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.

The present invention relates to a method for sludge safe disposal and resource recovery through sludge liquefaction and stratification. The method is to completely liquefy the organic matters in the sludge into soluble organic matters through a thermal-alkaline synergistic treatment. After the treatment, the sludge is stratified, and an anaerobic digestion is performed on a high-concentration soluble liquid of an upper layer to convert organic carbon, nitrogen and phosphorus into biogas, ammonia nitrogen and phosphate, a crude protein recovery is performed on a sludge protein of a middle layer, and a dewatering and a landfill on a sludge inorganic solid of a lower layer.

An apparatus, method and system is provided for treating sewage sludge by dewatering the sewage sludge, heating the sewage sludge being treated to destroy pathogens, and then reducing volatile solids in the sewage sludge being treated through biochemical decomposition to produce a treated biosolids product that meets government regulations for pathogen reduction and vector attraction reduction.

A method for treating tailings includes the step of S1: mixing the tailings to be treated with a neutral active aqueous solution and then drying the tailings, wherein the neutral active aqueous solution is prepared from water via an electrocatalytic water device, and the circulation time of the water in the electrocatalytic water device is 5-60 min, and the mass ratio of the tailings to the neutral active aqueous solution is 1:1-10:1.

The specification describes a system and process for treating a sludge or slurry to produce biochar. The sludge or in slurry may be digestate produced by an anaerobic digester that receives waste activated sludge from a wastewater treatment plant. In a process, digestate is dosed with metal ions, dewatered, and pyrolized. A corresponding system includes a reactor, a dewatering unit and a pyrolysis unit. In an example, the digestate is air stripped in the reactor and a metal salt is added to it. The metal ions form precipitates in the digestate that remain in the biochar. In some cases, a precipitate such as struvite is formed that also increases the phosphorous content of the biochar. The biochar may be used as a soil amendment, wherein the metal and phosphorous are beneficial to the soil.

The specification describes a system and process for treating a sludge or slurry to produce biochar. The sludge or in slurry may be digestate produced by an anaerobic digester that receives waste activated sludge from a wastewater treatment plant. In a process, digestate is dosed with metal ions, dewatered, and pyrolized. A corresponding system includes a reactor, a dewatering unit and a pyrolysis unit. In an example, the digestate is air stripped in the reactor and a metal salt is added to it. The metal ions form precipitates in the digestate that remain in the biochar. In some cases, a precipitate such as struvite is formed that also increases the phosphorous content of the biochar. The biochar may be used as a soil amendment, wherein the metal and phosphorous are beneficial to the soil.

The invention pertains to methods of reducing dissolved elements such as arsenic, selenium and mercury in aqueous solutions using, for example, various barium compounds to partition said elements to a solid phase. Such methods are particularly useful for reducing such elements at various points in coal and oil-fired power plants prior to final waste water treatment.

The invention pertains to methods of reducing dissolved elements such as arsenic, selenium and mercury in aqueous solutions using, for example, various barium compounds to partition said elements to a solid phase. Such methods are particularly useful for reducing such elements at various points in coal and oil-fired power plants prior to final waste water treatment.

The present invention relates to a composite treatment and recovery technique of polluted water body and soil. Iron-rich straw biomass, after being crushed, is mixed and granulated with sludge, and is pyrolytic charred by programmed heating, to obtain bulk loaded zero-valent iron biochar and sludge biochar composite particles, which are packed as fillers in a filled bed or as filters in filter cells of a fixed bed, for effective recovery of complex polluted water, polluted by heavy metals, organics, nitrogen, phosphorus, and the like.

A method of separating sludge which involves adding an insoluble mineral colloidal suspension into an industrial sludge to destabilize the industrial sludge and separating destabilized components of the industrial sludge. The insoluble mineral colloidal suspension includes magnesium hydroxide. In an alternative embodiment dry finely divided magnesium hydroxide can be added and then dispersed into an industrial sludge. Conventional flocculants and/or coagulants can also be added. Conventional physical separation processes can be used to separate the destabilized industrial sludge.