Constructed Wetlands (CWs) are a sustainable choice for tertiary wastewater treatment. In these environments, microbial communities play a significant role in pollutant removal. However, little is known about how microbial communities in full-scale CWs contribute to maintaining water quality or how their dynamics change in response to pulse disturbances. We characterized the microbial communities in the Seadrift Operations Constructed Wetland (SOCW), a full-scale CW that provides tertiary wastewater treatment to a chemical production plant. The SOCW sampling campaign was conducted over a 12-month period that included a 100-year freeze event. Analysis of 16S rRNA gene amplicon sequences revealed that the microbial communities experienced a temporal shift. Six months after the freeze the removal of water quality constituents began to return to their former removal trends in the SOCW. This suggests CW functional resilience despite the shift in microbial community structure in the wetland.