Overview
EN 1899-2:1998 - Water quality: Determination of biochemical oxygen demand after n days (BODn) - Part 2: Method for undiluted samples (ISO 5815:1989, modified) specifies a laboratory procedure for measuring biochemical oxygen demand (BOD) in undiluted water samples. The method is intended for waters with BOD values ≥ 0.5 mg/L and ≤ 6 mg/L of oxygen. It adapts the ISO 5815 dilution/seeding approach for low‑BOD, undiluted matrices and defines sample handling, reagents, incubation and quality checks required for reliable BODn results.
Key topics and technical requirements
- Scope and limits: Applicable to undiluted waters with BOD in the 0.5–6 mg/L range.
- Sample handling: Store samples at 0–4 °C in filled, sealed bottles and begin analysis as soon as possible, preferably within 24 hours of collection.
- Incubation conditions: Incubate completely filled, stoppered bottles in the dark at 20 ± 1 °C for the defined period (standard is 5 days, with guidance on alternative periods/temperatures).
- Dissolved oxygen (DO) measurements: Measure DO before and after incubation using the iodometric (Winkler) method or an electrochemical probe (ISO 5813 / ISO 5814).
- Seeding and blanks: Use seeded dilution water if the sample lacks adapted micro‑organisms; seed volumes typically range (example guidance) and blank runs on seeded dilution water are required to correct results.
- Nitrification control: Option to suppress nitrification (e.g., allylthiourea addition) where necessary and document suppression in reports.
- Quality control: Carry out a check test with a glucose–glutamic acid standard; typical recovery range for the check is about 180–230 mg/L (method check).
- Reporting: Test report must reference the standard, sampling/storage details, seeding type, incubation period, suppression of nitrification (if used) and final BODn result.
Applications and who uses it
- Environmental and water quality laboratories performing low‑level BOD measurements.
- Regulatory bodies and consultants monitoring river water, drinking‑source impacts, or low‑strength effluents.
- Wastewater treatment operators and process engineers needing precise BOD data for process control where undiluted sample measurement is preferred.
- Research groups studying organic loading in low‑pollution waters.
Related standards
- ISO 5815 (basis for BOD methods and seeding/dilution approach)
- ISO 5813 (iodometric DO determination)
- ISO 5814 (electrochemical DO probe method)
This part of EN 1899 provides a practical, standardized approach to determine low‑level biochemical oxygen demand in undiluted waters - essential for compliance monitoring, process control and environmental assessment where sensitive BODn measurement is required.
