Professional Online Ph Probe

In recent years, with the continuous improvement of water quality management technology and level in water plants, online water quality monitoring system has been integrated as an emerging management method, triggering industry changes. With the help of advanced sensor technology and automation equipment, the system can monitor the quality of raw water, water production process and outgoing water in water plants 24 hours a day. From key indicators such as pH, turbidity to residual chlorine content, they can all be accurately measured, and data can be fed back in real time, which completely changes the lag and limitations of traditional manual sampling and monitoring. ​
After the online monitoring system is put into use, the water plant can capture subtle changes in water quality in a timely manner, quickly adjust the water production process, and ensure that the water quality is stable and meets the standards. This not only effectively improves the safety of water supply and ensures the health of residents' water use, but also greatly improves the operating efficiency of water plants and reduces labor costs and management difficulties. At present, the online water quality monitoring system has become an important measure for many water plants to optimize management. With the continuous iteration of technology, it is expected to be popularized in more water plants in the future, promoting the entire water supply industry to move towards intelligent and refined management, and building a solid line of defe

ACITEK G300 Online DO Transmitter + DO6800 High-temperature Dissolved Oxygen Electrode

1. Project Background
A fine chemical enterprise produces 50,000 tons of acrylate annually. Its reaction kettles operate at 80–120℃ and 0.6–1.0 MPa. Dissolved Oxygen (DO) must be strictly controlled within 0.5–1.5 mg/L. Excess DO causes side reactions and reduces product purity, while insufficient DO leads to incomplete chemical reaction and lower output.

The traditional polarographic electrodes suffered severe signal drift above 60℃, with membranes aging every 2–3 weeks. Frequent shutdown for calibration and replacement brought high maintenance costs and disrupted continuous production. The site adopted ACITEK G300 DO Transmitter + DO6800 High-temperature DO Electrode to solve the problems.



2. Product Specifications
ACITEK G300 Online DO Transmitter

Measuring range: 0.00–40.00 ppm, Accuracy: ±0.01 ppm
Working temperature: -10.0–130.0℃, automatic temperature compensation
Output: 4-20mA & Modbus RTU, compatible with DCS system
Protection class: IP65, explosion-proof design







ACITEK DO6800 High-temperature DO Electrode

Temperature resistance: 0–130℃, supports 130℃ SIP sterilization
Housing: 316L stainless steel, acid & alkali resistant
High-temperature resistant membrane, anti-aging and anti-fouling
Response time: t90 ≤ 60 s




3. Installation & Commissioning

Mounted on DN50 side port of reaction kettle, immersed 20–30 cm below liquid level, away from agitator and inlet to avoid bubble interference.
Shielded cabling to prevent electromagnetic interference.
Two-point calibration with oxygen-free water and air-saturated water. Stable performance lasts over 6 months after one calibration.
Linked with DCS: Automatic nitrogen purge when DO below set value; cut off nitrogen supply when DO exceeds limit.

4. Application Results (6-month operation)

Stable measurement: No signal drift at 120℃, DO fluctuation controlled within ±0.1 mg/L.
Low maintenance: Membrane service life extended from 2–3 weeks to 8–10 months. Calibration cycle reaches 6 months, maintenance workload reduced by over 70%.
Quality improvement: Acrylate purity rose from 99.2% to 99.7%, high-grade product rate increased by 12%.
Higher efficiency: Gas consumption cut by 18%. Shutdowns caused by DO faults were eliminated, with annual output increased by 2000 tons.
Durable performance: Continuous trouble-free operation for 180 days, no corrosion orscaling on electrode.

5. Customer Feedback
"This high-temperature DO monitoring solution perfectly solves our pain points of unstable reading and frequent maintenance. The G300 transmitter delivers reliable data and smooth communication. The DO6800 electrode works well under high temperature. It greatly guarantees our continuous production and product quality." — Manager Wang, Equipment Department

6. Applicable Scenarios

Chemical industry: High-temperature reaction kettles, polymerization & oxidation processes, high-temperature wastewater
Pharmaceutical industry: Fermenters with 121℃ SIP sterilization
Power industry: Boiler feed water and condensed water trace oxygen monitoring
Environmental protection: High-temperature industrial wastewater & leachate treatment

Updated Environmental Regulations Bring New Compliance Requirements for Wastewater Online Monitoring Equipment


With the official implementation of China’s HJ 212-2025 Technical Requirements for Data Transmission of Pollutant Automatic Monitoring System and the upcoming enforcement of the Ecological Environment Code, stricter supervision is being carried out on wastewater discharge monitoring. Regulators have raised higher standards for online water quality instruments used at wastewater outlets, including pH, dissolved oxygen and conductivity sensors. Factories in chemical, pharmaceutical, food & beverage industries, together with industrial wastewater treatment plants, are now entering a critical period to evaluate and upgrade their monitoring systems.

Core Updates in New Environmental Standards

Full data traceability to prevent distorted monitoring results Unique device identification codes are required for all field monitoring instruments during network access. Raw measurement data, calibration logs and equipment operation records must be stored for long-term review. Any modification to instrument parameters will be recorded automatically. Unauthorized devices cannot connect to official environmental monitoring platforms.
Higher standards for long-term measurement stability Wastewater usually contains sludge, weak acid, alkali and dissolved salts. Regulators demand sensors with reliable temperature compensation and low measurement drift. Sensors prone to corrosion, scaling and frequent deviation will be regarded as invalid monitoring equipment during official inspections.
Unified communication protocol for seamless data networking New standards standardize data interaction between sensors, transmitters and data collectors. Instruments shall support standard Modbus-RTU and stable 4–20mA analog signals. Outdated equipment with unstable signal output or incompatible communication cannot meet current compliance demands.

ACITEK Solutions for Regulatory Compliance
ACITEK offers a complete portfolio of water quality sensors and transmitters fully adapted to the latest environmental monitoring requirements: • AC580 series conductivity sensors, industrial pH electrodes and DO sensors feature built-in PT1000 temperature compensation. Wetted SS316L material provides anti-corrosion performance in complicated wastewater media. • G100 compact DIN rail transmitters support 4–20mA active output + RS485 Modbus dual signals. All parameter changes are logged automatically to meet traceability requirements. • Complete accessories including flow cells, immersion holders and mounting fittings comply with HJ installation & operation specifications.

Recommendations for End Users & System Integrators

For existing monitoring stations: Test sensor accuracy and signal stability in advance. Replace aging instruments in phases to avoid compliance risks.
For new wastewater treatment projects: Adopt integrated monitoring systems with both analog and digital communication to satisfy long-term regulatory demands.
Form standardized maintenance schedules, regularly clean and calibrate sensors and archive all calibration documents.

ACITEK provides professional technical support and customized online monitoring packages for wastewater discharge applications. If you need a complete solution for pH, DO and conductivity monitoring in wastewater projects, please contact our engineering team.