3 Process Study The operation and operation in the SBR process are performed periodically, and the operation control is complicated. On the other hand, SBR process optimization control can greatly improve efficiency and reduce energy consumption. Therefore, how to effectively control the process is of great importance to the theoretical research and practical application of the SBR process. 4 Conclusion SBR reactor has been widely used in the research and application of a variety of difficult-to-degrade organics, and has achieved better results. However, due to the intermittent cycle operation of the SBR process, the concentration of DO and organic substances in the reactor continuously changes with time, and the degradation mechanism, reaction kinetics, and engineering design of microorganisms that are in a cyclically changing environment for refractory organics are designed. Process control, among other things, is more complex, giving researchers greater challenges than studying continuous activated sludge processes for the treatment of refractory organics. Although the current SBR process mechanism and design research are still in the initial stage, due to SBR's flexible operation and strong anti-shock load capacity, it can adapt to the intermittent and irregular discharge of wastewater, and it also shows good degradation effect on continuous non-degradable organics. The process will have very broad application prospects in the treatment of refractory organics, especially small and medium-sized petrochemical, papermaking, printing and dyeing, oil refining, and pharmaceutical companies.  (Author: Wang Donghai, Wen Xiang Hua, Qian Yi / "China Water & Wastewater")  Ningbo XISXI E-commerce Co., Ltd , https://www.petspetsaccessories.com
Sludge swelling is a common problem in continuous process operation, and SBR can successfully prevent the sludge from swelling. For this reason, many scholars tried to clarify the mechanism of sludge swelling and its control method through the study of SBR inhibition mechanism of filamentous bacteria. Steven C. Chiesa et al.'s study confirmed that microorganisms are in an environment where eutrophication and oligotrophy are alternately changed, that is, under the conditions of significant increase in initial substrate concentration, high growth rate (high substrate concentration), and long oligotrophic time, all Can effectively inhibit the growth of filamentous bacteria. The magnitude and timing of oligotrophy have an important influence on the relative amount of flocculent sludge and on the ability of microorganisms to synthesize extracellular enzymes that maintain the integrity of flocculent sludge. For this purpose, Chie sa discovered that the special ecological environment in SBR provided a certain biological selection ability by comparing the continuous and intermittent operation, the growth conditions of the filamentous fungi in the reaction pool, and the control method. This ability can be obtained from the substrate. Non-filamentous microorganisms that absorb organic matter and maintain high activity in the delayed endogenous metabolism stage become dominant microorganisms. The ability of SBR to select organisms is determined by many factors such as the feeding method, DO, organic loading rate, the maximum growth rate and the duration of its maintenance, the range and range of oligotrophic nutrients, and the frequency of rich and poor nutrition alternating. The maximum growth rate of the selected organism depends on the nutritional properties of the matrix, and different substrate organisms require different concentrations of choice. Based on the above conclusions, Chiesa believes that although the continuous method operation can maintain good sludge settling performance, the organic load rate has a very small variable range and is prone to sludge expansion when the organic load is adjusted and the DO in the reactor is controlled. When it is not possible to avoid sludge expansion, the continuous operation can be changed to intermittent operation. Franta et al. found that if the reaction time is too short and lean nutrient time is insufficient, sludge swelling will occur more easily. 
2.3 Microbial characteristics
Robert L. Irvine studied the biodegradation mechanism of SBR by studying the microbiological characteristics of refractory organics. From the microbiological point of view, the biggest feature of SBR is that microorganisms are in an environment rich in nutrients, oligotrophic, aerobic, anoxic, and anaerobic. The decrease in nutrient concentration in the reactor can increase the rate of intake of nutrients and increase the range of available matrices. By controlling changes in operating cycles, flow rates, nutrient concentrations, and environmental pressures such as DO, the choice of microorganisms in the reactor can be enhanced because different microorganisms are at work under different conditions. SBR not only has the advantage of changing the operating mode, but also controls the operating cycle, inlet and outlet water flow, nutrient concentration, and DO conditions. SBR can also change the environmental pressure of microorganisms and strengthen microorganisms. The specific microorganisms enriched under the conditions determined by the influent water will be strengthened in the reaction section, which will in turn lead to changes in biophysiology and yield, which will further promote the selection of organisms by SBR. Cristiani Urbina et al. studied the growth kinetics of Torulopsis cremoris in batch or continuous operation in SBR-treated milk wastewater and found that the growth rate of T. cremori in SB R was 26% faster than that of the continuous type. M.Okada studied the biological activity of SBR in the treatment of phenol-containing wastewater and compared the activity of bacteria in continuous anaerobic SBR and anaerobic / aerobic SBR in the degradation of phenol under two shock loads. The results showed that the best biological activity and patience were high. Phenol loaded aerobic SBR was obtained. The high initial phenol concentration in SBR contributes to the increase of biological activity, and the biological activity is lower at the continuous low phenol concentration. SBR can give proper phenol loading and stable sludge activity to the sludge, so that it can also run stably under high impact load. The enhanced bacterial activity of degraded phenol is mainly the ability of bacteria to degrade and endure phenol, rather than the total number of bacteria. . Wilson et al. isolated two aerobic gram-negative bacterium strains containing only Diterpene and Isopimaric Acid as the carbon source and electron donor from SBR used to treat high-concentration papermaking wastewater. The growth characteristics and nutrient sources of these two kinds of bacteria were studied to improve the effect of SBR in treating papermaking wastewater. 
3.1 Online Control
Yongzhen Peng et al. studied the aeration operation using ORP to control SBR. Since the ORP sensor can accurately display the biooxidation state in the reactor, the ORP can be used to control the aeration time in the SBR, and the dynamic online adjustment of the aeration time length can be used to minimize the aeration amount to avoid the waste of energy. The experiment found that at the end of the oxidation (reflected by the balance of the COD), the ORP in the SBR rapidly increases. In a particular wastewater treatment, the ORP platform appears within a narrow range, depending on the influent composition, aeration time, MLSS value, and system organic load, so the ORP platform can be used to end the aeration to save energy. Y.Hamamoto et al. used “fuzzy logic†control to automatically determine the optimal agitation and aeration phases. Parameters in the fuzzy control were DO, pH, ORP, and the water level in the reaction cell. After the fuzzy control, the energy was significantly reduced. Consumption. 
3.2 Process Design
Many scholars have studied the design process of SBR. Ketchum LH analyzed the SBR design process and physical characteristics of different processing targets. In the design, the incoming water will be static water (completely restricted), stirred water (half-limited), and aeration water (not limited). According to different treatment targets, the operation strategy is broadly divided into five types. It is recommended that the operation methods aiming at the treatment of industrial waste water and toxic and hazardous waste water are: short-time agitation plus long-term aeration.
3.3 Startup Strategy
M.Muniz et al. studied the start-up strategy for SBR treatment of waste water containing refractory organics to reduce start-up time, save inoculant sludge volume, and reduce start-up costs. The operating period is 6 h, the influent aeration time is 4 h, the precipitation time is 1.5 h, and the effluent time is 0.5 h. The start-up phase is divided into an inoculation phase and a conditional control phase in time. Inoculation with less sludge at the inoculation stage not only saves sludge volume and transportation costs, but it also acquires microorganisms that are more adaptable to new wastewater. In the feeding stage, according to the requirements of the microorganisms on the COD and the inhibitory effect of the toxicity on the microorganisms in the treated object, the amount of toxic and harmful substances is gradually increased to the final content, so as to achieve a constant growth rate constant of the feed section, a high COD removal rate, and sludge Good settling performance. 
2.2 Sludge bulking mechanism