Tracer study

MCR 08 essai a la rhodamine 2Tracer study with rhodamine WT has several practical applications in the field of wastewater treatment. MCR used this tool since 1995 and has conducted several evaluation projects of lagoons short-circuiting and flow measurements.

To make these services we have the Trilogy fluorometer from Turner and all the necessary equipment to inject meter rhodamine and sampled it at various points.


Short-circuiting in basin is a very common cause of treatment efficiency losses. Before considering a wastewater treatment plant expansion with the costs engendered by such work, it may be interesting to check beforehand if they can be optimized. If so, significant savings can beings realized.

The tracer study is designed to provide very accurate information on basin short-circuiting. Based on the results, it can be established by calculation key analysis parameters of the basin's hydraulic (see example screenshot below).

MCR variations des conditions de rhodamine

After analyzing the results from the previous step, we are able to suggest corrective measures including:

  • Adding and positioning of curtain walls to increase retention time and treatment capacity
  • Adding mixers at specific points
  • Changing the layout of the aeration system if possible.

Very often the treatment plants are equipped with a distribution chamber with two (2) or more weirs without any possibility to know the flow that flows on each of them.

With a tracer as the rhodamine it is possible to measure the flow rate on each weir (or valves) and get the flow rate adjusts accordingly.


Clarifier short-circuiting, whether is primary or secondary, can have detrimental effects on the operation of downstream process or on the final effluent results

Using a tracer test it is possible to identify preferential current zones and propose adjustment of weirs or baffles addition.


Sometimes flow measurement in pipes is not possible with traditional equipment like portable weirs.With the use of a tracer, such as rhodamine, it is possible to determine the instantaneous flow rate of a pipe quickly and with excellent precision. It requires only to inject a tracer at a known concentration and to a known and fixed flow rate to a point upstream of the measuring point. Then measuring the concentration of the tracer at the measuring point it is pretty easy to determine the flow rate using the relation Q1C1=Q2C2.