Optimized Aluminum Hydroxide Adsorption-Precipitation for Improved Viral Detection in Wastewater

Wastewater-based epidemiology (WBE) is a valuable tool for monitoring pathogen spread in communities; however, current protocols mainly target non-enveloped viruses. This study addresses the need for standardized methods to detect both enveloped and non-enveloped viruses by testing four aluminum hydroxide adsorption-precipitation techniques. Wastewater samples were spiked with an enveloped virus surrogate (Φ6 bacteriophage) and a non-enveloped virus surrogate (MS2 coliphage), and viral recovery was assessed using reverse-transcription quantitative PCR (RT-qPCR). The highest recovery for the enveloped virus was achieved with AlCl₃ at pH 3.5, a 15 min flocculation time, and a 3% elution solution concentration. For the non-enveloped virus, optimal recovery was found with AlCl₃ at pH 6.0, no flocculation time, and a 10% elution solution. The best method for recovering both virus types used AlCl₃ at pH 6.0, 15 min flocculation, and a 3% elution solution concentration. This study shows that while optimal conditions vary between virus types, a standardized AlCl₃ flocculation protocol can efficiently recover both, providing a cost-effective approach for outbreak monitoring in Grenada.