University workshop aims to spread awareness of recycled fertilisers

A recent interactive workshop held by the University of Limerick showcased recycling-derived fertilisers as a viable option for Irish farmers and agricultural stakeholders

Attendees of the interactive workshop 'Supporting the Market for Recycled Fertilisers in Ireland', hosted at UL in collaboration with Munster Technological University earlier this month.

A recent workshop to inform agricultural stakeholders of the positives of recycling-derived fertilisers (RDFs) was held at the University of Limerick (UL) this month.

The interactive workshop hosted at UL in collaboration with Munster Technological University (MTU) saw conventional and organic farmers, policy makers, personnel working in the agricultural sector and members of advisory boards attend the event.

The workshop set out to showcase RDFs as viable fertilisers for farmers and offer up a more sustainable product instead of the more widely and conventionally used chemical fertilisers.

“RDFs are a broad term for fertilisers that come from recycled sources. So, it can be anything from taking your manure and putting it into a digester. It can be composting. It could be any type of bio-based fertilisers that come from recycled sources,” explained Dr Niamh Power, a lecturer and researcher at MTU and part of the MTU team researching RDFs.

RDFs can be derived from animal manure, urban waste, human waste, in the form of sewage sludge, and products that have undergone treatments to make them viable as fertilisers. Some forms of RDF include compost, digestate pellets, struvite, ashes, ammonium sulphate, and ammonium nitrate.

A clear benefit of RDFs for farmers is that the application of the products can be used with existing machinery.

Part of Dr Power’s work is to bridge the knowledge gap with farmers and agricultural stakeholders on RDFs.

“Chemical fertilisers are the status quo. Farmers are very comfortable with using them. It's easy for them to use. They can go to the local co-op, they can pick up a bag, they can go out, and it's job done. Whereas these alternative fertilisers are just as easy to use, but farmers haven't come across them before, so they just don't quite know,” she explained.

Another key point Dr Power’s team hope to promote is that with their tests in MTU comparing RDF struvite with triple superphosphate (TSP) fertiliser, they found the RDF performed comparably to the chemical fertiliser and, in some cases, performed betterm but had slow-release qualities.

It has a slightly different growth pattern than other fertilisers, and that's something that farmers need to be aware of, that with slow-release fertilisers, you may not get an instant result when you put it on, but actually, it's been released when the crop needs it.” 

Dr Power is currently working on three projects looking at the benefits of RDFs and recycling nutrients, the ReNu2Cycle and SIMONE projects, both supported under the Interreg North-West Europe programme, and the newly announced REGENERATE project, supported by Bioeconomy Ireland.

REGENERATE, which will begin this year and span a period of four years, aims to separate and harness nutrients from digestate to maximise the value of agricultural residues.

Residues from livestock and milk processing waste and digestate from anaerobic digestion facilities will be processed in a plant and on composting sites to extract essential nutrients and remove contaminants. This will create a value chain which can produce peat-free alternatives, benefiting soil health.

This project is in collaboration with Greenville Energy, EnviroGrind, MTU, University College Cork, Nua Fund and Foster Environmental.

ReNu2Cycle and SIMONE are projects that are working alongside each other in the efforts to research and promote RDFs in Ireland. In Ireland, these projects are researched in collaboration between MTU, UL, South East Technological University and Teagasc.

ReNu2Cycle looks into how nutrients can be recycled back into the farm and tests different types of recycled and recovered fertilisers, and reduces the dependence on imported fossil-based fertilisers.

Teagasc leads the field-testing and on-farm demonstrations of recycled fertilisers as viable alternatives, with several farmers in partnership with Teagasc and UL trialling RDFs on their farms.

SIMONE works more broadly with a focus on agroecological transitions in north-west Europe, including sustainable crop nutrition, integrated weed management and resilience measures, with RDFs featuring in the Irish work within the project.

Talking to the Irish Examiner, Dr Power explained part of the aim of the joint projects was to “also make sure that farmers are aware that these are a very valuable source of nutrients. So not just your NP and K, which your chemical fertilisers have, but they also often have micronutrients and macronutrients, which are also very good for soil health as well.” 

Certain challenges that come with RDFs are the lack of knowledge in key stakeholders for the product, such as farmers and anaerobic digestor plant personnel, as well as the added costs due to the additional processing the RDFs undergo to become viable fertilisers and extract the necessary nutrients from the original material.

A barrier to the widespread utilisation of RDFs in Ireland is also the technology available currently in the country.

There are currently no RDF struvite producers in Ireland, making it more difficult to offer it as a viable option for Irish farmers.

In countries such as Germany, where farm-scale digestors are not uncommon, our German counterparts can utilise and incorporate RDFs into their farming practices more easily than Irish farmers, as RDFs, like liquid digestate, are more readily available to them.

In Ireland, there are a few large digestor plants with plans for more to be developed in the next few years, making it possible for farmers to begin having more widespread availability of liquid digestate to utilise on their farms.