A method and a device for the continuous purification of a domestic or industrial water stream. After passing through a biological reactor to obtain a sludge of between 4 and 12 g/l of Dry Solids, the method involves feeding a series of chambers separated by restrictions at a flow rate q, injecting air into a second chamber at a flow rate Q>q, in order to obtain an emulsion, injecting a flocculant into a third chamber, and recovering the degassed emulsion in a drain pan. Flocculated and aerated sludge floats on top, such that the remaining liquid centrate has a Dry Solids content less than 100 mg/l and has a positive redox potential >50 mV and a value greater than 100 mV relative to the redox potential of the sludge at the inlet of the chambers, and is reinjected upstream from or into the biological reactor.

A water neutralization system that includes a first source of water that is acidic and a second source of water that is basic. A storage reservoir communicates with each of the first source and the second source, and includes a pH sensor that is configured to transmit a signal indicative of a pH of the water stored in the storage reservoir. At least one valve controls fluid communication between the storage reservoir and at least one of the first source and the second source, and a controller communicates with each of the pH sensor and the valve. Based on the signal indicative of the pH of the water stored in the storage reservoir, the controller instructs the valve to adjust an amount of water received from at least one of the first source and the second source to neutralize a pH of the water stored in the storage reservoir.

A wastewater evaporation system for spray evaporating water comprising: a wastewater feed inlet; a pump, wherein an outlet of the wastewater inlet is fluidly connected to an inlet of the pump and wherein an outlet of the pump is fluidly connected to an inlet of a manifold; a drip orifice, wherein an outlet of the manifold is fluidly connected to an inlet of the drip orifice; a container, wherein an upper portion of the container is enclosed with a demister element; a packing system and/or a tray system disposed within the container, wherein the outlet of the drip orifice discharges water droplets onto the packing system and/or the tray system; a discharge outlet, wherein a bottom of the container is fluidly connected to the discharge outlet; and an air system comprising an air blower and optionally an air preheater, wherein the air system is disposed through a wall of the container and wherein the air system discharges air flow counter to the water droplets from the drip orifice. A method of spray evaporating water while limiting emission of particles regulated as pollutants is also disclosed.

The present invention provides a method and apparatus for controlling gas flow rate to the membrane of a membrane aerated biofilm reactor (MABR) in order to effect one or more process outcomes, in particular to reduce or minimize N.sub.2O emissions in the exhaust gas from the MABR while managing gas delivery to mixing apparatus of the MABR and maintaining NH.sub.4 and NO.sub.3 targets in the treated effluent, the method comprising monitoring one or more parameters of the wastewater and the exhaust gas and modulating the supply of feed gas to the membrane based on the one or more parameters in order to control the composition of the exhaust gas.

A method to control a process variable in a process by means of a control unit comprises: sequential determination of values of a reference variable to be supplied to the first control unit based on the values of a first measurand; sequential determination of values of a regulating variable using both values for the reference variable and sequentially determined values for the process variable; with a current value for the reference variable being determined: by sequentially saving values of the first measurand, or values derived therefrom, in a first FIFO memory having a number K of memory locations for saving one value respectively, namely a memory featuring a number K of logically consecutive memory locations (j=i) in such a way that the oldest of the values saved in the first FIFO memory is saved in a first memory location (j=1) and the value saved last in the first FIFO memory is saved in a final memory location (j=k); and by using only the n oldest values saved in the first FIFO memory to determine the current value for the reference variable, with n being a number of values that is smaller than the number K of the values saved in the memory locations of the first FIFO memory and greater or equal 1.

Apparatus is disclosed for separating an amount of a substance from groundwater, comprising an elongate chamber (18) having an inlet (22) which is arranged in use to admit groundwater into the chamber near a lower first end (24). There is also a gas sparger (26) located near the first end (24) which admits gas into the chamber for inducing groundwater to flow from the first end (24) of the chamber toward a second end upper end, and for producing a froth layer (32) which rises above an interface with the groundwater including a concentrated amount of the substance. A suction hood (38) can be moved downward from the top of the chamber (18) into a position to collapse the froth layer (32) and to cause it to be removed from the well body (14). The suction hood (38) (acting as a froth depth regulation device) controls the amount of groundwater in the froth layer (32), which influences the concentration of the contaminant substance achieved in the froth layer (32).

A de-watering system for liquid industrial waste from an industrial cleaning process is provided. The liquid industrial waste has an initial water content, and comprises detergents and solid waste. A de-watering bed (430) holds the liquid industrial waste. Air in a first zone (420) is enclosed by a transparent structure (410) and is heated by the sun during daytime. A first controllable opening (450) controls a rate of flow of air in the first zone (420). Water from the liquid industrial waste evaporates into heated air in the first zone (420). An air removal conduit (440) allows heated air to vent to the atmosphere. A control system (380) selectively opens the first controllable opening (450), to regulate the flow of air. De-watering continues until a selectable end point, based on residual water content of the waste, or a final concentration of non-water components.

Apparatus is disclosed for separating an amount of a substance from groundwater, comprising an elongate chamber (18) having an inlet (22) which is arranged in use to admit groundwater into the chamber near a lower first end (24). There is also a gas sparger (26) located near the first end (24) which admits gas into the chamber for inducing groundwater to flow from the first end (24) of the chamber toward a second end upper end, and for producing a froth layer (32) which rises above an interface with the groundwater including a concentrated amount of the substance. A suction hood (38) can be moved downward from the top of the chamber (18) into a position to collapse the froth layer (32) and to cause it to be removed from the well body (14). The suction hood (38) (acting as a froth depth regulation device) controls the amount of groundwater in the froth layer (32), which influences the concentration of the contaminant substance achieved in the froth layer (32).

An anaerobic purification device for purification of wastewater, the anaerobic purification device comprising: a reactor tank (10) configured to, when in operation, have a sludge blanket formed at the bottom part; a fluid inlet (12) for, in operation, introducing influent into the reactor tank, the fluid inlet located in the lower section of the reactor tank (10); at least one gas-collecting system (13); at least one gas-liquid separation device (30); at least one riser pipe (22) connected to the at least one gas-collecting system (13) and discharging into the gas-liquid separation device (30); a downer pipe (24) connected to the gas-liquid separation device (30) and discharging into the bottom of the reactor tank (10); and a fluid outlet (16) comprising means for, in operation, varying the height of the fluid level (19) in the reactor tank within a predetermined range, the fluid outlet arranged at the upper section of the reactor tank (10);
wherein the fluid level control means comprises: a fluid valve (15) configured to control the height of the fluid in the reactor tank within the predetermined range, a fluid level detector (17), a gas flow meter (33) configured to measure the production rate of gas in the anaerobic purification device, and
a controlling unit configured to regulate the fluid valve (15) to vary the height of the fluid level in the reactor tank (10) based on at least one of the fluid level detected by the fluid level detector (17) and the gas production rate detected by the gas flow meter (33).

A membrane separation type activated sludge treatment method according to an aspect of the present invention includes a step of performing biological treatment on waste water and a step of performing membrane separation on water having been treated in the biological treatment step. The membrane separation step employs a plurality of filtration modules including a plurality of hollow fiber membranes arranged adjacent to one another and oriented in one direction and a pair of holding members fixing both ends of the plurality of hollow fiber membranes, and a plurality of cleaning modules supplying air bubbles from beneath the filtration modules. An amount of treated water sucked by the filtration modules and an amount of air bubbles supplied by the cleaning modules are varied in response to variations in an inflow rate of the waste water in the biological treatment step.