In the fields of modern Industrial Internet of Things (IIoT) and smart environmental protection, system integrators face core challenges that go beyond the physical and chemical removal of pollutants; it is about how to drive automated processes through high-precision real-time monitoring data to achieve compliant discharge and cost reduction with efficiency gains.

As a manufacturer deeply involved in the field of industrial water quality monitoring, YEXSENSOR is committed to providing global integrators with high-stability, multi-protocol compatible sensor core components. This article will analyze the technical characteristics and integrated treatment paths of 21 common pollutants in wastewater treatment from a professional engineering perspective.

1. Oxygen-Consuming Organic Matter and Biochemical Degradation Monitoring (COD/BOD/TOC)

Oxygen-consuming organic substances (such as proteins, sugars, esters, etc.) are the most basic monitoring dimensions for urban sewage and industrial wastewater. In system integration, how to accurately convert Chemical Oxygen Demand (COD) and Biochemical Oxygen Demand (BOD) is the core of process logic.

1.1 Pollutant Characteristics and Sources

• Main Sources: Paper making, petrochemical, food processing, and pharmaceutical industries.

• Technical Challenge: Traditional laboratory analysis has time lags and cannot meet the needs of automated aeration control.

1.2 YEXSENSOR Real-time Monitoring Technology Solution

For system integrators, we recommend using full-spectrum UV method sensors or electrochemical sensors to achieve second-level response.

2. Refractory Organic Matter and Advanced Oxidation Processes (AOPs)

For refractory organic matter such as organic chlorides and organophosphorus pesticides, conventional biochemical methods (Activated Sludge) are often ineffective. Systems usually need to integrate anaerobic acidification or Advanced Oxidation Processes (AOPs) modules.

• Integration Point: After AOPs processes (such as Fenton reaction, ozone oxidation), the Oxidation-Reduction Potential (ORP) must be monitored in real-time to ensure the reaction is complete.

• Solution: Recommend integrating YEXSENSOR industrial grade ORP transmitters, supporting RS485 (Modbus RTU) protocol for direct connection to PLC or edge computing gateways.

3. Nutrient Removal: Nitrogen and Phosphorus Monitoring and Closed-loop Control

3.1 Nitrogen Cycle Control (Nitrogen Removal)

Wastewater containing nitrogen comes from a wide range of sources, from coking and chemical fertilizers to meat processing. Integrators usually design "nitrification/denitrification" processes (A/O).

• Monitoring Key: Dynamic balance between Ammonia Nitrogen (NH3-N) and Nitrate Nitrogen (NO3-N).

• Sensor Selection: Using Ion Selective Electrode (ISE) technology enables long-term operation without reagents.

3.2 Phosphorus Removal Optimization

Chemical phosphorus removal requires precise dosing of PAC or PFS.

• Integration Solution: Combined with an online total phosphorus analyzer, real-time feedback via 4-20mA analog or digital signals to the metering pump control system prevents sludge increase caused by over-dosing.

4. Metal Processing and Electroplating Wastewater: Heavy Metals and Acid-Base Balance

Heavy metals (Silver, Nickel, Lead, Chromium, Mercury, Cadmium, Arsenic) have strong biological toxicity. Their monitoring accuracy is directly related to the compliance risk control of the project.

4.1 Heavy Metal Monitoring Matrix

4.2 Acid-Base Balance and Neutralization Systems

Acid-base wastewater treatment systems have extremely high requirements for the corrosion resistance of pH sensors. The industrial grade pH probes provided by YEXSENSOR use a rugged polytetrafluoroethylene (PTFE) annular liquid junction, specifically optimized for wastewater containing fluorine and high salt, reducing cleaning frequency.

5. Oil Pollutants and Physical-Chemical Separation

Petroleum oils and greases are mainly divided into free state, mechanically dispersed state, emulsified state, dissolved state, and solid attached oil.

• System Integration: Grease traps (API) and Dissolved Air Flotation (DAF) units are standard configurations.

• Automation Point: Integrators need to configure oil detectors (light scattering method or UV fluorescence method) at the outlet to ensure emulsified oil is effectively treated, preventing damage to downstream membrane modules.

6. Selection Guide for System Integrators

In industrial projects, sensor selection directly determines the delivery quality of smart solutions.

6.1 Communication Protocol and Electrical Compatibility

• Digital Transformation: Prioritize RS485 (Modbus RTU) protocol, which supports long-distance transmission and multi-node networking, simplifying wiring costs.

• Redundancy Design: It is recommended to retain 4-20mA analog output for core monitoring points as a secondary guarantee for the local control system.

6.2 Adaptability to Harsh Environments

• Material Grade: For strong acids and alkalis, sensor housings should be made of titanium alloy, Hastelloy C-276, or high-density PVC.

• Self-cleaning Mechanism: For wastewater with high Suspended Solids (SS), a compressed air cleaning or mechanical brush system must be configured.

6.3 System Compatibility Parameter Table (Partial)

7. Application Case: Smart Aquaculture and Industrial Circulating Water

In a large-scale project for 20,000 aquaculture monitoring units, the main issue integrators faced was the drastic fluctuations in nitrite and dissolved oxygen (DO) levels in the water.

• Solution: By deploying YEXSENSOR fluorescence-based dissolved oxygen sensors and digital ammonia nitrogen sensors, integrators built an automated aeration prediction model, reducing energy consumption by 18% while avoiding economic losses caused by toxic substance accumulation.

8. FAQ: Frequently Asked Questions for Engineering Integration

Q1: Can YEXSENSOR sensors be directly connected to Siemens or Schneider PLCs?
A1: Yes. Our sensors' standard output is Modbus RTU (RS485), which can directly interface with the communication modules of mainstream PLCs on the market, providing standard register address tables.

Q2: How do you solve the scaling problem of sensors in a sewage environment?
A2: We provide models with automatic cleaning functions (such as brush cleaning or air purging), specifically designed for industrial wastewater containing high grease or prone to scaling.

Q3: How is nitrate and nitrite monitoring achieved in the denitrification process?
A3: In system integration, it is recommended to place sensors at the end of the anoxic and oxic stages to real-time adjust carbon source dosing by monitoring nitrate nitrogen concentration.

Q4: When treating acid-base wastewater, how long is the maintenance cycle for pH sensors?
A4: It depends on the concentration of acid/base and impurities in the wastewater. In automated systems, we recommend combining automatic cleaning devices to extend the manual calibration cycle to 3-6 months.

Q5: For heavy metal monitoring, do the sensors need to be used with color-developing agents?
A5: For online monitoring, we have two solutions: electrochemical method (reagent-free) and photometric method (with reagents). For integrators, the electrochemical method is more suitable for IIoT projects with low maintenance costs.

Q6: Does the sensor support remote configuration of parameters?
A6: Yes. Via the RS485 bus, technicians can use host computer software to remotely modify the sensor slave address, baud rate, and slope compensation.

Q7: How to prevent lightning strikes or surges in the industrial field from damaging the sensors?
A7: YEXSENSOR products have built-in TVS surge protection and anti-reverse connection designs. It is recommended that integrators configure additional isolation barriers at the PLC end.

Q8: Do you provide OEM/ODM services?
A8: For large-scale projects or specific brand owners, we provide deep customization services, including sensor appearance, communication protocol customization, and private labeling.

9. Summary

The efficacy of water treatment systems highly depends on the data quality of the "perception layer". For system integrators, choosing a supplier who understands industrial conditions, provides multi-dimensional parameter support, and has a strong communication background is crucial. YEXSENSOR provides not just sensors, but the underlying technical guarantee that empowers integrators.

When facing the challenge of 21 complex pollutants, precise monitoring is the cornerstone for achieving zero-violation discharge and optimized operating costs. We will continue to provide global environmental engineering companies with "small and beautiful" and extremely stable monitoring solutions in vertical fields.