710827An innovative new technique for improved separation of liquid digestate to concentrate & retain valuable nutrients and reduce costs of liquor processing through sustainable reed beds - UltrafloccClosedGRD Proof of ConceptInnovate UKAnaerobic digestion (AD) of biowaste is becoming an increasingly popular means of recycling unwanted materials to generate both energy (in the form of biogas/electricity) & reusable materials (fertilisers). In the UK, the number of AD plants has increased dramatically since 2013, from 106 to 246 plants. However a major problem faced by entire sector is dealing with the large amounts of liquid digestate produced as a by-product of the process; 80% of the input feedstock is typically collected as liquor. Control & handling of the digestate liquor is regulated, so dealing with the large volumes (~40,000 tonnes per average size plant) can be extremely difficult and costly. Ideally, reed beds would be used, but are not viable due to the high solid content that tend to choke the reed beds, along with the loss of the valuable nutrients the liquor contains. Consequently, the most common disposal method is to transport the liquor to farms where it is spread directly as a fertiliser at considerable cost. Land application of fertiliser can also lead to run-off & leaching, creating a risk of eutrophication. The ideal solution would be to lower the suspended solid digestate content of the liquor (to 5 wt% max.) to generate a digestate liquid which could subsequently be processed using reed beds; dramatically reducing transport costs & enabling recovery of valuable nutrients (eg. nitrogen & phosphorus) in a solids concentrate. Our innovative new concept will accelerate the flocculation of particles & encourage sedimentation. It is envisaged that the development of the new technology will: • Reduce costs of dealing with digestate liquor; lower capital & operating costs vs SOA • Reduce solid content of digestate liquor from 10% to less than 5% • Facilitate release of liquor to reed beds – less solid content in liquor will reduce risk of blockage • Recover valuable nutrients (nitrogen & phosphorus) in a concentrated form