New mobile slurry separation service to be offered in the Mid Ulster area

The initiative, one of three envisaged for Northern Ireland, will be supported through funding secured from the Department of Agriculture, Environment and Rural Affairs (DAERA), linked to the Small Business Research Initiative (SBRI).

The project will be delivered under the aegis of Northern Ireland’s Centre for Competitiveness.

A total of £12M will be made available to help fund the slurry separation projects, which will be developed into holistic farm waste treatment initiatives focussed on the attainment of the following objectives within the next three years: the trialling of anaerobic digestion (AD) at scale to produce biomethane and the active extraction of phosphate from animal slurries.

Previously, Blakiston Houston Estates in Co Down had been confirmed as the first slurry separation and treatment hub. Details of the third project will follow.

Research and development work carried out by teams at both the Agri-Food and Biosciences Institute (AFBI) and Queen’s University has indicated that large scale AD could produce up to 83% of the natural gas currently used in Northern Ireland with biomethane.

There are also a number of options available when it comes to the use of extracted phosphate including the development of organic manures and new, Portland cement-free concrete mix specifications.

But the bottom line is that all of the removed phosphate must be exported out of Northern Ireland or put to uses, which does not see the chemical put back out on to local agricultural land.

It is envisaged that the second slurry separation and ant treatment project will be officially named: The Mid Ulster Slurry and Nutrient Management Project.

It has already secured commercial support from four businesses with a significant footprint within the envisaged catchment area of the new slurry separation service: Cemcor, the RSC Group, Tobermore Concrete Products Ltd and Alltech.

Farmers were recently invited to a meeting, held at the College of Agriculture’s Food and Rural Enterprise’s Lougry campus. Its purpose was to profile the scope of the Mid Ulster slurry separation and treatment project.

AFBI’s Chris Johnston spoke of the absolute need to reduce the levels of phosphate reaching Northern Ireland’s water courses at the present time.

“Currently 11,000t of excess phosphate is reaching rivers and streams each year with animal slurries making a key contribution in this regard in this regard,” he explained.

“The plan is to reduce this surplus to around 5,000t per annum.

“If this level can be reached the improvements in water quality that can be achieved will be significant.

“Slurry separation is at the start of a process that can bring about significant reductions in phosphate application rates to agricultural land.”

Johnston added: “Many parts of the world are currently dealing with phosphate deficits.

“Here in Northern Ireland, the polar opposite is the case.

“This is attributable to the fact that our livestock sectors rely on large tonnages of imported grains and proteins for inclusion within compound rations.”

Dr James Young is the Project Technical Lead: Mid Ulster Project (Centre for Competiveness).

Courtesy of his presentation to the Loughry meeting, Dr Young confirmed that the new mobile, slurry separation service will be available in the very near future.

It is envisaged that the initiative will be ‘cost neutral’ from the participating farmers’ perspective.

Slurry separators can deliver a range of physical results. However, it is anticipated that, on average, they can take out approximately 30% of the phosphate contained in slurries within the solid fraction that is produced.

James Young further explained: “Separation, in its own right, delivers significant benefits for livestock farmers. In the first instance, it reduces the storage capacity required on farms. But, in addition, the liquid fraction that remains can be more easily applied using low emission spreading systems.”

He continued: “The Centre for Competitiveness is delighted to facilitate this innovative sustainability programme on behalf of the Mid Ulster project.

“It will enable farms to manage and track their nutrients on-farm, deal with capacity issues, and get ahead of increasing compliance from customers (agri-processors) and regulatory changes from government, ensuring business resilience.

“Above all else this will begin to shape and show how agriculture can lead the way in increased sustainability practices on a cross-sectoral basis.”

Queen’s University Belfast

Ian Marshall, from QUB, also attended the Loughry meeting. He foresees the three pilot slurry-related projects as being forerunners of bio-refineries, which will act to deliver a coherent response key climate change on behalf of Northern Ireland as a whole.

Marshall continued: “This initiative is about much more than the processing of slurry. It places the farming sectors at the strategic centre of our response to climate change.

“In other words: farming is the solution.

“And by taking this approach the pressure to reduce livestock numbers no longer becomes an issue.”

DAERA officials believes that the three pilot slurry-focused project have the capacity to reduce phosphate loading on to Northern Ireland’s soils be approximately 1,000t per annum.

The Department’s deputy director for green growth, Jonathan McFerran, attended the Loughry meeting.

He explained: “Farmer engagement in slurry separation and export of slurry solids for anaerobic digestion is a crucial first step in a much wider process that can lead to a more sustainable agri-food sector.

“Farmers will see early benefits with a reduction in the nutrient loading of their farms, extra capacity in their slurry tanks and less issues with the use of low emission slurry spreading equipment due to the more liquid nature of the remaining liquid fraction.”

McFerran continued: “However, farmers will also be contributing to a chain of positive impacts well beyond the farm gate, with slurry solids being used to produce renewable gas and electricity to help decarbonise other sectors of the economy and providing the raw materials to develop a range of innovative products, high in excess nutrients, which can be exported outside of Northern Ireland.”

A number of farmers in attendance at the Loughry event signed up to avail of the new slurry separation service on the night.

The financial viability of slurry processing depends on large-scale, centralised systems.

The Mid Ulster Project aims to both prove the concept and value of mobile slurry separation to the agri community, supporting them with their nutrient management through certified separation and removal of excess nutrients, creating a higher quality liquid fraction to fertilise their land.

The costs benefits model of farmers involved in the project and development of the centralised plant will be established throughout the duration of the three-year project.

Benefits include certified removal of phosphorus of the farms, reduced farm carbon footprints, improved compliance with regulations, and lower reliance on imported fertilisers.

There are also potential cost savings for farmers through reduced fertiliser costs and improved resource efficiency.

Ian Marshall again: “We are actively working towards advancing Ireland's potential by establishing partnerships with farmers and grid operators, north and south.

“We are looking forward to seeing advances in planning regulations that will help speed-up development times so that we can achieve decarbonisation goals.

“We also know that many of the gases produced by way of AD can have significant values in their own right.

“For example, methane can be used to produce amino acids, a fundamental component of protein.

“So, there is no reason why we cannot produce significantly higher proportions of the protein needed for animal diets, thereby reducing our reliance on imported soya.

“In addition, ammonia is an extremely effective carrier of hydrogen.”

Marshall concluded: “The commercial development of these hubs by organisations not directly involved in production agriculture takes the pressure off individual farmers to establish their own AD operations.

“Such an approach will also reduce the amount competition for land at farm level, from an energy production perspective.”

“Significantly, Northern Ireland’s agriculture minister, Andrew Muir, is making no secret of his absolute support for the slurry separation and AD projects.”

He believes they have the “potential to radically change the way nutrients are managed by the farming community.”

A political perspective

Declan McAleer MLA is the vice chairman of the Stormont Agriculture Committee.

He believes that the £12M of DAERA funding to assist in the development of a bio circular economy will deliver a significant dividend

McAleer commented: “The new project will make a significant reduction on the current levels of excess phosphorus by reducing the excess nutrient from slurry by at least 1,000 tonnes per year by the end of year three.

“This will provide an on-farm solution and is about the separation of slurry on-farm. Similar to a milk run, someone will go around farms with a mobile unit separating slurry and take away the solids to an anaerobic digestion plant.

“The focus is on cattle and pig farmers.”

According to McAleer the development of new phosphorous extraction technologies will deliver numerous benefits, on-farm, across Northern Ireland.

He continued: “They will allow farmers to put out slurry when best use can be made of the soil nutrient rather than spreading it when they have to.

“In addition, these new technologies will free up space in tanks while also linking-in with the soil nutrient health scheme.”

AFBI

Meanwhile, ongoing Agri-Food and Biosciences Institute (AFBI) research is looking at the feasibility of physically extracting phosphorous from animal slurries.

The work focussed on the effectiveness of two mechanical separation technologies (screw press and decanter centrifuge) to reduce phosphorous levels in land-spread slurry and anaerobic digestate.

Technologies are available to separate phosphate from livestock slurries, reducing the P-load applied to agricultural land from these sources and helping to lower environmental risks to water quality.

Such treatment technologies, allied with separated solids processing and P export to areas where it is required, would improve the environmental sustainability of dairy farm nutrient management.

AFBI has undertaken a comprehensive review of published scientific literature on the effectiveness of these separation technologies to reduce the phosphate loading of slurry and digestate before land application.

Both separation technologies partition a proportion of the insoluble materials (including the P) in slurry in to a separated solids fraction and also produce a separated liquid fraction with lower solids and P content.

The research examined capital and operating costs, separation efficiency and throughput, the use of chemical additives, management and processing of separated fractions including transport costs, environmental impacts and the biosecurity of separated solids for export.

Of the two technologies reviewed, Screw Press separation is a more cost effective option when lower amounts of export of P off-farm are acceptable.

For farms and those with anaerobic digesters managing larger volumes of manure/digestate, screw press separation is possible.

However if higher levels of P removal are required, the use of decanting centrifugation is a viable option.