Can wastewater free of ammonia nitrogen be treated using SBR?

Of course. SBR is not designed specifically for removing ammonia nitrogen; however, compared to conventional activated sludge processes, by properly adjusting its operating parameters, it can be used to remove organic matter, ammonia nitrogen, and phosphorus.

Sure, SBR is just one of the processes used for wastewater treatment; it can not only remove ammonia nitrogen from water but also eliminate organic substances and other impurities. I’ve never heard that SBR reactors are designed specifically for treating ammonia nitrogen. Introduction to the SBR process: SBR is the abbreviation for Sequencing Batch Reactor Activated Sludge Process. It was initially proposed by British scholars Ardern and Lockett in 1914, but due to issues such as the easy clogging of aerators at that time, low levels of automatic control, and complex operational management, it was soon replaced by the continuous activated sludge process. Until the 1970s, with the development of various new types of aerators, floating outlet weirs, as well as hardware and software technologies for automatic control and monitoring – particularly the continuous improvement of computer and industrial automation technologies – it became possible to automate the wastewater treatment process. The SBR process, thanks to its unique advantages, attracted widespread attention and was rapidly developed and applied; today, hundreds of SBR wastewater treatment plants are in operation around the world. The U.S. **Environmental Protection Agency (EPA) considers the SBR process to be an environmental treatment technology with low investment costs, low operating and maintenance expenses, and high efficiency. SBR is a type of activated sludge process; its reaction mechanism and the way in which pollutants are removed are essentially the same as those of conventional activated sludge processes, with the only significant difference being the operating procedures. It divides the various units of the process in chronological order, with the entire process occurring intermittently for each individual operation unit. A typical SBR combines aeration and sedimentation in one tank, eliminating the need for a secondary sedimentation tank and sludge return equipment. In this system, the reaction tank is filled with wastewater at regular intervals, operating in an intermittent manner. After treatment, the mixture is allowed to settle; the supernatant is removed using specialized drainage equipment, while the settled biological sludge remains in the tank to be mixed again with wastewater for further treatment. This process is repeated sequentially, constituting the batch processing technique. A typical SBR system operates in five stages: water inlet, reaction, sedimentation, water discharge, and idle mode. The SBR process has the following main advantages: 1. It requires few treatment structures; a single SBR reactor combines aeration and sedimentation functions, eliminating the need for primary sedimentation tanks, secondary sedimentation tanks, and sludge return pump rooms. Therefore, **it reduces the space required for treatment structures, as well as the connection pipes and fluid transport equipment between them, which can generally lower the total project cost by 10% to 20%. 2. Due to its intermittent water supply, the duration and amount of water input can be adjusted, allowing it to adapt well to changes in water volume and quality; thus, there is no need for a separate regulation tank. 3. It requires less space – 30%-50% less than traditional activated sludge processes – making it one of the most space-efficient wastewater treatment methods available today. 4. It can remove nitrogen and phosphorus. By adjusting the aeration time and intermittent time, the wastewater is kept in alternating aerobic, anoxic, and anaerobic conditions within the reaction tank, thereby creating the conditions necessary for nitrogen and phosphorus removal in this process. At the same time, such changes in environmental conditions can also effectively suppress the growth of filaments, thereby reducing the impact of sludge bulking. 5. When a wastewater treatment plant is first put into operation, the flow rate is generally lower than the designed value. The SBR system can increase or decrease the number of operating tanks according to the requirements regarding water volume and quality, which helps to avoid unnecessary energy consumption – a feature not available in other treatment processes. The main disadvantages of the SBR process are as follows: 1. The processes of water inflow, aeration, and water outflow in the reaction tank change frequently, making it impossible to rely on manual control. Therefore, high requirements are placed on the equipment and instruments used in wastewater treatment plants, and the operators need to possess certain technical skills. 2. When the water volume is high, the issue of low volume utilization rate becomes apparent.

Yes, it is an improved version of the conventional activated sludge process

Personal opinion: For water qualities that do not contain ammonia nitrogen or have no requirements regarding ammonia nitrogen in the effluent, the SBR process is not recommended. Reason: This issue should be analyzed in this way. From a process perspective, SBR can be used to remove COD and ammonia nitrogen. So the SBR process can be used. But if further design is carried out, problems will arise. If there are no requirements for denitrification, or even for nitrification, and only the removal of COD is considered. The sludge load is often relatively high, generally above 0.2, and can reach 0.5. In such a situation, if the COD concentration of the incoming water is not high, it will inevitably result in an excessively short residence time and a high discharge rate; moreover, for reactors of a certain depth, the depth of liquid removal becomes too great. Therefore, from a process perspective, the effluent can meet the standards, but from an engineering perspective, choosing BiShui equipment presents difficulties. Therefore, it is not recommended. Furthermore, to ensure effective sludge sedimentation when the exclusion rate is too high, a greater depth of the tank is necessary, which is also unfavorable from an engineering perspective.

The treatment of nitrogen-free wastewater using biochemical processes does not yield very good results, regardless of the type of process used. The reason for this is that the biodegradability of wastewater depends on the proper proportions of its nutrient elements; the ideal C:N:P ratio is 100:5:1, as this ensures that the needs of microorganisms for growth and metabolism are met. Otherwise, it becomes difficult for microorganisms to grow, and the effectiveness of biochemical treatment is reduced. If trace elements are artificially added from the outside to meet the growth requirements, any biochemical process can be used.