Assessment of pathogenic parasitic agent removal in wastewater for agricultural and aquaculture reuse: a case study of municipal wastewater treatment plants in Northwest Iran

The shortage of freshwater resources and the growing need for wastewater reuse have increased the importance of investigating the pathogenic agents present in wastewater. Given the agricultural conditions of Ardabil Province, this study aimed to evaluate the efficiency of municipal wastewater treatment plants in removing pathogenic parasites. This descriptive–cross-sectional study was conducted over one year (from April 2023 to March 2024) in four wastewater treatment plants in Ardabil Province, Iran. Samples were collected biweekly from the influent and effluent, resulting in a total of 192 samples. Geographical heterogeneity and seasonal patterns was observed for several parasites. Spearman correlation analysis revealed strong associations among several parasites for instance, a strong positive correlation was found between Fasciola sp. and Dicrocoelium sp. (r = 0.736, p < 0.001). According to the results of present study, Ardabil wastewater treatment plants have an effective ability to remove important parasitic agents, including protozoa and helminths.