Study On The Process Theory Of The New Composite Bioreactor

With the swiftness and violence developing of our country industry and agriculture produces and course of urbanization's ceaselessness acceleration, the industrial sewage and city waste water amounts discharging in the water environment also in escalation. That cause the water environment contaminated gravely in the whole nation range, and has bringing about extremely large damage to development of national economy and the people health already. The main expressions find in: Water resource shortage aggravating has restricted the national economy sustainable development; The drinking water security reduces threaten the people health directly; In waste water, various pollution is endangering river system ecological environments such as rivers and lakes, and ocean, and being damaging gravely the produce of industry , agriculture and fishery. Austere water pollution circumstance has already threatens our country national economy sustainable development, it not only can affect the realization of the magnificent strategic objective, but also the harmonious and stabilization of our country. Therefore, the more advanced process, technology and countermeasure must be adopted for the effective treatment and regeneration of wastewater, to guarantee national economy sustainable development. Cut down the totality of discharged pollutants thereby further, to keep dynamic balance with the self function of the water environment.That so far, biological treatment handicraft is still most economic and environmental benefits to removing the organic pollutants from wastewater. According to the microbe's growth state in the reactor, wastewater biological treatment process attached growth process and suspended growth process, the former takes living things boil process as representative, the microorganism is fixed on some species carriers with film shape;the latter takes activity sludge process as representative, the microorganism assumes suspension state within the reactor with activity sludge form. Whether having oxygen participation time operation, biological treatment process owing to may divide aerobic process and anaerobic process.But with prompt development of modern industry, the amounts the city and the industrial sewage are discharged enlarge, the quality and quantity of water become more instability, kind and quantity of difficult to degradation organic increase unceasingly, tradition biological treatment process shortage has being revealed gradually; with the living standard rise and the enhancement of the environmental protection and health awareness, the request to the area wave environmental quality living improves also unceasingly. Bringing about to dislodge the suspension thing and organic pollution succeeds this factor in two aspects for the target tradition sewage treatment handicraft is difficult to be.During the past scores of years, at home and abroad, the researcher has carried out unremitting efforts and the exploration, and put up amounts improvement and innovation, such as operation and oxygen supply, run conditions, reactor form, and intensifying processing. For the high-effect and energy conservation aspect of the activity sludge development, processes such as A/B process, anaerobic-aerobic activity sludge process (A/O , A2/O etc.), batch activity sludge process(SBR , CAST , UNITANK , MSBR etc.) studying the personnel develops out diversified new model activity sludge law handicraft, anaerobism gradually at home and abroad. Among them, the dyadic activity of intermittence sludge follows handicraft arousing home and abroad in recent years taking seriously broadly, whose studies and applies increasing by days. Successive steps is at the same time thorough with the fact that cognition and basic theory about characteristic studies to biomembrane, gradually, developing out various new model biomembrane reactor handicraft and system , moving bed living things reactor, tiny hole film living things reactor such as and so on.Besides, to improving the microbe amounts in the aeration reactor, strengthen waste water treatment ability, overcome sludge bulking, and to improve the running stability basing on the sludge handicraft, people has invented the method of adding the carriers into the aeration reactor, also namely combined bioreactor. In which, the suspended and attached growth microbe are exist at the same time. Abroad research is indicated, combined bioreactor can improve the sludge settlement function noticeably, overcomes the sludge bulking, the nitrifying bacteria to adhering and growthing on the carriers firstly, and to make the sludge age of the suspened growth microbe has nothing to do with the nitrification. For the advantage of the economy and hi-effect, the technology provided a practical feasible approach, with which can resolved the insufficient of sewage treatment establishments, and weakness problem of economic basement of our country. However the overseas manufacturer blanked off the combined bioreactor technologies, the correlative informations is very limited. Our research in this field is still in the fumbling stage, the majority design parameter depends on the experience. It is not the idealer state, yet, that union aspect in theory and application, at present.Basing on the study on the abroad combined bioreactor achievement deeply, and start with the increasing mass tranfer rate and improving microbe amount, choose the cycling activity sludge technology (CAST), which have high-effect founction of denitrification and phosphate removalthe,as the study objec. The issue takes the lead in uniting the bio-carriers with the CAST, and empolder the cycling actived sludge biofilm technology(CAS-BT).The research started with the combined bioreactor dynamics mechanism. Under the think , the the combined bioreactor keep the main structure of the original handicraft. However the added carrier has changed the sewage treatment mechanism and efficacy extremely. The microbe living environment has been changed, which was from the gas-liquid two-phase to the gas-that in this system, the microorganism survival basis environment reason turns out to gas-liquid-solid three-phase. The change riched the microbe living form, and to make a more complicated ecosystem. When biofilm on the carrier surface reach the stable state, it works with the suspension sludge at the same time. Each of them brings self degradation function, correlate at the same time on two direction vertical and horizontal. The suspended activited sludge will lose in the system only, with the excess sludge and secondary settling tank. Therefore the suspened sludge age can be defined conveniently, whose mathematics expression is:If the separation rate of s secondary settling tank is 100%, i.e. X v , se= 0,the expression can be simplified as:Subsequently, the traditional CAST was innovated adopting the above-mentioned dynamics model. At first, the microbe selector was comparted with clapboards, use for reference of the anaerobic baffled reactor(ABR). It has provided the PF nearly water flow on macroscopic view, and created more advantageous microbe entironment. Secondly, added the suspended carriers into the microbe treatment unit,so the cycling actived sludge biofilm reactor has been developed out.Adopt the organic glass experimental model to treated the contain beer foul water in the laboratory. The carrier was self-made with polypropylene multy-hole shell and foam blocks inside. The filling rate inne reactor was 20%. The results indicated: when inflow water COD under 4500 mg/L, the outflow under 100 mg/L, the inflow COD change has limited effect with outflow; when inflow water COD was above 4500 mg/L, the outflow under 200 mg/L. The COD removing rate was comparatively high throughout the experiment period, between 91.88%～98.91%. when inflow water BOD5 under 2700 mg/L, the outflow under 20 mg/L; when inflow water BOD5 was above 2700 mg/L, the outflow under 60 mg/L. The BOD5 removal rate was above 96% during the experiment. The BOD5 removal rate change was relativly bigger in prophase of testing, and stabilized comparatively in 99% in anaphase.The result is indicated, because the microbe selector was set up in the foreside of the reactor, suspended activity sludge, recirculated from the main react unit to selector, mixed with inflow water, and went through a high-load (anaerobic) period, these are equal beneficial to growth of system flocculation bacterium, and retrained silk bacterium growth and propagate; Otherwise, the filling carrier can increased the microbe amounts in the reactor, face to the chang of inflow water COD loading having stronger acclimatization, and keep higher removing rate. When COD load within 4.5 Kg/m3-d, outflow water COD thickness may reach the first discharge standards.The experiment has also examed the pH, the sludge settlement capbility, mixture liquid supened solid (MLSS), and discovered: under the condition restrict sludge discharging, inflow COD, the sludge settlement capbility, microbe amount on the biofilm has been relatived with MLSS. According to MLSS changing curve, the MLSS was increase by sometimes and decrease in other times, but change is not big collectivity. That explained the handicraft has self-adjust capbility.In experiment, the sharp change thichness of sewage has been simulated, in order to exame the resistance to impact load of reactor, and the twice power cut condition has also appeared during the test period. But test result indicates not outflow COD rise obviously, it explain that the cycling actived sludge biofilm handicraft has stronger resistance ability to impact load.The dynamic simulattion experiment has reached various anticipate target completely. In order to examine the CAS-BT traetment capbility to the actual sewage, and to accumulate experience for the more generalizing and application, be further application and dissemination, specifically for project application of X power plant residential area domestic sewage project and Chang Chun City Shuang Yang Qu wastewater treatment factory handicraft reconstruction project.X power plant residential area domestic sewage project becomes the representativeness of sewage discharge and resuse after treated, which comes from mines and enterprises far away from the city. Project 3500 m3/d processing scale, the outflow qulity request reaches the country "synthetical discharge standard of wastewater" (GB8978-96) first discharge standard.That project working stabilized since bing established, outflow water quality reaching the country accordingly discharge standard completely, and resolved the environmental pollution by the discharged domestic sewage radically. The treated sewage has been reuse to manufacture and virescence, what was benefit to water saving, energy conservation and envionment protection and so on at the same time, has created notable economic benefit, environment benefit and social benefit.The Chang Chun Shuang Yang wastewater treatment factory builds in 2000, designed by Chinese municipal engineering design institute in northeast, adopt CAST handicraft. The factory has been located in Chang Chun City drinking water source field upper reaches, the designing scale is 25000 m3/d. Take up 3.2 hectares of field. The Chang Chun Shuang Yang Qu domestic sewage (account for 80% in total) and the Yinu brewery industrial sewage mainly (account for 20% in total). Because of the effect of the water temperature and the variety water quality, the microbe treatment process could not reach the design target all along, and outflow water quality being not enough to stabilize. Therefore, adopt the CAS-BT handicraft to carry out a skill reform.The running results demonstrating: reforming system has reached or better than designing target. When inflow water CODCr far exceeding the designing level in May, outflow CODCr still being lower than the designing target, visible that system have certain resistance to impact load. System capbility of phosphate removal is fairly good, removal rate amounting to 51.6% ~ 77.7%; NH3-N removal rate amounts to 58.9% ~ 98.7%. When the water temperature is lower especially in winter, outflow water quality though being worse than summer, it still can stabilize operation, and reach the water quality. adopt research result, may on in existence sewage treatment factory structure basis, consider every aspect factor synthetically, improve the treatment capability without more its building size addition, through adding the low-cost carrier. This process is more competitive, in technology and economy, and is suitable to our country. Its application will help improve sewage treatment water level, will reduces sewage treatment cost. The CAS-BT will have the extremely vast application prospect on the wastewater treatment plant extension and reconstruction of our country in the future.