Emerging investigators series: virus mitigation by coagulation: recent discoveries and future directions

Waterborne viruses are widespread and persistent in the environment. Coagulation is an effective process for mitigating viruses in drinking water. This review examines recent studies of virus mitigation by coagulation processes in the context of the latest scientific advances. Virus sorption is impacted by electrostatic forces, as well as the hydrophobic effect, steric hindrance, hydrodynamics and interactions with the water matrix. Organic matter in the water may hinder or enhance sorption, depending on virus structure and environmental factors. In addition to physical separation in flocs, coagulation processes have been shown to inactivate viruses. This review evaluates reports of virus inactivation due to coagulation processes from both a process and experimental perspective. The use of bacteriophages as surrogates for human viruses is discussed, and future research needs relevant to virus coagulation are identified. Forces influencing virion sorption and recent findings of coagulation-based inactivation inform new research directions for mitigating waterborne viruses by coagulation.