Sewage treatment plan

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1. Treatment method of industrial sewage The sewage treatment center is a method for treating industrial sewage and belongs to the technical field of sewage treatment. It directs the sewage to the sump, adjusts the pH at the end of the sump, lifts it to the primary pressure dissolved gas tank with a primary dissolving water pump, and inhales the air and the coagulation bleaching agent. The first-stage saturated gas dissolved water is suddenly released into the primary air flotation tank to form primary treatment water; the primary treatment water overflows into the buffer tank, and then the secondary dissolved air pump is used to raise the primary treatment water to secondary pressure at the controlled pH. Dissolve air and decolorization agent in the air in tank, and release secondary saturated gas in secondary pressure tank to secondary air floatation tank to form secondary treated water and self-discharge to settle in sedimentation tank. First, the floating mud in the secondary air floatation tank enters the floating mud pool, and is pressure filtered into a filter cake, and the filtrate is returned to the collection tank. The removal rates of CODcr, decolorization rate, SS, and BOD5 of the industrial wastewater treated by this method are 80-90%, 95%, 90%, and 75-80%, respectively, and meet the first-grade water discharge standard of GB8978-1996. Biogas power generation is a new energy comprehensive utilization technology integrating environmental protection and energy saving. It uses the biogas produced by anaerobic fermentation of industrial wastewater to drive biogas generators to generate electricity, and can make full use of the residual heat of the generator set for biogas production, so that the overall thermal efficiency reaches about 80%, which is much higher than that of the general 30 to 40%. Efficiency, the user's economic efficiency is a great way to deal with industrial wastewater.

Micro-electrolysis for Industrial Water Treatment 1. Technical Overview:

Microelectrolysis technology is currently an ideal process for the treatment of high-concentration organic wastewater, also known as internal electrolysis. It uses the 1.2V potential difference generated by the micro-electrolyte material filled in the waste water to electrolyze the waste water in order to achieve the purpose of degrading organic pollutants. When the system is watered, numerous micro-battery systems are formed inside the equipment, forming an electric field in its working space. The new ecology [H], Fe2+, etc. generated in the process can undergo redox reactions with many components in the wastewater, such as the chromophoric group or the chromophoric group that can destroy the colored substances in the colored wastewater, or even the broken chain. , to achieve the role of degradation and decolorization; generated Fe2 is further oxidized to Fe3+, their hydrates have strong adsorption-flocculation activity, especially after adding alkaline pH value to generate ferrous hydroxide and floc ferric hydroxide colloidal coagulant Their adsorption capacity is much higher than that of ferric hydroxide colloidal hydrolyzed by general agents, which can absorb large amounts of dispersed fine particles, metal particles and organic macromolecules in water. Its working principle is based on the combined action of electrochemistry, oxidation-reduction, physical adsorption and flocculation precipitation to treat wastewater. The method has the advantages of wide application scope, good treatment effect, low cost, convenient operation and maintenance, and no power consumption. The process for the treatment of high-concentration wastewater that can hardly be degraded can greatly reduce the COD and chroma, improve the biodegradability of the wastewater, and can have a good effect on the removal of ammonia nitrogen.

Micro-electrolytic tower application of industrial water treatment Micro-electrolytic materials traditionally used in micro-electrolysis process are generally iron scraps and charcoal, and should be activated before use. The use of the process is very easy to passivate the compaction, because iron and carbon are physical In contact, it is easy to form a separation layer so that microelectrolysis can not continue to lose its effect, which leads to the frequent replacement of micro-electrolytic materials, not only the high workload and high cost also affect the treatment efficiency and efficiency of wastewater. In addition, the traditional micro-electrolytic material surface area is too small also makes the waste water treatment takes a long time, increased the investment cost of tons of water, which have seriously affected the use and promotion of micro-electrolysis process.

2, technical characteristics:

(1) The reaction rate is fast, and general industrial wastewater only takes half an hour to several hours;

(2) The organic pollutants have a wide range of effects. For example, difficult-to-degrade biodegradable organic substances containing a couple of fluorine, a carbon double bond, a nitro group, and a halogenated structure have a very good degradation effect;

(3) The process flow is simple, the service life is long, the investment cost is small, the operation and maintenance is convenient, the operation cost is low, and the treatment effect is stable. Only a small amount of micro-electrolytic reagents are consumed in the process. The micro-electrolytic agent only needs to be added periodically without being replaced, and the addition can also be performed without directly activating.

(4) The waste water will be treated with micro-electrolysis to form the original ferrous or iron ions in water. It has better coagulation than ordinary coagulants, no need to add iron salt and other coagulants, COD removal rate is high, And will not cause secondary pollution to water;

(5) It has good coagulation effect, high chroma, COD removal, and the same amount can greatly improve the biodegradability of wastewater.

(6) The method can achieve the effect of chemical precipitation of phosphorus, and can also remove heavy metals through reduction;

(7) For the high-concentration organic wastewater treatment projects that have not yet reached the standard, the technology is used as a pretreatment of the already-built engineering wastewater, and the biodegradability of the wastewater is improved while COD is degraded, which can ensure the stable discharge of wastewater after treatment. The biochemical wastewater can also be further treated by a micro-electrolysis or micro-electrolysis combined with a biological filtration bed.

(8 Each unit of this technology can be used as a separate treatment method, and can also be used as a pre-treatment process for biological treatment, which is conducive to the settlement of sludge and bio-filming 3, applicable types of wastewater:

This technology is especially aimed at the treatment of wastewater with high concentration of organic matter, high toxicity, high chroma, and difficult to biochemical wastewater, which can greatly reduce the color and COD of wastewater, increase the ratio of B/C, that is, increase the biodegradability of wastewater; it can be widely used Printing and dyeing, chemical industry, electroplating, pulp and paper, pharmaceuticals, wool, pesticides, alcohol and other industrial wastewater treatment and treatment of water reuse projects.

(1) Dye, printing and dyeing wastewater; coking wastewater; petrochemical wastewater;

------ At the same time as the above wastewater was decolorized, BOD/COD values ​​in the treated water were significantly increased.

(2) Petroleum wastewater; leather wastewater; papermaking wastewater, wood processing wastewater;

------ The above-mentioned BOD/COD values ​​of the wastewater treatment water have been greatly increased.

(3) electroplating wastewater; printing wastewater; mining wastewater; other wastewater containing heavy metals;

------ Remove heavy metals from the above wastewater.

(4) organic phosphorus agricultural wastewater; organic chlorine agricultural wastewater;

------ greatly increase the biodegradability of the above wastewater, and can remove phosphorus, in addition to sulfide catalytic activity of micro-electrolytic filler 1, product overview:

The new type of catalytically active micro-electrolyte packing was jointly developed by our company and research institutes. It is produced by a metal alloy fusion catalyst with a high potential difference and adopts high-temperature microporous activation technology. It has an iron-carbon integration, a fusion catalyst, and a micro-hole structure. Alloy structure, large specific surface area, light weight, strong activity, current density, and high efficiency of the water effect. Acts on the waste water, can remove COD efficiently, reduce the chroma, improve the biodegradability, the treatment effect is steady, can avoid the passivation of the filling in the course of running, the phenomenon of compaction and so on. This filler is an important guarantee for the continuous action of microelectrolysis reaction.

2, technical characteristics:

(1) The anodes and catalysts are integrated by high-temperature smelting to form iron and charcoal to ensure the continuous action of the "primary battery" effect. The separation of cathode and anode is not likely to occur as in the iron-carbon physical mixing configuration, which affects the galvanic reaction.

(2) The fillers form a framework-type microporous alloy structure through high-temperature smelting, which has a large specific surface area, strong activity, non-passivation, and no consolidation. The cathode and the anode are proportioned to different wastewater, and provide greater current density and more for wastewater treatment. The effect of a good micro-electrolysis reaction, the reaction rate is fast, general industrial wastewater only takes 30-60 minutes, stable and effective long-term operation.

(3) Technical parameters:

Specific gravity: 1.0 t/m3, specific surface area: 1.2 m2/g, porosity: 65%, physical strength: ≧ 1000 KG/CM

Chemical composition: 75-85% iron, 10-20% carbon, catalyst 5%

(4)Specifications: 1cm*3cm (size can be customized)

2. Treatment of Agricultural Wastewater Since agricultural sewage is widely dispersed and difficult to collect and control, it can only remove contaminants through the use of biological functions. For example, high-density and high-efficiency decontaminating bacteria can be directly put into polluted water. To achieve the purpose of water purification.

3. Treatment methods for medical sewage, which usually include primary treatment and secondary treatment. Generally speaking, if the effluent is discharged into the municipality after treatment, the sewer is usually treated only at the first level; if the treated effluent is directly discharged into the river, the first-level treatment and the second-level treatment are required; in areas with strict discharge standards, the water body is prevented from The eutrophication requires three stages of phosphorus and nitrogen removal. Special hospital wastewater such as acidic wastewater, phase-washing wastewater and radioactive sewage should be strictly collected and disposed of. In some areas, in order to ease the tension in the water supply, advanced treatment and recycling of hospital sewage have been carried out. What kind of way to actually treat hospital sewage should comprehensively consider various factors such as the source of sewage, the flow of sewage, and the local water supply situation. In addition, a very important aspect of hospital sewage treatment is that it must be disinfected to kill various pathogenic microorganisms.

Hospital Wastewater Treatment 1. Rural Living Sewage Treatment Methods For rural domestic sewage, the following treatments can be performed:

Domestic sewage → septic tank → anaerobic pond → constructed wetland (plants with well-developed root system, hi wetness, strong cannabis, scallions, calamus, etc.) are treated after being “filtered” and discharged, and are mainly suitable for rural distribution. Domestic sewage treatment, after completion of the operating costs are basically zero, the service life of more than 10 years.

2. Treatment of urban domestic sewage The following treatment can be performed for urban domestic sewage:

The urban domestic sewage is transported to the countryside around the city, and the vast rural land is used to purify the urban domestic sewage. It will be a good way to use it once and for all. Take the example of large and medium-sized cities that supply 100-m3 cubic meters of tap water daily: the cost of ordinary sewage treatment facilities is 1,000 yuan/cubic. The construction cost is 1 billion, and the annual operating cost is 100W cubic meters/day × 365 × 0.5 yuan/cubic = 180 million. The construction cost of soil purification method is 1000 yuan/cubic, and the annual operating cost is 100W cube/day × 365×0.1 yuan/cubic=0.4. Billion. At the same time, it saves 360 million cubic meters of agricultural water resources, saves about 10,000 tons of chemical fertilizers per year, reduces the amount of pesticides used by 5 tons per year, and has comprehensive benefits.

There are many sewage treatment facilities, but the main ones are the following:

Centrifuges are mainly used to separate the solid particles from the liquid in the suspension; or to separate the two incompatible emulsions in the emulsion (for example, to separate cream from the milk); it can also be used to eliminate Liquids in wet solids, such as washing wet clothes with a washing machine; special overspeed tube separators can also separate gas mixtures of different densities; use different characteristics of solid particles of different densities or particle sizes in the liquid, some settlement Centrifuges can also classify solid particles by density or particle size.

Sludge dewatering machine is characterized by automatic control, continuous production, stepless speed regulation, applicable to various sludges, and suitable for sludge dewatering in water supply and drainage, papermaking, casting, leather, textile, chemical, food and other industries. .

The aerator is used to inject the “microbubbles” directly into the untreated sewage through the diffuser impeller. Under the joint action of the coagulant and the flocculant, the suspended solids undergo physical flocculation and chemical flocculation to form large suspended solids. The flocculation, under the buoyancy action of the bubble group, “flocculation” floats on the liquid surface to form scum, and is separated from the water by a slag scraper; there is no need to clean the nozzle and no blocking phenomenon will occur. The equipment is of good integrity, easy to install, and saves operating costs and floor space.

Microfiltration is a type of drum screen filter. The treated wastewater enters the drum in an axial direction and flows out radially through the screen. Impurities (fine suspended solids, fibers, pulp, etc.) are trapped on the inner surface of the filter screen on the drum. When impurities trapped on the screen are carried to the upper part by the drum, they are backwashed by the pressure flushing water and flow out into the slag tap. During operation, the diameter of the drum 2/5 is partially exposed to the water surface, the number of revolutions is 1-4 r/min, the filter speed can be 30-120 m/h, the flushing water pressure is 0.5-1.5 kg/cm2, and the amount of flushing water is the amount of water produced. 0.5-1.0% for reservoir water treatment, the efficiency of algae removal is 40-70%, and the efficiency of plankton is 97-100%. Microfiltration machine covers an area of ​​small, large production capacity (250-36000m3 / d), convenient operation and management, has been successfully applied to water supply and wastewater treatment.

Air flotation machine is a kind of equipment to remove suspended solids, grease and various gums in various industrial and municipal sewage. The equipment is widely used in the treatment of industrial waste water and municipal sewage such as oil refining, chemical industry, brewing, slaughter, electroplating, printing and dyeing.

Divided by dissolved gas: inflatable air floatation, dissolved air floatation and electrolysis air floatation. The principle is to efficiently mix gases that are difficult to dissolve in water or two or more different liquids (produce fine air bubble particle size of 20-50 microns). The microbubbles are used as carriers to adhere the impurities in the water, and the particles are floated up to the water surface and separated by water bubbles to achieve the purpose of solid-liquid separation.

In the process of sewage treatment, major rivers and lakes in China are polluted by phosphorus, and eutrophication is serious. The State Environmental Protection Agency has set stricter standards for phosphorus emission in order to control phosphorus pollution. The chemically-enhanced biological phosphorus removal wastewater treatment process mainly removes organic pollutants and various forms of phosphorus in the sewage. The wastewater treatment process integrates chemical phosphorus removal and biological phosphorus removal, and produces activated sludge through anaerobic digestion of biological systems. Volatile organic acids, as a substrate for the growth of polyphosphate, or as a nutrient, allow polyphosphate-accumulating bacteria to selectively proliferate in activated sludge and return them to the biological system, making the biological wastewater treatment system work efficiently. Phosphorus status; Simultaneous release of phosphorus from sludge under anaerobic conditions is eliminated by chemical phosphorus removal. This is an efficient municipal wastewater treatment technology that satisfies the current stage in China. To solve the eutrophication of water, it is required to further remove phosphorus on the basis of conventional secondary wastewater treatment.

There is a big difference in the level of China's economic development, and cities with lagging economic development cannot yet use a lot of funds for sewage treatment. Therefore, how to use limited funds to reduce environmental pollution is a problem faced by many urban governments. In the aspect of sewage treatment, until recently, some cities have adopted the first-level or first-level enhanced treatment process technology, and the water discharge has failed to meet the requirements of the national secondary emission standards for the removal of organic pollutants. The cyclical intermittent aeration process takes full advantage of the high efficiency of the high-load oxidation ditch treatment, and makes full use of the characteristics of the sequential batch type activated sludge sewage treatment process, which ensures that the system effluent meets the national wastewater discharge primary standard and removes organic pollutants. Aspects of the request. The investment and operating costs are about 30% lower than those of secondary biological wastewater treatment systems, which are usually based on the removal of organic pollutants. This is a suitable process technology for wastewater treatment at the present stage in China.

Rotary contact oxidation wastewater treatment technology is a new generation of aerobic bio-film processing technology developed on the basis of biological rotating disc technology combined with the advantages of biological contact oxidation technology. Rotary contact oxidation wastewater treatment technology and complete sets of equipment provide a simple and reliable method of wastewater treatment. The entire shaft of the sewerage system is the only rotating part. Once the machine fails, the general mechanic can perform maintenance. System biomass is automatically compensated for changes in organic load. The microorganisms attached to the turntable are alive. When the organic matter in the sewage increases, the microorganisms increase. On the contrary, when the organic matter in the sewage decreases, the microorganisms decrease. Therefore, the working efficiency of this sewage treatment system is not easily affected by sudden changes in flow and load and power outages. The operating costs are low, only one-eighth to one-third of the power consumed by other aeration wastewater treatment systems. The footprint is only half that of conventional activated sludge processes. Due to the variety of microorganisms that grow in biological systems, it is possible to efficiently treat various refractory industrial wastewaters.

ContinuousCycleAerationSystem is a continuous-feed SBR aeration system. The wastewater treatment process CCAS is based on SBR (Sequencing Batch Reactor). The CCAS sewage treatment process does not require a high level of sewage pretreatment. Only a 15 mm mechanical grating and grit chamber are provided. The core of biological treatment is the CCAS reaction pool. The functions of phosphorus removal, nitrogen removal, organic matter degradation, and suspended solids are all completed in this tank, and the effluent can meet the standard emission.

The unique advantages of the wastewater treatment process CCAS:

(1) At the time of aeration, the sewage and sludge of CCAS sewage treatment are in a perfectly mixed state, which ensures the removal rate of BOD and COD, and the removal rate is as high as 95%.

(2) The "aerobic-anoxic" and "aerobic-anaerobic" modes of repetitive operation have enhanced the absorption of phosphorus and nitrification-denitrification, resulting in a nitrogen and phosphorus removal rate of more than 80%, ensuring that the effluent criteria are met. .

(3) During the precipitation, the entire CCAS reaction tank is in a perfectly ideal state of precipitation, so that the effluent suspended matter is extremely low, and the low value also ensures the removal effect of phosphorus.

The disadvantage of the CCAS wastewater treatment process is that each pool is intermittently operated at the same time, manual control is almost impossible, and it depends on computer control. The quality of the management personnel of the treatment plant is very high, and the requirements for design, training, installation, and debugging are strict.

Brief introduction of sewage treatment process: Biological aerated filter is to set the filler in the biological filter treatment device, and through artificial oxygen supply, a large amount of microorganisms are grown on the filler. The sewage treatment process device consists of a filter bed, a gas distribution device, a water distribution device, a drainage device, and the like. The aeration device adopts a dedicated aeration head, and the resulting small and medium bubbles are repeatedly cut through the filler to achieve near-micro-controlled aeration. Due to the high concentration of sludge in the reaction tank, the treatment facilities are compact, which can greatly save the floor space and reduce the reaction time.

Introduction to wastewater treatment process: The main cause of eutrophication of water is that humans discharge large amounts of ammonia nitrogen and phosphorus into water bodies, and phosphorus is the most important factor in the eutrophication of water bodies. Taking a look at the domestic sewage treatment process, phosphorus removal technology has always been a problem that hampers the operation of sewage treatment plants. Traditional physical and chemical phosphorus removal technology requires a large amount of pharmaceuticals, which has the disadvantages of high operating costs and large sludge yield. The pre-anaerobic biological phosphorus removal process has the advantage of low operating costs, but is completely dependent on the phosphorus intake and release of microorganisms. Phosphorus effect, it is difficult to meet the national wastewater treatment process requirements. When considering the reuse of water, it is even more difficult to meet the requirements.

Sewage treatment process description: Due to the scattered residential areas in China's small towns, there are a lot of sewage sources distribution points, and the scale of urban-level wastewater treatment plants is often less than 10,000 tons per day. At present, domestic large and medium-sized urban sewage treatment plants often use the traditional activated sludge process, A2/O, SBR, oxidation ditch, etc. If these technologies are used to build small town sewage treatment plants will result in high operating costs due to , unable to continue running. Must be based on the characteristics of small towns to adopt investment provinces, low operating costs, stable and reliable technology, operation and management of a relatively simple process.

The MBFB process is used for advanced treatment of wastewater and can reduce the COD, NH-N, turbidity, and other indicators on the basis of the discharge of the original wastewater and the biological fluidized bed and ceramic membrane separation system. On the one hand, it can be reused directly. On the one hand, it can also be used as a pretreatment process for desalination of RO to replace the lengthy filtration processes such as sand filtration, security filtration, ultrafiltration, etc. Meanwhile, the reduction of organic content greatly increases the service life of RO membranes, reduces the cost of reuse water treatment, and inorganic ceramic membranes. The separation system is the world's first inorganic membrane separation system dedicated to wastewater treatment. Compared with other organic membranes and inorganic membranes, it has the advantages of large membrane flux, backflushing, and automatic operation.

European Urban Wastewater Treatment Technology - Sustainable Biological Dephosphorization and Denitrification Process The removal of nitrogen and phosphorus for the purpose of controlling eutrophication has become a major national goal. Undoubtedly, due to the stricter emission standards, traditional craftsmanship will be aggravated by the above-mentioned drawbacks. In this situation, the development of sustainable wastewater treatment processes becomes imperative. The so-called sustainable sewage treatment process is to minimize the COD oxidation, the lowest CO2 release, the least surplus sludge production, and to achieve phosphorus recovery and treatment of water reuse. This requires a more comprehensive approach to solve the problem of sewage treatment, that is, sewage treatment should not merely satisfy a single water quality improvement, but also need to consider the resource and energy of sewage and contained pollutants, and it must be taken into consideration. The technology must be based on the premise of low energy consumption (to avoid pollution transfer) and low resource consumption.

The development of novel sewage biological treatment processes relies on new discoveries or new understandings in microbiology and biochemistry. Dutch researcher Mulder discovered anaerobic ammonia (nitrogen) oxidation 10 years ago. At the same time, scientists in South Africa, the Netherlands, Japan, and other countries have re-understood the metabolic mechanism of bio-intake/phosphorus release and established a new approach to denitrifying phosphorus removal. The development and application of these two new technologies have epoch-making impetus for the development of sustainable biological wastewater treatment processes. Based on anaerobic ammonia oxidation and denitrification phosphorus removal technologies, this paper describes in detail their technical principles, process flow, and their application in Europe; on this basis, a proposal is made to convert organic energy (methane) and recover phosphorus compounds ( Bio-phosphorus and denitrification technology recommended for sustainable urban wastewater targeting struvite and reuse of treated water (non-drinking purposes).

In the practice of sewage biological phosphorus removal, researchers from the University of Cape Town, South Africa (UCT) first discovered that obligate aerobic bacteria are not the only species that act on the biological uptake/release of phosphorus. Facultative denitrifying bacteria also have a strong Biological photo / phosphorus phenomenon. The biological uptake/dephosphorization of denitrifying bacteria was confirmed by researchers from Delft University of Technology (TUDelft) and the University of Tokyo (UT) in Japan. The denitrifying bacteria was named denitrifying dephosphatation. During the biological uptake/release of phosphorus, denitrifying phosphorus removal bacteria use nitrate nitrogen instead of oxygen as an electron acceptor. That is to say, denitrifying phosphorus removal bacteria can denitrify nitrogen and biological phosphorus, which are considered to be independent of each other. The role of the two combined. Obviously, in the combined dephosphorization and denitrification process, COD and oxygen consumption can be saved accordingly. Compared with the traditional special aerobic phosphorus removal process, denitrifying phosphorus removal bacteria can save about 50% and 30% of COD and oxygen consumption respectively, and correspondingly reduce the amount of residual sludge by 50%. In the process of denitrifying phosphorus removal, due to the large reduction of COD requirement, excess COD can be separated and methanated, thereby avoiding COD single oxidation stabilization (to CO2). Due to the reduction of aeration energy and the generation of energy after methanation of excess COD, this comprehensive energy saving will eventually lead to a significant reduction in the amount of CO2 released to the atmosphere. Therefore, a treatment system with enriched denitrifying phosphorus-removing bacteria can be considered as a sustainable treatment process. Traditionally, two well-established biological pathways, nitrification (NH+4→NO3-) and denitrification (NO3→N2) have been applied to biological nitrogen removal from wastewater treatment. This traditional biological denitrification pathway is not optimal from a sustainability point of view because fully oxidizing ammonia nitrogen to nitrate nitrogen consumes a large amount of energy (due to aeration); secondly, sufficient carbon source (COD) is required to restore it. Nitrate nitrogen to nitrogen. Improvements to this traditional denitrification pathway can be achieved with SHARON, a mid-temperature nitrosation technology recently developed by TUDelft in the Netherlands. In the nitrification/denitrification denitrification pathway, nitrite nitrogen is the only intermediate transitional form; this pathway can be used to minimize the quantification of both oxidation (NH+4→NO2-) and reduction (NO2-→N2). The effect means a double saving of O2 and COD consumption. Obviously, the nitrification/denitrification denitrification pathway can be a sustainable nitrogen removal technology.

In addition, TUDelft researchers in the Netherlands also tested and confirmed a new ammonia nitrogen conversion pathway during almost the same period. This made it possible for ammonia nitrogen to be directly oxidized to nitrogen with nitrous nitrogen as an electron acceptor. This combination of ammonia oxidation under anaerobic conditions and the nitrosation process (such as the SHARON process) can realize the shortest path conversion of ammonia nitrogen in engineering, which means that it is possible to minimize the energy and resource consumption during the biological denitrification process. . All possible conversion pathways of nitrogen in the wastewater treatment process are shown in Fig. 1. Compared with the conventional denitrification process, it is clear that the complete autotrophic conversion of nitrogen combined with anaerobic ammonia oxidation and nitrosation processes is the most Continuous wastewater denitrification.

Overview China's sewage treatment industry has developed at a relatively late stage. Since the founding of the People's Republic of China, until the reform and opening up, China's sewage treatment demand has been mainly based on cutting-edge use of industry and national defense. After the reform and opening up, the rapid development of the national economy and the remarkable improvement in the people’s living standards have boosted the demand for sewage treatment. After entering the 1990s, the sewage treatment industry in China entered a period of rapid development, and the growth rate of sewage treatment demand was much higher than the global level.

Since 1990, the apparent consumption of global wastewater treatment has grown at an average annual rate of 6%. In the decade of the 1990s, the average annual growth rate of apparent consumption of wastewater treatment in China reached 17.73%, which is the world's average annual growth rate. 2.9 times. In the 21st century, China's sewage treatment industry has grown rapidly. From 2000 to 2004, China's sewage treatment consumption increased from 1.88 million tons to 4.47 million tons, an increase of 2.3 times, and the average annual growth rate was above 27%. Among them, in 2001, China's apparent consumption of sewage treatment reached 2.25 million tons, which surpassed the United States as the world's largest consumer of sewage treatment. At the same time, sewage treatment imports have also increased significantly. In 1998, China imported 1 million tons of sewage treatment, which has become the world's largest importer of sewage treatment. Compared with 2004 and 2004, the average annual growth rate of sewage treatment imports reached 27.14%. It is expected that in 2005, China's apparent consumption of sewage will reach 5 million tons, and imports will still remain at around 3 million tons.

With the rapid development of the sewage treatment market, China's sewage treatment output has also ended the long-term embarrassing situation, and achieved rapid growth. China's sewage treatment output increased from 460,000 tons in 2000 to 2.36 million tons in 2004. The average annual growth rate was 82.6%. The proportion of domestic market demand also increased from 24.47% in 2000 to 52.80% in 2004. In the same period, the world's sewage treatment output only increased at a rate of about 6%.

Since the late 1990s, China’s Taigang, Baosteel, Baoxin, Zhangpu and other state-owned and joint ventures have successively established a series of sewage treatment production lines through the introduction and technological transformation. The sewage treatment technology and equipment have reached the international advanced level, and sewage treatment Production begins to take shape. The structure of sewage treatment plants has also undergone positive changes, and the quality of sewage treatment products has rapidly increased. In particular, the domestic sewage treatment cold-rolled steel sheet has grown rapidly. In 2003, the domestic cold-rolled sheet production reached 1.7 million tons, exceeded imports for the first time, and the self-sufficiency ratio reached 66%; in 2004, the domestic cold-rolled sheet production reached 2 million tons, and self-sufficiency rate More than 70%. From the end of 2004 to the end of 2005, the domestic cold rolled sewage treatment capacity will increase by about 1.5 million tons, basically meeting the domestic market demand. By 2007, China will become a net exporter of sewage treatment.

In general, China's sewage treatment is undergoing a profound change from a small scale, low level, single species, serious inability to meet demand, to considerable scale and level, significant improvement in the quality of varieties, and preliminary satisfaction of national economic development requirements. Gradually achieve self-sufficiency.

(Difficulty 1) The increase in population and the increase of sewage in China. With the increase of urban population and the development of industrial and agricultural production, the discharge of sewage is also increasing. Water pollution is very serious, and it is almost everywhere in the country. By the end of 2000, 310 of the 663 cities across the country had built sewage treatment facilities and built 427 sewage treatment plants. The annual sewage treatment capacity was 11.36 billion cubic meters, and the sewage treatment rate was only 34.23%.

(Difficulties 2) Accelerate Development and Urgently Need Funds In the socialist market economy, sewage treatment begins with a certain amount of capital investment. The scale of the sewage treatment funds determines the scale of the sewage treatment. The speed of development of the sewage treatment fund itself determines the speed of sewage treatment development and the speed of progress in sewage treatment technology. In actual sewage treatment, the decision-making scheme with advanced technology and low processing cost is usually a scheme with a large amount of prepaid funds. In this sense, the faster the development of the fund itself, the faster the sewage treatment technology can be developed and applied, and the faster the sewage treatment can be.

(Difficulties 3) Disposal of Funds, Source Difficulties 1. Difficulties of China's Urban Wastewater Capital Sources For a long time, China's urban sewage treatment facilities adopted a free-use policy, which not only expanded financial production through remanufacturing, but also required financial allocation for simple reproduction. Upon completion, the financial allocation became the only source of investment in the maintenance and construction of the sewage treatment facilities. Only at different times, the names of the sources are different, but they are all finance-centric financial cycles. The reform of the economic system has negated China's traditional grand unified "fiscal model", negating the identity of the state as a producer and operator, and also negating the unity of the ownership of the means of production and the exercise of the power of the political power, requiring the separation of government and enterprises, and separation of government and capital. Adapted to the premise that the country is the mainstay of unified finance, China’s finances are divided into two parts: public finances and state-owned asset management.Public finance is a state that appears as a political power executor and raises funds mainly in the form of taxation to address market allocation of resources. Problems that cannot be solved to meet public needs: Urban sewage treatment is a public welfare undertaking, and the financial allocation for the sewage treatment fund should be public expenditure, as the reform of China's socialist market economy system is still deepening, public finance revenue accounts for the proportion of GDP, central public The proportion of fiscal revenue to public finances is currently not reasonable enough. Urban sewage treatment funds are hardly like most developed countries like the United States come from financial allocations or loans.

2. Difficulties in the source of sewage treatment borrowed funds The demand for urban sewage treatment funds is huge. Bank loans are an important source of sewage treatment funds. Bank loans are divided into commercial bank loans and China Development Bank loans. The sources of funds for commercial banks are residents and corporate deposits. Most of them are short-term funds. Although some medium- and long-term loans can also be used, the proportion should not be too large. The use of commercial banks’ funds requires the unification of "three properties" of safety, liquidity, and profitability. The use and return of sewage treatment funds are difficult to match with the "three properties" of commercial bank funds. Therefore, it is difficult for commercial banks to make loans for sewage treatment projects.

(breaking method 1) Intensify financial appropriation The part of the urban sewage treatment fund is under the conditions of the socialist market economy. The government must also provide the necessary subsidies. The reasons are many. The main issues are: 1. Sewage treatment is generally characterized by a low price elasticity of demand and the government's "monopoly" operation. The fees must be formulated in consideration of the affordability of residents, and cannot rely on competitive prices to completely solve the problem of facility construction and enterprise development. 2. The services provided by sewage treatment are public, and the use of many facilities is difficult to calculate, and their service charges cannot be directly entered into the market for equivalent exchange, but can only become part of public consumption. 3. The services provided by sewage treatment have a wide range of social and external economic characteristics. When measuring the investment benefits, the first is social benefits.

The national financial allocation for urban sewage treatment mainly includes investment in basic construction arrangements in China, and special funds allocated by the central government and local financial allocations. Investment in capital construction arrangements is divided into two types: national budget and local self-raising. The basic construction within the national budget is determined by the central government and the Ministry of Finance shall submit a unified arrangement to the State Planning Commission. Local self-raised capital construction investment is an investment arranged by the local self-raised funds within the limits set by the state. Central and local financial appropriations, one is based on the need for fiscal allocation of a certain amount of funds each year as a special fund for sewage treatment; the other is a fixed amount of subsidies for the project, the project completed, subsidies stopped.

(breaking method 2) Increase the self-raised level of enterprises Under the conditions of a market economy, wastewater treatment can only realize the reproduction of sewage treatment only by converting its value into the return of capital in the course of its construction and operation activities. According to the requirements of the law of value, the input and output of sewage treatment should be streamlined to the new order of the market economy, which is an objective requirement for speeding up the urban sewage treatment in China. Sewage treatment charges should not be a temporary fund-raising measure, but rather a market-oriented way to realize compensation for sewage treatment funds, and it is also an economic measure to regulate the rational use of sewage treatment facilities.

Self-raised funds for sewage treatment, under the conditions of the socialist market economy, shall formulate sewage treatment fee standards in accordance with the law of value, and extract production development funds, fixed asset depreciation funds, and overhaul funds from operating income in accordance with state regulations. Sewage treatment units must not only rely on their own strength to complete simple reproduction and expand reproduction, but also pay taxes and fees to the state. For this reason, reasonable charges for sewage treatment must be based on reasonable costs and reasonable profit margins.

The reasonable cost of sewage treatment charges should generally include production costs, operating expenses, depreciation of fixed assets, overhaul funds, and interest on loans. The depreciation of fixed assets must have an appropriate depreciation rate, and the current practice of depreciation for a long period of time and a low depreciation rate should be changed so as to prevent companies from losing real profits. The reasonable profit rate of sewage treatment charges means that the approval of the profit rate should not only consider the reasonable benefits and necessary accumulation of the enterprises, but also consider the characteristics of small demand for wastewater treatment charges and low social elasticity, so as to prevent the use of its monopolistic pursuit. High profit.为防止垄断强加给用户的负担,政府可通过行政和经济手段对经营者加以限制,使其可能获得的利润不超过全社会的平均利润。














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