Abstract: Apparatus and method are provided for separating grit from liquid sewage while retaining organic solids in suspension. A sustained rotational liquid sewage first fluid flow, an induced upward liquid sewage second fluid flow, and a sustained rotational liquid sewage third fluid flow are employed in an apparatus having a cylindrical grit settling main chamber, a grit storage secondary chamber including a central grit settling access top mouth opening, a vertical shaft, a means for causing rotation of the vertical shaft, and a partition extending transversely through the main chamber and forming upper and lower subchambers. A fluid flow speed gradient is established between the liquid sewage third fluid flow and the liquid sewage first fluid flow. In this manner, grit is separated from liquid sewage.

Abstract: An avalanche photodiode (APD) has a first semiconductor substrate having a first doping type. A first semiconductor layer is on top of the first semiconductor substrate. The first semiconductor layer is doped with the first doping type. A second epitaxial layer is on top of the first semiconductor layer. The second epitaxial layer is in-situ doped with the first doping type at a concentration higher than a concentration of the first doping type in the first semiconductor layer. A third epitaxial layer is on top of the second epitaxial layer. The third epitaxial layer is in-situ doped with a second doping type. The doping of the third epitaxial region forms a first p-n junction with the doping of the second epitaxial layer, wherein a carrier multiplication region includes the first p-n junction, and wherein the third epitaxial layer forms an absorption region for photons. A first implanted region is within the third epitaxial layer. The implanted region is doped with the second doping type.

Abstract: Apparatus for separating grit from liquid sewage while retaining organic solids in suspension. The apparatus includes a grit settling chamber, a grit storage chamber positioned below the settling chamber, and a rotating vertical shaft positioned centrally in the settling chamber. A propeller is rotatably mounted around the shaft. A conical partition extends transversely through an intermediate section of the settling chamber. Liquid sewage engages the lower part of settling chamber beneath the conical partition, and liquid separated from grit escapes from the upper part of settling-chamber above conical partition. The partition has a peripheral edge integrally mounted in fluid tight fashion to the peripheral wall of the settling chamber, and defines a central annular opening between the shaft and the partition to provide for upward flow of liquid from the lower subchamber to the upper subchamber.

Abstract: A rake, in which its tines are inserted and moved between the parallel, uniformly spaced, bars of a grating for debris removal. The rake includes a base and plurality of equally spaced parallel tines forming blades integrally moulded with the base out of a thermoplastic with memory characteristics. The thickness of each blade is about 1/16 its width, each blade is easily flexible thicknesswise, that is in a direction transverse to the grating bars but has practically no flexibility in the direction of the grating bars. The distance between the grating bars is two to four times the rake tines thickness so that at least two rake tines can be inserted between two adjacent grating bars.