WTW OxiTop-i IS6 Laboratory BOD Analyzer

Overview

The WTW OxiTop-i IS6 is a precision-engineered laboratory BOD (Biochemical Oxygen Demand) analyzer designed for standardized, traceable, and operator-independent determination of oxygen consumption in aqueous samples over defined incubation periods. It operates on the pressure difference principle: microbial degradation of organic matter in sealed, stirred sample bottles consumes dissolved oxygen, generating a measurable pressure drop across a mercury-free, high-stability piezoresistive sensor. This differential pressure is converted in real time to oxygen demand (mg O₂/L), enabling direct calculation of BOD₅ or extended BOD_n values (n = 2–28 days) without manual titration or reagent handling. The system complies with core regulatory frameworks including ISO 5815-1:2019 (Water quality — Determination of biochemical oxygen demand after n days — Part 1: Dilution method) and ASTM D5210-19 (Standard Test Method for Determining Anaerobic Biodegradation of Plastic Materials Under High-Solids Anaerobic-Digestion Conditions), supporting laboratories subject to GLP, ISO/IEC 17025, or municipal wastewater compliance reporting.

Key Features

• Six independent, color-coded measurement channels—each equipped with an integrated stirring motor and calibrated pressure transducer—allow parallel analysis of heterogeneous sample sets without cross-interference.
• Automatic temperature compensation: the instrument detects ambient or incubator temperature and adjusts timing logic to initiate measurement only after thermal equilibrium is reached at the selected incubation setpoint (15–30 °C).
• Real-time data acquisition and visualization: BOD concentration (mg/L) and cumulative oxygen consumption curves are displayed directly on the device’s OLED interface; no external PC required for basic operation.
• Mercury-free pressure sensing architecture ensures long-term stability, eliminates hazardous material handling, and meets RoHS and REACH requirements.
• Robust mechanical design with IP54-rated enclosure enables reliable deployment in shared lab environments with variable humidity (≤95% RH) and operating temperatures from 5–40 °C.
• Integrated status LED indicators provide immediate visual feedback on channel readiness, measurement progress, error conditions, and power integrity.

Sample Compatibility & Compliance

The OxiTop-i IS6 accepts standard 60 mL or 250 mL BOD glass bottles (DIN EN ISO 5815-compliant), accommodating raw wastewater, treated effluent, surface water, groundwater, drinking water, and industrial process streams. Sample preparation follows standard dilution protocols when necessary (though full-range measurement up to 4000 mg/L often eliminates pre-dilution). All measurements adhere to internationally recognized validation criteria: detection limit ≤1 mg/L ensures sensitivity for low-BOD potable water assessments; repeatability ≤5% RSD supports method transfer between shifts or analysts; and accuracy ±10% relative to NIST-traceable BOD reference materials satisfies QA/QC requirements for accredited environmental testing labs. CE marking confirms conformity with EU safety, health, and environmental protection directives, while EMC certification guarantees electromagnetic compatibility in multi-instrument laboratory settings.

Software & Data Management

Data export is supported via USB 2.0 to standard CSV format for integration into LIMS or statistical analysis platforms (e.g., JMP, Minitab, or validated Excel templates). While the instrument operates autonomously, optional WTW LabX® software provides enhanced audit trail capabilities—including user login tracking, parameter change logs, and electronic signature support—aligning with FDA 21 CFR Part 11 requirements where electronic records are mandated. All measurement sessions retain timestamps, incubation duration, temperature profiles, and raw pressure differentials for full traceability. No proprietary drivers or cloud dependencies are required; data integrity is preserved through local non-volatile memory with battery-backed retention during power interruption.

Applications

• Regulatory BOD₅ compliance monitoring for municipal wastewater treatment plants (WWTPs) under national discharge permits.
• Process control and optimization in activated sludge, MBR, and SBR systems by quantifying biodegradable load variations.
• Environmental impact assessment of industrial effluents prior to discharge into receiving waters.
• Research on biodegradability kinetics of novel organic compounds, pharmaceuticals, or microplastics under controlled aerobic conditions.
• Drinking water quality assurance, particularly for source water vulnerability studies and post-treatment stability verification.
• Academic teaching laboratories requiring robust, low-maintenance instrumentation for standardized environmental chemistry curricula.

FAQ

Does the OxiTop-i IS6 require a dedicated incubator?
Yes. The instrument itself does not regulate temperature; it must be placed inside a certified, stable incubator set to the desired temperature (15–30 °C). WTW recommends incubators with ±0.5 °C uniformity and forced-air circulation.
Can I measure BOD beyond 7 days?
Yes. The system supports user-defined incubation durations from 2 to 28 days, enabling extended BOD_n studies and evaluation of slowly degradable fractions.
Is calibration required before each use?
No routine recalibration is needed. The pressure sensors are factory-calibrated and thermally compensated. A zero-point verification using air-saturated water is recommended before each batch as a QC check.
What bottle types are compatible?
Standard DIN/ISO-compliant glass BOD bottles (60 mL or 250 mL) with integrated stoppers and magnetic stir bars. PET or HDPE bottles are not recommended due to oxygen permeability.
How is data security ensured for regulated environments?
When used with LabX® software, the system supports role-based access control, electronic signatures, and immutable audit trails compliant with 21 CFR Part 11 and ISO/IEC 17025 clause 7.7.