Investigation on the removal efficiency of non-enveloped and enveloped viruses by coagulation

The number of patients suffering from water-borne diseases has risen along with the increase of population, and pathogenic viruses have been proven to be a causative agent in many outbreaks. The high concentration of the pathogenic viruses such as norovirus, adenovirus, rotavirus etc. in water sources that are used for drinking water production has been reported in many studies. Because of their public health implication and high prevalence in water, effective drinking water treatment methods are needed for the removal of those viruses to prevent disease among drinking water consumers. Typically, non-pathogenic viruses which are structurally and physiologically similar to the pathogenic viruses are used as a surrogate for estimating virus removal efficiency of treatment processes, and the most well-known virus is bacteriophages.  Bacteriophages or bacteria-infecting viruses have been recently applied for the testing of virus removal in both wastewater and water treatment process and the most widely used are MS-2, T4 and Q-beta, which all are a non-enveloped virus. Nonetheless, severe water-borne outbreaks related to enveloped viruses are increasingly recorded, especially Ebola virus. The Ebola virus is an enveloped-virus causing Ebola virus disease with a high fatality rate. It has been concerned by environmental scientists and engineers since it can be transmitted and spread through water bodies. Therefore, there is a need to develop a surrogate virus that can be a representative for pathogenic enveloped viruses like Ebola virus and to investigate its removal efficiency and mechanisms in the water treatment process. In this study, a bacteriophage, phi 6 is proposed as a surrogate for pathogenic enveloped viruses to be used for evaluating its removal efficiency by coagulation, a treatment unit in water treatment processes. The study will consist of two main parts: (1) the investigation of an optimum condition for the virus removal and (2) investigation of virus removal mechanisms of the enveloped virus compared with non-enveloped viruses by coagulation. Results from this study can develop an understanding of how enveloped-virus is being removed during the coagulation and can be basic information that can be used to apply for operating coagulation in practice. As safe drinking water is a basic need for human health, this study will fulfill Thailand’s 20-Year National Strategy, especially the 5^th strategy on environmental-friendly development and growth.