| With the development of urbanization in our country, the population of city increases rapidly, the dimensions of city expand constantly and the productive and domestic water demand enhances suddenly. The statistic results of the whole surroundings indicate: during the recent 10 years the let gross of waste water in the whole country kept steadily, the let gross of industrial wastewater declined slowly, the let gross of domestic wastewater shown the ascending tendency, the charge of city domestic wastewater exceeded the industry wastewater for the first time in 1999. Consequently, it is urgent for our country to find some new wastewater treatment techniques which are scanty, inexpensive and efficient to solve the water environment problem brought by domestic wastewater of cityAnaerobic biology treatment technology is couple with wastewater treatment and energy sources reclaim for utilize. People pay attention to it for its low cost, high efficiency and stabilization. Owing to the traditional anaerobic methods have so many defects such as hydraulic retention time (HRT) to long, organic loading rate (OLR) too low and the effect too bad; the further generalization is been confined. The appearance of high speed anaerobic reactor promoted the further development of anaerobic treatment technology which be used in high concentration organic wastewater treatment, what's more, the kind of reactor shows vast potential in low concentration organic wastewater treatment. Some researchers view anaerobic treatment of domestic wastewater (typically the low concentration organic wastewater) as a new development of anaerobic treatment. The famous anaerobic digest expert G. letting a professor asserted: if some suitable treatment can be match to anaerobic biology treatment technology, then the technology will be the main method in dispersive domestic sewage treatment.Since the 70's invented the Up flow Anaerobic Sludge Bed(UASB),due to its perfect treatment effect, it has been applied to deal with all kinds of wastewater, especially in the treatment of high concentration organic wastewater. For the low concentration domestic sewage, the urban sewage treatment factory which principal part is UASB hasbeen built in the Torrid Zone and sub-torrid zone countries such as Brazil, Mexico, Columbia. Researcher in our country and other countries do a lot of work on it, but as a whole the study on using UASB reactor to deal with low concentration organic wastewater under normal temperature do not go deep into. Some aspects are just in the beginning, although it has some research reports, the example of practical engineering appliance is few, and the research report on UASB treatment of urban low concentration domestic sewage in south cities such as Wuhan is very few.Magnetic treatment technology made great progress in wastewater treatment in recent years. One of the developmental directions of magnetic treatment techniques is to make microbe decompose organic polluted matter through positive biology effect on microorganism produced by magnetic field. The magnetic treatment technology coupling with well-developed biology treatment technology can by way of efficient measure of organic sewage spiritualization due to its merits such as small volume, simple structure, easy maintenance, low cost, little occupation and none-second pollution.This research is according to the "948" innovative item of ministry of water conservancy The study sets up a set of middling experiments system of coupling domestic sewage treatment, using UASB anaerobic treatment technology, magnetic treatment and artificial ecosystem. The experiment is about UASB reactor's start-up in domestic sewage and operation rule, and operation effect of magnetic treatment coupling with UASB reactor. The paper consists five parts:1. The first part introduces the present state of aquatic pollution in our country and the development of wastewater treatment techniques; systemically expatiates on the anaerobic microorganism treatment techniques and magnetic treatment techniques in wastewater treatment, especially on the principle and development of domestic sewage, and points out the development direction of UASB treatment techniques coupling with magnetic treatment techniques.2. The second part attempts using granular sludge which deal with beer wastewater to start up directly the UASB reactor which deal with low strength sewage under normal temperature, discuss the feasibility, and study the parameter such as the sludge loadingrate, the COD volume loading rate, the water power loading rate and temperature which effect on the start-up of the reactor. After the UASB reactor start up successfully, study the operation performance of the UASB reactor which deal with domestic sewage under normal temperature. The experiment which dealing with domestic sewage at circumstance temperature (7-31°C), studies the efficiency of the reactor at different temperature and different loading rate, and discusses the reactor operation because of the impact of those parameters, and provides academic and practical guidance for the UASB reactor dealing with domestic sewage under normal temperature.3. The third part is about the impact of the coupling system because of different magnetic field strength. And owing to magnetic treatment techniques have so many merits such as the small volume, the simple structure, the easy maintenance, the low cost and none-secondary pollution, the experiments study magnetic treatment techniques coupling with the UASB anaerobic treatment technology. The results of experiments show the system which can improve treatment efficiency is a good domestic sewage treatment technique in development direction, especially at low temperature.4. The fourth part analyzes BP artificial neural network model applying in domestic sewage with UASB anaerobic reactor system; establishes the artificial neural network model of simulation and forecast; utilizes the strong non-linear of artificial neural network to simulate and forecast the performance variety and estimate the impact of the system. The model can be used to simulate and forecast the effect of the system, to stimulate and forecast the operation condition, and can offer available reference accordance for the optimization of the system.5. The fifth part demonstrates the technical rationality and the economic feasibility of the coupling system via analyzing coupling system which deal with low strength or ultra-low strength urban sewage on the technical and economic level; shows that the system is a kind of scanty investment, low operation cost , obvious economic benefits and abroad appliance direction new domestic sewage treatment one.Though middling experimental research on domestic sewage treatment with the combination of UASB and magnetic fields, the innovative fruits can be concluded asfollows:1. The UASB reactor for low concentration domestic sewage treatment can be started up by using the granule sludge of beer waste water. The method solves one difficult problem, which UASB reactor startup is so difficult, too long time cost and no ideal effect acquired when using other granule, and finds a new way for UASB reactor startup conveniently and quickly. Though the concentration of domestic sewage is low, organic loads can be increased by enhancing hydraulic loads. Despite Sludge Loading Rate is low, only 2 ~ 13 gCOD/(kgvss.d) in this experimentation, the phenomena of granule decomposed and cracked didn't occur during the reactor startup. The results show that it is feasible the Startup of UASB reactors using mature granule sludge as seed sludge can be carried out successfully under domestic sewage condition. The inoculative number of granular sludge is great and reactor startup is quick. The volumes of the inoculative number of granular sludge occupy 20% of total reactor volumes in this test. The startup of reactor can almost execute immediately. Many investigations show that temperature is an important factor influencing the startup and running of UASB reactor. The startup is quicker and effect is better as temperature is enough high. But, the results show that it is feasible completely that UASB reactor start and run under normal temperature condition.2. The temperature varies from 7°C to 31°C during the UASB reactor being operated in this research. The results obtained in this test demonstrate that the optimal HRT, when temperature is grouped as 29~31"C, 26~28°C, 23~25°C, is 1.5 hours, 2 hours and 2.5 hours separately. The optimal HRT is 3 hours as below 22 °C. The conclusion mentioned above is very significant to the application in practice engineering.3. On the condition of water temperature of 25 °C and HRT as low as 2.5h, the UASB reactor produced very good results in terms of COD removal as fed with six COD concentration extent from(in the range of) 70 to 610mg/l. The results obtained so far demonstrate the feasibility of the UASB reactor for the different COD concentration domestic sewage treatment at ambient temperature, even in less favorable situation when the sewage presented very low concentration in terms of COD. This can become a favorable conclusion promoting the popular application of UASB.4. The research in this test show that the removal rate in terms of COD have no relation with Volume Loading Rate at high sewage concentration. The reactor can process stably in the situation of Volume Loading Rate of less than 2.5KgCOD/m\d When Volume Loading Rate is certain, the more high temperature is, the more high efficiencies in terms of COD removal has.5. Magnetic device may be used for a long time and never consume energy sources The UASB/magnetization coupling system was capable of promoting the removal in terms of COD and CODf to a certain extent. The results show that although the UASB reactor had presented very good efficiencies in terms of COD removal, the magnetic fields can improve and enhance anaerobic process, and promote additional removal in terms of COD. Another important result is that the action that magnetization processing enhances the effect of anaerobic process is even more impressive for lower COD concentration sewage. The experimental research project comprised the investigation of two different magnetic fields (2680GS and 3220GS) association with UASB reactor for the domestic sewage, each one testing different COD concentration sewage in the coupling system. The results obtained in the test show that 2680GS is an optimal magnetic fields intensity for the total system. In terms of COD removal, 2680GS magnetic fields and UASB coupling system can produce higher efficiency than the system using 3220GS magnetic fields and no magnetic fields. A trend in terms of COD removal of the coupling system is observed that the increasing amplitude of efficiencies has been on the decline with the temperature is on the rise, corresponding with all magnetic fields intensity tested. This phenomena indicates that magnetization-process was capable of producing even more remarkable effect on the condition of low temperature. Thus, magnetization-process can be utilized as a strengthening step of anaerobic-process to complement and promote the organic matter removal at low temperature and low concentration.6. Utilizing the several favorable characteristics of artificial neural network (ANN), such as computing precision and simplicity etc., a back-propagation (BP) artificial neural networks (ANN) prediction model was developed for UASB reactor to be designed for the treatment of low concentration domestic sewage in accordance with the theory andmethod of ANN. Because there was only an average error of about 6 4% between the predictions results of the model and the test data, the model was comparatively accurate to forecast the results of reactor. Furthermore, the model has the characteristics of fine flexibility, high efficiency and can assist user to ascertain the optimal operation state of reactor, which provide an effective and convenience way for realizing intelligentized control of the process of UASB reactor for the treatment of low concentration domestic sewage.7. From an economical study developed in order to evaluate the feasibility of the UASB, magnetization and artificial ecosystem coupling system for the treatment of domestic sewage, it can states that this system could become a promising alternative for the treatment of domestic sewage in the middling and small cities, where secondary sewage farm could not afford to construct for a lack of capital and the large drainage quantity domestic sewage, since the system can be designed at small land to occupy, without consuming large amounts of electrical energy and low maintenance costs, together with the remarkable economy benefits.The system connects magnetic treatment, anaerobic wastewater treatment techniques and artificial ecosystem in a certain order. This can transform the contamination into hurtles and useful products. It brings us clear water and benefits. The system has all of the merits of the three ones, and attempt to avoid the shortcomings of them. Aiming at the present state which is starve for the wastewater treatment techniques, which have such characteristics as high disposal efficiency, low energy resource consume, low construct and operate cost, high resource reclaim rate in wastewater and abroad appliance, the system offers a innovative technical method and thought.
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