The invention relates to a filter unit (1, 19), having: at least one warp-knitted spacer (3) which comprises a first and a second cover layer (4; 5) having in each case a multiplicity of openings (6) which are delimited by peripheral regions (7), wherein threads (8) extend from the peripheral regions (7) of the first cover layer (4) to peripheral regions (7) of the second cover layer (5), and wherein the at least one warp-knitted spacer is rolled, twisted, and/or at least in one portion is compressed.

A device and method for shortcut nitrogen removal and nitrite-oxidizing bacteria activity inhibition are disclosed herein. An embodiment of the present invention provides a hollow fiber diffuser comprising: a plurality of hollow fibers on which bacteria can be attached and grow; and an inlet capable of supplying gas to one sides of the plurality of hollow fibers, wherein the gas includes oxygen and carbon dioxide, nitrite can be produced by the oxygen, and the concentration of oxygen in the gas is adjusted by the oxygen and the carbon dioxide.

Disclosed is a method for preparing the same. The method for preparing a carrier including ammonium oxidizing bacteria immobilized therein includes: preparing a PVA-alginate mixed solution containing PVA mixed with alginate; adding sludge containing ammonium oxidizing bacteria and sodium bicarbonate (NaHCO.sub.3) to the PVA-alginate mixed solution to obtain a foaming-beading solution; and dropping the foaming-beading solution to a saturated boric acid solution to obtain beads including sludge immobilized therein, wherein sodium bicarbonate (NaHCO.sub.3) is decomposed to produce carbon dioxide (CO.sub.2) which is discharged to the exterior of the beads to form pores in the beads, when the foaming-beading solution is dropped to the saturated boric acid solution to obtain beads including sludge immobilized therein.

For bio-electrically generating electric power from organic ingredients of a waste water flowing in a flow direction, an anode is immersed in the waste water in a first spatial area, and oxygen is supplied to a cathode which is electrically connected to the anode and arranged in a second spatial area delimited from the first spatial area by means of a proton-permeable membrane. A voltage between the anode and the cathode is increased by a DC/DC converter located at the anode and the cathode, and a further voltage between a further anode in said or a further first spatial area and a further cathode in said or a further second spatial area is increased by a further DC/DC converter located at the further anode and the further cathode. A DC voltage link is charged with the DC/DC converter and the further DC/DC converter connected in parallel to the DC voltage link.

A water treatment system comprising a first reactor and a second reactor arranged to be placed in series in a body of water, the first and/or second reactor comprising at least one cell for housing biomedia. A mid-settling zone is provided between the first and second reactors for separating solids in the water. A method of treating water, the method comprising passing water to be treated through a first reactor and then a second reactor arranged in series in a body of water, the first and/or second reactors comprising at least one cell for housing biomedia, wherein the water is passed through a mid-settling zone between the first and second reactors before passing through the second reactor.

The invention relates to bio-electrochemical systems for the generation of methane from organic material and for reducing chemical oxygen demand and nitrogenous waste through denitrification. The invention further relates to an electrode for use in, and a system for, the adaptive control of bio-electrochemical systems as well as a fuel cell.

The invention relates to a method for nitrogen removal from aqueous medium, comprising steps of (a) converting NH.sub.4.sup.+ in the aqueous medium to NO.sub.2.sup.− by partial aerobic nitrification, (b) partially reducing the obtained NO.sub.2.sup.− to N.sub.2O in anoxic conditions, and (c) decomposing N.sub.2O to N.sub.2 with energy recovery. A mixture of ferrous sulfate and ferric sulfate is used in step (b) for reduction of NO.sub.2.sup.− to N.sub.2O.

[Problem] A carrier for retaining anammox bacteria, an anammox bacteria-adhered particle, and a wastewater treatment apparatus are provided that can remarkably reduce the start-up period for obtaining a nitrogen removal speed of 1 kg-N/m.sup.3/day. [Solution] A carrier for retaining anammox bacteria includes carbon particles. The carbon particles are desirably graphite particles, particularly isotropic graphite particles. The carbon particles desirably have a zeta potential of −35 mV to 0 mV and an average particle size of 2 μm to 1000 μm.

Provided is a biological treatment method and an apparatus that allow organic wastewater from a manufacturing process of electronic devices to be neutralized efficiently during its biological treatment with a less neutralizer in contrast to excessive use thereof in the conventional biological treatment and thereby make it possible to reduce an amount of an inorganic coagulant used in the downstream coagulation step and to reduce salt loads in RO membrane separation and ion exchange treatment. Wastewater from a process of manufacturing electronic devices is passed sequentially through two or more biological treatment tanks that include at least two aerobic biological treatment tanks including the final-stage aerobic biological treatment tank while adding a neutralizer to the biological treatment tank or tanks except the final-stage biological treatment tank so that an M-alkalinity of the liquid in the final-stage biological treatment tank is maintained at not more than 50 mg/L as CaCO.sub.3.

Processes and compositions for removal nitrogen, organic and inorganic contaminants from wastewater using Feammox bacterium are provided.