Abstract: A flexible membrane disk diffuser having an improved arrangement for sealing the membrane to the diffuser body. An enlarged sealing bead on the circumference of the membrane fits in an annular channel on the diffuser body. A retainer ring threads onto the diffuser body to compress the sealing bead against a base surface of the channel. A discontinuity on the base surface provides an effective seal with the bead without requiring undue tightening force of the retainer ring. The discontinuity may take the form of a ridge or a rut on the base surface of the channel.

Abstract: A diffuser module and system for diffusing gas into liquid such as in aeration/mixing of wastewater. Each module has a header pipe and diffusers which receive gas from the header pipe. Each header pipe is equipped with a truss for enhanced structural strength and resistance to bending. The truss may take the form of a buoyancy/ballast pipe connected with the header pipe by purlins.

Abstract: A diffuser assembly with a buoyancy vessel and a chamber for buoyantly raising the diffuser assembly for maintenance work. The diffuser assembly has a support structure, diffusers connected to the frame, and a buoyancy vessel positioned on the frame, capable of alternating between a state of buoyancy or ballast.

Abstract: A diffuser module and system for diffusing gas into liquid such as in aeration/mixing of wastewater. Each module has a header pipe and diffusers which receive gas from the header pipe. Each pipe is equipped with a smaller internal pipe arranged concentrically to provide an annular space which receives the gas and supplies it to the diffusers. The volume within the internal pipe can serve as a ballast chamber or a buoyancy chamber or both.

Abstract: A flexible diffuser membrane for diffusing gas into a liquid includes a substrate covered wholly or partially by a thin fluorocarbon elastomer coating. The coating is applied after the substrate has been fully constructed and cured. The coating is then mixed with an adhesive catalyst and applied by spraying or in another suitable manner to the substrate. The substrate and coating are then heated to a temperature such as 350° F.-800° F. adequate to form a strong chemical, molecular and adhesive bond between the coating and substrate. Perforations are formed in the membrane, the substrate may be treated with a biocide allowing the uncoated edges of the perforations to be coated with the biocide and resist biological growth.

Abstract: Submerged media useful with or without aeration and/or mixing to enhance an aquatic environment by promoting and retaining biogrowth. The media takes the form of a cluster of individual flexible elements having free ends. The media are submerged in a liquid such as a water or wastewater treatment basin or an aquaculture environment. The media are characterized by the ability to promote and retain microbial growth. The media clusters have substantial flow through thicknesses to provide a three dimensional effect along with baffling for increased contact with the liquid being treated. The media may be thin strips constructed to avoid sticking together to allow maximum exposed surface area. The media clusters can create oxic, anoxic and anaerobic environments for maximum treatment during flow through the media cluster. The flexibility of the media elements and their free ends automatically dislodges excessive biomass buildup to avoid clogging of the media.

Abstract: Submerged media useful with or without aeration and/or mixing to enhance an aquatic environment by promoting and retaining biogrowth. The media takes the form of a cluster of individual flexible elements having free ends. The media are submerged in a liquid such as a water or wastewater treatment basin or an aquaculture environment. The media are characterized by the ability to promote and retain microbial growth. The media clusters have substantial flow through thicknesses to provide a three dimensional effect along with baffling for increased contact with the liquid being treated. The media may be thin strips constructed to avoid sticking together to allow maximum exposed surface area. The media clusters can create oxic, anoxic and anaerobic environments for maximum treatment during flow through the media cluster. The flexibility of the media elements and their free ends automatically dislodges excessive biomass buildup to avoid clogging of the media.

Abstract: A flexible diffuser membrane is provided with a unique system of perforations arranged to result in uniform distribution of gas even though the membrane deflects to different extents or the submergence varies in different parts of the membrane. The perforations are arranged to provide less perforation area per unit of perforated membrane surface area in the membrane parts that deflect the most or are submerged least and greater perforation area in membrane parts that deflect the least or are submerged most. The perforations can be slits arranged in parallel rows on a tubular membrane, in concentric circles or another pattern on a disk membrane, or in still a different pattern on a flat panel diffuser membrane. The slit length or separation can be varied between different zones on the membrane surface or the spacing between rows or circles can be varied.

Abstract: A method and apparatus for building a lagoon based advanced treatment system or upgrading an existing lagoon system for advanced treatment of wastewater. The lagoon is provided with a baffle to create a complete mix zone in which an aeration system and bioconcentration modules are installed. Biological solids are concentrated in the modules and drop through their open bottoms where the solids are recirculated and mixed by the aeration system. Once a biomass equilibrium is reached in the complete mix zone, excess solids are passed into the rest of the lagoon for standard treatment there. The complete mix zone is operated as a low rate activated sludge process with a detention time much less than for the rest of the lagoon, maintaining sufficient heat and sludge aging to effect complete biological nitrification and/or denitrification.

Abstract: A wastewater aeration system that can be pivoted upwardly to expose the treatment basin floor for removal of accumulated grit or other solids. The aeration system includes a blower and a rigid or flexible supply conduit extending into the basin to supply lateral pipes with air. The laterals normally extend horizontally along the basin floor and carry air diffusers which discharge air into the basin. A winch and cable system or other mechanism can be operated to pivot the lateral pipes and diffusers upwardly away from the basin floor so that they are out of the way of equipment used to remove grit from the floor. A vertical track may be provided along a wall of the basin to accommodate raising of the lateral pipes and diffusers out of the basin.

Abstract: A method and apparatus for building a lagoon based advanced treatment system or upgrading an existing lagoon system for advanced treatment of wastewater. The lagoon is provided with a baffle to create a complete mix zone in which an aeration system and bioconcentration modules are installed. Biological solids are concentrated in the modules and drop through their open bottoms where the solids are recirculated and mixed by the aeration system. Once a biomass equilibrium is reached in the complete mix zone, excess solids are passed into the rest of the lagoon for standard treatment there. The complete mix zone is operated as a low rate activated sludge process with a detention time much less than for the rest of the lagoon, maintaining sufficient heat and sludge aging to effect complete biological nitrification and/or denitrification.

Abstract: A fine bubble diffuser membrane used in the aeration of wastewater is treated with biocide to inhibit growth and accumulation of biological materials on the membrane. The membrane may be constructed of EPDM rubber or urethane. The biocide may be carbolic acid either dispersed throughout the membrane or applied as a coating on the surface of the membrane exposed to the wastewater. The membrane is a flexible and elastic structure impervious to liquid and provided with slits that close to prevent wastewater inflow in the absence of aeration and open in response to aeration pressure to discharge air into the wastewater.

Abstract: A diffuser mounting assembly includes two saddle sections having integral outlet fittings to which elongated air diffusers can be mounted for aerating liquid in a basin. Air laterals installed in the basin receive the saddle sections on opposite sides so that the outlet fittings and diffusers extending on opposite sides of the laterals. Wedge fasteners are applied to flanges on the top and bottom edges of the saddle sections to secure them on the laterals. The outlet fittings are offset below center on the saddle sections so that both the laterals and diffusers can be located adjacent to the floor. The diffusers with a saddle section attached to each can be shipped in a compact configuration in shipping cartons.

Abstract: A diffuser mounting assembly includes two saddle sections having integral outlet fittings to which elongated air diffusers can be mounted for aerating liquid in a basin. Air laterals installed in the basin receive the saddle sections on opposite sides so that the outlet fittings and diffusers extending on opposite sides of the laterals. Wedge fasteners are applied to flanges on the top and bottom edges of the saddle sections to secure them on the laterals. The outlet fittings are offset below center on the saddle sections so that both the laterals and diffusers can be located adjacent to the floor. The diffusers with a saddle section attached to each can be shipped in a compact configuration in shipping cartons.

Abstract: An improved air diffuser and mounting arrangement for mounting diffusers on submerged air laterals in a wastewater treatment system. The diffuser is formed form a cylindrical pipe which is flattened on most of its length but left partially cylindrical for convenient mounting. The mounting arrangement includes a removable saddle on the air lateral and a Tee fitting for mounting the diffusers. The saddle has an outlet spout which fits directly against and is connected directly to an inlet leg of the Tee fitting. The saddle construction in one form accommodates either standard U.S. or metric pipe fittings and in another form accommodates two different sizes of pipe fittings.

Abstract: An improved air diffuser and mounting arrangement for mounting diffusers on submerged air laterals in a wastewater treatment system. The diffuser is formed form a cylindrical pipe which is flattened on most of its length but left partially cylindrical for convenient mounting. The mounting arrangement includes a removable saddle on the air lateral and a Tee fitting for mounting the diffusers. The saddle has an outlet spout which fits directly against and is connected directly to an inlet leg of the Tee fitting. The saddle construction in one form accommodates either standard U.S. or metric pipe fittings and in another form accommodates two different sizes of pipe fittings.

Abstract: An aeration/mixing system for applying air or another gas to wastewater or another liquid. A main air supply pipe receives air from a blower and directs the air to a plurality of aeration modules each including a submerged conduit and a plurality of diffusers on the conduit. Flexible hoses connect the main pipe with the conduit of each module. In one form of the invention, a flexible line connected with each module has a sliding connection with a ballast block and may be pulled tautly and secured at the surface to hold the module down in the basin. Retrieval of the module for maintenance requires only that the line be released so that the buoyancy of the module floats it upwardly. A modified embodiment includes an inflatable bladder on each module which can be inflated to cause the module to float upwardly for retrieval.

Abstract: A wastewater aeration system in which the volume of wastewater is divided into a plurality of different zones which are aerated sequentially one at a time with the full capacity of the blower supply sized for oxygenation needs. In the case where the oxygenation needs ar significant, the number is obtained by dividing the aeration rate required for mixing by the aeration rate required for oxygenation and rounding upwardly to the nearest integer. The blower capacity should continuously deliver the oxygenation rate to assure adequate aeration for both oxygenation and mixing while minimizing energy consumption. The air supply pipe network includes a header supply pipe for each zone and a valve for each header supply pipe which is automatically controlled by a programmable programmer. In the case where mixing only is required, the number of zones is limited by practicalities in order to prevent undue settling.

Abstract: A tubular membrane diffuser for a wastewater aeration system. The diffuser includes a pipe having spaced apart outlet ports and a porous membrane sleeved around the pipe for discharging air in bubbles. An adjustable plug can be located at the outboard end of the diffuser pipe in a fully buoyant application, near the inboard end of the diffuser pipe in a non-buoyant application where water occupies the outboard half of the diffuser, or anywhere between the diffuser pipe ends in a partially buoyant application. The plug includes a ring with a tapered bore and a tapered plug that threads into the bore to radially expand the ring for securing it in place.

Abstract: A generally tubular coarse bubble diffuser for aerating waste water is constructed of polyvinyl chloride or a similar plastic material. The diffuser body has a main section with flat side walls through which outlet ports are formed. The opposite ends of the diffuser body are cylindrical and are connected with the main section by transition sections which avoid abrupt changes in the wall thickness or diffuser connector diameter. One end is solvent welded in a plastic Tee fitting and the other end receives a removable end cap. The flat walls provide efficient oxygen transfer and the cylindrical ends allow the use of a threaded end cap and a secure large diameter solvent weld connection to the Tee fitting which directs air to the diffuser.