Abstract: In a sewage treatment plant with a membrane bioreactor (MBR), raw untreated or partially treated wastewater (influent) and/or mixed liquor in the intensified process is superoxygenated. In a preferred form of the process the influent is superoxygenated such that membrane air scouring requirements are reduced. Influent may be fed to a swing zone where denitrification and nitrification occur simultaneously through process control. In one embodiment superoxygenation is conducted in an internal recycle stream of the mixed liquor, with oxygen content supersaturated preferably to over 300 parts per million. Due to the active evolution of oxygen gas from the supersaturated stream, occurring preferably by seeding the supersaturated stream with air bubbles, the supersaturated oxygen can serve the dual purposes of meeting process oxygen demands and providing part of air scouring requirements for the membranes.

Abstract: In a sewage treatment plant with a membrane bioreactor (MBR), raw untreated or partially treated wastewater (influent) and/or mixed liquor in the intensified process is superoxygenated. In a preferred form of the process the influent is superoxygenated such that membrane air scouring requirements are reduced. Influent may be fed to a swing zone where denitrification and nitrification occur simultaneously through process control. In one embodiment superoxygenation is conducted in an internal recycle stream of the mixed liquor, with oxygen content supersaturated preferably to over 300 parts per million. Due to the active evolution of oxygen gas from the supersaturated stream, occurring preferably by seeding the supersaturated stream with air bubbles, the supersaturated oxygen can serve the dual purposes of meeting process oxygen demands and providing part of air scouring requirements for the membranes.

Abstract: In a sewage treatment plant with a membrane bioreactor (MBR), raw untreated or partially treated wastewater (influent) and/or mixed liquor in the intensified process is superoxygenated. In a preferred form of the process the influent is superoxygenated such that membrane air scouring requirements are reduced. Influent may be fed to a swing zone where denitrification and nitrification occur simultaneously through process control. In one embodiment superoxygenation is conducted in an internal recycle stream of the mixed liquor, with oxygen content supersaturated preferably to over 300 parts per million. Due to the active evolution of oxygen gas from the supersaturated stream, occurring preferably by seeding the supersaturated stream with air bubbles, the supersaturated oxygen can serve the dual purposes of meeting process oxygen demands and providing part of air scouring requirements for the membranes.

Abstract: In a sewage treatment facility that employs on the liquid side a basin or basins with membrane separators or MBRs for dewatering sludge, filtration is suspended or “relaxed” in short, rapid cycles, with air scour during relaxation, with the result of more efficient stripping of accumulated solids on the membranes, better membrane efficiency and lower overall air scour requirements. Another aspect of the invention is to increase air scour rate during relaxation periods and decrease air scour rate during filtration, whether or not this is in combination with the shorter cycles just described. Another feature of the invention is a liquid valving scheme and mechanism by which liquid/permeate flow can be quickly and smoothly shut off and turned on to transition from relaxation to filtration and vice versa.

Abstract: In a wastewater treatment plant, the liquid side of the plant has preferably four stages for nitrification and/or denitrification, prior to further treatment such as a clarifier. Energy requirements are reduced by reducing aeration requirements. Four or more tanks/zones comprise serial anoxic and aerobic stages, but in the anoxic stages simultaneous nitrification/denitrification takes place in accordance with the known process of U.S. Pat. No. 5,906,746. By this arrangement the system can achieve a volume ratio of about 20% aerobic tankage to the total tankage volume, as compared to a much higher ratio in a typical prior art system of serial aerobic/anoxic stages, and greatly reducing aeration requirements.

Abstract: An aerobic digester system in a wastewater treatment plant is made more versatile for different conditions by addition of an equalizer basin or in some embodiments, a bypass pipe. If infeed is received from a sequential batch reactor or from a concentrated septage, for example, the equalizer basin can contain one batch, and then deliver the batch out incrementally to a gravity thickener basin. The equalizer basin also enables the gravity thickener of the system to be removed from service when needed, providing increased flexibility for the system. Importantly, the equalizer or bypass enables versatile modes of operation so that a plant designed for a larger, later flow can operate at an initially low flow or at several levels of flow before reaching the largest design flow. This applies to other conditions of variable flow as well such as seasonal.

Abstract: In a wastewater treatment system and process utilizing membrane bioreactors (MBRs), multiple, parallel series of tanks or stages each include, an MBR stage. Under conditions of normal flow volume into the system, influent passes through several parallel series of stages or process lines, which might be, for example, an anoxic stage, an aeration stage and an MBR stage. From the MBR stages a portion of M.L.S.S. is cycled through one or more thickening MBRs of similar process lines, for further thickening and further processing and digesting of the sludge, while a majority portion of the M.L.S.S. is recycled back into the main process lines. During peak flow conditions, such as storm conditions in a combined storm water/wastewater system, all of the series of stages with their thickening MBRs are operated in parallel to accept the peak flow, which is more than twice normal flow. M.L.S.S.

Abstract: A sewage treatment plant, on the liquid side, is operated so as to effect nitrification and denitrification within a single tank and simultaneously to remove water, without the need for separate clarification. An aerobic/anoxic zone is maintained in a single tank, wherein the SymBio process of U.S. Pat. No. 5,906,746 is maintained. This is combined with the advantages of an MBR process, by placing a series of membrane separators within the tank and continuously withdrawing nearly pure water. Supplemental process air provided in the MBR tank is controlled by the SymBio process to maintain simultaneous nitrification and denitrification in a single tank and thus reducing the additional process air requirements.