Abstract: A flexible aeration panel is described, which does not include a rigid support plate. The flexible aeration panel can include a first perforated, flexible sheet sealed to a second non-perforated flexible sheet at their peripheral edges, thereby defining one or more cavities that are in fluid communication with at least one gas inlet. The flexible aeration panel can be configured to produce preferably evenly spaced bubbles of gas when positioned in a liquid body. Applications include, but are not limited to, aeration of wastewater, lakes, streams, water basins and the like.

Abstract: The disclosed process and system are used for the denitrification of wastewater. The system comprises: an influent concentration analyzer for measuring an influent dissolved oxygen concentration, an influent nitrate concentration, and an influent nitrite concentration; and a feed chemical controller for providing a feed chemical at a controlled rate. The feed chemical controller is responsive to one or more output signals provided by an automated control loop that accepts input signals from the influent concentration analyzer, which input signals relate to at least two of the influent nitrate concentration, the influent nitrite concentration, and the influent dissolved oxygen concentration.

Abstract: The disclosed process and system are used for the denitrification of wastewater. The system comprises: an influent concentration analyzer for measuring an influent dissolved oxygen concentration, an influent nitrate concentration, and an influent nitrite concentration; and a feed chemical controller for providing a feed chemical at a controlled rate. The feed chemical controller is responsive to one or more output signals provided by an automated control loop that accepts input signals from the influent concentration analyzer, which input signals relate to at least two of the influent nitrate concentration, the influent nitrite concentration, and the influent dissolved oxygen concentration.

Abstract: A flexible aeration panel is described, which does not include a rigid support plate. The flexible aeration panel can comprise a first perforated, flexible sheet sealed to a second non-perforated flexible sheet at their peripheral edges, thereby defining one or more cavities that are in fluid communication with at least one gas inlet. The flexible aeration panel can be configured to produce preferably evenly spaced bubbles of gas when positioned in a liquid body. Applications include, but are not limited to, aeration of wastewater, lakes, streams, water basins and the like.

Abstract: A disclosed sand washing apparatus may be used for separating organic material from a mixture comprising sand and organic material. The apparatus may comprise: a wash chamber for accepting a mixture comprising sand and organic material, an agitator, a collection chamber, and a conveyor configured to transport sand away from the collection chamber. The disclosed method for recovering sand from a mixture comprising sand and organic material may comprise the steps of: introducing the mixture into a chamber, allowing organic material to ascend while allowing sand to descend, subjecting a portion of the descending sand to a turbulence that creates a lifting action, and recovering sand that has descended past the turbulence.

Abstract: The disclosed process and system are used for the denitrification of wastewater. The system comprises: an influent flow meter for measuring an influent flow Q; an influent concentration analyzer for measuring an influent dissolved oxygen concentration DOin, an influent nitrate concentration NO3—Nin, and an influent nitrite concentration NO2—Nin; an effluent concentration analyzer for measuring an effluent nitrate concentration NO3—Neff, and an effluent nitrite concentration NO2—Neff?, and a feed chemical controller for providing a feed chemical at a controlled rate. The feed chemical controller is responsive to one or more output signals provided by an automated control loop that accepts input signals from the influent concentration analyzer and the effluent concentration analyzer, which input signals relate to at least NO3—Nin, NO2—Nin, NO3—Neff, and NO2—Neff.

Abstract: A process and system for denitrification of wastewater. The process includes the steps of measuring an influent flow rate, measuring influent concentrations of nitrates, nitrites, and dissolved oxygen in the wastewater, and using the influent concentrations to determine a nominal amount of methanol to be provided for denitrification. The invention also contemplates the measurement of effluent concentrations of nitrates and nitrites (i.e., NOx), and optionally using the effluent concentrations to adjust the nominal amount of methanol being provided.

Abstract: A porous media support plate module may be used to construct a new filter underdrain or to rehabilitate an existing filter underdrain. A porous plate replacement module may be inserted between two existing cell dividers to replace a damaged porous media support plate, which may be allowing media leakage. The design of the replacement module provides an improved plenum structure, which enhances the backwash process and reduces the drawbacks of applying adhesives in varying weather conditions. In an alternative design, a module may be provided to enhance the backwash process of existing cells.

Abstract: In the typical embodiments disclosed in the specification, a ballasted flocculation liquid treatment arrangement includes a mixing chamber in which liquid to be treated, flocculating agents and granular material are mixed. The mixture is supplied to the bottom of a flocculating chamber adjacent to the mixing chamber through an opening in a common wall between the chambers and is maintained in suspension in the flocculating chamber by turbulence generated by a rotating blade array. Ballasted flocs are transferred from the flocculation chamber to an adjacent sludge tank through a first opening in a common wall between them and liquid which contains lighter flocs is returned to the flocculation chamber through a second opening in the common wall. Liquid from the flocculation chamber passes upwardly through a turbulence control arrangement where flocs and particulates are substantially removed and into a clarification chamber where clarified liquid is passed over a weir to an outlet.

Abstract: In the typical embodiments disclosed in the specification, a ballasted flocculation liquid treatment arrangement includes a mixing chamber in which liquid to be treated, flocculating agents and granular material are mixed. The mixture is supplied to the bottom of a flocculating chamber adjacent to the mixing chamber through an opening in a common wall between the chambers and is maintained in suspension in the flocculating chamber by turbulence generated by a rotating blade array. Ballasted flocs are transferred from the flocculation chamber to an adjacent sludge tank through a first opening in a common wall between them and liquid which contains lighter flocs is returned to the flocculation chamber through a second opening in the common wall. Liquid from the flocculation chamber passes upwardly through a turbulence control arrangement where flocs and particulates are substantially removed and into a clarification chamber where clarified liquid is passed over a weir to an outlet.

Abstract: A treatment system for treating water/wastewater includes two continuously operating granular media filters that are operated together in series. The water/wastewater to be treated is introduced as an influent into the first of the granular media filters and is treated therein. Treated, processed water/wastewater or effluent is produced as is a first reject which contains impurities separated from a granular media bed in the first granular media filter and which is discharged from the first granular media filter. The effluent from the first granular media filter is further filtered in the second continuously operating granular media filter such that the effluent from the second granular media filter is clarified water and a second reject discharged from the second granular media filter contains impurities separated from a granular bed in the second granular media filter.

Abstract: An elongated suction header for use in a sludge removal system is mounted transversely on a track guide that is mounted on and driven along a track rail affixed to a floor of a tank in a water treatment facility. As the track guide moves along the track rail, the header is moved transversely to the rail adjacent the floor of the tank. In cross section, the header has a top section that is generally dome shaped and extends from a bottom wall of the header. The ends of the top section overhang beyond or extend below the bottom wall along a longitudinal axis of the header. Inlet orifices are provided in the bottom wall of the header so that sludge is drawn into an inner compartment of the header when vacuum is applied to a vacuum port that extends through the top section of the header into the header compartment. In order to assist in channeling the sludge to the inlet orifices, flow splitters extend from the bottom wall between adjacent pairs of the inlet orifices.

Abstract: In the submerged diffuser arrangement described in the specification, a plurality of submerged air diffuser arrangements are disposed adjacent to the bottom of in a body of wastewater to be aerated and connected an air supply pipe extending along the surface of the wastewater. Air is supplied from the air supply pipe through downcomers leading to the diffuser arrangements. The diffusers may be suspended from the air pipe above the bottom or they may rest on the bottom. In order to raise the diffuser arrangements to the surface of the wastewater for servicing, inflatable buoyant members are affixed to each diffuser arrangement or to the lower ends of the associated downcomers. The inflatable buoyant members are connected through tubing to valves from which air may be supplied under pressure, either from the air supply pipe or form a portable air compressor or a compressed air container or through an air pressure line leading from a remote air supply located on the shore of the basin.

Abstract: In the embodiments of the invention described in the specification, an arrangement for biological treatment of wastewater includes a basin with an aeration region and a clarification region separated by a movable wall having a passage between the bottom of the wall and the bottom of the basin. The aeration region includes a plurality of diffuser arrangements for aerating the wastewater and the clarification region includes a sludge removal duct and at least one turbulence generator for periodically stirring up sludge particles which have been deposited on surfaces of the clarification region remote from the sludge removal duct and recirculating sludge through the wall passage to the aeration region and permitting sludge to resettle on surfaces closer to the sludge removal duct. The movable wall may be positioned to include one or more diffuser arrangements from the aeration region within the clarification region.

Abstract: In the aeration reactor described in the specification, an aeration basin has two aeration cells separated by a dividing curtain and connected in series so as to normally receive wastewater in the first aeration cell and then pass the wastewater to the second aeration cell which is followed by a clarifier to separate sludge from the treated wastewater. A liquid level detector in the reactor responds to surges in the rate of flow of the wastewater through the reactor to redirect incoming wastewater and return sludge from the first aeration cell into the second aeration cell and isolate the first aeration cell to preserve active sludge in that cell.

Abstract: In the aeration panel structure described in the specification, a porous membrane is mounted on a flat plate with peripheral hold-down strips secured at spaced points to the plate and a foam tape having adhesive on both surfaces is interposed between the plate and the membrane and between the membrane and the peripheral hold-down strips to retain the membrane in place and assure a good seal with the support plate. In addition, middle hold-down strips are provided to prevent billowing of the membrane and, at each end, the middle hold-down strips extend above the peripheral hold-down strips to assure air distribution beneath the membrane. Adjustable anchor bolts are provided to mount the aeration panel structure to the bottom of a liquid container.

Abstract: In the representative embodiments of diffusion devices disclosed in the specification, a diffusor support member and a flexible sheet-like diffusor are connected in sealing relation along peripheral edges by continuous clamping and sealing arrangements. One form of the clamping and sealing arrangement comprises a U-shaped clamp which embraces the edge of the support member and the peripheral edge of the diffusor. In another form of clamping and sealing arrangement, two strip members held apart by a third strip are inserted into a groove in the support member so as to clamp the diffusor in the groove. Additional strengthening members for the support member and hold-down members for the diffusor are also disclosed.

Abstract: In the representative liquid removal system described in the specification, a suspension of solid particles in a liquid received, for example, from a gravity separator, is directed to a tank having an upwardly inclined moving screen forming one wall and gas bubbles or gas-saturated liquid are injected into the suspension at the inlet. As a result, the liquid removed through the screen in the lower portion of the tank carries fewer solid particles onto the screen, preventing the screen from becoming blocked and thereby inhibiting liquid removal.