Simultaneous phosphorus and nitrogen removal method for micro-polluted water

Abstract

The invention discloses a simultaneous phosphorus and nitrogen removal method for micro-polluted water. The method comprises the following steps: step 1, allowing raw water to enter a mixing zone at the bottom of a reactor; step 2, allowing the mixed solution to enter a lifting zone isolation hood under drive of an impeller of a mechanical lifting device; step 3, allowing the mixed solution to enter a mud layer reaction zone between a sleeve and an inner wall of the reactor after the mixed solution enters the lower part of the reactor, wherein diatomite is arranged in the mud layer reaction zone; step 4, allowing mud pie collected in the mud layer reaction zone to enter the mixing zone under the action of gravity along with a guide plate at the bottom of the reactor; step 5, performing intermittent reflux recoil by virtue of a recoil pipeline arranged at the bottom of the mixing zone. According to the process, the problem that phosphorus and nitrogen in the micro-polluted water exceed the standard is effectively solved, water eutrophication caused by standard exceeding of phosphorus and nitrogen can be prevented by virtue of phosphorus and nitrogen removal, and the method is suitable for deep phosphorus and nitrogen removal in rivers, lakes and other landscape water bodies.

Description

technical field [0001] The invention relates to a method for treating slightly polluted water, in particular to a treatment method for synchronous denitrification and phosphorus removal of slightly polluted water. Background technique [0002] Slightly polluted water is mainly for natural water bodies, canals, and reservoir waters. Often due to pollution, the water body itself cannot meet the corresponding functional requirements. The main problem is that nitrogen and phosphorus exceed the standard. Due to the accumulation of nitrogen and phosphorus nutrients, the algae proliferate abnormally. When the temperature is high, it is easy to produce "algae bloom", the transparency of the water body decreases, the dissolved oxygen decreases, and the water quality deteriorates seriously. [0003] The main characteristic pollutants of micro-polluted water are total nitrogen, nitrate nitrogen and total phosphorus. Between mg / l. [0004] The emergence of slightly polluted water is d...

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Problems solved by technology

[0006] The existing large-scale water purification process mainly focuses on drinking water source water treatment process and sewage treatment process. The drinking water source water treatment process is mainly based on activated carbon adsorption, coagulation filtration, and membrane filtration. For micro-polluted water treatment, because the water quality of micro-polluted water is lower than the water quality requirements (total nitrogen is not more than 1.0mg / l, total phosphorus is not more than 0.2mg / l, and total phosphorus in lakes and reservoirs is not more than 0.05mg / l), The biggest problem is that the investment in equipment is large and the treatment cost is too high; while the existing sewage treatment process takes A 2 O. Biological aerated filter is the main method, and it is difficult to achieve a higher degree of removal of nitrogen and phosphorus

[0007] Applied on August 22, 2001, the application number is 01249195.0, and the utility model name is "Diatomite Dynamic Membrane Ultrafiltration Machine", which discloses a diatomite for beverage, wine making, swimming pool circulating water, and oil field sewage treatment Dynamic membrane ultrafiltration machine, this technology injects diatomite into the filter press, and uses the mechanical strength of diatomite to form a diatomite layer on the filter membrane through pressure, thereby improving the effect of press filtration. It is a fixed filter It has a certain effect in removing oil and suspended solids, but it does not have the effect of nitrogen and phosphorus removal in water treatment

[0008] Applied on May 5, 2002, the application number is 02234404.7, the name of the utility model is "high-efficiency mud-water separation and filtration integrated sewage treatment device", which discloses a reactor structure, and the patent proposes to use diatomaceous earth as a water treatment device The reactor is used to remove pollutants in water and finally separate mud and water. This technology has too short a journey from water inlet to final water outlet. A large amount of diatomite needs to be discharged and cannot be circulated in the reactor. The amount of sludge discharged is large and the moisture content is high. The subsequent dehydration of diatomite requires high energy consumption. It is far from being able to meet the use requirements only by drying. At the same time, the pollutants adsorbed on diatomite cannot be removed by drying, so the regeneration of diatomite also increases the difficulty of putting this type of reactor into production.

A large amount of chemical sludge will be produced at the same time as phosphorus removal, which has no obvious advantages compared with the traditional chemical phosphorus removal process; this technology uses diatomaceous earth, polyacrylamide, aluminum salt as sewage treatment agent or enhanced coagulation mechanism removal Impurities in water. In addition, the type of pollutants to be removed is not clearly mentioned in this process. It can be considered as a pretreatment for the subsequent oxidation process. There is no clear purpose of pollutant removal, but the result of enhanced coagulation will cause diatoms A large amount of chemical sludge in the soil is deposited, so this process will increase the treatment cost of sewage and chemical sludge; the third process is to use oxidants to convert ammonia nitrogen into nitrate nitrogen or nitrite nitrogen, which does not effectively remove nitrogen from water , the strong oxidant added at the same time may also bring disinfection by-products such as salts and halogenated hydrocarbons into the water

To sum up, this technology uses physical and chemical methods to remove and transform some pollutants in water, the addition of water treatment chemicals, and the treatment of chemical sludge are all more expensive than traditional biological treatment processes, and nitrogen Elements are only transformed, not effectively removed from the water

[0010] Applied on March 29, 2004, the application number is 200410023855.2, and the title of the invention is "a method and special equipment for treating dyeing and finishing wastewater with diatomite and activated carbon". The treatment method of the whole wastewater. The patent adds diatomaceous earth and decolorizer to the mechanically accelerated clarifier, which solves the technical problem of chroma removal in the dyeing and finishing wastewater, but does not involve the problem of denitrification and phosphorus removal of sewage

Shell consumption powder, diatomaceous earth or modified clay are all powdery substances, which are easy to lose with the movement of water flow. This technology has no way to effectively separate solid-liquid in the reactor, and there is no internal circulation system in the reactor. There will be problems of filler loss and affecting the quality of effluent water. Without effective mud-water separation measures, it will not be put into use

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