A mixer configured for releasing large bubbles into wastewater is provided. The mixer can include a central draft tube, an upwardly-extending member surrounding the draft tube, and an accumulator surrounding both the upwardly-extending member and the draft tube. A lower end of the draft tube sidewall may be sealed and not include any openings beneath the lower end of the upwardly-extending member, so as to prevent liquid pumpage through the draft tube. A method for treating wastewater in a system that includes at least one large bubble mixer and at least one fine bubble diffuser is also provided. The large bubble mixer and fine bubble diffuser may be supplied gas independently from one another. The method can include multiple modes of operation wherein gas is either supplied to the mixer, to the diffuser, to neither the mixer or the diffuser, or to both the mixer or the diffuser.

A vertical motion mixer has a drive mechanism with two axes of guidance for vertical motion. A reciprocating yoke is fixedly secured to the driving shaft for the mixer, without any guide bearing for the mixer driving shaft. The mixer drive unit is of compact and simplified design with minimal moving parts, and including drive gearing with planetary gears to minimize wear during reciprocating movement.

A device for injecting a secondary fluid into a main liquid, includes a first part able to convey a secondary fluid in a substantially longitudinal direction; a second part able to eject the secondary fluid from the device, so as to inject the secondary fluid into a main liquid, the second part being in fluidic connection with the first part and comprising an open end; the device comprising at least a first position, referred to as the low position, and a second position, referred to as the high position, and further comprising a positioning means able to position the device in a position comprised between the first position and the second position.

A method and system for treating wastewater is disclosed. In one example the method comprises activating a mixing system that imparts a motive force on wastewater in a vessel, measuring at least one property of a first portion of the wastewater at a first time, measuring the at least one property of a second portion of the wastewater at a second time subsequent to the first time, calculating a difference between the at least one property measured at the first time and the at least one property measured at the second time, performing a determination of whether the difference is within a predetermined allowable range of differences, and responsive to a result of the determination, controlling a component of the mixing system.

Disclosed is a method for managing the operation of an apparatus for injecting oxygen into a purification basin. The oxygen notably being used by the biomass present in the purification basin to consume the pollution present in an effluent feedstock contained in the basin. The method comprises varying a rotational speed of the shaft by using a frequency variator, wherein an applied variation in speed is between plus 15% and minus 15% of the nominal speed of the shaft.

A bubble generating device for sewage purification includes: an outer cylinder 6 vertically placed in water; an injection port 2A placed at a lower central portion in the outer cylinder 6 for upwardly injecting air as bubble flow supplied from an air supply source; and microbubble generating device 3 placed higher than the injection port 2A for refining bubbles injected from the injection port 2A. A throat portion 30 for narrowing a flow path of bubble flow and water flow which rises in the outer cylinder 6 is placed between the injection port 2A and the microbubble generating device 3.

A submersible agitator device for circulating drinking water includes a submersible motor including a cylindrical housing, from one end of which there extends a shaft, a hyperboloid agitator mounted on the shaft, a frame with a plurality of supports extending along the housing and connected to the housing, wherein the supports have radially outwardly angled bend portions, which extend over a peripheral edge of the hyperboloid agitator body in order to support the frame on a base, and a flow-guiding element, which is annular in plan view and which is mounted on the bend portions of the supports.

A method for realizing heterotrophic and autotrophic coupling advanced nitrogen removal and simultaneous sludge reduction in an anaerobic-aerobic-anoxic sequencing batch reactor (AOA-SBR) is disclosed. Municipal sewage and sludge fermentation mixture is allowed to simultaneously enter into the AOA-SBR; in the anaerobic stage, the organic matter in the sewage and sludge fermentation mixture is converted into polyhydroxyalkanoates (PHA) and stored in the body; in the aerobic stage, the dissolved oxygen (DO) at 0.5˜1 mg/L is maintained by a real-time control, the aeration time is set for 1˜3 h, and when the mass concentration ratio of NO.sub.2.sup.−—N to NH.sub.4.sup.+—N is in a range from 1.5 to 2.0, the aeration is stopped, that is, ammonia-nitrogen is partially converted into nitrite-nitrogen through short-cut nitrification; in the anoxic stage, the remaining ammonia-nitrogen and nitrite-nitrogen undergo anaerobic ammonia oxidation (anammox), and meanwhile the remaining nitrite-nitrogen and nitrate-nitrogen generated by anammox is reduced by denitrifying bacteria to nitrogen to achieve advanced nitrogen removal. A related apparatus is also provided, which simultaneously realizes advanced nitrogen removal of sewage and reduction of sludge.

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.

The present invention relates to a method and a device for controlling pollutants in basin water resources cycling utilization in agricultural activity areas. The method includes: providing an acidification tank, an aeration tank and a multi-media constructed wetland connected in sequence, which are 4˜10 m far from basin revetment, feeding basin water into the constructed wetland, adsorbing or degrading heavy metals and organic pollutants by the constructed wetland, and then transporting the treated basin water to the agricultural activity areas. The present invention effectively controls the content of heavy metals that will enter the agricultural activity areas, fundamentally reduces the content of heavy metals in the crops, promotes the growth of the crops, maintains sustainable and healthy development of agriculture, and therefore guarantees human health and safety.