Hydrothermal Liquefaction (HTL) is a moderate temperature-high pressure depolymerisation process that converts organics in wet biomass into crude-like oil. HTL feedstock properties and characteristics will influence the conversion of organics into crude-like oil and other by-products. The aim of the investigation is to quantify specific feedstock (biosolids) parameters to determine optimal feedstock properties for converting biosolids into crude-like oil. The properties of the feedstock which included moisture content, ash content, particle density, bulk density, porosity and particle size were analytically determined which are useful data for reactor design. The data presented in this study analyses the behaviour of biosolids using batch settling experiments and pumping studies. The influence of particle size and solid concentration of biosolid slurries on the processability in terms of stability and pumpability of the feedstock slurry was assessed. Biosolid slurries with 60 w/w% dry solids were determined to be the minimum solid concentration that demonstrated no visible settling characteristics within an observation period of 30 min. Pumpability was achieved with slurries between 30 w/w% to 60 w/w% dry biosolids using a laboratory scale peristaltic pump. Pumping power required to transport biosolid slurries increased exponentially with an increase in solid concentration. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.