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 system and method for combined microorganism degradation and air sparging-soil vapor extraction (AS-AVE) of oil-containing sludge can include a microorganism-adding unit, an AS-SVE unit, a metering-feeding layer, a mixing layer, a material discharging layer and a crawler-type conveyor. In some embodiments the microorganism-adding unit and the AS-SVE unit can include a microorganism storage tank and an AS-SVE storage tank. In some embodiments, the metering-feeding layer can include a valve, a pressure gauge, a flowmeter, a feeding chamber. In some embodiments, the mixing layer can include pipeline connectors and a stirrer. In some embodiments, the material discharging layer is mainly for transporting the treated soil away. The system can remove petroleum, petroleum hydrocarbons, volatile organic compounds (VOCs), and degradable and extractable contaminants from oil-containing sludge by a method combining microorganism degradation, mechanical stirring, AS-AVE and the like, thereby achieving soil remediation and automatic treatment in a large scale.

A system and method for combined microorganism degradation and air sparging-soil vapor extraction (AS-AVE) of oil-containing sludge can include a microorganism-adding unit, an AS-SVE unit, a metering-feeding layer, a mixing layer, a material discharging layer and a crawler-type conveyor. In some embodiments the microorganism-adding unit and the AS-SVE unit can include a microorganism storage tank and an AS-SVE storage tank. In some embodiments, the metering-feeding layer can include a valve, a pressure gauge, a flowmeter, a feeding chamber. In some embodiments, the mixing layer can include pipeline connectors and a stirrer. In some embodiments, the material discharging layer is mainly for transporting the treated soil away. The system can remove petroleum, petroleum hydrocarbons, volatile organic compounds (VOCs), and degradable and extractable contaminants from oil-containing sludge by a method combining microorganism degradation, mechanical stirring, AS-AVE and the like, thereby achieving soil remediation and automatic treatment in a large scale.

Uses of a method of producing small bubbles of gas in a liquid include gas transfer in airlift bioreactors and anaerobic digesters, and particle separation. The method uses a source of the gas under pressure, a conduit opening into a liquid and oscillating the gas passing along the conduit. The oscillation is effected by fluidic oscillator, comprising a diverter that divides the supply into respect outputs, each output being controlled by a control port, wherein the control ports are interconnected by a closed loop. Separation of algae from water involves delivering a laminar flow of microbubbles in the range 10 to 100 m diameter. Such bubbles also deliver a laminar flow in bioreactors that delivers enhanced liquid flow despite the small bubbles, which improves mixing and also enhances efficiency of gas exchange and retention of the bubbles in the reactor.

A method and device used for treating effluents by the biological aerobic activated sludge process with hydrodynamic separation, sludge collection, internal sludge recirculation and atmospheric air or oxygen dissolution functions implemented by a device that accumulates the functions of solids retention and gas dissolution in the biological reactor, increasing the hydraulic load capacity of the secondary settler, as well as the load absorption capacity of the biological reactor, thus almost doubling the treatment capacity in relation to a conventional activated sludge process.

A method and device used for treating effluents by the biological aerobic activated sludge process with hydrodynamic separation, sludge collection, internal sludge recirculation and atmospheric air or oxygen dissolution functions implemented by a device that accumulates the functions of solids retention and gas dissolution in the biological reactor, increasing the hydraulic load capacity of the secondary settler, as well as the load absorption capacity of the biological reactor, thus almost doubling the treatment capacity in relation to a conventional activated sludge process.

A common final clarifier is provided downstream of a two-stage or three-stage activated sludge (AS) system that includes: (A) one or more flow equalization basin (FEB) reactors and a nitritation reactor as the first AS stage, and an anammox reactor as the second AS stage, or (B) a carbonaceous biological oxygen demand (BOD) removal reactor and one or more FEBs as the first AS stage, a nitritation reactor as the second AS stage, and an anammox reactor as the third AS stage. A first return activated sludge (RAS) flow is conducted from the final clarifier to the first AS stage and a second segregated RAS flow is conducted to the second AS stage. Alternatively, a third segregated RAS flow is conducted to the third AS stage.

A common final clarifier is provided downstream of a two-stage or three-stage activated sludge (AS) system that includes: (A) one or more flow equalization basin (FEB) reactors and a nitritation reactor as the first AS stage, and an anammox reactor as the second AS stage, or (B) a carbonaceous biological oxygen demand (BOD) removal reactor and one or more FEBs as the first AS stage, a nitritation reactor as the second AS stage, and an anammox reactor as the third AS stage. A first return activated sludge (RAS) flow is conducted from the final clarifier to the first AS stage and a second segregated RAS flow is conducted to the second AS stage. Alternatively, a third segregated RAS flow is conducted to the third AS stage.

An air infusion aeration system includes a submersible downdraft tube that carries fluid from its inlet opening to the outlet opening vertically above the inlet opening. The system includes an impeller coupled to the outlet opening and configured to: draw fluid into the inlet opening and provide the drawn fluid into a discharge pressure manifold (DPM) as a fluid stream. The system includes a turbo blower that injects air into the DPM, and the DPM, which includes a center portion and a smaller diameter end portion at opposite ends of the center portion. The DPM is configured to: reduce pressure of the fluid stream at a center of the DPM; within the end portions, receive the air injection into the pressure-reduced fluid stream thereby infusing the injected air into the fluid steam; and forcibly discharge the air-infused fluid stream down toward the body of fluid.

An air infusion aeration system includes a submersible downdraft tube that carries fluid from its inlet opening to the outlet opening vertically above the inlet opening. The system includes an impeller coupled to the outlet opening and configured to: draw fluid into the inlet opening and provide the drawn fluid into a discharge pressure manifold (DPM) as a fluid stream. The system includes a turbo blower that injects air into the DPM, and the DPM, which includes a center portion and a smaller diameter end portion at opposite ends of the center portion. The DPM is configured to: reduce pressure of the fluid stream at a center of the DPM; within the end portions, receive the air injection into the pressure-reduced fluid stream thereby infusing the injected air into the fluid steam; and forcibly discharge the air-infused fluid stream down toward the body of fluid.