New phage-based wastewater pollution control solution with safe reuse

Abstract

This study aims to demonstrate a cost-effective, efficient, and chemical-free solution for rapid wastewater treatment processes. The Nile's and drainage water, were used to isolate and identify 146 presumptive Escherichia coli strains. It was found that 73.9 % of these strains were verified using 16S‐rDNA. Coliphages, specifically three new phages (MCn10/MCn11/MCn12), were found in all sampled sites, with the highest levels at drain outfalls. The Siphovirus MCn10, Myoirus MCn11, and Podovirus MCn12 as recognized using morphological and molecular analysis have exhibited different burst sizes, with 95, 100, and 70 plaque-forming units (pfu) per infected cell with latent periods 35, 40, and 60 min, respectively. These phages show a remarkable ability to inhibit the growth of seven diverse bacterial strains under neutral conditions, highlighting their polyvalence. The removal efficiency (%) of Escherichia coli colonies reached 95.2 %, while for Citrobacter freundii it was 91 %, Proteus vulgaris 73.3 %, Salmonella sp. 98 %, Pseudomonas aeruginosa 50 %, Pseudomonas fluorescens 80 % and Enterococcus faecalis 96.1 %. Significant improvements were observed in the physicochemical parameters of treated wastewater with polyvalent phage mix. The treatment process demonstrated an average increase rate of (69.1 %) in dissolved oxygen (DO), while the average reduction rate in total dissolved solids (TDS) (59.46 %), turbidity (57.15 %), chemical oxygen demand (COD) (58.75 %), ammonia (NH₃) (70.4 %), electrical conductivity (EC) (60.91 %), nitrate (NO₃^–) (60.1 %), and biochemical oxygen demand (BOD) (65.45 %) compared to untreated wastewater. The quality of the treated wastewater gradually increased and reached its peak after 12 h, indicating a nearly 100 % improvement after beginning inoculation with the phage mix. This investigation presents a novel candidate for polyvalent phages that can be safely produced with non-pathogenic production hosts. This technology is an innovative development in wastewater reuse management and reduces the risk of unexpected pathogen leakage which may offer significant economic gains.