Northern Ireland is working to channel as much of its slurry’s phosphorus through anaerobic digesters as is possible, in a bid to address water quality challenges.

Doing so will allow surplus phosphorus to be exported in solid form, while producing gas that can be used to generate electricity, AFBI’s Chris Johnston, project leader in environment and renewables, said.

Johnston told an Irish Bioenergy Association conference that the past decade has seen an increase in phosphorus imports on to NI farms “mainly animal feed” to drive dairy production resulting in “quite a big jump” in the phosphate entering waterways.

“What we want to do is gather up as much slurry from farms as we possibly can. We are not talking about transporting slurry at 5-6% solids, we want to process the slurry on-farm,” he explained.

“What that will do is partition a significant portion of the phosphorus into that solid material and we can transport that solid material off to 75 biorefinery systems in this case referring to our existing AD plants that we have.”