10 Ways Flow Meters Help Water and Wastewater Treatment

10 Ways Flow Meters Help Water and Wastewater Treatment

The safe and efficient operation of water and wastewater treatment systems relies on precise control of flow parameters. As core monitoring equipment, flow meters operate throughout the entire process chain from drinking water source collection to terminal distribution and wastewater collection to regeneration/discharge. Through their diverse functions, they provide critical support for the treatment process. This article will examine 10 key ways flow meters contribute to water and wastewater treatment, combining the core processes of these two systems.

1. Five core ways flow meters assist drinking water treatment

The core goal of drinking water treatment is "safe water quality and stable and reliable supply". Flow meters are involved in the entire process from source control and process optimization to terminal distribution, ensuring the quality of system operation through five key methods.

(1) Method 1: Ecological management of water source to avoid the risk of over-exploitation

1.1 Application Scenario

Installed at the outlet of the main drinking water intake pump, it monitors the flow rate of raw water extracted from surface water rivers, lakes or deep groundwater wells.

1.2 Assistance principle and effect

a. Ecological carrying capacity guarantee : Real-time tracking of raw water extraction flow rates ensures that the water withdrawal rate does not exceed the ecological carrying capacity threshold of the water source. For example, groundwater withdrawal should avoid excessive water level drop that may cause land subsidence, and surface water withdrawal should comply with the requirements of the watershed water withdrawal permit, thus protecting the ecological balance of water resources at the source;

b. Supply and demand matching warning : The water intake flow rate is linked to the subsequent purification treatment capacity. When the flow rate exceeds the treatment capacity, an automatic warning will be issued to avoid the accumulation and deterioration of raw water, or insufficient flow rate leading to material shortage in subsequent processes;

c. Rapid fault location : Monitor abnormal flow fluctuations. When the flow rate suddenly increases (indicating filter damage or abnormal pump load) or suddenly decreases (indicating water intake blockage or pump failure), the linkage alarm system triggers an investigation to reduce the scope of the fault impact.

1.3 Key supporting requirements

The flow meter needs to be adapted to the raw water quality characteristics, such as the sand content of surface water and the corrosiveness of groundwater, and a model with anti-clogging and anti-interference functions should be selected; at the same time, it should be linked with the water source level monitoring system to achieve dual control of flow and water level.

a. Water source protection and control : Real-time monitoring of raw water extraction flow rates to ensure that the rate of water withdrawal does not exceed the ecological carrying capacity of the water source (e.g., groundwater withdrawal should avoid excessive water level drop, and surface water withdrawal should comply with the watershed water withdrawal permit) to prevent ecological damage;

b. Production scheduling basis : cumulatively record the total amount of water intake, compare it with the subsequent purified water volume and finished water volume, calculate the loss rate of each link, and provide data support for production plan adjustments;

c. Fault warning triggering : When the flow rate suddenly increases, it may be due to the damage of the filter screen causing impurities to enter, abnormal pump load, or a sudden decrease may be due to the blockage of the water intake or pump failure, the flow meter will be linked to the alarm system to trigger the troubleshooting process in time.

(2) Method 2: Accurately adding purification agents to improve treatment efficiency and reduce costs

Purification treatment is the core link in achieving drinking water quality standards, covering key processes such as coagulation and disinfection. The flow meter accurately feedbacks water volume data to achieve dynamic matching of chemical addition, and is the core support for process optimization.

2.1 Application of coagulation and sedimentation process

A flow meter installed in the sedimentation tank's inlet pipe transmits real-time flow data to the coagulant dosing control system. The system automatically adjusts the coagulant dosage based on the "flow rate x target concentration" formula. As the raw water flow increases, the system increases the dosage to ensure that fine suspended matter fully agglomerates into flocs. As the flow decreases, the dosage is reduced accordingly to prevent potential water quality risks from residual coagulant.

At the same time, by monitoring the outflow rate of the sedimentation tank, it is possible to determine whether the sludge is discharged in a timely manner. When the outflow rate continues to decrease, it indicates that there is too much sludge accumulated at the bottom of the tank, resulting in a reduction in the flow area, triggering the automatic sludge discharge process to ensure the sedimentation effect.

2.2 Application of disinfection process

High-precision flow meters are installed in the disinfection reactor's water inlet pipes to provide accurate data support for the addition of disinfectants such as chlorine and chlorine dioxide. The flow meters provide real-time feedback on water volume changes, and the dosing pump automatically adjusts the dosage, ensuring the killing of microorganisms such as bacteria and viruses while controlling the residual chlorine in the terminal water within the specified range, thereby preventing excessive production of disinfection byproducts.

(3) Method 3: Filtration system status monitoring to ensure water purity and extend service life

3.1 Application Scenarios

Flow meters are installed on the inlet and outlet pipes of core filtration units such as sand filtration and activated carbon filtration to monitor key conditions such as filter layer blockage and backwashing effect.

3.2 Assistance principle and effect

a. Accurate blockage warning : By comparing the difference between the inlet and outlet water flow rates, the degree of filter layer contamination can be determined. If the filter layer retains too much suspended matter, causing blockage, the backwash process can be started in a timely manner to avoid excessive turbidity in the outlet water due to decreased filtration efficiency.

b. Backwash parameter optimization : During the backwash process, the flow meter monitors the flushing water flow in real time and controls it within a reasonable range, preventing excessive flow from damaging the filter layer structure and insufficient flow from causing incomplete flushing.

c. Refinement of loss calculation : record the total amount of water in and out of the filtration unit, calculate the water loss during the filtration process, provide data basis for process parameter adjustment, and improve overall processing efficiency.

(4) Method 4: Water level balance in the water storage link to adapt to peak water consumption fluctuations

4.1 Application Scenarios

Flow meters are installed on the inlet and outlet pipes of water storage facilities, such as clear water tanks and elevated water tanks, to enable bidirectional monitoring of inflow and outflow. As a critical buffer between continuous purification and intermittent water use, water storage requires dynamic flow control to balance supply and demand, avoiding water outages during peak hours and overflows during low hours. Flow meters are the core data collection unit in this process.

4.2 Assistance Principle and Effect

a. Dynamic water level control : The flow meter collects inlet and outlet flow data in real time and transmits it to the PLC control system, forming a "flow-water level" linkage closed loop. During peak water usage in the morning and evening, the outflow rate surges, causing the water storage level to drop. The system automatically increases the capacity of the water intake and purification processes based on the flow difference, accelerating water replenishment. During low-peak periods such as nighttime, the outflow rate decreases, and the system simultaneously reduces the inflow rate, stabilizing the water level within a safe range of 30%-80% of the tank capacity. This eliminates the risk of water supply interruptions and avoids water waste caused by overflows.

b. Analysis of water usage patterns : Flow meters record daily and weekly water storage turnover data. Data analysis tools are used to identify fluctuations in water usage. This provides a basis for developing flexible production capacity plans for the purification process, improving purification efficiency, reducing equipment idling energy consumption, and enhancing system operating economics.

c. Accurately detect potential leaks : By comparing the theoretical difference between inflow and outflow rates with actual water level fluctuations, a leak warning model is established. When the inflow rate consistently exceeds the outflow rate but the water level does not rise significantly, the system immediately triggers an audible and visual alarm, directing operations personnel to investigate cracks in the water storage facilities, leaking pipe connections, or valve failures, ultimately minimizing leakage in the pipeline network.

4.3 Necessity of flow measurement and application of flowmeter

The core contradiction in water storage is the mismatch between supply and demand. Flow measurement is key to resolving this conflict: without real-time data from a flow meter, it's impossible to accurately determine the cause of water level fluctuations, leading to the risk of blind replenishment or supply disruptions. In practice, high-precision electromagnetic flowmeters are used at the water inlet and ultrasonic flowmeters at the water outlet. Their data is coordinated to achieve balanced supply and demand management.

4.4 Key supporting requirements

a. The flow meter needs to be deeply linked with the liquid level sensor and PLC control system to ensure that flow data and water level data are collected and analyzed synchronously to avoid inaccurate control caused by data delay;

b. Select models with IP68 protection level and support 24-hour continuous operation, suitable for the humid and continuous operation environment of water storage facilities;

c. Establish a flow calibration mechanism once a month, verify the accuracy through standard flow devices, and ensure that the data error is controlled within ±1%.

(5) Method 5: Pipeline network transmission status diagnosis to reduce leakage and energy consumption risks

5.1 Application Scenarios

Flow meters are installed on the main pipes, key branches and user entrances of the municipal water supply network according to the level to build a flow monitoring network for the entire network.

5.2 Assistance Principle and Effect

a. Leak and blockage location : The main pipeline flow meter monitors the total flow rate, which is then compared and analyzed with the branch flow data from each area. A sudden drop in flow in a certain area indicates a pipeline blockage. A large difference between the total flow rate and user usage indicates the leak area, providing a basis for precise maintenance and reducing the leakage rate of the pipeline network.

b. Collaborative optimization of pressure and flow : Flow meter data is linked to pipe network pressure monitoring to dynamically adjust the booster pump speed based on flow demand. During peak hours, the speed is increased to increase flow and maintain stable pressure; during off-peak hours, the speed is reduced to achieve energy-saving operation and reduce energy costs.

c. Terminal metering and traceability : Household flow meters accurately record user water consumption, providing an authoritative basis for water fee calculation. At the same time, by monitoring abnormal flow at the user end, we can reversely check for minor leaks in the household pipes to protect users' water rights.

5.3 Necessity of flow measurement and application of flowmeter

The flow rate in this link is the "barometer" of the operating status of the pipeline network. Flow meters are installed in layers on the main pipeline, key branch pipes and household ends.

a. Pipeline network status monitoring : The main pipeline flow meter monitors the total transmission flow, and combined with the data from the branch flow meters in each area, the flow distribution is analyzed to determine whether there is pipeline blockage or leakage;

b. Collaborative control of pressure and flow : Flow meter data is linked to the network booster pump to adjust the pump speed according to flow demand. For example, during peak hours, the speed is increased to increase flow, maintain stable pressure, and reduce energy consumption.

c. Terminal metering and traceability : Household flow meters record user water consumption and provide a basis for water fee calculation. At the same time, through abnormal flow at the user end (such as long-term unoccupied but with continuous low flow), we can reversely check for minor leaks in the household pipes.

2. Five core ways flow meters assist in wastewater treatment

Wastewater treatment takes "environmentally friendly discharge and resource recycling" as its core goal. The flow meter covers the entire process from collection, pretreatment, core treatment to terminal output, improving treatment efficiency and compliance through 5 key methods.

(1) Method 6: Control the total amount of wastewater collected to avoid impact on the treatment system

1.1 Application Scenarios

Flow meters are installed at the sewage network access points, industrial wastewater collection points, and lift pump station inlets and outlets in each area to achieve full monitoring of the wastewater collection process.

1.2 Assistance principle and effect

a. Industrial pollution source control : Flow meters at the industrial wastewater collection point are linked with online water quality monitoring equipment such as COD and ammonia nitrogen to calculate the total amount of pollutant emissions (concentration × flow rate) in real time. When the collection point exceeds the collection standard, the shutoff valve is triggered to prevent high-concentration wastewater from impacting the treatment plant's biochemical system.

b. Basis for capacity planning : Monitor the sewage inflow from different areas, including residential, commercial, and industrial areas, and cumulatively calculate regional wastewater generation to provide accurate data support for treatment plant expansion, renovation, and process adjustments;

c. Pump station operation optimization : By improving the monitoring of the water flow in and out of the pump station, the operating load of the pump group is determined, and the standby pump is automatically started during peak hours to avoid overload failures; when the flow drops suddenly, it indicates that the pipe network is blocked, and dredging operations are arranged in time to prevent sewage backflow.

1.3 Necessity of flow measurement and application of flowmeter

The flow rate in this link is the core basis for the treatment plant's capacity planning and pollution source control. Flow meters are installed at the pipe access ends of each area, the industrial wastewater collection ends, and the inlets and outlets of the lift pump stations.

a.Capacity matching planning : Monitor the inflow of residential, commercial, and industrial wastewater in each area, cumulatively calculate regional wastewater generation, and provide data for treatment plant expansion and process adjustments;

b.Industrial pollution source control : Industrial wastewater inlet flowmeters combined with online water quality monitoring of COD and ammonia nitrogen control the company's wastewater discharge volume and concentration. If the limit is exceeded, the shut-off valve is triggered to avoid impact on the treatment system.

c.Pump station operation optimization : monitor the water flow in and out of the pump station, determine the operating load of the pump group, start the backup pump during peak hours to avoid overload failures; when the flow drops suddenly, the flow change can be used to detect pipe network blockage.

(2) Method 7: Control pretreatment process parameters to improve impurity removal efficiency

Wastewater pretreatment aims to remove large particles of impurities, sediment, etc., and protect subsequent core equipment. The flow meter improves the screen interception, sand settling and water quality and quantity regulation effects by adjusting key parameters.

2.1 Application of screen and grit chamber

A flow meter is installed at the water inlet of the screen. When the flow rate drops by more than 20%, it indicates that the screen residue is blocked, triggering the automatic residue cleaning device or manual cleaning process to avoid sewage overflow; the flow meter at the water inlet of the sand settling tank controls the stable value of the water flow velocity in the tank by adjusting the water inlet valve, ensuring that inorganic particles such as mud and sand are fully settled, reducing subsequent wear on the pump body.

2.2 Regulating pool application

Flow meters are installed on the inlet and outlet pipes of the regulating tank respectively. Through liquid level-flow linkage control, the water level in the tank is maintained stable to avoid peak flow impacting subsequent processes; the accumulated inlet and outlet water flows are used to analyze the pattern of wastewater generation, providing a basis for the operation and scheduling of the core treatment process, ensuring a stable and continuous treatment process.

(3) Method 8: Biochemical treatment load is stable to ensure pollutant degradation effect

Biochemical treatment is the core link in the degradation of wastewater pollutants. The flow meter maintains a stable environment for microbial growth by controlling the inlet flow.

3.1 Application Scenarios and Principles

A flow meter is installed in the biochemical reactor's inlet pipe to strictly control the inlet flow rate and ensure a stable hydraulic retention time, allowing microorganisms ample time to absorb and degrade pollutants such as COD and ammonia nitrogen. When flow fluctuations exceed the specified value, the regulating tank outlet valve is linked to provide buffering, preventing shock loads that could cause mass microbial death and ensuring treatment effectiveness.

3.2 Accessibility

The pollutant removal rate can be accurately calculated through the inlet and outlet water flow and pollutant concentration data, providing a basis for adjusting parameters such as aeration intensity and sludge return ratio, thereby optimizing the biochemical treatment efficiency.

(4) Method 9: Sludge treatment process control to achieve reduction and harmlessness

4.1 Application Scenarios

Flow meters are installed at the sludge thickening tank, the feed end of the dehydration equipment and the filtrate return pipe to cover the whole process monitoring of sludge "concentration-dehydration-filtrate return".

4.2 Assistance Principle and Effect

a. Improved treatment efficiency : Monitor the feed flow rate of the thickening tank and control the thickening time to ensure that the sludge moisture content reaches the ideal effect; the flow meter at the feed end of the dehydration equipment accurately controls the feed speed to avoid inadequate dehydration caused by overload or idling and wasteful equipment caused by insufficient feed;

b. Filtrate return balance : The high-concentration filtrate generated by sludge dehydration needs to be returned to the pretreatment stage for reprocessing. The flow meter monitors the return flow rate and controls it within the capacity of the pretreatment system to avoid impacting the water quality of the regulating tank;

c. Accurate production calculation : By converting flow rate and sludge concentration data, the amount of sludge generated is recorded in real time, providing data support for the optimization of disposal options such as composting, incineration or landfill, and achieving harmless sludge management.

Function : Remove trace pollutants and suspended solids to make the water quality meet the recycled water standards and sewage recycling project design standards, and be used for green irrigation, industrial cooling, road cleaning, etc.

Key requirements : The membrane assembly needs to control the water flow and pressure to prevent membrane fouling; the activated carbon needs to be replaced regularly to ensure the adsorption effect.

Flow meter application : Install a high-precision flow meter on the water inlet pipe of the membrane module to maintain a constant water inlet flow and avoid membrane damage caused by flow fluctuations; record the deep treatment water output, calculate the recycled water utilization rate, and optimize the recycled water distribution plan.

(5) Method 10: Emission and recycling flow accounting to ensure compliance and resource utilization

5.1 Application Scenarios

Flow meters are installed at the wastewater discharge outlet, recycled water transmission main pipeline and user end to realize full monitoring and accounting of the terminal output.

5.2 Assistance Principle and Effect

a. Environmental compliance monitoring : Electromagnetic flowmeters and other equipment that meet environmental certification standards are installed at the discharge outlets to record discharge flow in real time. This information is then linked to online water quality monitoring data to generate a total discharge report, which is accurately reported to the environmental protection department to ensure that discharges comply with pollutant discharge standards for sewage treatment plants.

b. Efficient reclaimed water dispatch : Flow meters on reclaimed water mains monitor total delivery volume. Combined with data from user-side flow meters for green irrigation, industrial cooling, and other applications, water allocation is optimized, prioritizing high-demand users and improving reclaimed water utilization.

c. System efficiency calculation : By comparing the total amount of water intake with the amount of discharged/recycled water, the water loss during the treatment process is calculated, providing a basis for process water-saving modifications and improving overall resource utilization efficiency.

5.3 Necessity of flow measurement and application of flowmeter

The flow rate in this link is the key data for environmental accounting and resource utilization. The flow meter is installed at the discharge port, recycled water transmission main pipeline and user end.

a. Environmental compliance monitoring : GTRF50 electromagnetic flowmeters that meet environmental certification standards are installed at the discharge outlets to record discharge flow in real time. This is linked to online water quality monitoring data to generate a report on total discharge volume and report it to the environmental protection department.

b. Recycled water dispatch management : The flow meter on the recycled water main pipe monitors the total delivery volume, and the allocation plan is optimized based on the flow meter data at each user end;

c. Operation efficiency calculation : By comparing the total amount of water intake with the amount of discharged/recycled water, the treatment process losses are calculated and the water-saving effect of the process is optimized.

Core guarantee points for flow meter application

The efficient application of flow meters in water and wastewater treatment systems requires three key guarantees: accurate selection, system linkage, and regular maintenance.

a. You can select the JUJEA manufacturer's flow meter selection table according to the water quality characteristics, such as the GTUL30 ultrasonic flow meter for drinking water, which is suitable for low turbidity, and the GTRF50 electromagnetic flow meter for wastewater, which is suitable for anti-suspended matter interference;

b. Deeply linked with PLC control system and water quality monitoring equipment to achieve real-time data sharing and automatic control;

c. Establish a regular calibration and maintenance mechanism to ensure long-term accurate and reliable flow data. Through scientific application, flow meters can fully leverage their four core values of "monitoring, control, early warning, and accounting," providing solid support for the safe, efficient, and compliant operation of water and wastewater treatment systems.