Multiple bench-scale filtration campaigns of Hanford tank waste supernatant on a backpulseable dead-end filtration skid have provided greater insight into the solids that cause fouling and reduce filter performance. The solids collected during each campaign were concentrated from the backpulse solutions and examined using automated particle analysis (APA) methods with scanning electron microscopy and X-ray energy dispersive spectroscopy to categorize particle types and their morphological characteristics. We show that with APA, thousands of particles can be analyzed to provide accurate insight into the phases that may be impacting filter performance. Display omitted •APA successfully characterized many particles from supernate tank waste samples.•Solid samples showed evidence of the impact of the water addition.•Effective APA depends on careful sample preparation to reduce bias in particles distribution.•Analysis shows that gibbsite and calcite particles tend to be larger than the metal hydroxide phases.