Provided are a water treatment method and a water treatment device wherein in a biological treatment of ammonium nitrogen-containing water to be treated, the water to be treated can be treated stably at a high treatment speed even when the nitrogen concentration of the water to be treated is high. This water treatment device biologically treats ammonium nitrogen-containing water to be treated. The water treatment device (water treatment method) is provided with: a nitrification device (nitrification step) for oxidizing ammonium nitrogen to nitrite or nitrate nitrogen using nitrifying bacteria including autotrophic ammonia-oxidizing bacteria and nitrite-oxidizing bacteria contained in microbial activated sludge; and a nitrification rate control means which maintains a molybdenum compound in the nitrification device in such a manner as to control the molybdenum concentration of the water to be treated to 0.025 mg Mo/gN or more, and controls the nitrification rate for the sludge to 0.11 [kgN/(kgVSS.Math.day)].

A combination biological contactor and self-backwashing filter system for water treatment is disclosed. The system may include a treatment vessel defining an upper chamber and a lower chamber. A biological contactor may be disposed within the upper chamber, and a filter may be disposed in the lower chamber. A contactor outlet conduit and inlet manifold may be used to transfer water from the biological contactor to filter cells within the filter.

A multi-stage system comprising a digester, a bioreactor, a scrubber, a biofilter, and a membrane filter extracts and purifies biogas from a wastewater feed. The digester separates raw biogas from wastewater, the wastewater is then purified with a three-stage bacterial process in a bioreactor. The scrubber receives raw biogas from the digester under pressure, dissolving waste gases and purifying the methane, which can be further condensed and purified in the membrane filter. The bioreactor receives waste gases from the scrubber and membrane filter, with the ammonia portion of the waste gases rising through water from the bioreactor and being converted by annamox bacteria into nitrogen gas. The multiply recycled gas and water feeds produce a biogas having high purity and reduced atmospheric emissions of waste gases.

Described herein are methods and devices for treating water, wastewater, and organic wastes. The methods and devices are mixed by using hydraulic surge mixers. This surge mixer is driven by gas and can provide occasional surges of water using large bubbles which are able to move great volume of liquid while minimizing dissolved oxygen transfer to the surrounding liquid. Use of the devices and processes herein provides a simple, eloquent approach to water and wastewater treatment with less operation and maintenance costs than conventional devices and/or processes. The same surge lifting device can also be installed in other reactors to mix the tank content and enhance reaction with reduced energy use and maintenance needs.

[Problem] A microorganism immobilized carrier is provided that is easy for microorganisms to adhere to, and is able to reduce the manufacturing cost of the microorganism immobilized carrier and the running cost of an apparatus that uses the microorganism immobilized carrier.

[Solution] A microorganism immobilized carrier is characterized by including a carbon component and a resin, having a zeta potential of from −25 mV to 0 mV, and containing microorganisms adhered to a surface thereof and/or an interior thereof. The microorganisms are preferably nitrifying bacteria. The carbon component preferably has a particle size of from 1 μm to 1000 μm.

A method and composition for treating drinking water for animals is disclosed. A method for treating drinking water for animals includes providing a plurality of sporulated microbes to metabolize an organic matter in the drinking water. A composition for treating animal drinking water includes a plurality of sporulated microbes.

[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 m to 1000 m.

A method and system to significantly reduce odor emissions caused by ammonia and other noxious gasses and reduce nitrogen levels in animal husbandry wastewater effectively and efficiently by the use of flush water that has been biochemically conditioned to lower the pH thus reducing the level of un-ionized compounds including NH.sub.3 which can volatilize into the atmosphere and which method and system can also be used to remove ammonia and nitrogen from the wastewater system. The present disclosure includes the use of flush water that has been biochemically conditioned to lower its pH thus sequestering non-ionized ammonia from being released from a liquid as ammonia gas. This disclosure relates to the new use of nitrification for biochemical conditioning of wastewater for use as flush water to reduce atmospheric ammonia emissions.

Described herein are methods and devices for treating water, wastewater, and organic wastes. The methods and devices are mixed by using hydraulic surge mixers. This surge mixer is driven by gas and can provide occasional surges of water using large bubbles which are able to move great volume of liquid while minimizing dissolved oxygen transfer to the surrounding liquid. Use of the devices and processes herein provides a simple, eloquent approach to water and wastewater treatment with less operation and maintenance costs than conventional devices and/or processes. The same surge lifting device can also be installed in other reactors to mix the tank content and enhance reaction with reduced energy use and maintenance needs.

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 yarn fiber diffuser comprising: a plurality of yarn fibers on which bacteria can be attached and grow; and an inlet capable of supplying gas to one sides of the plurality of yarn 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.