Chromatotec Group

Case study - N°AA2 – Ambiant air monitoring – WWP TRSMEDOR deodorisation


Courtesy of Chromatotec Group

Context & Challenges

Globally, the wastewater treatment is the first public health issue. Urban development leads to urbanization near waste water treatment plant and extension of sewerage network. These aspects induce to an augmentation of sulfur compounds (H2S, mercaptans and sulfides) which are very corrosive, odorant and toxic. To monitor this compounds online CHROMATOTEC® offers high meteorological solutions.

At the entrance of the waste water plants, where the waste water arrives, strongly smelling and polluted air is captured and neutralised by a chemical cleaning process called ‘’Stripping’’.

The correct amount of chemical products needed to neutralise the polluted air has to be calculated.

Chromatotec® Solutions

TRS MEDOR ppb or ppm for up to 14 compounds

With only one instrument, it is possible to analyse up to 14 sulfur compounds. Thanks to specific sulfur detector (SSD) and AIR or N2 carrier gas, the separation and sensitivity is excellent down to 1 ppb levels and low odor unit/m3.

The instruments are being calibrated with primary gas standard certified at ±2%. There are no interferences due to the gas chromatography separation and the sulfur specific detector. The analyzer is LINEAR: range 0 / 100 ppb.

The instruments are fully automated thanks to internal calibration (airmoCAL). The VISTACHROM software controls the analyzers, multiplexer, meteorological station and enables storage and display of the chromatograms thanks to Peak Viewer.

It is possible to transfer data to a data logger or modelling software with the communication protocols MODBUS RTU, JBUS, German PROTOCOL and X-Path.

TRS MEDOR system

  • At the point of arrival of the wastewater at the stripping area of the plant, the polluted air is captured and thereafter passed in a circuit that neutralises it. These odors are caused by bacteriological fermentation. Successive chemical cleanings in the deodorisation towers neutralize these odors.
  • The bad odors are largely due tthe transformation of sulfides intH2S by the bacteria in the fermentation process.
  • Placed at the outlet of the stripping process, the TRS MEDOR measures the H2S concentrations and pilots the adjunction of calcium nitrate. This process allows tthe bacteria thave an oxygen reserve and therefore tstop sulfate transformation intsulfides and then in H2S.


  • Automatic regulation of odor neutralisation.
  • Time needed ttechnically pilot the process is decreased.
  • Cost savings with much less calcium nitrate used.


TRS MEDOR, the adequate solution for in situ sulfur analysis and odor monitoring for surveillance of wastewater treatment plant:

  • Fully automated with gas generator (N2 or Air/Calibration gas)
  • Data transfer ta data logger or by modem or Ethernet
  • Stability and repeatability (from 1 ppb t1000 ppm, areas and retention times)
  • Linearity (from 1 ppb t1000 ppm)
  • In compliance with IS6326/2 norm and DIN 51855/7, ninterferences
  • Approval on sulfurs (ASTM D7493-08 2008)
  • In standard TRS MEDOR analyse 7 compounds H2S,SO2,MM,EM,DMS,DES and DMDS
  • In option up t14 sulfurs THT, H2S, SO2, MM, EM, DMS, IPM, TBM, NPM, MES, 2BM, DES, NBM and DMDS.
  • NEW: manage meteorological station and communicate with odor modelling software.
  • OPTION ppt range with a pre concentration trap for DMS/DES and DMDS.

Customer comments

No comments were found for Case study - N°AA2 – Ambiant air monitoring – WWP TRSMEDOR deodorisation. Be the first to comment!