Essential in the water treatment industry | Comprehensive analysis of the application of four sensors

1. Flow Sensor Core application scenarios
• Raw water inlet monitoring: At the inlet of water treatment plants and sewage treatment plants, install electromagnetic flowmeters or ultrasonic flowmeters to measure the intake volume of raw water in real time, providing a basis for the parameter regulation of subsequent coagulation and sedimentation processes, and serving as the core data source for water resource measurement and cost accounting.
• Precise control of chemical dosage: In water treatment processes, the dosage of flocculants, disinfectants, etc. needs to be strictly matched with the water flow rate - the flow sensor is linked with the dosing pump, providing real-time feedback on water flow changes and automatically adjusting the dosage of chemicals to avoid waste (excessive dosage increases costs) or non-compliance with treatment standards (insufficient dosage cannot remove pollutants).
• Flow regulation in intermediate processes: In sedimentation tanks, filtration tanks, disinfection tanks, etc., monitor the flow rate of water to ensure that the residence time of water in each process unit meets the standards (such as slow water flow in the disinfection tank easily leads to bacterial growth, and fast water flow in the disinfection tank makes disinfection incomplete), ensuring stable treatment effects.
• Outflow discharge measurement: Install Flow Sensors at the outlet to accurately measure the discharge volume of treated wastewater/clear water, meeting the emission supervision requirements of environmental protection departments on the one hand, and providing data support for the efficiency assessment and process optimization of the water treatment system on the other hand.
• Sludge Flow Monitoring: In the sludge return and dewatering processes, monitor the sludge flow to optimize the sludge treatment process, avoiding sludge accumulation that causes system blockage and improving sludge disposal efficiency [6].
2. Pressure Sensors Core application scenarios
• Pump body operation monitoring and protection: Install pressure sensors at the inlet and outlet of the pump to monitor the suction pressure and discharge pressure of the pump. This prevents the pump from idling (low suction pressure) or operating under excessive pressure (high discharge pressure), thereby extending the service life of the pump body. At the same time, the pressure data is used to adjust the pump speed to achieve energy-saving operation.
• Pressure difference monitoring of filters/membrane modules: Install pressure sensors at the inlet and outlet of filters, ultrafiltration membranes, and reverse osmosis membranes to monitor the pressure difference between the inlet and outlet. When the pressure difference is too large, it indicates that the filter material or membrane module is clogged. An early warning is issued promptly to remind the staff to perform backwashing or replacement, avoiding a decrease in filtration efficiency and damage to the membrane module. This is also crucial for ensuring the stability of the filtration process.
• Backpressure monitoring of the dosing system: Install pressure sensors at the outlet of the metering pump to monitor the backpressure of the dosing system. Insufficient backpressure will cause inaccurate dosing volume, while excessive backpressure will increase the risks of the pump body and pipeline. The pressure feedback can precisely adjust the dosing pressure to ensure uniform drug addition.
• Pipeline pressure monitoring: Install pressure sensors in municipal water supply pipelines and industrial circulating water pipelines to monitor the pressure distribution of the pipelines. Timely detection of pipeline leaks (sudden drop in pressure) and local overpressure is carried out. This assists in pipeline scheduling and ensures the stability of water supply/circulating water.
• Pressure control of water quality sensor sampling systems: Monitor pressure changes at the inlet and outlet of sampling cells for pH, ORP, residual chlorine, etc. water quality sensors. Ensure stable pressure in the sampling cells and prevent air bubbles from entering to ensure accurate and reliable water quality test data. Many abnormal water quality data have their root cause in unstable pressure.
3. Level sensors Core application scenarios
• Control of the water level in the raw water tank / clear water tank: Install Liquid Level Sensors in the raw water tank and clear water tank to monitor the liquid level of the tanks. When the liquid level is lower than the set value, the water replenishment pump will automatically start to replenish water; when the liquid level is higher than the set value, the water replenishment will be stopped and the drainage pump will be started to prevent overflow and ensure the stable water supply for subsequent processes.
• Liquid level regulation of the reaction tank: Monitor the liquid level height in reaction tanks such as coagulation tank, sedimentation tank, and disinfection tank to ensure that the water retention time in the tanks meets the standards, and avoid overflow of water due to excessive liquid level or impact on the reaction effect due to insufficient liquid level, providing a basis for the adjustment of parameters for processes such as stirring and aeration.
• Liquid level monitoring of the sludge tank: Install liquid level sensors in sludge concentration tanks and sludge storage tanks to monitor the sludge liquid level. When the liquid level is too high, the sludge pump will be activated to transport the sludge in time to avoid sludge accumulation and overflow, and prevent environmental pollution; when the liquid level is too low, the sludge pump will be stopped to avoid idle operation and equipment damage.
• Liquid level monitoring of the chemical tank: Install liquid level sensors in chemical storage tanks and mixing tanks to monitor the chemical liquid level. When the liquid level is too low, an alarm will be triggered to remind the staff to replenish the chemicals to avoid treatment not meeting standards due to insufficient chemicals; at the same time, prevent chemical overflow and reduce chemical waste and safety hazards.
• Liquid level control of the rainwater tank: Install liquid level sensors in rainwater storage tanks in the rainwater recovery system, and link PLC to achieve automatic control of the inlet valve and water pump. When the liquid level is lower than the middle level, the inlet valve will be automatically opened to replenish water; when the liquid level is higher than the upper limit, the inlet valve will be closed to ensure the stable operation of the rainwater recovery system.
4. Temperature sensors Core application scenarios
• Temperature control in biological treatment processes: In the biochemical tanks (such as aeration tanks) of wastewater treatment, monitor the water temperature - microorganisms (such as nitrifying bacteria and denitrifying bacteria) are sensitive to temperature, and the optimal temperature range is 20-35℃. If the temperature is too low, the microbial activity will decrease, and the treatment efficiency will drop; if the temperature is too high, the microorganisms will die, and the system will collapse. By using temperature sensors to provide feedback data, adjust the aeration intensity and heating equipment to maintain stable water temperature.
• Temperature regulation in disinfection processes: In the disinfection stage (such as ultraviolet disinfection, chlorine disinfection), temperature will affect the disinfection effect - for example, when ultraviolet disinfection is carried out, if the water temperature is too high, it will reduce the penetration rate of ultraviolet rays, affecting the disinfection and sterilization effect; when adding chlorine for disinfection, if the temperature is too low, it will reduce the dissolution efficiency of chlorine gas, resulting in incomplete disinfection. The temperature sensor monitors the water temperature of the disinfection tank in real time and adjusts the disinfection parameters in time to ensure the disinfection meets the standards.
• Monitoring of circulating water temperature: In industrial circulating water treatment systems, monitor the inlet and outlet water temperatures of the circulating water, adjust the operating parameters of the cooling tower and heat exchanger, reduce the circulating water temperature, improve heat exchange efficiency, and reduce energy consumption.
• Foundation for parameter correction: Temperature directly affects the dissolved oxygen content in water and the chemical reaction rate, and is the basic parameter for correcting the readings of other water quality sensors, ensuring the accuracy of all monitoring data.
• Winter anti-freezing protection: In northern regions or in low-temperature environments, monitor the water temperature of pipelines and tanks. When the temperature is below 0℃, start anti-freezing equipment (such as heating pipes) to prevent pipeline freezing and cracking, ensuring the normal operation of the system in winter.