One article understands the 6 mainstream domestic wastewater treatment processes in Inner Mongolia ~ According to incomplete statistics, the number of sewage treatment plants that have been completed and operated nationwide is about 4,000, of which there are about 30 sewage treatment processes with statistical data. This article focuses on the summary. 6 domestic mainstream wastewater treatment processes! The oxidation ditch process covers the whole country. As a mature activated sludge wastewater treatment process, the oxidation ditch process has been widely used throughout the country. It is a variant of the activated sludge process. Its aeration tank is a closed trench type. Therefore, it is different from the traditional activated sludge method in the hydraulic flow state, but is a circulating flow aeration ditch connected end to end, and the sewage infiltrates and is purified.
2. Process characteristics (1) Simplified the pre-treatment oxidation ditch hydraulic retention time and sludge age ratio compared with general biological treatment plants, suspended organic matter can be removed more thoroughly and dissolved organic matter at the same time, the remaining sludge discharged has been highly stable Therefore, the oxidation ditch may not be provided with an initial sink, and the sludge does not need to be anaerobic digested.
2) Less floor space Because the primary sedimentation tank, sludge digestion tank is omitted in the process, and the secondary sedimentation tank and sludge return device are sometimes omitted, the total area of the sewage plant is not increased, but can be reduced on the contrary. .
(3) The characteristics of the push flow type oxidation ditch have push flow characteristics, so that the concentration of dissolved oxygen forms a concentration gradient along the length of the tank, and forms aerobic, anoxic and anaerobic conditions. Through reasonable design and control of the system, better nitrogen and phosphorus removal effects can be achieved.
(4) Simplified process The oxidation ditch and the secondary sink are integrated into an integrated oxidation ditch, and the alternate working oxidation ditch developed in recent years can eliminate the secondary sink, thereby simplifying the processing flow.
The A2 / O process focuses on dephosphorization and nitrogen removal. 1. Introduction A2 / O process is the English abbreviation of Anaerobic-Anoxic-Oxic, which is the abbreviation of anaerobic-anoxic-aerobic biological nitrogen and phosphorus removal process. The efficiency of this process can generally reach: BOD5 and SS are 90% to 95%, total nitrogen is more than 70%, and phosphorus is about 90%. Inner Mongolia wastewater treatment is generally suitable for large and medium-sized urban sewage plants that require nitrogen and phosphorus removal.
However, the capital cost and operating cost of the A2 / O process are higher than the ordinary activated sludge method, and the operation and management requirements are high. Therefore, for the current national conditions in China, when the treated sewage is discharged into closed water or slow-flowing water, it causes eutrophication. This process is only used when it affects the water supply source. 2. Process characteristics (1) Advantages: high pollutant removal efficiency, stable operation, and good impact load resistance. The sludge sedimentation performance is good. The three different environmental conditions of anaerobic, anoxic, and aerobic, and the organic combination of different types of microbial flora, can simultaneously have the functions of removing organic matter, removing nitrogen and phosphorus. The nitrogen removal effect is affected by the reflux ratio of the mixed solution, and the phosphorus removal effect is affected by the entrained DO and nitrate oxygen in the reflux sludge, so the nitrogen removal efficiency cannot be very high. In the process of simultaneous deoxidation and phosphorus removal of organic matter, the process is the simplest, and the total hydraulic retention time is also less than other similar processes. Under the anaerobic-hypoxic-aerobic alternating operation, filamentous bacteria will not multiply, SVI is generally less than 100, and sludge swelling does not occur. The phosphorus content in the sludge is high, generally above 2.5%.
(2) Disadvantage: The volume of the reaction tank is larger than that of the A / O denitrification process. The sludge internal flow is large and the energy consumption is high. It is expensive for small and medium-sized sewage plants. The economic benefits of biogas recycling are poor. The sludge exudate needs chemical dephosphorization. Traditional activated sludge process used in large sewage treatment plants
1. Introduction: Activated sludge process is one of the most widely used aerobic biochemical treatment technology for wastewater. It mainly consists of aeration tank, secondary sedimentation tank, aeration system and sludge return system.
2. Process characteristics (1) Advantages: Relatively mature process, accumulated accumulated operating experience, and stable operation; Inner Mongolia wastewater treatment organic matter removal efficiency is high, the removal rate of BOD5 is usually 90% to 95%; the aeration tank has a low impact load capacity ; It is suitable for large-scale urban sewage treatment plants that treat the influent water with relatively stable water quality and high treatment requirements. (2) Disadvantages: large aerobic and aerobic spears, insufficient oxygen supply at the head of the tank, and oxygen supply at the end of the tank is greater than aerobic, resulting in waste; the traditional activated sludge method aeration tank stays longer and the aeration tank has a large Large area, high infrastructure costs, large power consumption; Inner Mongolia wastewater treatment efficiency of deoxidation and phosphorus removal is low, usually only 10% to 30%.
SBR process is suitable for intermittent emissions
1. Introduction The treatment process is mainly completed by several purification processes including initial removal and adsorption, microbial metabolism, floc formation and flocculation and sedimentation performance.
The core of the SBR technology is the SBR reaction tank, which integrates functions such as homogenization, primary sedimentation, biodegradation, and secondary sedimentation in a single pond, and has no sludge return system. It is especially suitable for occasions with intermittent emissions and large changes in flow.
2. Process characteristics (1) Advantages: The ideal push flow process increases the driving force of the biochemical reaction and improves the efficiency. The anaerobic and aerobic conditions in the tank are in an alternating state, and the purification effect is good. The running effect is stable, the sewage is settled in the ideal static state, it needs short time, high efficiency and good effluent water quality. Resistant to impact loads. There is treated water left in the pond, which has a dilution and buffering effect on the sewage, and effectively resists the impact of water and organic pollutants. Each step in the process can be adjusted according to water quality and water volume, and the operation is flexible. Fewer processing equipment, simple structure, easy operation and maintenance management.
There are DO and BOD5 concentration gradients in the reaction tank, which can effectively control the expansion of activated sludge. The process is simple and the cost is low. The main equipment has only one batch-type batch reactor. There is no secondary sedimentation tank and sludge return system. The adjustment tank and primary sedimentation tank can also be omitted. The layout is compact and the floor space is saved. (2) Disadvantages: intermittent cycle operation, high requirements for automatic control. Variable water level operation increases power consumption. The nitrogen and phosphorus removal efficiency is not very high. Sludge stability is not as good as anaerobic nitrification.
A / O process is widely used in small and medium-sized cities 1. Introduction A / O process was produced in the 1970s. Inner Mongolia wastewater treatment has been widely used because it has the function of degrading organic matter and denitrification, and is easy to operate and manage. Since the sewage treatment process is determined based on various factors such as the amount of sewage, water quality, effluent requirements, and local actual conditions, small and medium-sized urban domestic sewage treatment stations generally use A / O and other processes.
2. Process characteristics
(1) Advantages: high efficiency This process has a high removal effect on organic matter, ammonia nitrogen, etc. in wastewater. When the total residence time is greater than 54h, the effluent after biological denitrification is coagulated and precipitated, and the COD value can be reduced to less than 100mg / L. Other indicators also meet the emission standards, and the total nitrogen removal rate is above 70%. The process is simple, the investment is low, and the operation cost is low. The process uses organic matter in wastewater as a carbon source for denitrification, so no additional carbon source such as methanol is needed.
(2) Disadvantages: Because there is no independent sludge return system, sludge with unique functions cannot be cultivated, and the degradation rate of refractory substances is low. In order to improve the nitrogen removal efficiency, the internal circulation ratio must be increased, thus increasing the operating costs. In addition, the internal circulating fluid comes from the aeration tank and contains a certain amount of DO, which makes it difficult for the A section to maintain the ideal anoxic state, which affects the denitrification effect, and the denitrification rate is difficult to reach 90%.
Six, the biofilm process is used in the field of industrial wastewater 1. Introduction The biofilm method is an artificial enhancement of the soil self-purification process, which mainly removes soluble and colloidal organic pollutants in the wastewater, and also has a certain amount of ammonia nitrogen in the wastewater. Nitrification capacity. Biofilm method has been widely used in the treatment of industrial wastewater. 2. Process characteristics (1) Advantages: The diversity of microorganisms and the length of the biological food chain are conducive to improving the sewage treatment effect and the processing load per unit area. The superior bacteria group runs in stages, which is beneficial to improve the degradation efficiency of organic pollutants by microorganisms and increase the removal rate of difficult-to-degrade pollutants. Inner Mongolia wastewater treatment can improve the effect of nitrogen and phosphorus removal. It has strong adaptability to water quality and water volume changes, and has increased impact resistance. The sludge has good sedimentation performance, is easy for solid-liquid separation, and has less residual sludge output, which reduces the sludge treatment costs and further reduces investment costs. Suitable for low concentration wastewater treatment. Easy maintenance, convenient operation management and low energy consumption. (2) Disadvantages: Compared with the activated sludge method, the biofilm method has higher requirements on the ambient temperature. Too high or too low temperature will affect the biofilm activity. Inner Mongolia sewage treatment will cause biofilm necrosis and shedding. In addition, the specific surface area of the carrier has a great impact on the effect of biofilm treatment. If the specific surface area of the selected filter material fails to meet the requirements, the area of the treatment tank needs to be increased to achieve the expected treatment effect, which increases the investment cost. .