In a process for treating wastewater from a combined gasification and Fischer-Tropsch (F-T) process, feedstock derived from Municipal Solid Waste or the like is gasified in a reactor (R) and treated in a cleanup unit (C) which generates a first wastewater stream (1st WWT STREAM) containing salts and inorganic pollutants. The first wastewater stream is treated in a treatment unit (T1) to remove inorganic pollutants derived from the syngas The treatment comprises a) degassing, and subsequently b) neutralising the first wastewater stream before treatment in a Dissolved Air Flotation unit (72c) and filtering in a moving sand bed or similar (72d) to remove solids, and a stripping process to remove ammonia. A second wastewater stream (2.sup.nd WWT Stream) containing organic pollutants but being low in salts arises from the F-T process and is treated separately to allow recycling within the F-T process.

A method for removing soluble and/or colloidal Si-compounds from an aqueous stream of a minerals processing plant is provided. The method includes adding coagulant(s) and/or flocculant(s) and/or flotation chemical(s) to the aqueous stream in order to facilitate formation of flocs comprising at least some of the Si-compounds, and in order to form a treated aqueous stream, subjecting the treated aqueous stream to cleaning flotation in order to separate at least some of the Si-compounds as a cleaning flotation overflow, and removing the cleaning flotation overflow. The cleaning flotation comprises gas bubbles, at least 90% of the gas bubbles having a diameter of from 0.2 to 250 μm.

A water treatment system that removes calcium and magnesium using coagulants and pH controls, aqueous phase organic materials from water using a biological removal system that includes microorganisms and a physical separation system that includes sparging equipment for sparging the water to remove non-aqueous phase liquid organic materials, volatile phase organic materials. An apparatus, system and method for pretreating oilfield produced water to completely remove or significantly reduce concentrations of substances that are known to interfere with downstream recovery of metals including lithium. This technology facilitates a more efficient and cost-effective extraction method from alternate sources to meet the increasing global demand.

A method for treatment of mixed electroplating wastewater without a cyanide and a phosphorus-containing reductant without a cyanide and a phosphorus-containing reductant. A ferrous chloride solution is added into electroplating wastewater without a cyanide and a phosphorus-containing reductant. The pH of wastewater is adjusted to 10.5-12. Pollutants such as sodium cyanide and hydroxyl-containing organic amine complexants are oxidized with sodium hypochlorite. Carboxyl-containing organic acid complexants are precipitated. Hexavalent chromium is reduced to trivalent chromium to form chromium hydroxide precipitate. Precipitate is removed by filtering and wastewater is adjusted to pH 4.5-5.5. Heavy metal ions are precipitated with sodium dimethyldithiocarbamate or sodium diethyldithiocarbamate. Precipitate and heavy metal capturing agents are adsorbed with activated carbon followed by removal of precipitate. Wastewater is adjusted to pH 6-8. Aliphatic polyamine complexants are destroyed using an available biological degradation technique to reduce chemical oxygen demand.

Provided herein are processes for the removal and/or recovery of a target metal from a liquid sample, said process comprising: [1] applying acoustic cavitation to the liquid; and [2] adding an iron (II) salt, or a precursor form thereof, to the liquid sample and allowing Fenton oxidation reaction to occur between the iron and hydrogen peroxide in the liquid, thereby producing hydroxyl radicals; thereby producing a target metal salt or metal oxide having a reduced solubility in the liquid sample, leading to removal of the target metal from the liquid sample. The use of metal ligands in such processes is also described, as well as systems for performing such processes. Methods, processes, and systems for removing organic contaminants from a liquid sample are also described.

Method for dewatering sludge assisted by flocculating reagent, said method comprising an injection of flocculating reagent into the sludge and a step for dewatering said sludge, characterized in that it comprises a preliminary step for mixing (4) said sludge so as to destructure it and reduce its viscosity. Installation for implementing this method.

To provide a filter medium, a process for producing filter medium, a filtration device, a method for operating the filtration device, and a filtration system, which are capable of promptly regenerating the adsorption power by backwashing and realizing efficient operation of a filtration device. The filter medium of the present invention contains a carbon-based material in which a cumulative pore volume of pores having a pore radius of 2 nm or less is 25% or less with respect to a cumulative pore volume of pores having a pore radius of 50 nm or less.

A method for efficiently removal of oxidised selenium from liquid, such as FGD wastewater. The method involves adding a non-iron-based reducing agent (e.g. sodium dithionite) and preferably Fe(II) ions to the liquid at a pH of above 7.5 or 8 and precipitating elemental selenium from the liquid.

This disclosure relates to red mud compositions. This disclosure also relates to methods of making red mud compositions. This disclosure additionally relates to methods of using red mud compositions.

Disclosed are methods of treating wastewater using a membrane bioreactor and achieving a target phosphorus concentration for the membrane permeate stream. These methods include the steps of dosing a wastewater stream with a rare earth clarifying agent and passing the dosed wastewater stream through the membrane to obtain a membrane permeate stream with a permeate concentration that is less than the phosphorus concentration of the influent stream. This permeate concentration also can be equal to or less than a target phosphorus concentration. In the methods as disclosed herein, the rare earth clarifying agent can be chloride salts of one or more rare earth elements and in certain embodiments, the rare earth clarifying agent can be CeCl.sub.3 and LaCl.sub.3.