Abstract: In an activated sludge process for treating wastewater, waste activated sludge is directed to a digester and subjected to sequential aerobic, anoxic and anaerobic treatment. Internal recycling of sludge may be carried out. The oxidation reduction potential during the anoxic and anaerobic cycles is carefully managed so that there is a significant reduction in the quantity of sludge that must be disposed of.

Abstract: A system and method for processing heat-developed or chemically-developed photographic film. The heat-developed film is transported through a pair of driven heated rollers that are of different durometer that eliminate the curl in the film. The driven heated rollers preheat the film and transport it into a hot air chamber where the film is further heated to development temperature in an expansion free environment. The temperature of the preheat rollers and the hot air chamber are maintained within a predetermined set point range and the speed with which the film travels from the preheat rollers through the hot air chamber is progressively decreased with increasing length of the film being processed through the system. A similar method and system for controlling chemical activating agents concentration and speed of the photographic film being developed therethrough is also disclosed.

Abstract: A combined oxidation orbital ditch and intraclarifier has the intraclarifier in the form of an elongated clarifier vessel positioned on the top of a section of the center partition between the ditch sidewalls so that the overall clarifier vessel extends laterally into both of a pair of flow channels formed between the ditch sidewalls and the center partition but is spaced from the ditch sidewalls so as to minimize impediment of the mixed liquor flow being treated in the channels. A gated inlet below the flow surface is provided in the one half of the bow of the vessel facing into the mixed liquor flow for diverting a portion of the flow into the clarifier. That flow portion is distributed over the entire width of the vessel and arrested in flow velocity so that settling of sludge can be performed downstream in the vessel.

Abstract: An improved wastewater aeration and mixed liquor pumping arrangement for an orbital-type actuated sludge purification method includes the addition of a radial flow impeller on a shaft extension below the normal surface aerator. Both the combined radial flow impeller and surface aerator are positioned with respect to an end of a partition wall forming the flow channels of the orbital system such that both the impeller and the aerator pump the mixed liquor in the same direction, so that the mixed liquor is moved at a sufficient velocity through and around the various channels and returned. The radial flow impeller is positioned adjacent to the bottom of the orbital channel and enhances the propulsion of the mixed liquor along the bottom of the channel thus permitting deeper channels with attendant concrete and land area savings in constructing the system.

Abstract: There is provided a system for treating wastewater having a tank and a partition mounted in the tank to define an endless circuitous channel. An aerator and impeller is mounted in the tank to cause the liquid to flow through the channel. A clarifier is disposed in the channel and has a liquid outlet in its upper portion.