Stage-skip AAO sewage treatment method adopting filter tank

Abstract

The invention discloses a stage-skip AAO sewage treatment method adopting a filter tank. The method comprises an anaerobic zone, an anoxic zone, an aerobic zone, a secondary sedimentation tank and other treatment units of an AAO activated sludge process, and further comprises a filter tank and a backwashing water reservoir. Different from a traditional AAO method, the stage-skip type AAO method makes sewage enters the anoxic zone from the anaerobic zone, pumps the sewage to the aerobic zone with the highest water level by a lift pump, and then makes the sewage sequentially and automatically flow into the secondary sedimentation tank, the filter tank and the backwashing water reservoir; mixed liquid in the aerobic zone flows back to the anoxic zone without a pump, and advanced sludge in the secondary sedimentation tank flows back to the anaerobic zone without a pump through automatic siphoning; and the filter tank adopts automatic siphon backwashing, and backwashing water is automatically discharged into the anaerobic zone or the anoxic zone, so that zero-power and zero-discharge filtration is realized. Compared with a traditional AAO method, an integrated sewage treatment device adopts the pump-free automatic backflow technology, only needs one water pump and one fan; the integrated sewage treatment device can be automatically started and stopped according to actual water inflow, investment is saved, operation cost is low, and the integrated sewage treatment device adapts to the variable water inflow. With a double-filter integrated filter tank adopted, the effluent of a first-stage B can be lifted to a first-stage A in a zero-power and zero-emission manner.

Description

Technical field: [0001] The invention relates to a step-type AAO sewage treatment method with a filter tank, which belongs to the field of water treatment. Background technique: [0002] Anaerobic-anoxic-aerobic activated sludge sewage treatment process refers to the removal of organic pollutants, nitrogen and phosphorus in water through different combinations of anaerobic zone, anoxic zone, aerobic zone and different sludge return methods. and other activated sludge treatment methods, referred to as AAO method (National Environmental Protection Standard HJ-576-2010). There are many variants of the AAO method to meet the needs of different water quality; when nitrogen and phosphorus removal is required at the same time, an anaerobic anoxic aerobic process is required, and it is equipped with mixed liquor reflux and aged sludge reflux. [0003] At present, the AAO method is a very common activated sludge sewage treatment process, and its treatment effect has been generally r...

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Problems solved by technology

[0006] However, these products have the following obvious deficiencies: (1) Generally, only AO process can be achieved, lack of anaerobic zone and sludge return, so it is necessary to add phosphorus removal agent to remove phosphorus; some domestic manufacturers have also developed the use of air to lift return sludge It is indeed a return sludge, but it will bring in a large amount of air at the same time, so that the oxygen content in the anaerobic zone exceeds the relevant specification requirements, and its essence still turns the anaerobic zone into an anoxic zone, still only AO Process, generally need to add phosphorus removal agent and other methods to remove phosphorus

(2) The water flows by itself, and it is difficult to control the automatic start-stop control of the fan according to the sewage flow rate. Therefore, the fan generally needs to work 24*7 days. If the energy consumption cannot be reduced accordingly, the energy consumption per ton of water will increase exponentially, resulting in waste of energy consumption

(3) The efficiency per unit volume of the whole process is low, requiring a large amount of processing by an integrated processor, which instead results in high equipment costs

(4) For household and other small integrated sewage processors, the fan cannot be installed in the integrated equipment, and it needs to be installed on the wall separately, resulting in a large workload for on-site installation and requiring professional personnel, thus limiting the popularization of the product

(5) The effluent standards of the two processors are not too high, and it is best to only reach the first-class B effluent standard

(1) Higher effluent standards require simultaneous denitrification and phosphorus removal, and the discharge level A is even higher; (2) Low operating costs are required. Although MBR biofilms can achieve good effluent standards, the operating costs increase on average 1 yuan / ton, the rural market is unacceptable; (3) A large number of household and micro-scale domestic sewage processors are required, such as farmhouses, small restaurants, scattered residents in rural areas, especially in mountainous areas, small natural villages, etc., not only require these households to be integrated low investment, low operating cost, reliable operation, and easy installation and maintenance

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