In wastewater treatment systems, the application of measurement and automation technologies plays a key role. These technologies not only ensure strict control over effluent quality but also optimize operation, save energy and costs, and comply with increasingly stringent environmental standards.
Key Parameters to be Monitored in Wastewater Treatment
To maintain stable and efficient system operation, the following important parameters must be continuously monitored:
- pH: Evaluates the acidity/alkalinity of water.
- DO (Dissolved Oxygen): Critical in aerobic biological processes.
- ORP (Oxidation-Reduction Potential): Indicates oxidation-reduction capacity in water.
- TSS (Total Suspended Solids): Measures the total amount of suspended solids in wastewater.
- COD, BOD: Chemical and Biological Oxygen Demand – essential criteria for evaluating pollution levels.
- Flowrate and Totalizer: Controls inlet and outlet flow, as well as dosing and inter-stage transfers.
- Level: Monitors water levels in tanks, clarifiers, and reactors.
- Pressure: Protects pumps and pipelines, detects blockages or clogged filters.
- Temperature: Influences reaction rates and microbial activity.
- Turbidity: Checks effluent clarity and water quality after treatment.
- Residual Chlorine: Monitors chlorine concentration after disinfection (if chlorine is used).
- Ammonia (NH4⁺): Measures ammonia concentration after treatment.
- Total P & Total N: Evaluates total phosphorus and nitrogen after treatment.
- Salinity (Salt concentration): Monitors salt content in cases of saline wastewater.
Common Measurement Devices
- Online pH/ORP sensors: Continuous monitoring; signals sent to PLC/SCADA for automatic chemical dosing control.
- Optical DO sensors: Long lifetime, low calibration needs; suitable for aerobic and AO tanks.
- Level sensors: Ultrasonic, radar, hydrostatic, or capacitive technologies for tank monitoring and automatic pump/valve control.
- Level switches: Float or electrode type; detect low, medium, or high levels for pump/valve switching or pump protection.
- Flow sensors: Electromagnetic or ultrasonic – accurate and unaffected by solids.
- Online sensors for TSS/COD/BOD/Turbidity/Ammonia/Total P/N/Chlorine/Salinity: Provide real-time pollution monitoring to ensure effluent compliance.
- Pressure sensors: Installed in pipelines, pump suction/discharge lines, closed tanks, or before/after filters – enable pump control, equipment protection, and blockage/leak detection.
- Temperature sensors: Monitor wastewater temperature, assess influent quality, track biological treatment efficiency, or control heating/sludge drying systems.
Automation and Control Systems
- PLC (Programmable Logic Controller): The “brain” of the system; processes signals from sensors and controls pumps, blowers, and valves.
- SCADA (Supervisory Control and Data Acquisition): Centralized interface for process visualization, data logging, alarms, and reporting.
- HMI (Human Machine Interface): Local control screens for easy operation, monitoring, and system configuration.
- Inverter (Variable Frequency Drive): Controls pump and blower speeds for precise process control, energy savings, and extended equipment lifetime.
- Effluent automatic and continuous monitoring system: Transfers treated wastewater quality and quantity data to environmental authorities to meet legal requirements.
Benefits of Measurement and Automation Technologies
- Improve treatment efficiency
- Save chemicals and energy
- Detect and resolve failures promptly
- Ensure compliance with discharge regulations
- Reduce operator workload and optimize operating costs
Conclusion
The application of measurement devices and automation technologies is an inevitable trend in today’s wastewater treatment industry. It ensures system efficiency and safety, helps businesses maintain legal compliance, and supports sustainable development.
Viet Nhat Measurement Equipment & Industrial Valves JSC (VNTECH GROUP) is proud to provide comprehensive solutions in measurement, control, and automation for the water and environmental industries. With prestigious brands such as UWT (Germany), PR Electronics (Denmark), BD Sensors, Suku, TA, Yokogawa, we are committed to delivering high-quality products and professional technical services to customers nationwide.