Wastewater Treatment Plant Online Monitoring Solution: Digital Engine for Refined Process Control and Energy Saving & Emission Reduction

Industry Pain Points and the Urgency of Process Optimization

As the core ecological water purification facility for cities and industrial parks, modern wastewater treatment plants face dual pressures of increasingly stringent environmental discharge regulations and internal cost control. Traditional extensive operation models can no longer meet the demands of refined and intelligent development.

Industry Problems

• High risk of effluent exceedance due to water quality fluctuations: Illegal industrial wastewater discharge or concentrated inflow during heavy rain often causes sudden spikes in influent load (such as high COD or toxic substances), severely impacting activated sludge microorganisms in the biochemical system and triggering sudden effluent exceedance.

• Aeration and chemical dosing rely entirely on experience, resulting in high energy consumption: Blower aeration systems and carbon source/phosphorus removal agent dosing often lack real-time feedback. To blindly pursue compliance, operators usually choose excessive aeration and overdosing, causing electricity and chemical costs to erode most of the enterprise's profits.

• Traditional wet chemical analyzers are extremely cumbersome to maintain: Previously widely used chemical reagent analyzers have complex structures, pipelines prone to scaling and blockage, and huge monthly reagent consumption and waste liquid treatment expenses, making it difficult to achieve second-level response.

Why Online Monitoring is Needed?

Wastewater treatment is essentially a dynamic and complex biochemical reaction process. Relying solely on manual periodic sampling analysis results in data lag of several hours, which cannot guide real-time process adjustments. Online monitoring can convert physicochemical indicators of biochemical reactors (such as anaerobic, anoxic, and aerobic tanks) and effluent outlets into continuous time-series data. It serves as the "eyes" of wastewater plant process automation switching. Only with second-level perception can return ratios be adjusted promptly during influent fluctuations or aeration machines be precisely shut down when nitrification ends.

What Can YEXsensor Wastewater Treatment Plant Online Monitoring System Solve?

The wastewater treatment plant online monitoring system developed by YEXsensor uses advanced digital physical optical and electrochemical sensors to fully replace traditional high-maintenance chemical reagent instruments. The system not only accurately monitors compliance indicators at the final effluent outlet but can also be deployed in-situ at core process nodes such as coarse screens, equalization tanks, aeration tanks, and secondary sedimentation tanks. Through standard Modbus-RTU protocol, the system seamlessly integrates into existing SCADA plant control systems and directly participates in closed-loop feedback control such as variable frequency aeration and automatic dosing, achieving significant reduction in plant-wide energy and chemical consumption while ensuring effluent compliance.

Wastewater Treatment Plant Online Monitoring System Application Scenarios

This system features strong anti-fouling and chemical corrosion resistance, perfectly covering the entire process control nodes of wastewater treatment:

• Influent equalization tank and inlet: Monitor high-concentration influent shocks, provide feedforward warnings for pretreatment and primary sedimentation processes to prevent toxic substances from damaging biochemical sludge.

• Biological reaction tanks (anaerobic/anoxic/aerobic): Accurately capture the core biochemical status of each zone to guide aeration distribution and nitrification/denitrification switching.

• Secondary sedimentation tank and sludge return system: Monitor sludge interface and suspended solids concentration to prevent sludge loss and optimize sludge return ratio (R) and excess sludge discharge in real time.

• Final effluent outlet (compliance discharge monitoring): 24-hour continuous monitoring of discharge indicators to ensure 100% compliance with national and local environmental regulations.

• Industrial wastewater pretreatment facilities: Suitable for automated control in internal wastewater stations of high-concentration industrial enterprises such as chemical, paper, printing and dyeing, and electroplating.

Wastewater Treatment Plant Online Monitoring System Components

1. Industrial-grade Water Quality Sensor Cluster (Physical Perception Layer)

• YEX-S1-COD UV Absorption Analyzer: Reagent-free 254nm UV optical physical absorption method, automatically eliminates suspended solids interference, outputs organic load trends in seconds, zero waste liquid.

• YEX-S1-NHN Ion Selective Electrode NHN-S-Online-Ammonia-Nitrogen-Sensor.html">Ammonia Nitrogen Sensor: Advanced non-reagent ISE method, integrated ammonium, potassium (interference elimination), and pH electrodes for in-situ rapid response.

• YEX-S1-PH Industrial pH Sensor: Large-area PTFE ring double salt bridge design, highly resistant to fouling by surfactants and organic solvents.

• YEX-S1-ORP Oxidation-Reduction Potential Sensor: High-purity platinum sensing surface, accurately reflects nitrification and denitrification control endpoints in aeration tanks.

• YEX-S1-ZS Suspended Solids/Turbidity Module: Infrared dual-wavelength scattering and transmission light compensation technology for accurate MLSS or SS measurement.

2. Plant Digital Data Acquisition Telemetering Terminal (Control Convergence Layer)
   IP65 protected intelligent IoT control cabinet with high-performance 32-bit processor for data reading, local display, and analog/switch output.

3. Communication Links and SCADA System Interface (Network Transmission Layer)
   Modbus-RTU/TCP support for seamless integration with Siemens, Hollysys and other PLC systems. Dual redundancy with 4G/LoRa for large plants.

4. Low-power Solar Power Supply (Optional Energy Layer)
   100W solar panel + 60Ah lithium battery for remote nodes without mains power.

5. YEXsensor Intelligent Wastewater Plant Cloud Platform (Decision Application Layer)
   B/S architecture remote visualization dashboard with process flowcharts, trend analysis, multi-channel alarms, and report export.

Monitoring Parameters and Working Principle

Key Features

• Reagent-free physical measurement, eliminating secondary pollution from waste liquid

• Built-in compressed air/mechanical self-cleaning, resistant to extreme fouling

• Multi-layer hardware and software filtering to suppress bubble interference

• Seamless high-integration integration with SCADA systems

System Architecture

The system adopts a classic three-layer industrial IoT architecture with high decoupling and high cohesion:

[On-site Process Node In-situ Sensing (RS485 Bus)] → [Plant Local Control & Transmission] → [Central Command Application Layer]

YEX-S1-COD, YEX-S1-NHN, YEX-S1-PH, YEX-S1-ORP, YEX-S1-ZS → Industrial Intelligent Telemetering Cabinet (Modbus-TCP) → Plant Central SCADA System → YEXsensor Intelligent Wastewater Cloud Platform (via 4G/LoRa)

Customer Value and Benefits

• Comprehensive digitalization of processes, strengthening 100% effluent compliance底线

• Refined control of aeration and dosing, significantly reducing operating costs (15-25% energy saving, over 20% chemical reduction)

• Greatly reduces frontline operation and maintenance workload

Recommended Sensor Product List

1. Effluent Compliance Three-parameter Integrated Unit: Reagent-free COD + ISE Ammonia Nitrogen + pH, with stainless steel explosion-proof enclosure and automatic air backwash.

2. Biochemical Tank ORP & Sludge Concentration Kit: High-purity platinum ORP + high-range sludge concentration meter.

3. Digital Plant Communication Control Cabinet (YEX-RTU-1): Siemens-compatible, 4G router, touch screen, surge protection.

Project Case

Case 1: Smart Aeration Energy Optimization Project at a Municipal Wastewater Treatment Plant in Central China (50,000 tons/day)

Background: Long-term fixed power aeration, high summer electricity costs, and excessive aeration at night leading to sludge disintegration.

Solution: Deployed YEX-S1-ORP and YEX-S1-ZS sensors in aerobic tanks, integrated with Siemens S7-1500 PLC via Modbus-TCP.

Results: After 8 months, aeration energy consumption decreased by 21.4% while maintaining effluent ammonia nitrogen better than Class A standard, saving tens of thousands of RMB in monthly electricity bills.

FAQ

Q1: How does the optical COD sensor (YEX-S1-COD) prevent lens fouling in oily and high-suspended solids wastewater?
Answer: The sensor housing uses fluid dynamics inclined surface design to reduce adhesion. It is equipped with industrial-grade automatic air backwash or mechanical brush assembly. High-pressure air is sprayed or the brush is activated before each measurement to remove oil and biofilm instantly.

Q2: Will the ion selective electrode ammonia nitrogen sensor (YEX-S1-NHN) be interfered by potassium ions in water?
Answer: Yes, potassium and ammonium ions have similar characteristics. YEXsensor uses multi-parameter integrated compensation technology with dedicated potassium electrode inside the probe. The microprocessor automatically subtracts interference through mathematical models to ensure accurate net ammonia nitrogen readings.

Q3: Why use ORP for auxiliary process control? What is the difference from dissolved oxygen (DO)?
Answer: DO only reflects free oxygen and often reads 0.0 mg/L in anoxic/anaerobic tanks, becoming ineffective. ORP reflects the overall macroscopic oxidation-reduction state and can capture reaction endpoints through combined oxygen (nitrate) changes, enabling refined control that DO cannot achieve.

Contact YEXsensor for Intelligent Wastewater Solutions

Looking for core control transmitters for variable frequency aeration renovation or optimization of carbon source dosing pump linkage logic? Welcome to contact the YEXsensor industrial water treatment expert team for one-stop technical support.

Technical Consultation: +8615111147890

Email: sales@yexsensor.com