1、 1 The status quo and development of UASB anaerobic process Abstract: This paper introduces the origin of UASB reactor, the working principles, characteristics, the development and application of the latest research progress, pointing out that the recent UASB reactor research focus. Key words: UASB；
2、 anaerobic treatment process； 1. Introduction : Anaerobic biological treatment as the use of anaerobic metabolism of microorganisms, without the provision of energy sources under the conditions of organic matter as to be restored by hydrogen donor, while generating energy value of the methane gas. A
3、naerobic biological treatment applies not only to high concentrations of organic wastewater, influent BOD up to the highest concentration of tens of thousands of mg / l, can also be applied in low concentrations of organic wastewater, such as sewage, and other cities. Anaerobic biological treatment
4、process and low consumption, organic volume load, generally 5-10 kgCOD/m3.d, up to a maximum of 30-50 kgCOD/m3.d； less residual sludge； on the nutritional needs of low anaerobes, MDR-toxic, biodegradable organic molecular weight high impact resistant capacity of strong output of methane is a kind of
5、 clean energy. In the whole of society to promote a recycling economy and the implementation of the concerns of the industrial waste recycling today, anaerobic biological treatment of sewage is clearly enables the optimization of resources. In recent years, the anaerobic wastewater treatment process
6、 developed very rapidly, with new technology, new methods emerging, including anaerobic contact method, the up-flow anaerobic sludge bed anaerobic stall plate, anaerobic biological filter , anaerobic expanded bed and fluidized bed, and the third generation of anaerobic process EGSB and IC anaerobic
7、reactor, developed very rapidly. And the up-flow anaerobic sludge blanket UASB (Up-flow Anaerobic Sludge Bed, Note: hereinafter referred to UASB) owing to the anaerobic process of anaerobic filters and activated sludge characteristics of the dual, as can be transformed into the pollutants in the sew
8、age 10% of renewable clean energy - a biogas technology. The different solid content of the sewage adaptability also strong, and its structure, operation and maintenance management operation is relatively simple and relatively low cost, technology is now mature, and increasingly sewage treatment ind
9、ustry attention, was widely welcomed and Application . This paper attempts to UASB technology and the operation of the UASB design features, as well as areas for a start briefly described. 2. The origin of UASB In 1971 Holland (Wageningen) Agricultural University Ladingge (Lettinga) Professor physic
10、al structural design, the use of the gravitational field of the role of different density material difference, invented the three-phase separator. The activated sludge wastewater retention time and stay separated, and formed a upflow anaerobic sludge blanket (UASB) reactor on the prototype. Netherla
11、nds CSM 1974 in its 6 m3 reactor sugar beet processing wastewater, it was found that the activated sludge formation mechanism of its own fixed biological polymer structure, granular sludge (granular sludge). 2 The emergence of granular sludge, not only for the promotion of a representative of the UA
12、SB anaerobic reactor, the second generation of applications and development, but also for the third-generation anaerobic reactor laid the foundation for the birth. Currently, the UASB process in Europe has been generally formed granular sludge, which makes anaerobic UASB technology in Europe have be
13、en quick to popularize. China in 1981 began UASB reactor research, the technology in China has been the actual application. UASB reactor is the most widely used high-rate anaerobic reactor, the technology at home and abroad anaerobic treatment has become one of the mainstream technologies. 3. UASB r
14、eactor structure and the basic principles (1) the composition of UASB reactor Figure 1 is a schematic diagram of the UASB reactor. UASB reactor, the main part of Mainly divided into two regions, namely, three-phase reaction zone and the area of separation. Reaction zone which UASB reactor for the ma
15、in work. (2) of the UASB reactor principle UASB sludge from the reaction zone, the gas-liquid-solid three-phase separator (including precipitation area) gas chamber composed of three parts. Reaction in the region hold a large number at the bottom of anaerobic sludge, sludge concentrations can reach
16、50 to 100 g / l or higher, the precipitation has good performance and cohesion of the sludge in the bottom of a sludge layer. To deal with the sewage sludge from the anaerobic sludge bed at the bottom and flows of sludge was mixed layer contacts, as water and upward mobility of the large number of g
17、as increased agitation to form a good natural role, and part of the sludge in the response the above form a relatively thin sludge suspension, suspended sludge concentration area generally from 5 to 40 g / l range. Suspension into the area of separation, the first gas chamber was set to enter separa
18、tion, slurry containing wastewater from 3 entering the settlement room, the sludge in the settlement, returned to the reaction zone by the slant to clarify the water from the overflow. Sludge in the microbial decomposition of organic matter in sewage, it turned into gas. Tiny gas bubbles to form the
19、 release, tiny bubbles rising in the course of the merger, and gradually form larger bubbles in the sludge bed methane because of the disturbance to form a sludge concentration in the sludge and thin together with increased access to three water phase separator, encountered gas separator plate at th
20、e bottom of reflection, the reflection plate% for the four weeks, and then enter the water through the chamber, concentrated in the gas chamber with catheter export, the solid-liquid mixture into the three-phase reflection Separator sedimentation, sewage sludge in the flocculation, particle graduall
21、y increasing, and the role of gravity in the settlement. Precipitation ramps to the wall of sewage quagmire oblique wall slip back anaerobic reactor area, the reaction region accumulated a large number of sludge, and sludge from the treated effluent from the upper sediment overflow weir area, and th
22、en discharged sludge bed. The basic requirements are: (1) To provide a conducive sludge flocculation of the physical, chemical and mechanical conditions, access to anaerobic sludge sedimentation and maintain a good performance； (2) Good sludge bed often form a fairly stable biological phase, and mai
23、ntain specific probiotics environment, the strong resistance to disturbance force, the larger floc precipitation has good properties, thereby enhancing the equipment sludge concentration； (3) in the sludge bed equipment through the establishment of a precipitation area, the fine particles of sludge
24、sedimentation in the sludge layer further flocculation and sedimentation, and then back into the sludge bed. 4. UASB reactor, the process features UASB reactor operation of three important premise: reactor in the form of a good settlement or granular sludge floc sludge； produced gas and uniform dist
25、ribution of water formed by mixing a good role rational design The three-phase separator, the good performance of precipitation can remain in the sludge in the reactor. (1) the use of microorganisms immobilized cell technology - sludge particles of UASB reactor using bacteria immobilized cell technology - Implementation of the sludge particles HRT and sludge retention time of the separation, thus prolonging the sludge sludge age, and
