Change in microbial profile and environmental conditions in a constructed wetland system treating greywater

• Published in: Environmental science and pollution research international 2021-07, Vol.28 (26), p.34539-34552
• Main Authors: Bernardes, Fernando Silva, de Souza Pereira, Mariana Antônio, Hassan, Ismail Abdallah Ismail, de Castro, Alinne Pereira, Roche, Kennedy Francis, Paulo, Paula Loureiro
• Format: Article
• Language: English
• Subjects: Acinetobacter; Anaerobic conditions; Anaerobic microorganisms; Aquatic Pollution; Artificial wetlands; Atmospheric Protection/Air Quality Control/Air Pollution; Bacteria; Candidatus Koribacter; Chemical oxygen demand; Desulfomonile; Desulforhabdus; Desulfovibrio; DNA sequencing; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental conditions; Environmental Health; Environmental science; Evapotranspiration; Greywater; Methanobacteria; Methanogenic bacteria; Methanosaeta; Microbial activity; Microorganisms; Nitrogen cycle; Nitrososphaera; Novosphingobium; Organic carbon; Organic matter; Oxidation; Physicochemical analysis; Redox potential; Research Article; Sulfate reduction; Sulfate-reducing bacteria; Waste Water Technology; Water Management; Water Pollution Control; Water reuse; Wetlands
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-021-12822-z

The objective of this work was to verify the relationships between environmental conditions and microbial processes along a raw-light greywater flow in an improved constructed wetland (CW) system. Physicochemical analysis and high-throughput DNA sequencing were performed in the different zones to investigate the environmental conditions and microbial communities. The results showed that the system operated predominantly under anaerobic conditions, with redox potential (Eh) increasing from the inlet (−342.9 mV) to the outlet (−316.4 mV). Conversely, the chemical oxygen demand (COD) decreased along the greywater flow, suggesting negative correlation between these characteristics. The zones of the evapotranspiration and treatment tank (CEvaT) were characterized by lower community diversity and richness and by the presence of specific groups: Proteobacteria and Synergistetes related to the first steps of the conversion of organic carbon, in the bottom layer inside the anaerobic chamber (AnC); methanogens ( Methanosaeta and Methanobacterium ) and sulphate-reducing bacteria ( Desulfovibrio , Desulforhabdus and Desulfomonile ) in the middle layer; and microorganisms associated with the nitrogen cycle and oxygen release ( Acinetobacter , Novosphingobium , Candidatus Nitrososphaera ) in the top layer. On the other hand, the increase of the ORP and decrease of organic matter concentrations were associated with higher community diversity and richness in the middle layer of the CW, which showed higher abundance of microorganisms involved in methane ( Methylobacterium and Candidatus Koribacter ) and sulphur ( Rhodoblastus and Thiobacillus ) oxidation.