Chemical Mitigation of Effluent Methane technology is now fully released in OverseerFM.
The mitigation technology, addition of Polyferric Sulphate to effluent systems, was added as a Beta implementation in model update Version 6.5.7 while peer review and final parameter confirmation were still in progress.
Generation 2 of this technology now replaces the beta version as the fully released implementation, using updated input parameters that reflect the most recent product specifications and application approach.
(This technology may be known to farmers and advisors as "EcoPondTM", developed by Lincoln University and marketed by Ravensdown, more information available here ).
The technology has already been included into the AIM National Inventory model (updated April 2026), and this release enables farmers and their advisors to understand the potential opportunities for the utilisation of this technology at a farm level.
NB. It should be noted that in line with the science presented to the Agricultural Inventory Advisory Panel (here) and included below, and detailed in the science report (here) the implementation of this mitigation technology in Overseer assumes Full season, continuous (i.e. application at least every 6 weeks) addition of the chemical mitigation, in line with the good management practise for this technology.
The mitigation can only be applied to “holding pond” and “2-pond+discharge” effluent systems in OverseerFM. Available scientific literature currently only describes the design and experimental testing on dairy cow farms using “2 pond + discharge” or “holding pond” effluent systems. Therefore, the applicability and considerations of this model change are only for these two types of systems. If the technology is applied to one of these effluent systems, the mitigation is only applied to the effluent from dairy cows.
Effluent system details are entered within the “Structures/Effluent” screen in OverseerFM when modelling a farm.
There is now a checkbox under the “Management System” labelled "Effluent is treated with chemical methane mitigation (acidification and ferric dosing) ". This is in line with Overseer policy of not including brand names within the model.
If the user selects this check box it is deemed the chemical methane mitigation is being added to the effluent.
If the technology is applied, a new line item will be visible within the farm level nutrient budget “Nutrients added” section which will include the additional sulphur (S), magnesium (Mg), and sodium (Na) which are applied to the effluent:
These additional nutrients will be managed and transferred within the farm system the same as any other nutrient from the effluent system therefore all other existing functionality remains the same.
Further reading on the implementation of this mitigation can be found in the Science Report here.