ACITEK's Dissolved Oxygen Meter for Wastewater

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

1. Product Overview
Manufactured in Shanghai, China, the ACITEK G400-COND is a fixed-installation 4-wire conductivity transmitter tailored for industrial production and laboratory precision monitoring. Featuring a glass bead reinforced PBT enclosure and PP structural materials, the device delivers ultra-wide-range conductivity measurement (0.000 μS/cm – 200.0 mS/cm). It supports all mainstream 2-electrode and 4-electrode sensors, with freely selectable cell constants from 0.005 to 20 cm⁻¹, and compatible with Pt1000 and NTC 30 kΩ temperature detectors.
Equipped with a high-contrast LCD display, dual current outputs, two floating relay contacts, and dual 24VDC/230VAC power supply options, the transmitter integrates real-time sensor monitoring and preventive maintenance prompts. It supports wall, pipe and panel mounting, features intuitive operation and on-site medium calibration, and offers OEM/ODM customization with a standard one-year warranty.
2. Core Product Advantages
The G400-COND solves key pain points of traditional conductivity monitoring with outstanding comprehensive performance. Its full-range measurement adapts to various liquid environments without equipment replacement. Dual independent outputs realize synchronous detection and signal transmission of conductivity and temperature, supporting precise system control. The built-in relay alarm function enables automatic on-site equipment linkage without additional modules.
With corrosion-resistant and durable industrial-grade housing, it adapts to harsh production environments. Meanwhile, portable calibration, factory reset function and intelligent maintenance reminders greatly reduce daily operation and maintenance costs, ensuring long-term stable and accurate measurement data.
3. Main Application Scenarios
3.1 High-Purity Water Monitoring (Pharmaceutical, Electronics, Power Industry)
Widely used in pharmaceutical water for injection, semiconductor cleaning water and power plant boiler feedwater monitoring. Matched with low cell constant electrodes, it realizes real-time monitoring of water ion purity and automatic temperature compensation. It triggers alarms and linkage protection when water conductivity exceeds the standard, effectively avoiding product contamination and equipment scaling, and meeting GMP and industrial safety supervision standards.
3.2 Industrial Circulating Water & Cooling Tower Control
Applied to factory cooling circulating water systems, it monitors conductivity changes caused by water evaporation and salt accumulation in real time. By setting threshold parameters, it automatically controls pipeline blowdown and scale inhibitor dosing, optimizes water circulation concentration ratio, reduces fresh water consumption and chemical costs, and prevents pipeline corrosion and blockage.
3.3 Chemical & Electroplating Process Concentration Control
Adaptable to acid-base mixing solutions and electroplating bath liquid monitoring. By configuring different cell constants for solutions of varying concentrations, it realizes closed-loop automatic control of solution concentration through relay-linked dosing pumps. It also monitors the salinity of factory wastewater discharge to ensure compliance with environmental protection discharge standards and stabilize product yield.
3.4 Sewage & Reclaimed Water Treatment
Installed in sewage treatment tanks and discharge pipelines, it uses conductivity data to reflect water TDS content, quickly identify sudden impact of high-salinity wastewater, and monitor the treatment effect of reclaimed water. Real-time data upload meets environmental supervision recording requirements and helps optimize biochemical treatment processes.
3.5 Food & Beverage CIP Cleaning Monitoring
Used for pipeline CIP acid-base cleaning process monitoring in food and beverage factories. It judges detergent concentration and fresh water rinsing endpoint through conductivity values, avoids residual cleaning agents affecting food safety, realizes automated cleaning control, and saves water and detergent resources.
3.6 Laboratory Analytical Testing
Suitable for long-term fixed monitoring of laboratory sample solutions. It supports flexible parameter calibration and cell constant adjustment, with a clear high-contrast display. The integrated temperature detection function realizes comprehensive analysis of solution properties, simplifying laboratory daily detection and instrument maintenance work.
4. On-Site Application Compatibility
The G400-COND boasts strong on-site adaptability. Three installation methods adapt to equipment rooms, outdoor stations and laboratory cabinets. The universal power supply design matches mainstream industrial power systems, and standard 4–20mA analog signals are seamlessly compatible with PLC, DCS and monitoring hosts. It supports most mainstream sensors on the market, reducing equipment upgrade costs. Customized services can meet the personalized needs of system integrators and manufacturers.
5. Conclusion
The ACITEK G400-COND conductivity transmitter is a multi-scenario, high-stability monitoring instrument integrating detection, alarm and signal transmission. With full-range measurement, intelligent control, simple operation and strong environmental adaptability, it covers mainstream monitoring scenarios such as industrial water treatment, chemical production, food processing and laboratory testing. With reliable quality and perfect after-sales guarantee, it provides efficient, low-cost and automated conductivity monitoring solutions for various industries.

1. Product Application Overview
ACITEK G100-DO is a miniature DIN rail-mounted dissolved oxygen (DO) transmitter specially designed for industrial process water quality monitoring. With an ultra-narrow 12.5 mm modular housing, 4–20 mA active analog output, RS485 communication, 24 VDC power supply and integrated temperature measurement function, it perfectly solves the installation limitation of narrow control cabinets, compact fermenters and small-scale process monitoring stations. Matched with 12 mm diameter 316L stainless steel DO sensor (IP65 protection), it delivers fast response within 1 minute and stable long-term measurement, widely deployed in chemical, pharmaceutical, biotechnology, food & beverage, energy industries, industrial wastewater treatment and laboratory process analysis. The complete package includes DIN rail transmitter, stainless steel DO sensor, mounting fittings, signal cable, flow cell and operation manual, supporting OEM & ODM customized service for diversified on-site working conditionsacitekinst....

2. Industry-Specific Application Scenarios
2.1 Biotechnology & Pharmaceutical Fermentation
Biopharmaceutical and microbial fermentation processes require precise real-time dissolved oxygen control to guarantee strain reproduction, metabolite yield and drug purity.


Core application: Small & medium-sized bioreactors, seed culture tanks, cell culture lines.
Application advantages:

Ultra-thin 12.5 mm body allows centralized installation in dense PLC control cabinets with multi-channel parameter transmitters (pH, conductivity, DO) without cabinet space shortage.
Built-in manual calibration keys (K3/K4) support on-site one-point/two-point calibration without extra handheld calibrators; calibration cycle is recommended once every 3 months to sustain measurement accuracy.
Stainless steel 1.4435 sensor probe adapts to repeated SIP/CIP high-temperature sterilization sanitary working conditions, avoiding corrosion from culture medium and organic solvents.
4–20 mA signal connects to DCS/PLC to realize automatic linkage of stirring speed and aeration flow, stabilizing DO concentration in fermentation broth and improving production batch consistency.


Typical case: Antibiotic, amino acid, vaccine cell culture production lines.

2.2 Food & Beverage Production
Dissolved oxygen directly determines product flavor, shelf life and oxidation stability in food processing.


Core application: Beer/wine fermentation, pure water production, beverage filling pretreatment, dairy processing.
Working value:

Monitor low-level residual oxygen in finished water and beverage pipelines to suppress fat oxidation, color fading and flavor deterioration.
Fermentation tank online monitoring: control oxygen supply in yeast growth stage to avoid excessive DO causing off-flavor in finished wine.
Compact DIN rail design fits small beverage factory central control cabinets, realizing multi-point DO monitoring for multiple production lines with low overall investment cost.


Matching hardware: 12 mm stainless steel sanitary DO sensor with silicone sealing, compatible with food-grade fluid pipelines.

2.3 Chemical Industry Process Monitoring
Chemical synthesis, polymerization and fine chemical reactions are sensitive to dissolved oxygen to prevent invalid oxidation side reactions.


Application points: Chemical reaction kettles, solvent recovery systems, intermediate water circulation pipelines, fine chemical pilot test lines.
Product highlights for chemical sites:

4-wire system with 14–24 VDC wide voltage power supply, stable signal transmission under factory electromagnetic interference.
RS485 Modbus communication supports distributed networking, enabling centralized remote data collection of dozens of monitoring points.
Low-cost modular measurement station solution, ideal for small-batch pilot chemical workshops with limited cabinet space.



2.4 Energy & Power Industry Water Treatment
High dissolved oxygen in boiler feed water, cooling circulating water and thermal power sampling water will cause pipeline and equipment corrosion, shortening service life.


Core scenario: Thermal power plant condensate sampling rack, boiler deaerator outlet monitoring, cooling water circulation system.
On-site advantages:

Slim DIN rail transmitter can be densely arranged on sampling rack small-sized control boxes.
Synchronous measurement of dissolved oxygen and medium temperature, providing dual-parameter data for water chemical supervision.
4–20 mA analog signal uploads DO data to power plant monitoring system to trigger deaeration equipment linkage control.



2.5 Industrial Wastewater & Environmental Water Treatment
Aerobic and anaerobic biochemical tanks rely on precise DO adjustment to optimize activated sludge treatment efficiency and reduce aeration energy consumption.


Applications: Factory sewage treatment stations, small municipal wastewater aerobic tanks, discharge water quality monitoring wells.
Field performance:

IP65 stainless steel sensor probe resists sludge adhesion and weak corrosive wastewater medium.
Fast 1-minute response time timely reflects DO fluctuation in biochemical tanks to adjust fan operation frequency and cut power consumption.
Low maintenance cost, suitable for scattered small sewage treatment stations with limited operation manpower.



2.6 Laboratory & Pilot Test Equipment
Universities, R&D laboratories and pilot workshops have compact test equipment with limited installation space.


Usage scene: Laboratory bench bioreactors, small water quality test circulation devices, material oxidation test systems.
Laboratory advantages: Miniature transmitter saves laboratory control box space; simple manual calibration operation meets frequent experimental parameter calibration demands; one-year warranty and customizable OEM labels support laboratory self-developed test equipment matching.

3. Installation & System Application Modes
3.1 DIN Rail Central Cabinet Installation
The G100-DO transmitter adopts standard 35 mm DIN rail mounting, dozens of units can be side-by-side installed together with pH, conductivity transmitters inside narrow control cabinets, realizing multi-parameter centralized monitoring of the whole production line, which is the most mainstream application mode for medium and small factories.

3.2 Independent Small-Scale Monitoring Station
Matched with flow chamber, mounting bracket and cable, it forms a complete compact DO measuring station for single reactor, single pipeline or single wastewater tank independent monitoring, without large integrated analysis cabinet, greatly reducing equipment procurement and cabinet transformation cost.

3.3 PLC/DCS Automatic Control System Integration

Analog output: 4–20 mA active current signal accesses PLC analog module to realize closed-loop automatic control of aeration, stirring, deaeration equipment.
Digital communication: RS485 Modbus-RTU connects to industrial gateway, uploading DO & temperature data to upper computer, SCADA or cloud platform for remote real-time viewing and historical data recording.

4. Application Advantages Over Traditional Large DO Transmitters

Space-saving layout: Only 12.5 mm width, solving the installation bottleneck of narrow cabinets and compact equipment that large display transmitters cannot fit.
Cost-effective construction: Low unit price plus modular assembly reduces the total investment of multi-point monitoring stations, especially suitable for small factories and pilot projects.
Wide universal compatibility: One set of equipment covers biotech, food, chemical, energy and environmental protection industries; stainless steel sensor adapts to sanitary, corrosive and aqueous working conditions.
Easy on-site maintenance: Independent K3/K4 calibration buttons support field calibration without removing the transmitter from the cabinet; recommended quarterly calibration ensures long-term stable measurement.
Dual signal output: Simultaneous 4–20 mA analog and RS485 digital communication, compatible with both traditional PLC control and modern industrial internet remote monitoring systems.

5. Application Matching Notes

For sanitary fermentation and food production, select 1.4435 stainless steel sanitary DO sensor; for chemical wastewater, 316L stainless steel probe is recommended.
The transmitter body protection grade is IP20, so it must be installed inside closed control cabinets; the matched DO sensor reaches IP65 and can be directly inserted into pipelines or tanks.
Power supply range: 14–24 VDC 4-wire connection, avoid long-distance thin wire power supply to prevent voltage drop affecting measurement stability.
OEM/ODM customization is available for special industrial application requirements, including logo printing, cable length adjustment and flow chamber modification.

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.