Evaluation of bacterial community in constructed wetlands treating different sources of wastewater

Abstract

Bacteria serve as important components of a constructed wetland (CW) system. Various bacterial communities aid in pollutant removal; however, environmental conditions and other external variables can greatly affect their performance and diversity. In this study, four constructed wetlands treating secondary livestock wastewater (LCW), agricultural runoff (ACW1 and ACW2) and urban stormwater (HCW) were investigated to evaluate the relationship between the inflow pollutants and the bacterial community. Based on the findings, the 20 dominant bacterial species in water samples collected from the livestock area (LCW) constituted 98.5% to 99.7% the total bacterial population. In the case of agricultural areas (ACW1 and ACW2), the 20 most abundant bacterial species constituted 99.7% to 99.8% of the total bacterial population. Similarly, the 20 dominant bacterial species found in the soil samples from livestock and agricultural areas made up 97.2% to 98.7% and 99.1% to 99.6% of the total bacterial population, respectively. Generally, the diversity of bacteria in soil was higher compared to water. It is important to establish a target bacterial habitat when creating CW for optimized ecological functions.