Water Quality Sensors: Intelligent, Real-Time Monitoring for Better Water Management

Water quality can change rapidly. Whether monitoring rivers and lakes, wastewater treatment processes, drinking water, groundwater, aquaculture systems, or industrial applications, reliable measurements are essential for understanding what is happening in the water and responding quickly.

AGISTAR develops professional solutions dedicated to water quality monitoring and analysis, combining intelligent sensors, online analysers, monitoring stations and autonomous platforms. Its 2026/2027 catalogue presents a broad range of multiparameter solutions designed for surface water, groundwater, wastewater, drinking water and industrial processes.

A complete range of intelligent water quality sensors

AGISTAR's sensor range covers many of the parameters commonly required for environmental monitoring and water treatment. The portfolio includes sensors for:

• Dissolved oxygen

• Turbidity

• Conductivity, salinity and TDS

• pH

• ORP

• Ammoniacal nitrogen

• Nitrate

• COD and TOC

• Suspended solids

• Residual chlorine

• Chlorophyll

• Cyanobacteria

• Chromaticity

  
  

This broad range makes it possible to build monitoring systems around the specific requirements of an application rather than relying on a single measurement technology.

Dissolved oxygen monitoring

The AGISTAR dissolved oxygen sensor uses fluorescence quenching technology to measure dissolved oxygen and temperature. It provides a measurement range of 0–20 mg/L or 0–200% saturation, with a response time of approximately 10 seconds.

The sensor incorporates automatic temperature compensation and digital signal conversion. With RS485 Modbus RTU communication and an IP98 protection rating, it is designed for integration into online monitoring systems and immersion applications.

Turbidity measurement

Turbidity is an important indicator of suspended particles and changes in water clarity. AGISTAR's turbidity sensor uses 90° infrared scattering technology, based on ISO 7027 principles.

The sensor offers a measurement range of 0.1–1000 NTU, automatic temperature compensation, RS485 Modbus communication and automatic brush cleaning. Its IP68 protection allows immersion to a maximum depth of 10 metres according to the catalogue.

The catalogue identifies applications including wastewater, surface water, groundwater, drinking water and industrial processes.

Measuring the chemical characteristics of water

Different applications require different chemical measurements. AGISTAR's range therefore extends beyond conventional physical parameters.

Conductivity, salinity and TDS

The conductivity sensor uses a four-electrode technology designed for stable measurement across a broad conductivity range. It measures conductivity, salinity, TDS and temperature.

With a measurement range of 1–2000 µS/cm, automatic or manual temperature compensation and RS485 Modbus RTU communication, the sensor can be incorporated into digital water monitoring systems.

pH and ORP

pH and oxidation-reduction potential are fundamental parameters for many water treatment and environmental applications.

AGISTAR's online pH sensor measures pH from 0 to 14, with a stated accuracy of ±0.02 pH. It incorporates automatic temperature compensation and digital signal conversion, while its RS485 output enables network integration without a dedicated controller.

The ORP sensor measures oxidation-reduction potential across ±2000 mV, together with temperature. Like the pH sensor, it uses industrial inline electrodes, automatic temperature compensation and RS485 Modbus communication.

Real-time monitoring of nitrogen compounds

Nutrients and nitrogen compounds are particularly important in wastewater treatment and environmental monitoring.

AGISTAR offers an ammoniacal nitrogen sensor based on an ion-selective electrode (ISE). It provides online, real-time measurement without reagents, with automatic compensation for pH and temperature and manual compensation for potassium ions.

The sensor measures ammoniacal nitrogen from 0–100 or 0–1000 mg/L, depending on the selected range, and includes automatic brush cleaning and RS485 Modbus communication.

For nitrate, AGISTAR provides an online ion-selective sensor with a measurement range of 0.1–100 mg/L. The catalogue describes applications in wastewater treatment plants, wastewater discharge points, surface and groundwater, drinking-water treatment and industrial processes.

Optical measurement of organic pollution

One of the more advanced instruments in the range is the UV254 sensor for COD and TOC.

The technology uses two wavelengths: 254 nm for measurement and 365 nm as a reference. According to the catalogue, this dual-beam approach helps compensate for optical-path attenuation and turbidity effects.

The sensor measures:

• CODCr

• TOC

• Turbidity

• TSS

• Temperature

  
  

The catalogue also indicates that conversion to BOD and CODMn is possible. The stated measurement ranges include 0–500 mg/L for CODCr, 0–250 mg/L for TOC and 0–500 NTU for turbidity, with a response time of approximately one second. Automatic brush cleaning and automatic temperature and turbidity compensation are also included.

Monitoring biological activity in water

Water quality monitoring is not limited to chemical parameters. AGISTAR also provides sensors for biological indicators.

The cyanobacteria sensor uses fluorescence to detect pigments such as phycocyanin and phycoerythrin. The fluorescence signal is converted into a value representing cyanobacterial density. Its stated measurement range is adjustable up to 200,000 cells/mL, with a detection limit of 300 cells/mL. CATALOGUE AGISTAR ANALYSE DE L'…

The chlorophyll sensor uses a similar fluorescence principle to measure chlorophyll concentration. It offers a measurement range of 0–400 µg/L or 0–100 RFU, with automatic brush cleaning and RS485 Modbus communication.

These technologies provide additional tools for understanding biological conditions in monitored water bodies.

Sensors designed for demanding environments

A common characteristic across several AGISTAR sensors is their focus on online measurement and field deployment.

Many of the sensors use IP68 or higher protection ratings and are designed for immersion. Digital RS485 Modbus RTU communication appears across much of the range, facilitating connection to monitoring systems, controllers and automation platforms.

For suspended solids, for example, AGISTAR offers a sensor using infrared backscattering technology. It measures 0.5–4000 mg/L, incorporates automatic compensation and brush cleaning, and is specified for immersion depths of up to 30 metres. The catalogue highlights wastewater treatment, sludge concentration monitoring and monitoring of sediment-rich natural waters as application areas.

From individual sensors to complete monitoring systems

AGISTAR's approach goes beyond individual probes. The catalogue presents a complete ecosystem around the sensors.

The BX-TERM 4G multiparameter controller can support several digital water-quality probes, with four sensor ports, RS485 Modbus connectivity and 4G communication for remote data transmission. The controller is also designed to support remote control and fault diagnosis. For automated monitoring, the AUMS-Station combines water collection and distribution, reagent-free online analysis using sensors and an industrial computer-based control system in a compact enclosure occupying less than one square metre.

This combination of sensors, controllers and monitoring stations allows AGISTAR solutions to be configured for both individual measurements and more comprehensive water-quality monitoring networks.

A modular approach to water-quality monitoring

The strength of a modern water-quality monitoring system lies not only in the individual sensor, but in the ability to combine measurements, transmit data and adapt the system to the application.

AGISTAR's portfolio brings together physical, chemical and biological measurements, including dissolved oxygen, turbidity, conductivity, pH, ORP, nitrogen compounds, organic pollution indicators, suspended solids, residual chlorine, chlorophyll and cyanobacteria.

Combined with digital communication, automatic cleaning, temperature compensation and online monitoring equipment, these sensors provide the building blocks for monitoring systems adapted to different water environments.

From a single parameter in the field to a multiparameter station or autonomous monitoring platform, AGISTAR's water-quality sensor range is designed around one objective: making water analysis and surveillance more accessible, connected and adapted to the needs of each application.