Sediment

Ecology

Bacteria

Biology

Wetland

Denitrification

Phosphorus

Proteobacteria

Nitrogen

Bacteroidetes

Firmicutes

16S ribosomal RNA

Paleontology

Genetics

Organic chemistry

Environmental chemistry

Denitrifying bacteria

Chemistry

Constructed wetland

The Science of The Total Environment

A multi-stage surface flow constructed wetland (SFCW) is used to treat decentralized rural domestic sewage. The performance of a multi-stage SFCW located in Hunan, China, and the associated microbial community structures were investigated. The average removal rates of the multi-stage SFCW planted with Myriophyllum elatinoides were 1.0 g m−2 d−1, 0.84 g m−2 d−1, 61.3 mg m−2 d−1, and 85.3 mg m−2 d−1 for total nitrogen (TN), ammonia (NH4+), nitrate (NO3−), and total phosphorus (TP), respectively. Furthermore, the sediment and presence of plants were found to be important for the removal N and P. The average removal rates by sediment and plants were 196.6 mg N m−2 d−1 and 49.9 mg P m−2 d−1, 17.6 mg N m−2 d−1 and 8.1 mg P m−2 d−1, respectively. The microbial community profiles demonstrated that Proteobacteria, Chloroflexi, Bacteroidetes, Firmicutes and Euryarchaeota were the predominant phyla in each stage and at different sampling times. The concentrations of NO3−, TP, TN, and NH4+, and the pH of the sediment and water had a significant effect on the presence of denitrifying bacteria in the anaerobic environment. Whereas, dissolved oxygen (DO) and redox potential (Eh) had a significant effect on the presence of nitrifying bacteria in the aerobic environment. This research strongly supports that the use of the multi-stage SFCW promotes bacterial diversity and changes bacterial community in the sediment.

Nitrogen and phosphorus removal performance and bacterial communities in a multi-stage surface flow constructed wetland treating rural domestic sewage