The invention relates to a method and an arrangement for wastewater treatment, in which at least portions of the sewage sludge contained in the wastewater (0) are subjected to a hydrolysis (8). The hydrolysis (8) is carried out as a thermal hydrolysis. After the hydrolysis step (8), a drying process is (19) carried out. The drying process (19) is a process operating with positive pressure in the steam region. At least parts of the steam resulting from the drying process (19), which operates with positive pressure, are fed (20) to the portions of the sewage sludge in the thermal hydrolysis (8).

A digester system for digesting feed material comprises a digester tank, a thickener, and a seal system. The digester tank generates a first digested material and biogas from the feed material. The thickener is operatively connected to the digester tank to remove a second digested material from the feed material to alter a solid content of the feed material in the digester tank. The seal system substantially prevents the thickener from removing biogas from the feed material with the second digested material.

The present invention discloses a composite biogenic flocculant for enhancing flocculation and dewaterability of chemically enhanced primary treatment (CEPT) sludge. The present invention also discloses method of conditioning CEPT sludge using the composite biogenic flocculant.

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.

A method and a system for treatment of a spent chloroaluminate ionic liquid catalyst and an alkaline wastewater, where the method includes: 1) mixing the catalyst with a concentrated brine for hydrolysis reaction until residual activity of the catalyst is completely eliminated, to obtain an acidic hydrolysate and an acid-soluble oil; 2) mixing the acidic hydrolysate with an alkaline solution containing the alkaline wastewater for neutralization reaction until this reaction system becomes weak alkaline, to obtain a neutralization solution; 3) fully mixing the neutralization solution with a flocculant, carrying out sedimentation and separation, collecting the concentrated brine at an upper layer for reuse in the hydrolysis reaction, and collecting concentrated flocs at a lower layer; 4) dehydrating the concentrated flocs to obtain concentrated brine for reuse into the hydrolysis reaction, and collecting a wet solid slag; and 5) drying the wet solid slag to obtain a dry solid slag.

A waste stream is treated by anaerobic digestion. A process is described involves a step of separating solids from digestate, and returning separated solids to a digester. Optionally, there may be a step of solids separation in which larger solids are removed from the digester. A process and apparatus are described for treating waste sludge from a wastewater treatment plant in an anaerobic digester. Feed sludge is thickened or solids are separated from digestate and returned to the digester. Additional co-digestion waste may be added to the digester. The process and apparatus may be used in a retrofit of an existing wastewater treatment plant.

Processes of consolidating oil sands tailings which includes fines and process water are disclosed. The processes include mixing the oil sands tailings with a highly water soluble salt or an aqueous solution thereof to destabilize and consolidate solids in the tailings, e.g., to destabilize and consolidate fines in the tailings and separating the consolidated solids from the process water. A water soluble polymer and coarse particles, e.g., sand, can also be used in the treatment of oil sands tailings.

A fluidized bed biogasifier is provided for gasifying biosolids. The biogasifier includes a reactor vessel and a feeder for feeding biosolids into the reactor vessel at a desired feed rate during steady-state operation of the biogasifier. A fluidized bed in the base of the reactor vessel has a cross-sectional area that is proportional to at least the fuel feed rate such that the superficial velocity of gas is in the range of 0.1 m/s (0.33 ft/s) to 3 m/s (9.84 ft/s). In a method for gasifying biosolids, biosolids are fed into a fluidized bed reactor. Oxidant gases are applied to the fluidized bed reactor to produce a superficial velocity of producer gas in the range of 0.1 m/s (0.33 ft/s) to 3 m/s (9.84 ft/s). The biosolids are heated inside the fluidized bed reactor to a temperature range between 900° F. (482.2° C.) and 1700° F. (926.7° C.) in an oxygen-starved environment having a sub-stoichiometric oxygen level, whereby the biosolids are gasified.

A method of providing, maintaining and using a youthful added microbe population for the treatment of wastewater. A method to obtain Class A sludge without the need for disinfecting procedures.