A compound device for nitrogen and phosphorus removal and method for removing nitrogen and phosphorus

Abstract

The invention discloses a denitrifying and dephosphorizing composite device and a denitrifying and dephosphorizing method thereof. The denitrifying and dephosphorizing composite device comprises a coagulating settling tank, a flow regulating tank, an anaerobic tank, an anoxic tank, a sequencing batch reaction tank, treated water tanks and nitrified solution transferring tanks, wherein the anaerobic tank is arranged inside the anoxic tank; the anoxic tank is arranged inside the sequencing batch reaction tank; the two ends of the anaerobic tank are open; the bottom end of the anaerobic tank is communicated with the lower part of the anoxic tank; the top end of the anoxic tank is open, and is communicated with the sequencing batch reaction tank through a sewage overflowing zone; and the nitrified solution transferring tanks are arranged at the upper part of the sequencing batch reaction tank. The denitrifying and dephosphorizing composite device is unique in design and small in occupied area; an anaerobic zone, an anoxic zone and an aerobic zone are communicated with one another, and water inletting, stirring and aeration are performed at regular intervals; during water inletting, a whole system switches among anaerobic treatment, anoxic treatment and aerobic treatment, and when water inletting stops, the anaerobic zone, the anoxic zone and the aerobic zone perform own microbial reactions, without mutual interference, so that forward dephosphorization and reverse denitrification of wastewater are performed circularly and steadily; therefore, the denitrifying and dephosphorizing composite device is low in running cost, and is suitable for popularization.

Description

technical field [0001] The invention belongs to the technical field of water treatment, and specifically relates to a nitrogen and phosphorus removal compound device and a method for removing nitrogen and phosphorus. Background technique [0002] The severe pollution and scarcity of water resources is a major international problem that plagues the world economy and human survival, especially the eutrophication caused by the discharge of a large amount of untreated or improperly treated sewage containing nitrogen and phosphorus. To an extremely serious point, many lake water bodies can no longer play their normal functions and seriously affect the industrial, agricultural and fishery production. [0003] Controlling the nitrogen and phosphorus content in water bodies is an important factor in inhibiting eutrophication of water bodies. The continuous improvement of the requirements for nitrogen and phosphorus removal in sewage treatment has made the sewage treatment process an...

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Problems solved by technology

However, this process also has certain defects: the anaerobic and aerobic reaction tank occupies a large area, the sludge return flow is large, and the energy consumption is high; the nitrogen and phosphorus removal and COD removal through the nitrification-denitrification process make the entire process flow A large proportion of sludge return and large air volume aeration are required to ensure the sludge concentration and oxygen supply, which increases the energy consumption in the process; the process is long and the control conditions are complicated; the system returns a large amount of sludge, which will bring back a large amount of Nitrate to the anaerobic pond, and the conditions for phosphorus accumulating bacteria to release phosphorus are anaerobic and soluble BOD at the same time. When a large amount of nitrate exists, denitrifying bacteria will use organic matter as a carbon source for denitrification, and so on. The anaerobic release of phosphorus can only start after the nitrogen is complete, which greatly reduces the effective volume of the anaerobic release of phosphorus in the anaerobic stage, reducing the effect of phosphorus removal, and the effect of nitrogen removal is better in comparison; If the nitrification in the oxygen section is poor, the amount of nitrate entering the anaerobic section with the return sludge will decrease, so that phosphorus can be fully released anaerobically and increase its phosphorus removal effect. Nitrogen is not effective

[0004] In short, in the current biological nitrogen and phosphorus removal process, the sludge is composed of nitrifying bacteria, denitrifying bacteria and phosphorus accumulating bacteria, and circulates between anaerobic, anoxic and aerobic stages. The growth environment is different, so there are often contradictions between biological denitrification and biological phosphorus removal, such as the distribution ratio of sludge volume in anaerobic and anoxic sections is different, the competition for carbon sources, and the length of sludge age are different. In the actual sewage treatment process It is easy to appear in the situation that it is difficult to achieve the best effect at the same time for denitrification and phosphorus removal

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