaimed for further use. The reject portion is introduced into a fluidized bed gasifier so as to gasify the plastics therein to produce a hydrocarbon product gas, which is thereafter separated from the metal material.

Abstract: A waste treatment system for solidifying and increasing the speed at which manure would dry. The waste treatment system includes support members; and also includes an elongate tubular member being mounted upon the support members and having an inlet end and an outlet end and having a bore being disposed therethrough; and further includes a waste holding/compressing assembly being mounted to the elongate tubular member; and also includes an incineration/discharge assembly being disposed in and about the elongate tubular member for incinerating waste material.

Abstract: An enclosed drainage facility to dry municipal waste combustion ash has a plurality of spaced elongated channels to drain by gravity, water from piles of ash into a disposal or reclamation pool. The channels are sloping concrete ditches leading to a common trough or pipe to a covered storage basin. Steel plates pierced with a plurality of spaced slender slits abut each other to cover each channel. The atmosphere in the facility is changed by being pumped into one side of the facility and exhausted adjacent an opposite side. Also, a process for drying municipal waste combustion ash includes dewatering and drying of ash piles in an atmosphere of warm dry air for a period of time necessary to reduce the moisture to about 28%.

Abstract: An arrangement for converting a conventional oil boiler to a boiler with moist, granular and solid fuel, utilizes a fuel combustion gas dryer connected to the combustion gas line of the boiler, and a solid fuel combustion device to replace the oil burner. The combustion gas dryer is a so-called circulating fluidized bed (CFB) dryer together with a particle separator and a combustion gas center tap has been fitted into the oil boiler, through which center tap hot combustion gas has been set to be mixed with combustion gases of the normal outlet in the desired proportion in order to regulate the temperature of the drying gas of the dryer. The combustion devices may include a cyclone burner.

Abstract: A treatment system is provided which can treat solid materials and/or liquid materials. Preferably, a separator initially separates liquid and solid materials, and the solid materials are deposited upon a substrate within a microwave cavity. Liquids remaining with the solid materials drain through the substrate, and the solid materials are subjected to microwaves. The liquids exiting the separator are preferably also passed through a filter assembly which retains any suspended particles remaining in the liquid, and subjects the particles to microwaves. Exhaust filters can also be provided for the microwave cavities, and the exhaust filters can also be subject to microwaves to incinerate any particles remaining in the exhaust gas. Fire tube arrangements for incinerating solid materials retained or extracted by substrates or filters are also provided.

Abstract: A materials treatment system which initially separates liquid and solid components with a separator. The system can be advantageously utilized for household sewage handling, however various components have other applications. Once the separator separates the solids and liquids, a fire tube combusts the solids with microwaves. The liquids exiting the separator are treated in a liquid treatment system which includes additional particle filtration/separation, treatment of the liquids with an oxidant liquid, and an ultraviolet treatment. An advantageous microwave cavity assembly is also provided for dehydration/combustion of solids exiting the separator and/or for solids filtered from liquids in the liquid treatment system.

Abstract: Process for autothermal incineration of sludge originating from urban and/or industrial water purification stations and of household refuse, wherein it consists in carrying out a dehydration of the sludge by centrifuging-drying while employing the sensible heat of the fumes produced in the incineration furnace, the said dehydrated sludge being introduced, in pulverulent form, into the incineration furnace at the same time as the household refuse.

Abstract: This invention relates to an improved process for the coincineration of municipal solid waste and municipal sewage sludge by dewatering the sludge, breaking it up into sufficiently small particles and employing oxygen enrichment of the combustion process. These small particles of sludge are introduced into the combustion zone above the grate in the combustion zone but at a distance above the grate no higher than that of the point of introduction of secondary air. This is accomplished without undesired excursions of flue gas flow rate and temperature.

Abstract: Dried fuel is at least partly combusted, gasified or carbonized in the presence of cooled solid residue in a reactor. Hot solid residue, which is at temperatures in the range from 500.degree. to 1200.degree. C., is withdrawn from the reactor and is mixed with water-containing fuel in the receiving region of a mechanical mixer, without a supply of fluidizing gas. The mixture is transported with further mixing from the receiving region of the mixer through a mixing section of 1 to 10 meters to an outlet. A fuel-containing, substantially water-free mixture at a temperature in the range from above 100.degree. C. to 150.degree. C. is fed from the outlet of the mixer to the reactor. A mixer which comprises two intermeshing shafts, which rotate in the same sense, may be employed in the process.

Abstract: A garbage disposal system includes a garbage classifier unit, which consists of a cutting mechanism, a separation water trough, squeezers, and a blower separator, and is controlled to separate plastics and mineral from garbage; a garbage furnace controlled to burn garbage being delivered from the garbage classifier unit, a waste gas treatment unit controlled to treat exhaust gas from the garbage furnace, and a sewage treatment unit controlled to treat waste water from the garbage classifier unit and the waste gas treatment unit for a repeat use.

Abstract: A container capable of dewatering wet mixtures and for transportation which comprises (1) an external cylindrical container with openings therein having a hanging member in an upper portion thereof, wherein the hanging member can shut the upper portion of the external cylindrical container, and wherein the external cylindrical container has an easy to open and shut closure at a bottom portion and (2) an internal porous container for dewatering a wet mixture is described. This container permits dewatering, packing, storing and transporting operations to be easily achieved.

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: This invention encompasses a process for the utilization of dried powdered waste as a fuel, in particular, dried powdered aqueous waste. The object of the invention is to eliminate the use of conventional auxiliary fuel to aid in thermal oxidation of waste materials containing a high percentage of water in relation to solids, thus improving the total efficiency of the process. The problems associated with handling the waste products are solved along with the expense of using conventional auxiliary fuels such as gas and fuel oils.

Abstract: A method for disposing by incineration of waste material containing sludge and garbage of various kinds which when combined results in a composite waste material prepared by performing multiple steps in its handling wherein the composite material is first subjected to a grinding step for thorough intermixing of the sludge that may contain a high percentage of moisture with garbage that can contain very little moisture. After grinding, the composite waste material is processed in a cyclone where the gases that are used to transport the ground matter can be separated while the solids are subjected to classification by the use of a vibratory screen where the paper, fluffy waste, and similar materials can be separated from the smaller and harder particulate components. The separated components are subjected to individual impact grinding steps prior to being recombined in the combustor where incineration takes place.

Abstract: To dispose of a dewatered collected product consisting predominantly of cellulosic materials in a solids phase and a residue consisting predominantly of plastics in wastepaper recycling, the collected product is dried to at most 25% weight percent moisture content as based upon the solids and is then layered onto an oscillating grate. The residue is applied as a second layer on the first layer and the resulting two-layer bed is burned on the grate with bottom-blowing with slag formation and collection. The heat content of the combustion gas can in part be recovered by the generation of steam.

Abstract: Gaseous discharge from a pelletizing drier used in the treatment of sewage sludge is partially directed back to a combustion chamber that generates an effluent which is fed to the drier. Volumetric requirements of a gas scrubber and an afterburner are reduced to the volume of gaseous discharge not recycled back to the combustion chamber. A concentrated stream of sewage sludge is mixed with a quantity of dehydrated particulate matter and supplied to a rotary pelletizing drier. Fuel and air undergo a combustion process and are mixed with additional air and part of the gaseous discharge in the combustion chamber which generates a hot gaseous effluent that is directed through the drier. The effluent removes moisture from the mixture of concentrated sludge and dehydrated particulate matter to provide dehydrated particulate sludge and the gaseous discharge. Entrained materials are initially separated from the gaseous discharge by cyclone separators.

Abstract: A sewage screenings disposal system where raw screenings are fed to a dewatering press (7) for reducing the moisture content of the screenings, slugs of pressed screenings are conveyed from the dewatering press (7) to a multi-compartment storage carousel (17), loader ram means (16) charge the slugs into empty carousel compartments (21) and feeder ram means (26) located remote from the loader arm ram means (16) push the slugs from the full carousel compartments (21) into an incinerator (29). The carousel drive means are connected through a compartment indexing mechanism and carousel locking means (22) whereby during loading or feeding the carousel is locked against rotation.

Abstract: A method and apparatus for reducing the moisture content of a moist sewage sludge having a moisture content of about 50% to 80% and formed of small cellular micro-organism bodies having internally confined water is provided. A hot liquid metal is circulated in a circulation loop and the moist sewage sludge is injected in the circulation loop under conditions of temperature and pressure such that the confined water vaporizes and ruptures the cellular bodies. The vapor produced, the dried sludge, and the liquid metal are then separated. Preferably, the moist sewage sludge is injected into the hot liquid metal adjacent the upstream side of a venturi which serves to thoroughly mix the hot liquid metal and the moist sewage sludge. The venturi and the drying zone after the venturi are preferably vertically oriented. The dried sewage sludge recovered is available as a fuel and is preferably used for heating the hot liquid metal.

Abstract: Method and apparatus for treating sewage to reduce total solids content. Involves separating sewage sludge from sewage liquid, dewatering and compressing the sludge, subjecting the sludge to microwave radiation to reduce sludge to ash-like residue, and adding the residue back to the sewage liquid. Optionally, to sterilize the sludge liquid with chemicals or ultraviolet light.

Abstract: Method for drying aqueous solid fuels, in which method the fuel is heated indirectly in a dryer by means of a heating medium heated in a boiler plant or the like and in which the steam formed in the dryer serves as a heating and transport medium. Oil or some other liquid having a boiling point higher than water is used as the indirect heating medium. Preferably oil is heated in the boiler plant up to the temperature of 300.degree. to 400.degree. C. at a 1 bar pressure. Heat surfaces of a lamella heat exchanger suitably serves as the heat transfer surfaces of the dryer.

Abstract: Gaseous discharge from a pelletizing drier used in the treatment of sewage sludge is partially directed back to a combustion chamber that generates an effluent which is fed to the drier. Volumetric requirements of a gas scrubber and an afterburner are reduced to the volume of gaseous discharge not recycled back to the combustion chamber. A concentrated stream of sewage sludge is mixed with a quantity of dehydrated particulate matter and supplied to a rotary pelletizing drier. Fuel and air undergo a combustion process and are mixed with additional air and part of the gaseous discharge in the combustion chamber which generates a hot gaseous effluent that is directed through the drier. The effluent removes moisture from the mixture of concentrated sludge and dehydrated particulate matter to provide dehydrated particulate sludge and the gaseous discharge. Entrained materials are initially separated from the gaseous discharge by cyclone separators.