Date lodged: 5 February 2019
To ask the Scottish Government what assessment it has made of the potential value of fats, oils and grease discarded into the sewer system as a bioresource, and of potential resource capture mechanisms for these.
Answered by: Roseanna Cunningham 20 February 2019
Scottish Water has conducted trials in conjunction with a biodiesel processor to assess the viability of recovering Fats, Oils and Grease (FOG) from the sewerage network. Due to the distributed nature of the sewerage network and the diffuse nature of FOG, recovering sufficient quantities for biodiesel production has so far proved uneconomic in Scotland.
Scottish Water has also participated in a number of research projects through United Kingdom Water Industry Research (UKWIR) which have examined the issue of FOG discharged to sewer. The latest project reported in 2018. The report examined means to improve the current controls on FOG discharges while also looking at future strategic options to better collect and recover FOG. Control and potential recovery of FOG at source is the long term aim. To this end Scottish Water has initiated a pilot project in St Andrews working with food service establishments to improve housekeeping and reduce the quantity of FOG discharged to the sewer network.
In addition to this, the value of FOG is captured to an extent already in plants where energy is produced from sludge and FOG becomes part of the feedstock.