Last updated November 2025
This FAQ page brings together answers based on independent New Zealand research, on-farm trials, and farmer experience, so you can find clear, evidence-based information about EcoPond’s benefits, performance, and practical use on farm.
Note: EcoPond™ is a developing technology. The information provided is based on research from Lincoln University and the references provided at the end of this document. While best efforts have been made to provide current understanding, we anticipate this will continue to evolve.
EcoPond™ is a clean, simple, and effective effluent pond treatment service that reduces methane emissions by 90%+ while improving your pond’s performance (Cameron & Di, 2021).
We start by collecting key details about your farm – pond size, location, and access. Once scheduled, we’ll notify you when our mobile-dosing truck is on its way.
No, farm staff won’t need to be involved in the treatment process. The EcoPond system uses a specialised truck to deliver and apply the treatment, so no chemicals are stored on the farm and everything is handled externally.
For a typical effluent pond, the treatment process is expected to take around 1 hour.
The dosing truck will visit approximately every 6 weeks. It should be treated like any other vehicle entering the farm. Notifications will be sent out ahead of time so designated staff are aware of when the truck will arrive and depart.
EcoPond will take care of the scheduling. We’ll work with the farmers to set up a treatment plan and send notifications when a dosing is due and when it’s been completed. The process is designed to be low-impact and shouldn’t interfere with daily farm operations.
Once treated, the effluent poses similar risks to any standard effluent pond. It should still be approached with care—think biohazard precautions and general safety around large bodies of liquid. Farm staff should avoid direct contact with both the effluent and any treatment chemicals.
EcoPond™ will work with the farmer to understand pond size and details on roughly how full the pond is prior to dosing.
The dosing system on the truck is automated and will apply the correct amount of treatment based on the volume present. This treatment is designed to last for 6 weeks, depending on the season.
Yes, pumping the pond down to a low level (e.g. around 500,000 L) before the truck arrives ensures efficient dosing. However, there must still be enough effluent left for the system to operate. We’re continuing to develop clear guidelines for ideal pond volumes before treatment.
Ideally, the truck should be able to get as close to the pond as possible to avoid using long connector pipes. In future, we’ll look at installing two permanent connector pipes on the farm can help make the process smoother.
Yes. Thicker effluent—meaning more organic matter—requires more additives to achieve effective treatment. The truck’s automated dosing system adjusts the dosage until the target redox potential is reached, ensuring the treatment is effective regardless of effluent thickness.
If a treatment is missed, methane emissions may resume once the previous dose wears off. The system will automatically adjust the next dose to ensure the pond returns to the correct treatment level.
EcoPond™ is designed to suit a wide range of effluent systems commonly found on New Zealand farms.
The dosing truck uses two hoses—one to draw effluent out of the pond and another to return the treated effluent back into the pond.
Based on over 12 months of use across three farms, there’s been no noticeable increase in wear and tear on existing irrigation or pumping equipment when using EcoPond-treated effluent.
Over time, less crust should form on the pond so there’s often less need to stir the pond, which could reduce the workload—and wear—on your stirrer over time.
EcoPond is designed to suit a wide range of effluent systems commonly found on New Zealand farms.
We’ll continue working with pilot farms to refine treatment protocols for each system type.
If you have any question or concerns regarding your particular pond type, feel free to contact us and we will be happy to talk through your options.
The dosing truck uses two hoses—one to draw effluent out of the pond and another to return the treated effluent back in. While many ponds already have entry and exit points, we’ll work with pilot farms to decide whether a semi-permanent pipes may need to be installed. This setup helps make the process more efficient, and keeps our operators safe by allowing them to stay outside the pond fence during treatment.
Based on over 12 months of use across three farms, there’s been no noticeable increase in wear
and tear on existing irrigation or pumping equipment when using EcoPond-treated effluent.
Farmers have also observed that once the pond is treated, a crust no longer forms on the surface.
This has been confirmed in EcoPond trials as well.
With less crust, there’s often less need to stir the pond, which could reduce the workload—and wear—on
your stirrer over time.
Not significantly. The main additives—poly-ferric sulphate and sulphuric acid—contain iron and sulphur, which are essential nutrients already present in soil.
To ensure best effectiveness of the EcoPond™ treatment, please allow a minimum of 3 days before irrigating effluent out of the pond, following the treatment. The standard withholding periods apply before grazing pasture after spreading effluent.
No, research shows that treated effluent does not negatively affect pasture quality or cow grazing. A 4-year on-farm trial found no significant differences in dry matter yield or nutrient composition between pastures treated with EcoPond ™ effluent and those treated with standard effluent (Che et al., 2023). Additional studies (Cameron & Di, 2019; Wang et al., 2019; Chisholm et al., 2020; Che et al., 2021) support this, showing:
No significant difference in phosphorus uptake or concentration in plants.
Slightly higher iron levels in treated pasture (176 vs 249 mg Fe/kg), but still well within the normal range for NZ pastures (41–3850 mg Fe/kg).
Slightly higher sulphur levels (0.275% vs 0.317%), which are not harmful.
No significant changes in other macro-nutrients, trace elements, or heavy metals.
Farmers, including those at LUDF, have been using treated effluent for over two years with no reported issues for grazing.
EcoPond-treated effluent has been shown to have no negative impact on soil biology or compaction:
No. Multiple trials have shown that applying EcoPond-treated effluent does not significantly change emissions of methane, nitrous oxide, or carbon dioxide from soil compared to untreated effluent (Chen et al., 2019; Wang et al., 2019; Chisholm et al., 2020).
The data in the table below shows no significant difference in GHG emissions from soil after treated effluent (TE) has been applied compared to untreated FDE (Wang et al. 2019)
The biological process that leads to methanogen suppression:
The addition of iron sulphate and sulphuric acid into the effluent pond has two main effects:
Cameron K, Di H 2019.
A new method to treat farm dairy effluent to produce clarified water for recycling and to reduce environmental risks from the land application of effluent. Journal of Soils and Sediments 19: 2290-2302.
Cameron KC, Di HJ 2021.
Discovery of a new method to reduce methane emissions from farm dairy effluent. Journal of Soils and Sediments 21: 3543-3555.
Che, X., Di, H. J., Cameron, K. C., & Dodd, R. (2021).
Treating farm dairy effluent with poly‐ferric sulphate dramatically reduces phosphorus and E. coli leaching through sub‐surface drains–a physical drainage model study. Soil Use and Management. https://doi.org/10.1111/sum.12809
Che, X, Di. HJ, Cameron,KC and Dodd, R. (2023).
Repeated applications of farm dairy effluent treated with poly-ferric sulphate did not adversely affect soil phosphorus availability, P fractions and pasture response — a 4-year field plot study. Journal of Soils and Sediments 23:2482–2493. https://doi.org/10.1007/s11368-023-03493-z
Chen S, Di HJ, Cameron KC, Podolyan A, He J 2019.
Effect of treated farm dairy effluents, with or without animal urine, on nitrous oxide emissions, ammonia oxidisers and denitrifiers in the soil. Journal of Soils and Sediments 19: 2330-2345.
Chisholm CMW, Cameron KC, Hong DJ, Green TC 2020.
The effect of polyferric sulphate treated farm dairy effluent and clarified water on leaching losses, greenhouse gas emissions and pasture growth. New Zealand Journal of Agricultural Research 64: 271-285. FDA 2017. Code of Federal Regulations Title 21, Chapter 1b, part 184. Direct Food substances affirmed as generally recognized as safe, Sec. 184.1307 Ferric Sulphate. Retrieved 14 June 2022.
Wang XM, Hong DJ, CAmeron KC, Bowen L 2019.
Effect of treated farm dairy effluent on E. coli, phosphorus and nitrogen leaching and greenhouse gas emissions: a field lysimeter study. Journal of Soils and Sediments 19: 2303-2312.
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