Lystek Biosolids Processing Technology and Beneficial Applications of the Processed Biosolids: Full Scale Results
Coffey, S.1, Singh, A.2, Mosher, F.2, Lugowski, A.1, Ward, O.3, Walsh, C.4, 1Conestoga-Rovers & Associates (Europe) Ltd, 2Lystek International Inc., 3University of Waterloo, 4 City of Guelph Wastewater Services Division
(free)
CRA has successfully developed and patented an innovative biosolid treatment and processing
technology (Lystek Process) that results in pumpable biosolids that have been approved as a
grade A fertiliser in the US. The technology has been developed over 3 years at bench- and
pilot-scale and further tested at full-scale at the Guelph wastewater treatment plant, Ontario,
Canada. The processing requires an optimum application of heat, alkali and mixing in a batch or
semi-continuous system to achieve a high solids concentration (15-18%), pathogen-free and
nutrient-rich liquid biosolids product that meets US EPA criteria for a Class A material for
agricultural land application. Unlike dewatered biosolid cake, which requires specialised pumps or
equipment to handle the biosolids, Lystek processed biosolids are fully compatible with
conventional equipment in use for land application of biosolids and liquid manure, storage, and
transport. The processed biosolid product retains pumpability suitable for beneficial re-use and
application as a fertiliser product even after prolonged seasonal storage at ambient temperature
in Canadian weather conditions. There was no evidence of re-growth of harmful pathogens such
as Escherichia coli, Salmonella and faecal coliforms even after storing the processed materials
over long periods (~3 years) at room temperature (17-22°C). Successful trials of the Lystek
process to treat raw wastewater and other intermediate wastewater biosolids indicated the
versatility of the process, with a potential to minimise the burden on the existing intermediate
biosolids handling processes within the wastewater treatment facility, increase energy recovery,
reduce total volumes of biosolids generated and reduced storage requirements in the plant.
