The invention concerns a gas mixer (1) comprising a first mixing vessel (42) and a second mixing vessel (52); a first line (22) for providing a first gas and a second line (32) for providing a second gas, the first and second lines (22, 32) being in fluid communication with the first mixing vessel (42) and with the second mixing vessel (52) for proving said first and second gases to said first and second mixing vessels (42, 52); and a third line (12) for providing a third gas, said third line (12) being in fluid communication with the second mixing vessel (52).

A method for preparing an aqueous solution of a defined pH comprising an acid, a base and optionally one or more additives is provided. The method comprises the steps of:

a) calculating the theoretical concentrations of acid and base for the solution to have the defined pH using the Henderson-Hasselbach equation in combination with the Debye Huckel theory for a range of different additive concentrations; b) preparing a sample of the buffer for the range of additive concentrations and measuring the actual pH for each additive concentration; c) calculating a value for delta pH, pH, being the difference between the theoretical pH and the actual pH, for each additive concentration; d) generating a mathematical model describing the relationship of pH with additive concentration; e) selecting the defined pH and additive concentrations; f) using the mathematical model generated in step d) to calculate pH for the defined pH and additive concentration; g) calculating a pH-corrected pH by summing the defined pH and delta pH; h) using the pH-corrected pH to calculate the concentrations of acid and base using the Henderson-Hasselbach equation in combination with the Debye Huckel theory; i) preparing the solution using the concentrations calculated in step h).

Fine-bubble-producing aeration units and large-bubble-producing (or other mechanical) mixing units are interspersed with each other in a given body of water to be treated. The two different types of units are independently controlled to independently regulate degrees of aeration and mixing in the given body of water.

The efficiency of water disinfection can be significantly increased by supplying the ozone in combination with oxygen to an inlet of a cavitation pump or a line atomizer. A compressor can be introduced at an inlet of the cavitation pump or the line atomizer, compressing the gas mixture at a pressure higher than the pressure within pump or the atomizer. The compressed gases are provided to the inlet of the atomizer or the pump, where the compressed gases mix with the water and enter the cavitation pump or the line atomizer (where most of the dissolution of the gases happens). The compressor allows to increase the amount of oxygen and ozone provided to the pump or the line atomizer, increasing their dissolved concentration. In addition to the disinfecting properties, the higher level of oxygen correlates to an improved taste of the water.

An algae cultivation system may include: a plurality of panels within a cultivation container, positioned along a first axis perpendicular to the gravitational force, wherein a cultivation volume is created between each pair of panels, and wherein the cultivation volumes are fluidly coupled so as to allow horizontal flow therebetween along the first axis; at least one first sparger, to distribute a first fluid into the container at a first operating flow rate; at least one second sparger, to distribute a second fluid into the container at a second operating flow rate; and at least one controller, to control the first operating flow rate and the second operating flow rate. The first operating flow rate may be adapted to allow turbulent mixing the algae in the cultivation container, and the second operating flow rate may be adapted to allow assimilation of materials in a liquid in the cultivation container.

The invention provides methods for assessing one or more predetermined characteristics or properties of a microfluidic droplet within a microfluidic channel, and regulating one or more fluid flow rates within that channel to selectively alter the predetermined microdroplet characteristic or property using a feedback control.

A water aeration system powers an air pump held in an encasement with a solar panel mounted directly or indirectly to the encasement or to the mounting pole supporting the encasement above a ground surface. An air conduit directs pumped air to one or more disc diffusers submerged in the body of water to be aerated. The disc diffuser(s) are supported by a floating platform that is suspended from a buoy or float so that the disc diffuser(s) are held at a desired depth below the water surface.

The present disclosure provides a system for producing carbon dioxide (CO.sub.2)-dissolved deionized water (DIW), the system comprising: a DIW source for providing DIW; a CO.sub.2 source for providing CO.sub.2; a pressurized tank, coupled to the DIW source and the CO.sub.2 source, the pressurized tank being arranged for generating CO.sub.2-dissolved DIW with a first concentration according to the DIW of the DIW source and the CO.sub.2 of the CO.sub.2 source; a mixer, coupled to the DIW source and the pressurized tank, the mixer being arranged for generating CO.sub.2-dissolved DIW with a second concentration according to the CO.sub.2-dissolved DIW with the first concentration and the DIW of the DIW source; and wherein the second concentration is lower than the first concentration.

A slurry injection system includes low and high pressure clear fluid manifolds. Low pressure clear fluid is pressurized and communicated to high pressure manifold. A blender unit communicates slurry through a sensor system that generates a flow rate signal and a density signal of the low pressure slurry. The slurry pressurizer is in fluid communication with the high pressure clear fluid manifold through a bypass pump, a mixer, the blender unit and the low pressure clear fluid manifold. The slurry pressurizer forms high pressure slurry that is communicated to the mixer and communicates fluid to the low pressure clear fluid manifold. The mixer mixes the high pressure slurry and high pressure clear fluid from the high pressure clear fluid manifold to form a mixture that is communicated to a slurry injection site. A controller controls the bypass pump using the flow rate and density to control a density of slurry.

An apparatus for mixing a first fluid into a flow path of a second fluid, the apparatus comprising: a chamber enclosing the flow path, the chamber including a second fluid first inlet for receiving its respective fluid. The apparatus also includes a second inlet arranged downstream of the first inlet and receiving the first fluid, as well as an outlet arranged downstream of the second inlet for discharging a mixture of the first fluid and the second fluid. The second inlet flows into the flow path and is formed by a shared fluid injector mounted transverse to the axial direction that one fluid and the two fluid flows through its chamber. The flow path includes two respective throttle bodies, each of which is pivotally arranged inside the chamber and attached to opposed sides of the chamber for controlling the flow area of the flow path.