초록 ▼

A method and apparatus for treating waste material to remove selected components form the waste is described using a reactor or a series of reactors in fluid communication with each other for receiving the waste to be treated as influent. The influent forms a biomass including the waste and microorg

A method and apparatus for treating waste material to remove selected components form the waste is described using a reactor or a series of reactors in fluid communication with each other for receiving the waste to be treated as influent. The influent forms a biomass including the waste and microorganisms and is treated by controlling the metabolic activity of the microorganisms by monitoring the oxygen utilisation rate or the potential oxygen utilisation rate of the biomass so as to determine the required amount of oxygen to be supplied to the biomass and to determine the period of aeration of the biomass in order to maintain a predetermined oxygen utilisation rate or value so as to remove the selected components of the waste. The preferred selected components to be removed are nitrogenous, carbonaceous and/or biological phosphorus containing materials or derivatives.

대표청구항 ▼

[ I claim:] [1.] A method of treating waste material forming at least a part of a biomass comprising a single activated sludge in a variable depth bioreactor using controlled intermittent and successive aeration sequencing and liquid decantation to concurrently grow and maintain a culture of autotro

[ I claim:] [1.] A method of treating waste material forming at least a part of a biomass comprising a single activated sludge in a variable depth bioreactor using controlled intermittent and successive aeration sequencing and liquid decantation to concurrently grow and maintain a culture of autotrophic, heterotrophic and facultative micro-organisms in the sequentially aerated single activated sludge for the biological removal of the organic carbon, nitrogen and phosphorus components from wastewater admitted to the bioreactor, said biomass being located in a variable depth operated reactor having at least two interconnected zones in series connection in which one of the zones is a first reaction zone and the other zone in a second or last zone, wherein at least a part of the treated contents of the second zone of the reactor is recycled to a partially segregated non-aerated volume of the first reactor zone for admixture with incoming influent waste, at least during an aeration sequence of operation of the second or last of the variable depth operated reactor, wherein the method comprises using one dissolved oxygen concentration sensor or probe means for automatically and continuously monitoring dissolved oxygen concentration in the biomass in the second or last zone of the variable depth reactor, said sensor or probe means being located in the biomass at a location such that at least that part of the biomass in that location is in motion during the time of automatically and continuously measuring the dissolved oxygen concentration, whereby the single sensor or probe means is used to cause operation of an oxygen input means during input into and aeration of the wastewater in the second or last zone, in combination with computer means to operate algorithms in order to operate to a set protocol of successively increasing dissolved oxygen concentration from zero to about 2.5 Mg/L in discrete predetermined adjustable time increments to optimize the retention of adsorbed organic substance within the biomass while maintaining co-current and optimal nitrification and denitrification during aerated operation, with phosphorus release during non-aeration and phosphorus uptake during adjacent and reactive influent aeration sequences, with the detection and automatic calculation of the oxygen utilization rate of that biomass in the second or last variable volume zone which adjusts the length of each aeration sequence exposure of the biomass, said determination and adjustments being characterized by the biomass in the second or last zone of the reactor having a potential oxygen uptake rate, measured using an aerated admixture of 80%/20% single sludge biosolids/influent mixture, being in excess of about three times the measured uptake rate of the single sludge biosolids as measured by the single dissolved oxygen sensor, such that combined with the preset oxygen transfer rate and the potential oxygen uptake causes a limitation to the nitrogen oxidation product to essentially nitrite nitrogen form, and to cause by aerated mixing in the second or last variable volume zone a concurrent reduction reaction of the nitrite nitrogen to essentially nitrogen gas, in such a way that at the end of the aeration sequence, the biomass oxygen utilization rate is automatically controlled to an operating set point, adjunctively with the introduction of air into one or more partially segregated volumes within the first zone of the reactor to partially limit the release of phosphate in the biological phosphorus removal mechanism, such that the first zone of the biological reactor can be continuously and automatically controlled to limit oxic, anoxic and anaerobic successive reaction environments in the first zone of the variable depth biological reactor. [31.] An apparatus for biologically removing carbon, nitrogen and phosphorus from wastewater, in the form of a partially enclosed water-retaining, multi-zone, variable-depth, cyclically-aerated reactor comprising at least a first hydraulic zone and a last hydraulic zone separated by a partial wall structure allowing fluid communication and transfer between the zones at least during a part of an air-on sequence, an aerator for selectively exposing the contents of the reactor to repeated air-on and air-off sequences, said first hydraulic zone provided with an inlet for introducing influent wastewater to the first zone during at least the air-on sequence, said last hydraulic zone for allowing separation of the wastewater into at least supernatant clear liquor, an aerator including a grid air bubble generation system for providing combined mixing and oxygen transfer in at least the last hydraulic zone mounted on the floor of the reactor and a means for directing a flow of process air to the reactor for in-reactor oxygen transfer at least two different mass flow rates during the air-on sequence, means for interrupting the flow of influent wastewater to the first hydraulic zone at least during a part of the air-off sequence, means for removing liquid contents from the last hydraulic zone to a position remote from the reactor during at least the air-off sequence, means for transferring the contents from the last hydraulic zone to the first inlet hydraulic zone at least during the air-on sequence, means for interrupting influent wastewater flow and the flow of process air to the reactor during at least a part of the air-off sequence, means for reducing the amount of supernatant clear liquid retained in the last hydraulic zone during the air-off sequence to a preselected lower level using a motor-driven decanter comprising a horizontal weir box, fitted with a positive floating solids excluding scum guard, connected by at least one downcomer member to a rotating drum shaft provided with liquid retaining seals and airlock release pipes, means for automatically maintaining an optimum mixture of process acclimated heterotrophic, autotrophic and facultative micro-organisms and wastewater through the continuous measurement of the rate of change of dissolved oxygen concentration in the reactor together with measurement of the potential oxygen utilization rate of the biomass, said rate change of dissolved oxygen being measured by a single dissolved oxygen sensor located in the biomass, such that at least part of the biomass is in motion at the time the measurement is taken in order to provide an indication of the utilization rate as a function of time, a means for analyzing successive rates of change of oxygen concentration taken at the end of each air-on sequence in the last hydraulic zone, a means for continuously measuring the rate of change of dissolved oxygen concentration at the beginning of each air-on sequence, means for adjusting set point operating positions of the rate of change of dissolved oxygen in the last hydraulic zone of the reactor taking into account process air flow rate, air-on time adjustment and mixed heterotrophic, autotrophic and facultative micro-organism culture, means for adjusting and operating with at least four set point positions for the dissolved oxygen concentration as a function of time profile in each air-on cycle in the last hydraulic zone in order to achieve an indication of the termination of the air-on sequence set point dissolved oxygen concentration rate of use, means for automatically adjusting theoperating time duration of each total cycle and successive cycle, means for operating with and determining the duration of air-off sequence time in successive cycle times in the last hydraulic zone, means for operating with and determining the time-based flow rate of process air introduced to the reactor, and means for determining and executing the time of operation within each cycle for the removal of a predetermined volume of a mixture of biomass and wastewater in successive air-off sequences from the reactor.