Microalgae-based systems can potentially inactivate E. coli and viruses. In this work, batch algal-bacterial photobioreactors were operated to elucidate the effect of zero-valent iron (ZVI) nanoparticles and light intensity on the reduction of viral RNA (MS2, Phi6 and Bovine coronavirus, BCoV) and uidA gene (E. coli) during secondary wastewater treatment. Biodegradation and abiotic control photoreactors were operated at high light intensity (1100 µE m