Abstract: A hollow, polymeric sludge collector flight is provided having a sigma-shaped cross-section, including a wedge-shaped transverse indentation on its forward face, a vertically extending wear lip on its scraping edge, and a transverse gap on its rear face. The gap allows free circulation of liquid within the non-buoyant flight. The indentation structurally stiffens the mid-span section of the flight. Where additional stiffness is required, filler blocks may be placed between mounting blocks.

Abstract: A side channel clarifier for use in wastewater treatment devices employing the circulation of water in a tank having a circuitous path for the purposes of aeration and biological digestion of wastes, wherein the clarifier is mounted in the wall of the channel so that the main flow of water in the tank is undisturbed, and that a portion of that flow is diverted into as quiescent clarification zone, where an inclined baffle collects settled sludge and returns that sludge to the main flow for further decomposition. Siphoning means are provided to ensure the return of a substantial portion of the sludge to the main flow before stagnation occurs and without disrupting the inflow of wastewater into said clarifier. Means are also provided to separate the clarified effluent for further treatment.

Abstract: A polymeric split sprocket wheel is provided having two mating portions that, when joined, form a split line at the junction of those portions, two side faces, a toothed outer rim and a central axial bore, and which is designed to be mounted on a relatively immobile yet rotatable keyed shaft, being secured thereon by means of a tripartite apparatus comprised of a captive slotted keyway molded into the central axial bore of the wheel, a circular band clamp capable of exerting a uniform degree of force all around the axial hub, and a plurality of wedge dog assemblies which join the wheel together along the split line by means of a plurality of wedge dog clamps which straddle the split line, are inserted into tapered receptacles, and are fixed to the wheel by fastening means.

Abstract: An apparatus for use in an activated sludge process for treating wastewater wherein raw sewage or the like is mixed with activated sludge and the resulting mixture is circulated in a confined aerated tank (usually in the form of additional subsurface aeration) so that the mixture follows a predetermined vertical flow cycle through a plurality of flow passageways created by gas impermeable baffle means in order to optimally increase the retention time of aerating air in the tank. The retention time of the air is increased by means of at least one secondary horizontal baffle means specifically designed to collect large bubbles of air trapped beneath said gas-impermeable baffle means and to be permeable to gases, so as to provide additional air/liquid surface area to escaping air. The secondary baffle is situated adjacently above and substantially parallel to the gas impermeable flow directing baffle means.

Abstract: A microscreen support wheel and assembly is provided comprising a polymeric support wheel having a crowned tread surface, an annular stress relief groove cut into each of its vertically flat, substantially parallel side faces and an axial bore designed to rotate around an axis included in a support wheel assembly constructed and arranged to hold a pair of microscreen support wheels in a laterally adjacent relationship on a rigid microscreen frame at an angle whereby optimum drum support is achieved.

Abstract: An industrial waste anaerobic digestion process takes place in a digester having separate sections within the digester, in which the acid forming and gas forming phases of the digestion process can occur separately under conditions optimized for each phase. A rotating biological contactor is provided in each section for increasing the liquid/gas interface to facilitate the anaerobic reaction. A series of partitions is provided in each section to create zones in which the waste concentration is extremely high and on which the biota can react at maximal reaction rates. The CO.sub.2 produced in the acid forming phase is used in both acid and gas forming sections to mix and achieve pH adjustment, and the methane can be used in the gas forming sections for mixing. A thermophilic chamber in the center of the tank is surrounded by the mesophyllic chamber to minimize and utilize conductive heat loss.

Abstract: A belt press for use in removing water from sewage sludge, and including a frame, a pair of belts for compressing sludge material therebetween, the said belts being water-permeable whereby water in said sludge may drain through said belts, and a gravity belt thickener adjacent the belt press. The gravity belt thickener includes a belt having a belt flight adapted to support sewage sludge thereon, the belt of the gravity belt thickener having a width greater than the width of the belt of the belt press.

Abstract: A basket frame for a traveling water screen includes a pair of hollow parallel lip beams connected together by end plates which are secured to the lip beams by plugs fixed to the ends of the hollow lip beams. The hollow cores of the lip beams are sealed against ingress of water so that the basket frame is buoyant in water. The lip beams are formed of pultruded fiberglass with cross sectional shapes which are provided with complementary curved surfaces so that the adjacent lip beams on adjacent baskets provide a close fitting seal on the vertical run of the basket train and also on the curved section at the bottom of the basket train where the baskets make the turn around the traction wheel.

Abstract: An industrial waste anaerobic digester is disclosed having separate sections therein, in which the acid forming and gas forming phases of the digestion process can occur separately under conditions optimized for each phase. A rotating biological contactor is provided in each section for increasing the liquid/gas interface to facilitate the anaerobic reaction. A series of partitions is provided in each section to create zones in which the waste concentration is extremely high and on which the biota can react at maximal reaction rates. The CO.sub.2 produced in the acid forming phase is used in both acid and gas forming sections to mix and achieve pH adjustment, and the methane can be used in the gas forming sections for mixing. A thermophilic chamber in the center of the tank is surrounded by the mesophyllic chamber to minimize and utilize conductive heat loss.

Abstract: A method and apparatus for increasing the capacity of an activated sludge wastewater treatment plant which utilizes microscreens in conjunction with rotating biological contactors that are placed in the primary settling tank, the aeration tank and the final clarification tank. A rotatable microscreen is placed upstream of the primary settling tank and downstream of the final clarification tank. The result is a more efficient and less energy consuming system which reduces the organic loads. Preferably, the microscreening preceding the biological treatment stage will have a mesh size in the range of about 50-200 mesh and the microscreen placed after the biological treatment stage will have a mesh size in the range of 6-44 microns. Additional benefits are obtained in recycling the treated water which is passed through the rotating biological contactor as well as utilizing it to aid in rotating the contactor.

Abstract: A final clarifier for a sewage treatment plant has a peripheral feed influent channel with lower distribution ports and is also provided with tubes to minimize the headloss in the clarifier. The minimum headloss tubes are set to allow the basin to operate at more than one limiting headloss set point. By increasing the available orifice area at a certain flow rate, a maximum or peak headloss limitation can be achieved without compromising the design (average) headloss.

Abstract: A rotating biological contactor is formed about a polygonal shaft. The contactor includes a hub formed of a series of hub rings disposed side by side along the length of the shaft with each hub ring formed of hub segments which are joined end to end. In one embodiment the hub segments are identical and there is one hub segment for each corner of the polygonal shaft. In a second embodiment there is one hub segment for each two corners. The hub segments also include a mounting portion which has welded to it alternating flat and formed thin walled sectors of contactor media. The sectors are joined to each by welding and successive layers of the sectors are angularly offset from each other so that some of the sectors span the joints between adjacent hub segments of a hub ring.

Abstract: A clamp strip is bolted to a frame member which may be one side or rail of the basket of a travelling water screen. The strip clamps a margin of the screening to the frame. The strip is of a durable non-metallic material of a high modulus of elasticity and of a general rectangular section. The strip initially is of an arcuate form so that the deformation effected by bolting exerts a force against an extended area of the screening to hold the latter securely. Each strip of one form is secured by a single central bolt. Each strip of another form is secured by two or more bolts including a bolt at each end of the strip.

Abstract: Each face of the disc for sewage aeration includes a multiplicity of recesses. The recesses of one face have no communication with those of the other face and are precisely dimensioned so that the sewage, which is essentially water, flows into and out of each recess without leaving an accumulation of deposits in the recess. This is accomplished with no reduction of and possibly an increase in the aeration efficiency of the disc.

Abstract: The chain-carried pawls which are to shift the plates on the rails of a filter press in successive order are provided with roller weights which ride on upper and lower tracks and provide the improved shifting of the plates and support of the lower runs of the chains.

Abstract: A hinged doctor blade is biased to its operative position respecting the belt of a belt conveyor. Shoes at each end of the blade ride on the belt ahead of the blade respecting belt travel and are positioned and connected to the blade so that the forward clips of the belt joint lifts the blade upon the first approach of either end of the joint and the other end is effective to hold the doctor blade in its raised position until the forward portion of the seam is beneath the blade and the blade can safely ride over the seam and then resume its operative position respecting the filter belt. Adjustment means are provided so that the positions of the shoes relative to the doctor blade may be set as required by the length of the seam having reference to the direction of belt travel.

Abstract: The open inlet end of a microscreen drum is defined by a circular track which is supported on rollers above the flow. The stationary wall supporting the rollers carries a flange-type flexible seal extending in a partial circle around the opening in the wall. The track carries a fully circular flange and a low-friction, slit tubing covers its axially projecting edge and is engaged by the flexible seal.

Abstract: A process for removing colloidal and soluble contaminants from impure water moving through a hollow, cylindrical microscreen under a positive head pressure, comprising dispersing insoluble, finely divided particulate matter into the impure water and rotating the microscreen at a rate that will form, during each rotation thereof, an intermixed layer of contaminants and particulate matter over substantially the entire inner surface of the microscreen through which the impure water is passing. The intermixed layer forms a filter substantially impermeable to contaminants and particulate matter of a size that could pass through the microscreen pores, but it is not impermeable to water. Preferably, the finely divided particulate matter can be a sorbent material, e.g. powdered activated carbon, so that contaminants are both filtered and sorbed from the water.

Abstract: A peripheral feed sewage treatment final clarifier having a channel with lower distribution ports is provided with a vertically adjustable riser which is placed in the port where the scum tends to collect in the channel. The riser is set vertically so that diurnal variations in the elevation of the flow in the channel raises and lowers the collected scum past the upper lip of the riser at which times the scum is removed.

Abstract: The specification discloses an improvement in rotary drum screens for the filtration of liquids which comprise (a) a drum having a central horizontal axis and a radially outer surface, (b) a plurality of microscreen grids mounted on the radially outer surface of the drum, each of the microscreen grids comprising a screen which is divided into a large number of small cells by walls which extend radially with respect to the drum, (c) means for introducing the liquid to be filtered into the interior of the drum, (d) means for rotating the drum about its central axis, (e) a backwash header mounted outside the radially outer surface of the drum, and (f) a backwash receiving trough mounted within the drum for collecting filtrate accumulated on the screen. The liquid to be filtered is introduced into the drum at one end thereof, and the drum is supported so that it is partially submerged in the filtered liquid.