Experimental Study Of Domestic Sewage With Low Carbon And Nitrogen Under Anaerobic Conditions

As the rapid developing of urbanization and industrialization, the small town sewage treatment has been put on the agenda. It is urgent to explore suitable economic sewage treatment application process for small cities and town in China. Small towns' sewage has low ratio of carbon and nitrogen. Low effectiveness of traditional bio-process is very difficult to meet discharge standards. Therefore, to seek a reasonable set of process which has reasonable technique and economic feasibility is the purpose of the study.Contemporarily, UASB process is the most popular process in application of urban sewage anaerobic treatment of currently around the world. Although China in the area of using UASB technology with high concentration of organic industrial waste water has made significant progress, using UASB treatment to treat low concentration sewage still at basic laboratory research stage. Given this, base on after collecting domestic and foreign empirical data of UASB process to treat low concentration sewage, the study focus on the UASB process improvement and innovation. First of all, improve the traditional water input way of UASB, the traditional UASB water input is at the bottom, sludge remains in dynamic situation. Now change to input water at middle part of the set, and without impact the bottom sludge in order to let sludge through the back mixed with input water; Second, improve the UASB high-ratio, reducing the high drive than the margin to occupy small space, so as to solve the problem of overtake the infrastructure space and high costs. By redesigning and innovating a new reactor, through libratory test to verify the feasibility of the process to treat low urban concentration sewage.The results are:(1) New reactor deal with the low concentration of urban sewage, direct use of sewage sludge particles training, will shorten the time of start and domesticated, with the second start within 10 days can be completed.(2) New reactor deal with urban sewage. When the temperature between 21 to 29℃, concentration of water COD is 234 - 366 mg / L, HRT = 18 - 24h time, COD removal rate can improve from 77 % to 84 %.(3) The use of the new reactor deal with sewage. Because of the sewage's COD is relatively low, and the water body have a certain buffer capacity, the reactor will not happen acidification, running in good condition.(4) In the new anaerobic reactor,using anaerobic activated sludge to rapid enrichment anammox bacteria,successfully launched the process of anaerobic ammonia nitrogen oxide.(5) The use of anaerobic activated sludge as ANAMMOX the kind of mud, control HRT in the 30 d, in the early granular sludge denitrification advantage, domesticated 54 d after the reactor in a ANAMMOX, denitrification And ANAMMOX coexistence to the first 90 d, has successfully developed a anammox activity of sludge, because of this that ANAMMOX of slow growth, in the early domesticated, the longer the HRT enrichment Anammox microorganisms Is of utmost importance.(6) In the anammox reaction starup process ,through measuring the ratio of NH4 +-N and the removal of NO2-N,COD concentration and the sludge color changes in the reactor,can understand the process of anammox reactor start-up.(7) Test conducted over five months, during sludge particle size, concentration, and the settlement of color are changing. Kind of mud (general anaerobic granular sludge) for the black ash, domesticated five months after the sludge gradually transformed into red-brown, forming ANAMMOX activated sludge. The scanning electron microscope to enlarge times after 6000 can be observed, ANAMMOX activated sludge from a large number of spherical rod-shaped bacteria and bacteria from polymerization, and internal particle form and basically can not observe the presence of filamentous.(8) Inspected water ammonia nitrite and the proportion of the anammox reaction of, in this experiment, the water for ammonia and nitrite ratio of 1:1.13, that is anaerobic Under the new reactor, there are a lot of sludge not only in the anammox bacteria, and the head of the existence of a small amount of nitrite bacteria, they co-exist in the system as a whole, the common matrix into ammonia, nitrogen and the ANAMMOX have Contribution.When the new reactor goes into stable operation, it will have a relatively strong capacity of impact. The reactor has a simple process, low construction and operating costs, operation and management is simple, and can complete sets of equipment. As for the kinds of structural forms of reactor research reports have been not found yet, the new research reactor deal with the sewage has practical values and scientific meanings.