Introduction to several advanced sewage treatment

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Introduction to several advanced sewage treatment technologies (1)

Introduction: This paper introduces: 1. Continuous circulating aeration system (CCAs); 2. SPR high turbidity sewage treatment technology; 3. BIOLAK sewage treatment technology; 4. "Wt--fg" biological method technology; 5. EWP high efficiency sewage purifier; 6. High efficiency vertical flow constructed wetland system water purification technology

key words: sewage treatment aeration wt--fg biological sewage purifier

relevant stations: aeration technology and equipment product application

I. continuous circulating aeration system (CCAs)

a, CCAs process introduction

ccas process, that is, continuous circulating aeration system process (conti reduces the production of coke by about 110000 tons nuous cycle aeration system), is a continuous influent SBR aeration system. This process is improved on the basis of SBR (sequencing batch reactor), which is the main reason for the current rise in vanadium prices. The SBR process was successfully developed as early as 1914, but it is difficult to be popularized and applied in large sewage treatment plants due to the cumbersome manual operation and management, backward monitoring methods and easy blockage of aerators. SBR process was widely considered to be suitable for small-scale sewage treatment plants. After entering the 1960s, automatic control technology and monitoring technology have developed rapidly, and a new non clogging microporous aerator has also been successfully developed, creating conditions for the widespread use of intermittent treatment. In 1968, the University of New South Wales in Australia and the U.S. F. cooperated with abj company, the data situation exporting country whose test results can be in Excel format, to develop the "aerobic activated sludge process with continuous influent, periodic drainage and delayed aeration using intermittent reactor system". In 1986, the U.S. National Environmental Protection Agency officially recognized CCAs process as an innovative alternative technology (i/a), which has become the most advanced computer-controlled biological phosphorus and nitrogen removal process

ccas process has low requirements for sewage pretreatment, and only mechanical grille and grit chamber with a gap of 15mm are set. The core of biological treatment is CCAs reaction tank, in which the functions of phosphorus removal, nitrogen removal, degradation of organic matter and suspended solids are completed, and the effluent can be discharged up to the standard

the pretreated sewage continuously enters the pre reaction tank in front of the reaction tank. In this area, most of the soluble BOD in the sewage is adsorbed by activated sludge microorganisms and enters the reaction area at a low flow rate (0..05m/min) from the eyelet at the lower part of the partition wall of the main and pre reaction areas. In the main reaction zone, it operates periodically according to the procedures of "aeration", idle, settlement and drainage ", so that the sewage can be decarburized and denitrified in the iteration of" aerobic anoxic "and phosphorus can be removed in the iteration of" aerobic anoxic ". The duration of each process and the operation of corresponding equipment are prepared in advance, and the literal program of the control system can be adjusted, which is centrally controlled by the computer

The unique structure and operation mode of CCAs process make it have unique advantages in the process:

(1) during aeration, sewage and sludge are in a completely ideal mixing state, ensuring the removal rate of BOD and COD, which is as high as 95%

(2) the repeated operation modes of "aerobic anoxic" and "aerobic anaerobic" have strengthened the absorption and nitrification denitrification of phosphorus, so that the removal rate of nitrogen and phosphorus reaches more than 80%, ensuring that the effluent index is qualified

(3) during sedimentation, the whole CCAs reaction tank is in a completely ideal sedimentation state, making the effluent suspended solids (SS) extremely low, and the low SS value also ensures the phosphorus removal effect

The disadvantage of CCAs process is that each tank operates intermittently at the same time, and manual control is almost impossible. It all depends on computer control. It has high requirements for the quality of management personnel in the treatment plant and strict requirements for design, training, installation, commissioning and other work

b, overview of the development of urban sewage treatment plants at home and abroad

water is an important factor in economic development and social sustainable development. With the continuous expansion of urban scale and the increase of population, water environment pollution has become a major problem. Urban sewage is an important cause of pollution in rivers and lakes at present, and is one of the main reasons that restrict the sustainable development of many cities. "Environmental protection" is China's basic national policy. China's strategy and Countermeasures for sustainable development set the 2000 governance goal, which requires the centralized treatment rate of urban sewage to reach 20%. At present, China is in a period of great development of urban sewage treatment, especially with the implementation of the national western development strategy, environmental and ecological protection in central and Western China has been put on the top agenda

since the industrial revolution 200 years ago, urban domestic sewage treatment has attracted more and more attention. Urban sewage treatment rate has become an important symbol of whether a region is civilized or not. In the past 200 years, urban sewage treatment has developed from the original natural treatment and simple primary treatment to the advanced treatment and reuse of sewage by using various advanced technologies. The treatment process has also developed from traditional activated sludge process and oxidation ditch process to a/o, a2/o, AB, SBR (including CCAs process) and other processes to meet different effluent requirements. Compared with foreign developed countries, urban sewage treatment in China started late. At present, the urban sewage treatment rate is only 6.7%. While vigorously attracting foreign advanced technology, equipment and experience, we must explore urban sewage treatment systems suitable for China's actual situation in combination with China's development, especially the local actual situation

in combination with the actual situation of our country and with reference to foreign advanced technology and experience, the construction of urban sewage treatment plants should conform to the following development directions:

(1) the total investment is less. China is a developing country, and the funds required for economic development are very large. Therefore, strict control of total investment is of great benefit to the national economy

(2) low operation cost. Operation cost is an important factor for the normal operation of sewage treatment plant, and it is one of the main indicators to judge the quality of a set of processes

(3) save land occupation. China has a large population and per capita land resources are extremely scarce. Land resources are an important factor in the development and planning of many cities in China

(4) effect of nitrogen and phosphorus removal. With the eutrophication of a large area of water environment in China, nitrogen and phosphorus removal from sewage has become an urgent problem. The latest national integrated wastewater discharge standard (GB) implemented in China also clearly stipulates that it is applicable to all pollutant discharge units, and very strictly stipulates the phosphate discharge standard and ammonia nitrogen discharge standard. This means that in the future, most urban sewage treatment plants should consider the problem of nitrogen and phosphorus removal

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