In the pharmaceutical and chemical industries, large amounts of acids, alkalis, inorganic salts, and organic solvents are used in synthesis, extraction, crystallization, washing, neutralization, and concentration processes. As a result, wastewater generated from these processes often features high salinity, high COD, strong toxicity, complex composition, large fluctuations, and poor biodegradability. For environmental engineering companies, system integrators, IoT solution providers, and project contractors, the challenge of high-salinity wastewater projects is not only selecting a suitable treatment process, but also building a stable, continuous, and traceable online water quality monitoring system.
In pharmaceutical and chemical high-salinity wastewater treatment projects, a water quality monitor should not be regarded as a single testing device. It should be positioned as the core perception layer of the wastewater treatment system. Through continuous monitoring of key parameters such as pH, ORP, conductivity, TDS, COD, ammonia nitrogen, turbidity, dissolved oxygen, temperature, liquid level, and flow, system integrators can achieve process judgment, automatic dosing, load adjustment, abnormal alarm, data retention, and remote operation and maintenance, thereby improving the stability of the overall treatment system and the quality of engineering delivery.
Typical Characteristics of Pharmaceutical and Chemical High-Salinity Wastewater
Pharmaceutical and chemical high-salinity wastewater generally comes from API production, intermediate synthesis, fine chemical reactions, equipment cleaning, mother liquor separation, acid-base neutralization, and reverse osmosis concentrate treatment. Its main water quality characteristics include:
1. High Salt Concentration
The TDS of some wastewater can reach tens of thousands to more than one hundred thousand mg/L, and the conductivity is significantly higher than that of conventional industrial wastewater.
2. High COD Concentration
Wastewater often contains refractory organic matter, aromatic compounds, heterocyclic compounds, and solvent residues. COD may reach several thousand to tens of thousands of mg/L.
3. Large Water Quality Fluctuations
Different product batches, reaction sections, and cleaning cycles can cause rapid changes in wastewater quality.
4. Poor Biodegradability
A high-salt environment inhibits microbial activity, resulting in slow start-up and weak shock resistance of traditional biological treatment systems.
5. Strong Corrosiveness and Toxicity
Acid-base fluctuations, chloride ions, sulfate, and toxic organic substances can affect the operation of equipment, pipelines, sensors, and biological systems.
Therefore, during the project design stage, system integrators need to consider the treatment process, monitoring points, sensor materials, communication protocols, control logic, and subsequent maintenance at the same time.
Analysis of High-Salinity Wastewater Treatment Process Routes
Pharmaceutical and chemical high-salinity wastewater is usually difficult to treat stably with a single process. In engineering projects, a combined process route of “pretreatment + desalination concentration + advanced oxidation + biological treatment + advanced treatment” is more commonly adopted.
Pretreatment Unit
The purpose of pretreatment is to reduce suspended solids, adjust pH, reduce part of COD, remove oil, and improve the influent conditions of subsequent systems. Common processes include screening, sedimentation, air flotation, coagulation, acid-base neutralization, iron-carbon micro-electrolysis, and Fenton oxidation.
For pharmaceutical and chemical wastewater with high COD, high chromaticity, benzene rings, or refractory organic substances, iron-carbon micro-electrolysis and Fenton reaction are often used for front-end enhanced treatment. Such processes can destroy part of the macromolecular organic structure, improve the B/C ratio, and create better conditions for subsequent biological treatment.
Desalination and Concentration Unit
The core of high-salinity wastewater treatment is salt separation. Common technologies include reverse osmosis, nanofiltration, multi-effect evaporation, MVR evaporation, membrane distillation, and electrodialysis.
Multi-effect evaporation and MVR evaporation are suitable for treating high-salinity concentrates. They can recover part of the fresh water and further concentrate salts. Membrane distillation technology is suitable for further separation of high-salt and high-concentration solutions. Its advantages include relatively low operating pressure and good adaptability to high-salt systems.
In engineering applications, desalination and concentration systems rely heavily on conductivity, TDS, temperature, pH, pressure, flow, and other parameters. Online monitoring data can be directly used to judge membrane fouling, evaporation load, concentration ratio, and system abnormalities.
Advanced Oxidation Unit
For refractory organic pollutants, advanced oxidation can be used as an important enhanced treatment method. Common methods include Fenton oxidation, ozone oxidation, catalytic oxidation, and electrochemical oxidation.
This unit usually requires linkage control of pH, ORP, COD, temperature, and dosing amount. Without online monitoring, the system may easily suffer from excessive dosing, insufficient reaction, increased operating costs, or unstable effluent quality.
Biological Treatment Unit
After pretreatment and appropriate desalination, part of the wastewater can enter the biological treatment system. Common processes include A/O, A2/O, SBR, MBR, salt-tolerant biological treatment systems, and PSB photosynthetic bacteria treatment systems.
Before pharmaceutical and chemical high-salinity wastewater enters the biological system, salinity, COD, pH, temperature, dissolved oxygen, and ammonia nitrogen should be closely monitored. If the influent salinity is too high or the shock load is too large, the microbial system may become unstable. Therefore, the online monitoring system should participate in influent diversion, bypass adjustment, aeration control, and abnormal alarms.
Integration Value of YexSensor Water Quality Monitors in High-Salinity Wastewater Projects
YexSensor provides water quality sensors and instruments suitable for online monitoring system integration in industrial water treatment, environmental engineering, smart water management, and IoT projects. For pharmaceutical and chemical high-salinity wastewater projects, YexSensor devices can serve as front-end sensing equipment for PLC, SCADA, data collectors, cloud platforms, or edge gateways.
Typical Monitoring Parameters and Application Locations
| Monitoring Parameter | Recommended Monitoring Position | Engineering Function | Integration Value |
|---|---|---|---|
| pH | Equalization tank, neutralization tank, Fenton reaction tank, biological influent | Controls acid and alkali dosing and protects downstream equipment | Supports automatic dosing and alarm linkage |
| ORP | Advanced oxidation tank, anaerobic/anoxic section | Judges oxidation-reduction status | Optimizes oxidant dosing and reaction conditions |
| Conductivity/TDS | High-salinity influent, RO concentrate, evaporation influent, reclaimed water | Judges salinity changes and concentration ratio | Supports desalination system operation judgment |
| COD | Equalization tank, pretreatment effluent, final discharge outlet | Judges organic pollution load | Used for process load adjustment and compliance analysis |
| Ammonia Nitrogen | Biological influent and effluent, final discharge outlet | Judges nitrogen removal performance | Supports aeration and reflux control |
| Dissolved Oxygen DO | Aerobic tank, MBR tank, PSB system | Controls aeration intensity | Reduces energy consumption and stabilizes the microbial system |
| Turbidity/SS | Sedimentation tank, filtration effluent, reclaimed water | Judges solid-liquid separation performance | Supports filter backwashing and abnormal alarms |
| Temperature | Main treatment units | Corrects water quality data and judges reaction conditions | Improves monitoring accuracy |
| Liquid Level/Flow | Equalization tank, dosing system, pipelines | Controls pump and valve start-stop and system load | Supports automatic operation |
Communication and System Compatibility
In B2B engineering projects, device compatibility often directly affects system integration efficiency. YexSensor water quality monitors can support RS485 Modbus RTU, 4-20mA, and other commonly used industrial signal methods according to project requirements, making them easy to connect to PLC, RTU, DTU, data collectors, HMI touch panels, SCADA systems, and cloud platforms.
For system integrators, RS485 Modbus RTU offers advantages such as simple wiring, strong anti-interference capability, high protocol universality, and suitability for multi-point access. If PLC or SCADA has already been deployed in the project, multiple-parameter water quality sensors can be quickly incorporated into the existing control system through unified address management, polling acquisition, and data mapping.
Selection Guide for Pharmaceutical and Chemical High-Salinity Wastewater Projects
1. Select Sensor Materials According to Water Corrosiveness
High-salinity wastewater may contain chloride ions, acids, alkalis, solvents, and strong oxidizing substances. Therefore, the sensor housing, electrode, sealing components, and mounting accessories need good corrosion resistance. During project selection, the wastewater pH range, temperature, salinity, oil content, strong oxidant content, and crystallization risk should be confirmed.
2. Select Monitoring Parameters According to Process Position
The equalization tank is suitable for pH, conductivity, COD, liquid level, and temperature monitoring. The advanced oxidation section is suitable for pH, ORP, and COD monitoring. The biological section is suitable for DO, pH, temperature, and ammonia nitrogen monitoring. The desalination and concentration section is suitable for conductivity, TDS, temperature, flow, and pressure-related signal monitoring.
3. Select Communication Method According to System Architecture
If PLC control is used on site, RS485 Modbus RTU or 4-20mA signal is recommended. If a remote cloud platform is used, data can be uploaded through a data collector or 4G gateway. For projects with multiple monitoring points, equipment addresses, communication distance, power supply mode, lightning protection, and grounding should be planned in advance.
4. Select Cleaning Method According to Maintenance Conditions
Pharmaceutical and chemical wastewater is prone to scaling, biofilm formation, sedimentation, and pollutant adhesion. For long-term online monitoring points such as COD, turbidity, DO, and ammonia nitrogen, sensors with self-cleaning structures or convenient maintenance designs should be prioritized to reduce manual maintenance frequency.
5. Configure Data Systems According to Project Acceptance Requirements
Some environmental engineering projects require data retention, report export, trend curves, alarm records, and remote access functions. System integrators can connect YexSensor sensors to local SCADA or cloud platforms to realize visual management of project operation data.
Integration Precautions
First, the sensor installation point should avoid strong bubbles, strong mixing dead zones, sedimentation areas, and direct chemical dosing points to prevent excessive data fluctuations.
Second, high-salinity wastewater has high conductivity. On-site wiring should pay attention to shielding, grounding, and separation of strong and weak currents to reduce signal interference.
Third, pH and ORP electrodes need regular calibration. Parameters such as COD and ammonia nitrogen should be maintained at reasonable intervals according to project requirements.
Fourth, if the wastewater contains a large amount of suspended solids or oil, a bypass flow cell, filtration protection, or regular cleaning structure should be considered before the sensor.
Fifth, in the PLC or SCADA system, data upper and lower limits, abnormal value filtering, communication interruption alarms, and equipment maintenance reminders should be configured.
Sixth, during project commissioning, it is recommended to keep comparison records between laboratory test data and online instrument data, which can support correction model establishment and project acceptance.
Typical Project Application Scenarios
API Production Wastewater Treatment Station
API wastewater usually has high COD, high salinity, and strong toxicity. System integrators can configure pH, conductivity, COD, and liquid level monitoring in the equalization tank; pH, ORP, and COD monitoring in the iron-carbon micro-electrolysis and Fenton reaction sections; and DO, pH, temperature, and ammonia nitrogen monitoring in the biological system, forming a complete monitoring chain from front-end pretreatment to final discharge.
Reverse Osmosis Concentrate and MVR Evaporation System
In RO concentrate and MVR evaporation systems, conductivity, TDS, temperature, and flow are key operating parameters. By monitoring the concentration ratio and inlet-outlet water changes online, engineering companies can judge system operation status, scaling risk, and maintenance cycle.
Centralized Wastewater Treatment Project in Pharmaceutical and Chemical Industrial Parks
Industrial park projects usually involve mixed wastewater from multiple enterprises, making water quality fluctuations more obvious. Online water quality monitors can be used at enterprise discharge outlets, equalization tanks, pretreatment sections, biological sections, and final discharge outlets to help operators establish classified management, abnormality tracking, and remote supervision systems.
FAQ
Q1: Why do pharmaceutical and chemical high-salinity wastewater projects need online water quality monitors?
Because high-salinity wastewater fluctuates greatly, manual sampling alone makes it difficult to detect shock loads in time. Online water quality monitors can continuously monitor key parameters such as pH, conductivity, COD, DO, and ammonia nitrogen, providing real-time data for PLC control, dosing adjustment, alarm linkage, and operation optimization.
Q2: What are the most commonly monitored parameters in high-salinity wastewater projects?
Common parameters include pH, ORP, conductivity, TDS, COD, ammonia nitrogen, dissolved oxygen, turbidity, temperature, liquid level, and flow. The specific configuration should be determined according to the process section and project objective.
Q3: Can YexSensor sensors be connected to PLC or SCADA systems?
Yes. YexSensor industrial water quality sensors can support RS485 Modbus RTU, 4-20mA, and other communication methods according to project requirements. They are suitable for connection to PLC, RTU, data collectors, SCADA systems, and cloud platforms.
Q4: Will high-salinity wastewater affect sensor service life?
High-salinity, high-COD, strong acid-base, or corrosive wastewater will increase sensor maintenance pressure. Therefore, material, range, installation method, cleaning structure, and maintenance cycle should be confirmed during selection.
Q5: What role do conductivity and TDS play in high-salinity wastewater treatment?
Conductivity and TDS can be used to judge salinity changes, desalination effect, concentration ratio, and the operating status of membrane systems or evaporation systems. They are core monitoring parameters in high-salinity wastewater treatment projects.
Q6: Where is COD online monitoring suitable for installation?
COD online monitoring can be installed in the equalization tank, pretreatment effluent, biological effluent, or final discharge outlet. If used for process control, it is recommended to arrange it before and after key treatment units. If used for discharge supervision, it can be installed at the final discharge outlet.
Q7: What information should system integrators confirm with customers during selection?
They need to confirm wastewater source, pH range, salinity, COD range, temperature, suspended solids content, oil content, strong oxidant content, installation method, communication protocol, power supply conditions, data platform requirements, and project acceptance standards.
Q8: Does a high-salinity wastewater online monitoring system have to be equipped with a cloud platform?
Not necessarily. If the project only requires local control, it can be connected to PLC or SCADA. If remote operation and maintenance, data reports, trend analysis, and multi-site management are required, it is recommended to connect to a cloud platform through a 4G gateway or data collector.
Conclusion
Pharmaceutical and chemical high-salinity wastewater treatment is a difficult industrial wastewater treatment application. A single treatment process is often unable to meet long-term stable operation requirements. For system integrators and engineering companies, a reasonable process combination should be designed together with a reliable online monitoring system.
YexSensor water quality monitors can provide multi-parameter sensing solutions for pharmaceutical and chemical high-salinity wastewater projects, covering pretreatment, desalination concentration, advanced oxidation, biological treatment, and final discharge monitoring. Through industrial communication methods such as RS485 Modbus RTU and 4-20mA, the equipment can be flexibly connected to PLC, SCADA, data collectors, and cloud platforms, helping projects achieve real-time monitoring, automatic control, abnormal alarms, and data traceability.
For high-salt, high-COD, highly corrosive, and complex water quality scenarios, the value of water quality monitors is not only data measurement, but also an important foundation for improving system stability, reducing operation and maintenance risks, and optimizing engineering delivery results. YexSensor can provide industrial-grade water quality monitoring products and technical support suitable for project integration for environmental engineering companies, system integrators, and industrial IoT solution providers.
