WTW VisoTurb 900-P Digital Infrared Turbidity Sensor with IDS Interface

Overview

The WTW VisoTurb 900-P is a high-precision, portable digital infrared turbidity sensor engineered for in-situ nephelometric measurement of suspended solids in liquid media. It operates on the principle of 90° scattered light detection at a fixed wavelength of 860 nm ±15 nm—optimized to minimize interference from color absorption and natural organic matter while maintaining compliance with ISO 7027 and EPA Method 180.1 for formazin-based turbidity calibration. Unlike traditional benchtop turbidimeters requiring sample extraction and cuvette handling, the VisoTurb 900-P enables direct immersion into water bodies—including rivers, effluent streams, distribution networks, and pump stations—delivering real-time, field-deployable FNU (Formazin Nephelometric Units) or NTU (Nephelometric Turbidity Units) values without dilution or filtration artifacts. Its rugged titanium shaft and IP68-rated housing ensure mechanical durability and long-term stability under submerged conditions, including pressurized applications up to 10 bar.

Key Features

• Digital IDS interface for plug-and-play integration with WTW MultiLine multi-parameter meters (e.g., Multi 3630 IDS, pH/Cond/O2/Turbidity combo setups)
• True 90° nephelometric geometry per ISO 7027, eliminating path-length variability and minimizing stray-light errors
• Titanium construction provides corrosion resistance in aggressive environments (seawater, wastewater, chlorinated systems)
• Factory-calibrated with traceable formazin standards; supports 2-point and 3-point user calibration using certified reference suspensions
• High-resolution output (0.1 FNU) across full 0–4000 FNU range, with dual-tier accuracy specification aligned with regulatory reporting thresholds
• No moving parts or optical windows exposed to fouling—optical path is sealed and self-contained within the sensor head
• Low-power consumption compatible with battery-operated MultiLine handheld instruments for extended field operation

Sample Compatibility & Compliance

The VisoTurb 900-P is validated for use in natural waters (surface water, groundwater), treated and raw wastewater, drinking water distribution systems, and industrial process streams. It meets the optical performance criteria defined in ISO 7027:2016 for turbidity measurement and is suitable for applications requiring conformance with EU Drinking Water Directive (98/83/EC), US EPA Clean Water Act reporting, and WHO Guidelines for Drinking-water Quality. When deployed with WTW’s GLP-compliant MultiLine IDS instruments, the system supports audit-ready data logging—including timestamped calibration records, sensor diagnostics, and operator ID—fully traceable under FDA 21 CFR Part 11 requirements when configured with electronic signature capability.

Software & Data Management

Data acquisition and configuration are managed via WTW’s proprietary MultiLab software or integrated directly into the MultiLine instrument’s firmware. All measurements include embedded metadata: sensor serial number, calibration date, temperature compensation value (via integrated Pt1000 thermistor), and measurement duration. Export formats include CSV and XML, supporting import into LIMS platforms (e.g., LabWare, STARLIMS) and statistical process control (SPC) tools. Firmware updates are delivered through WTW’s secure IDS update protocol, preserving calibration integrity during version upgrades. Raw signal diagnostics (LED drive current, photodiode response, ambient light offset) are accessible for preventive maintenance assessment.

Applications

• Real-time monitoring of turbidity spikes during stormwater events or filter breakthrough in drinking water plants
• Compliance verification at wastewater treatment plant discharge points per local environmental permits
• Field validation of online turbidity analyzers during QA/QC audits
• Process optimization in membrane filtration and coagulation-flocculation units
• Environmental impact assessments in riverine and estuarine ecosystems
• Emergency response testing following infrastructure failures or contamination incidents

FAQ

Is the VisoTurb 900-P compatible with non-WTW meters?
No—it requires an IDS-enabled host device (e.g., Multi 3630 IDS, Multi 9620 IDS) due to its proprietary digital communication protocol, sensor identification, and automatic parameter recognition.
Does it require periodic optical cleaning in high-fouling environments?
The sealed optical chamber eliminates routine window cleaning; however, titanium shaft inspection and gentle rinsing with deionized water are recommended after exposure to viscous or biofilm-prone matrices.
Can it be used for continuous submersion in flowing pipelines?
Yes—its 10-bar pressure rating and NPT-compatible mounting options (via optional adapter kits) support permanent installation in pressurized distribution or process lines.
How is temperature compensation handled?
An integrated Pt1000 platinum resistance thermometer measures sample temperature in real time; compensation follows the polynomial algorithm specified in ISO 7027 Annex B, applied automatically by the host meter.
What calibration standards are recommended for field verification?
Certified formazin suspensions (e.g., StablCal® or WTW-certified 20 FNU and 800 FNU standards) are required; polymer-based alternatives (e.g., AMCO AEPA) are not traceable to ISO 7027 and may introduce systematic bias.