The proposed project will evaluate new methods for synthesising novel fluorescent biopolymer nanoparticles (BNPs) in quantities that are suitable to facilitate challenge testing at full-scale and investigate techniques for stabilising the BPNs for distribution. The prepared BNPs will then be used to demonstrate a full-scale challenge test at a South East Water membrane treatment plant. The BNP test will be performed at the same time as a scheduled MS2 bacteriophage challenge test or pressure-based test in order to compare the two methods.