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Among the pillar industries of the 21st century are information, electronics, environmental protection, energy conservation, and biological engineering. With the development of the national economy, various types of enterprises have emerged. As cities expand and the demand for water for residential use increases, the treatment of industrial wastewater and domestic sewage has become a matter of priority. To achieve this, three things need to be done: 1. The discharge of wastewater and sewage must meet specified standards to prevent pollution of water sources in rivers, lakes, and seas; 2. After being treated, wastewater and sewage should be reused as much as possible; 3. Most cities in China suffer from water shortages, especially those in the north and west, so it is necessary to find new sources of water while reducing consumption. Saving water is just as important as saving electricity, and it is a crucial factor for the long-term sustainable development of the national economy. II. Waste occurs in the aeration process. 1. There are generally at least two aeration tanks, and the capacity of the equipment is determined based on the development of the enterprise. Generally, the capacity is on the high side while the actual amount of air used is low; as a result, it’s common for overcapacity to occur, leading to waste of electrical energy. 2. In many facilities, the oxygen supply to the aeration tanks is excessive, and manual methods are used to control the number of Rotary Vacuum Pumps (or ordinary blowers) in operation, which prevents timely and effective adjustment and results in waste of electrical energy. 3. The amount of oxygen supplied should take into account the volume of wastewater discharged, the quality of wastewater treatment, as well as temperature changes throughout the year and between day and night. When automatic speed control is not possible, electric energy is wasted; 4. An excessive amount of oxygen supplied can affect the quality of wastewater treatment, leading to a reduction in microorganisms and thus a decline in the treatment efficiency, which again results in waste of electric energy; 5. It is sufficient for wastewater to meet or slightly exceed the standards, and excessive oxygen supply through aeration is also uneconomical and leads to waste of electric energy. Therefore, there is an urgent need for automatic control based on preset parameters. 6. The main device used for supplying oxygen to the aeration tank is a Roots blower, which operates under constant-pressure variable-flow control. When a high air flow rate is not required, reducing the speed of the blower is sufficient to lower the flow rate. In other words, only by using variable-frequency speed control can this goal be achieved, thereby enabling efficient wastewater treatment while also achieving significant energy savings – typically over 30% reduction in energy consumption. Rotary vane fans operate as constant-torque loads, with flow rate Q being proportional to speed n; the degree of energy savings is proportional to speed. In contrast, centrifugal fans are secondary-square torque loads, where flow rate Q is proportional to speed n, while output power P is proportional to n3. As a result, they offer greater energy savings, but pressure H decreases in proportion to n2, which is different from rotary vane fans. In short, whether a Roots blower or a fan is used, adopting variable frequency speed control yields significant energy savings. III. Control methods for infinite loops 1. The single-value pH control method is used – it is simple and requires fewer wiring connections, offers excellent results, and is easy to adjust. The pH value directly reflects the quality of the water; a pH sensor is installed at the drainage outlet. It monitors changes in pH value online and generates an analog signal representing this pH value. After being processed by a PID regulator, a 4–20mA standard signal is produced, which is used to control the frequency output of the inverter and thus adjust the speed of the Roots blower, in order to regulate the amount of oxygen supplied to the variable-aeration tank. 2. The control method using two parameters, namely the oxygen content COD value and pH value, is \"complex and costly\" but highly effective: unlike Plan 1 mentioned above, it not only measures the pH value at the wastewater outlet but also monitors the oxygen content in the water in real time. A high oxygen content in the effluent indicates that the air supply to the aeration tank is too large; conversely, a low oxygen content suggests that the air supply is insufficient. This dual-control approach, which regulates both the pH value and the oxygen content, offers higher precision and better control results compared to the single pH control method mentioned earlier. However, it is more complex to adjust, and the addition of components such as PLCs and oxygen concentration meters results in higher costs for the system. IV. Advantages of the SANCH-S2000 (1) The S2000 inverter utilizes flux vector PWM control technology, enabling it to deliver 150% of its rated torque even under low-load conditions. Multiple control methods and comprehensive protection features. (2) The S2000 inverter features high frequency accuracy: +0.01% for digital settings and +0.2% for analog settings. The output frequency resolution is as high as 0.01S, ensuring smooth operation that meets the design requirements. (3) The S2000 series inverters feature overvoltage and overcurrent stall prevention functions; they allow the frequency to be maintained during acceleration and deceleration in the event of overvoltage or overcurrent, and will automatically resume acceleration and deceleration once the overvoltage or overcurrent condition is resolved. (4) Reliable torque control function: The product controls the output torque through an accurate torque limitation mechanism, making it suitable for use with high-inertia, impact-loaded applications in heavy lifting, starting machinery, and conveying equipment. (5) Independent air duct design with full sealing, providing protection against dust, air, and corrosion; it also has strong environmental adaptability and a longer service life. V. Conclusion: Nowadays, many cities have online monitoring systems for sewage discharge, providing 24/7 real-time surveillance. Whenever any unit emits wastewater that does not meet the standards, a warning is issued along with an alarm signal, thereby ensuring that the wastewater is discharged in accordance with the required standards. The computer-based management and monitoring system constantly reminds various units to properly manage the discharge of wastewater, as well as to impose fines on those that discharge wastewater below the specified standards. Whether single-value PH control is used or dual-value control involving both the oxygen content COD value and PH value, both methods can yield certain economic and social benefits, making them worthy of promotion. Our company has successfully applied this system in various enterprises, and it has been well received and favored by users