A novel integrative performance evaluation of constructed wetland on removal of viable bacterial cells and related pathogenic, virulent and multidrug resistant genes from wastewater systems

Abstract

Integrative performance evaluation of constructed wetland in removal different aspects of bacteria under specific local environmental conditions needs to be explored in detail to ensure selection of appropriate and highly efficient macrophytes candidates. To achieve this, integrative purification performance evaluation approach that holistically considers all the aspects of pathogenic bacterial biology (colony numbers, functional gene, species, virulent, pathogenicity and resistant genes) needs to be adopted rather than the commonly known unidimensional approaches that take into account a single bacterial aspect. This study experimentally evaluated the individual performance of three native and one exotic winter tolerant submerged macrophytes combined with a single emergent macrophyte in eradicating faecal related bacterial species and pathotypes across horizontal surface flow constructed wetland. It involved the new multi-dimensional approach that integrated the faecal bacterial colony numbers, functional gene copies, species survival, virulent and pathogenicity as well as antimicrobial resistant in constructed wetland purification evaluation. The results showed Elodea nuttallii and Myriophyllum spicatum as the best candidate partners to Typha latifolia for the highest Purification Efficiency (P < 0.05), of above 97% for removal of faecal bacteria colonies and functional genes, and more than 75% for removal of faecal bacterial strains, pathotypes, virulent and well as resistant genes. However, M. spicatum being a Chinese native species should be much preferred to the invasive E. nuttallii. Therefore, the study recommends the application of local macrophytes such as M. spicatum as the best candidates and the decision should emanate from such a multidimensional/intergrative purification-based evaluation approach.