A system for recovering fat, oil and grease (FOG) from wastewater has multiple annular flotation zones in a concentric configuration surrounding a central column to create progressively increasing surface areas for FOG and solid particles flotation. Each flotation zone may be equipped with an independent pressurized micro air and/or ozone bubbles distribution system. The FOG is recovered in the first flotation zone without chemical additions. Coagulant and flocculant may be added in the second flotation zone to maximize removals of biochemical oxygen demand (BOD), total suspended solids (TSS), and colloidal particulates and produce clear effluent. Magnesium chloride is added in the third flotation zone to remove phosphorus and to form struvite particulates that can be used as fertilizer. Since both organic loading and solid loading in the treated effluent are significantly reduced, poultry processing plants can more easily meet wastewater treatment plant discharge limits and avoid surcharges.

A system for recovering fat, oil and grease (FOG) from wastewater has multiple annular flotation zones in a concentric configuration surrounding a central column to create progressively increasing surface areas for FOG and solid particles flotation. Each flotation zone may be equipped with an independent pressurized micro air and/or ozone bubbles distribution system. The FOG is recovered in the first flotation zone without chemical additions. Coagulant and flocculant may be added in the second flotation zone to maximize removals of biochemical oxygen demand (BOD), total suspended solids (TSS), and colloidal particulates and produce clear effluent. Magnesium chloride is added in the third flotation zone to remove phosphorus and to form struvite particulates that can be used as fertilizer. Since both organic loading and solid loading in the treated effluent are significantly reduced, poultry processing plants can more easily meet wastewater treatment plant discharge limits and avoid surcharges.

Disclosed herein are systems and processes for treating a Waste Stream comprising biosolids, the Waste Stream provided at varying flow rates and solids concentrations so as to achieve an SOUR of 1.5 mg O.sub.2/g/hr or less and an ORP of at least +300 mV. The system includes a biosolids manipulation device to adjust the volume of suspended solids as a percent of the total volume of the Waste Stream to five (5) percent or less; a chemical oxidant feed device to dose the Waste Stream with an oxidant such as chlorine dioxide, ozone, or similar oxidant, and a treatment vessel associated with said chemical oxidant feed device through which said Waste Stream flows, wherein said chemical oxidant feed device and said treatment device are configured so as to achieve a dose rate between 25 and 200 parts per million of the Waste Stream and substantially complete mixing of the oxidant within 30 seconds of dose delivery in the treatment vessel.

Methods and systems for treating oil sands tailings streams at an elevated pH using lime are disclosed herein. In some embodiments, the method comprises providing a tailings stream including 10-55% solids by total weight, increasing the pH of the tailings stream by combining the tailings stream with lime to produce a lime-tailings mixture having a pH of at least 11.0, and dewatering the lime-tailings mixture to produce a first stream having 10% or less solids by total weight and a second stream having 50% or more solids by total weight. The first stream can correspond to a release water stream, and the second stream can correspond to a cake. The lime slurry can include about 10% lime by total weight, and can comprise lime hydrate, quicklime, or a combination thereof. Dewatering the lime-tailings mixture can include routing the lime-tailings mixture to a centrifuge unit and/or a pressure or vacuum filtration unit.

Methods and systems for treating oil sands tailings streams at an elevated pH using lime are disclosed herein. In some embodiments, the method comprises providing a tailings stream including 10-55% solids by total weight, increasing the pH of the tailings stream by combining the tailings stream with lime to produce a lime-tailings mixture having a pH of at least 11.0, and dewatering the lime-tailings mixture to produce a first stream having 10% or less solids by total weight and a second stream having 50% or more solids by total weight. The first stream can correspond to a release water stream, and the second stream can correspond to a cake. The lime slurry can include about 10% lime by total weight, and can comprise lime hydrate, quicklime, or a combination thereof. Dewatering the lime-tailings mixture can include routing the lime-tailings mixture to a centrifuge unit and/or a pressure or vacuum filtration unit.

In described embodiments, a method of processing sludge of a poultry plant into solids includes storing sludge in a tank where the sludge is a dissolved air floatation (DAF) float treated with Polymer Chemistry. A polymer is added to the sludge to produce a slurry that is separated into at least one liquid phase and solids in a horizontal decanter centrifuge having a weir ring. In conjunction with operating the centrifuge with a laminar flow, adjusted feed rate and polymer dosing, the system allows for production of low moisture solids (<50%) from the poultry plant DAF float and discharge of a clear liquid phase.

In described embodiments, a method of processing sludge of a poultry plant into solids includes storing sludge in a tank where the sludge is a dissolved air floatation (DAF) float treated with Polymer Chemistry. A polymer is added to the sludge to produce a slurry that is separated into at least one liquid phase and solids in a horizontal decanter centrifuge having a weir ring. In conjunction with operating the centrifuge with a laminar flow, adjusted feed rate and polymer dosing, the system allows for production of low moisture solids (<50%) from the poultry plant DAF float and discharge of a clear liquid phase.

Movable thick dehydration device and method for eluent sediment from medium- and low-concentration ammonia nitrogen are provided. The device integrates the existing eluent preparing mechanism, a transferring mechanism, pumping mechanisms, a transport vehicle, an automatic controlling system, an eluent collecting pool, primary and secondary sedimentation pools, and primary and secondary processing units. After post-treatment and recovery of eluent waste from rare earth mines, ammonia nitrogen and rare earth heavy metals in the eluent of rare earth mines can be recovered and disposed, and 90% of ammonia nitrogen and over 95% of rare earth in the eluent can be recycled. The device is movable and automated, and therefore suitable for environmental treatment of closed rare earth mines with residual ammonia nitrogen. Meanwhile, it is beneficial to reduce investment costs of capital construction, disposal site restoration of environmental treatment of rare earth mines with residual ammonia nitrogen.

The present disclosure provides a solid waste treatment method, including following steps: screening off masses having a particle size greater than 0.5 cm from solid waste; adding extraction agents to the solid waste and then heating and stirring so that the solid waste is fully dispersed in the extraction agents; placing the mixed extraction agent in a centrifuge and centrifuging the mixed extraction feeding liquid phase separated by centrifuging into a rectification tower for rectification and cooling, recovering residual oil substances in a rectification kettle, separating mixture of cooled extraction agents and water, continuously adding the separated extraction agents into an extraction kettle for cyclic extraction, and conveying sewage to a sewage treatment plant to treat and discharging the sewage after the sewage reaches a treatment standard.

An apparatus for facilitating particle separation by density includes a separator having an inner surface surrounding a rotation axis and defining a particle path from an input end to an axially spaced output end. The inner surface includes a plurality of axially spaced dividers having respective inner positions, defining at least in part respective axially spaced retainers for collecting particles during rotation of the separator. The retainers each include at least one fluid inlet for fluidizing particles in the retainer during operation. The dividers include a first pair of adjacent dividers and a second pair of adjacent dividers, the first pair nearer the input end than the second pair, wherein a first divider slope of the first pair is greater than a second divider slope of the second pair and wherein each of the first and second divider slopes is zero or positive. Other systems, apparatuses and methods are disclosed.