What is BS EN 16166 - Direct determination of organically bound halogens about?
BS EN 16166 is a series on soil, treated biowaste and sludge. Soil treated biowaste and sludge is the residual, semi-solid material that is produced as a by-product during sewage treatment of industrial or municipal wastewater. BS EN 16166 specifies an operationally defined method for the direct determination of organically bound halogens (chlorine, bromine, and iodine) adsorbed and occluded to the sample matrix.
AOX being a methodologically defined parameter, it is essential that the procedure is applied without any modification. BS EN 16166 is intended for analysis of sludge, treated biowaste or soil in concentrations ranging from 5 mg/kg dry matter. The upper limit and exact concentration range covered depend on the instrumentation used for determination.
Who is BS EN 16166 - Direct determination of organically bound halogens for?
BS EN 16166 on the direct determination of organically bound halogens is useful for:
- Chemical industries
- Municipal corporation department
- Water purification plant
- Quality control personnel
- Sewage management sector
Why should you use BS EN 16166 - Direct determination of organically bound halogens?
When fresh sewage or wastewater enters a primary settling tank, approximately 50% of the suspended solid matter will settle out in an hour and a half. This document is applicable and validated for several types of matrices as indicated in BS EN 16166. Activated carbon is added to a dried, homogenized solid sample. Inorganic halides are eluted and at the same time, water-soluble organic compounds are adsorbed onto the activated carbon by shaking with acidified nitrate solution. The loaded carbon/sample mixture is combusted in an oxygen stream. The hydrogen halides produced are absorbed followed by the determination of the halide ions, for example, by micro-coulometric titration. The result is expressed as the mass fraction of chloride.
The capability of the measuring device to determine halogen concentrations is to be checked over the whole working range according to the manufacturer’s instructions. It is recommended to check the recovery of the hydrochloric acid solution at least once before the initial check of the overall procedure. In case the same staff is carrying out analysis according to EN ISO 9562, using the same apparatus and applying the shaking method, the results of the initial check of the shaking method may be used instead of the initial check described in BS EN 16166. The daily check according to BS EN 16166is to be carried out in all cases. Using BS EN 16166 you can specify an operationally defined method for the direct determination of organically bound halogens (chlorine, bromine, and iodine) adsorbed and occluded to the sample matrix.
What’s changed since the last update?
BS EN 16166:2021 supersedes BS EN 16166:2012. BS EN 16166:2021 includes some technical changes with respect to BS EN 16166:2012. These include:
- Calculation harmonized with EN ISO 9562
- Initial check and daily check procedure harmonized with EN ISO 9562 and extended to include full measuring process

