Removal and Inactivation of Nonenveloped and Enveloped Virus Surrogates by Conventional Coagulation and Electrocoagulation Using Aluminum and Iron

Abstract

The continued threat of contamination of municipal water supplies necessitates the systematic evaluation of the efficacy of existing unit processes to protect public health and develop new technologies to better attenuate a wide range of viruses in the water we drink. We compared four coagulation approaches (conventional alum and FeCl 3 coagulation and aluminum and iron electrocoagulation) in terms of their ability to remove/inactivate an enveloped virus surrogate (ϕ6) and a nonenveloped virus surrogate (MS2) under identical experimental conditions. Facile removal and inactivation of ϕ6 by alum and FeCl 3 indicated the ability of existing conventional treatment plants to well-attenuate enveloped viruses. MS2 was attenuated to a lower extent than ϕ6, indicating relatively weaker protection against nonenveloped viruses by conventional coagulation. Performance of aluminum electrocoagulation was akin to that of alum. In contrast, iron electrocoagulation significantly outperformed the other three approaches (given sufficient time) and was the sole technique capable of simultaneously inactivating and removing both bacteriophages. However, all four coagulation approaches ruptured the ϕ6 phospholipid envelope and damaged its nucleocapsid's structural integrity. Only iron electrocoagulation resulted in the appearance of new presumptive carbonyl derivatives for MS2 and the trans geometric isomer of lipid hydrocarbon chains for ϕ6 in infrared spectra, indicating oxidative modifications to the MS2 protein capsid and the ϕ6 lipid envelope, respectively. Hence, this technology presents a harsh physicochemical environment capable of simultaneously removing and inactivating viruses.

Electro-Fenton and Induced Electro-Fenton as Versatile Wastewater Treatment Processes for Decontamination and Nutrient Removal without Byproduct Formation

“…It is noteworthy that the removal and inactivation of Phi6, a model-enveloped virus to respiratory syndrome viruses, were validated in the EF process (Figure S10). A higher level of inactivation of Phi6 than MS2 (3.6 vs 2.4-log) was observed at 30 min, which is in agreement with the previous studies that enveloped viruses are more susceptible to structural damage by oxidation. , …”

“…A recent study reported the EC removal of MS2 and phi6, where 5-log removal required a long residence time of 100–120 min . As a comparison, EF and I-EF showed significantly faster virus removal and inactivation kinetics (residence time <60 min).…”

“…A higher level of inactivation of Phi6 than MS2 (3.6 vs 2.4-log) was observed at 30 min, which is in agreement with the previous studies that enveloped viruses are more susceptible to structural damage by oxidation. 32,52 A recent study reported the EC removal of MS2 and phi6, where 5-log removal required a long residence time of 100− 120 min. 52 As a comparison, EF and I-EF showed significantly faster virus removal and inactivation kinetics (residence time <60 min).…”

“…32,52 A recent study reported the EC removal of MS2 and phi6, where 5-log removal required a long residence time of 100− 120 min. 52 As a comparison, EF and I-EF showed significantly faster virus removal and inactivation kinetics (residence time <60 min). This advantage could be attributed to the additional contribution of radical-and H 2 O 2 -mediated oxidation.…”

Indirect Evidence that Colloidal Deposition Inside a Hollow Fiber Ultrafiltration Membrane Exacerbated Fouling during Municipal Wastewater Reclamation

“…These conditions were chosen because they corresponded to excellent virus attenuation by conventional and electrocoagulation established in previous laboratory studies. 37 After pretreatment, the water was immediately and directly ultrafiltered (i.e., without sedimentation). Note that pH optimization can be a future direction of study because it has been recently recognized as a critical parameter impacting EfOM conformation and system polarity and subsequent fouling.…”