Removal processes of indicator organisms and opportunistic pathogens in an anaerobic digester‐constructed wetland system

Factors affecting the removal of opportunistic pathogens were evaluated in a hybrid constructed wetland (CW2) treating rural wastewater. The correlations between the bacterial population and the environmental variables showed that bacteria discharge was the result of abiotic factors change such as temperature (T), electrical conductivity (EC), dissolved oxygen (DO), organic matter and nutrient availability, as well as biotic factors like antagonism and competition with the native microbial community. However, the contribution of each factor depends on bacteria nature, on the influence of wetland design, availability of oxygen, season, presence of plant, and wastewater composition. Higher removals rates of biochemical oxygen demand BOD5 (94.64 ± 3.92%), chemical oxygen demand COD (90.91 ± 6.81%), total suspended solids TSS (98.05 ± 1.18%), nitrogen (total Kjeldahl nitrogen TKN (81.78 ± 11.01%), ammonia nitrogen NH4+ (92.17 ± 6.56%), orthophosphate PO43- (79.73 ± 10.41%) and bacteria (>98%) were observed in CW2.