A filtering medium, a method for the production thereof, the use of said filtering medium and a method for reducing the content of multiple contaminants simultaneously in fluids by means of said filtering medium, wherein said filtering medium has or includes at least one of the following: a mixture (A) containing a major part of an iron-based powder and a minor part of a silver powder, an iron-silver powder alloy (B), and an iron-based porous and permeable composite containing silver (C).

Various embodiments relate to denitrification of water using bacteria. A method of denitrification of water includes deoxygenated water including a water-soluble form of nitrogen. The method includes exposing the deoxygenated water to denitrifying bacteria to convert the water-soluble form of nitrogen in the water to nitrogen gas that is removed and to form a denitrified water. The method also includes reoxygenating the denitrified water. Denitrifying bacterial substrates and methods of making the same are also provided.

A method of treating a liquid by creating nanobubbles of a desired gas within a target liquid and allowing the desired gas to react with a target component of the target liquid. The desired gas can be selected to be reactive with the target component, and a desired liquid can be formed after the desired gas reacts with the target component.

Various embodiments relate to denitrification of water using bacteria. A method of denitrification of water includes deoxygenated water including a water-soluble form of nitrogen. The method includes exposing the deoxygenated water to denitrifying bacteria to convert the water-soluble form of nitrogen in the water to nitrogen gas that is removed and to form a denitrified water. The method also includes reoxygenating the denitrified water. Denitrifying bacterial substrates and methods of making the same are also provided.

Provided is a technique capable of efficiently removing nitrogen contained in water to be treated and efficiently recovering microplastics from the water to be treated. An aspect of the present invention is a water treatment system 10 including an aquaculture tank 20 and a water treatment tank 30. Aquatic organisms are cultivated in the aquaculture tank 20. In the water treatment tank 30, algae having a microplastic adsorption and recovery ability grow in the water to be treated introduced from the aquaculture tank 20. The microplastics contained in the water to be treated are recovered, and the nitrogen compounds contained in the water to be treated are removed, by the algae.

An activated sludge process for the treatment of municipal wastewater, particularly applicable to oxidation ditch activated sludge treatment systems which utilize a conventional race track or continuous loop reactor basin configuration. The process removes phosphorus and nitrogen from an activated sludge wastewater treatment system, with an anoxic cycle followed by an aerobic cycle, and followed by a surface wasting cycle until a low flow diurnal period is reached in a diurnal or twenty-four hour period. Automated microprocessor control system using “oxidation-reduction potential” (ORP) and “dissolved oxygen” (DO) as process variable inputs automate aerated and anoxic cycles to optimize phosphorus and nitrogen removal using the available carbon in the influent wastewater resulting in an energy efficient dynamic dissolved oxygen control during the aerated periods.

Disclosed is an electrified membrane flow-cell reactor system and method for nitrogen wastewater treatment and upcycling towards ammonia nitrogen without external acid/base consumption. This electrified membrane flow-cell reactor includes a cathodic membrane module having a gas-permeable or gas-exchange membrane and a cathodic catalytic layer, an anode, and a semi-permeable membrane between the cathodic and anodic chamber. Three chambers in the flow-cell reactor include (i) a cathode chamber for nitrate reduction and upcycling towards NH.sub.3, (ii) a trap chamber for NH.sub.3 capture and storage, and (iii) an anode chamber for H.sup.+ production and protonation of gaseous NH.sub.3 to NH.sub.4.sup.+. The cathodic membrane and anode are connected to an electric power source to provide a stable cathodic potential and enable electrode reactions. This method will continuously treat nitrate-containing wastewater and achieve simultaneous electrochemical nitrate reduction from the wastewater and ammonia recovery as ammonium salts in the trap chamber.

An organic wastewater treatment method based on a multi-element co-doping TiO.sub.2 nano photocatalytic material includes preparing a sulfur-titanium dioxide mixture, hydrothermally reacting the sulfur-titanium dioxide mixture with copper chloride, ammonia, strong alkali, a transition metal salt and the like, reacting the resulting reaction product with hydrofluoric acid, then performing temperature programming thermal treatment in air to obtain the multi-element co-doping TiO.sub.2 nano photocatalytic material, and then treating organic wastewater with the multi-element co-doping TiO.sub.2 nano photocatalytic material under the irradiation of visible light. The organic wastewater treatment method is efficient and rapid, safe and environmental-friendly, can thoroughly degrade many types of organic pollutants, ammonia nitrogen and the like, and does not cause secondary pollution; furthermore, the adopted multi-element co-doping TiO.sub.2 nano photocatalytic material can be regenerated and recycled only by simple calcination, and the cost is inexpensive.

The invention relates to a method for the biological treatment of nitrogen in the form of ammonium in wastewater, by nitritation in a biological reactor, comprising: at least one step a of aerating the biological reactor containing the wastewater to be treated, at least one step b of eliminating at least part of the nitrites produced in step a, and a step c of extracting, from the reactor, a fraction of the sludge resulting from steps a and b. The invention also concerns a method for the biological treatment of nitrogen in wastewater, by nitritation/denitritation and/or deammonification, wherein the nitritation is implemented using the nitritation method according to the invention.

Disclosed are decoupled systems and methods for producing an oxidized liquid. The method comprises the steps of generating an ozone strong water in a mass transfer unit, mixing the ozone strong water with a process liquid in a mixing unit to form a homogeneous and gas-free mixture of the ozone strong water and the process liquid, forwarding the homogeneous and gas-free mixture to a reaction unit, and producing the oxidized liquid in the reaction unit. The method utilizes the acidic feed liquid to generate ozone dissolved in water having a higher concentration at a saturated or nearly saturated concentration compared to prior art processes at atmospheric pressure and neutral or alkaline pH.