WTW ProfiLine Oxi 3315 Optical Dissolved Oxygen Meter

Overview

The WTW ProfiLine Oxi 3315 is a portable, optical dissolved oxygen (DO) meter engineered for high-accuracy, field-deployable water quality analysis. Unlike traditional electrochemical Clark-type sensors, the Oxi 3315 employs luminescence quenching technology—measuring the phase shift or intensity decay of fluorescent light emitted by an oxygen-sensitive dye layer upon excitation. This optical principle eliminates membrane fouling, electrolyte depletion, and zero drift associated with amperometric systems. The instrument integrates seamlessly with the intelligent digital sensor (IDS) platform, enabling plug-and-play connectivity, automatic sensor identification, and embedded calibration history. Designed for routine monitoring in wastewater treatment plants, surface water surveys, aquaculture operations, and environmental impact assessments, the Oxi 3315 delivers stable, interference-resistant measurements across diverse matrices—including samples containing CO₂, ethanol, or suspended bubbles that commonly compromise electrochemical DO sensors.

Key Features

• Optical DO measurement using the FDO 925 sensor—no membrane replacement, no electrolyte refills, no polarization time required
• Digital IDS interface ensures automatic sensor recognition, firmware version tracking, and secure parameter transfer
• Automatic barometric pressure compensation for accurate DO reporting at varying altitudes
• Configurable t₉₀ response time to optimize measurement speed versus stability per application
• Simultaneous display and logging of DO (mg/L, % saturation, partial pressure), pH, ORP, conductivity, and turbidity when paired with compatible IDS probes
• GLP- and AQA-compliant data management: timestamped entries, operator ID assignment, calibration event logging, and full audit trail support
• Graphical backlit LCD with intuitive icon-driven navigation and real-time trend visualization

Sample Compatibility & Compliance

The Oxi 3315 is validated for use across freshwater, seawater, wastewater effluents, and process streams with turbidity up to 1000 NTU and salinity up to 70 g/kg (adjustable salt correction). Its optical sensing mechanism remains unaffected by common interferences such as hydrogen sulfide, chlorine residuals, carbon dioxide, ethanol, or microbubble entrainment—making it suitable for BOD incubation monitoring, activated sludge characterization, and stormwater runoff assessment. The device conforms to ISO 5814:2012 (water quality — determination of dissolved oxygen — electrochemical probe method) for optical alternatives and supports compliance with EPA Method 360.1 and ASTM D888-22 where optical DO verification is permitted. All logged data meet GLP and GMP documentation requirements, including 21 CFR Part 11–ready export formats (CSV/ASCII) with metadata integrity.

Software & Data Management

Data acquisition and traceability are fully integrated into the instrument’s firmware. Up to 5,000 automatic or 500 manual measurements can be stored onboard with full contextual metadata: date/time, sensor ID, calibration status, temperature, pressure, user ID, and measurement mode. Export occurs via mini-USB in standardized CSV or ASCII format—compatible with LIMS, Excel, and statistical analysis platforms. No proprietary software is required for basic data retrieval; however, WTW’s MultiLab® Connect PC software enables advanced report generation, calibration certificate printing, and multi-instrument fleet synchronization. All exported files retain embedded timestamps and checksums to ensure data integrity during regulatory audits.

Applications

• Environmental field monitoring: rivers, lakes, estuaries, and groundwater wells
• Wastewater treatment: aeration basin optimization, nitrification/denitrification control, and effluent compliance verification
• Aquaculture and fish hatchery management: real-time DO profiling to prevent hypoxia stress
• Drinking water distribution system integrity testing
• Industrial process water quality assurance in food & beverage, pharmaceutical, and power generation sectors
• BOD₅ incubation monitoring per ISO 5815-1:2012 without sensor drift or membrane clogging

FAQ

Does the Oxi 3315 require periodic recalibration in the field?

Yes—while the FDO 925 sensor is factory-calibrated and drift-free over extended periods, WTW recommends air-saturation calibration before critical measurements or after prolonged storage. Steam-saturated air calibration is supported for enhanced accuracy at elevated humidity.
Can the Oxi 3315 measure dissolved oxygen in high-salinity seawater?

Yes—the instrument includes programmable salinity compensation (0–70 g/kg) and automatically adjusts DO concentration calculations based on measured conductivity or user-entered salinity values.
Is the data export format compatible with LIMS integration?

Yes—CSV exports contain column headers, timestamps, units, and sensor metadata, enabling direct ingestion into most laboratory information management systems without transformation.
What battery life can be expected during continuous operation?

With alkaline AA batteries, typical runtime exceeds 200 hours in logging mode; NiMH rechargeables provide ~150 hours and support USB-powered operation during data transfer.
How does the IDS interface enhance measurement traceability?

Each IDS sensor stores its own serial number, calibration history, firmware version, and last-use date—automatically uploaded to the Oxi 3315 and embedded in every logged record for full chain-of-custody documentation.