Polishing Domestic Wastewater on a Subsurface Flow Constructed Wetland: Organic Matter Removal and Microbial Monitoring

• Published in: International journal of phytoremediation 2011-11, Vol.13 (10), p.947-958
• Main Authors: Mina, I. Aguiar-Pinto, Costa, M, Matos, A, Calheiros, C. Sousa Coutinho, Castro, P. M. L
• Format: Article
• Language: English
• Subjects: Bacteria; Bacteria - growth & development; Bacteria - isolation & purification; bacterial communities; biochemical oxygen demand; Biodegradation, Environmental; Bioremediation; Biota; chemical oxygen demand; Cluster Analysis; coliform bacteria; Colony Count, Microbial; Constructed wetland; constructed wetlands; Denaturing Gradient Gel Electrophoresis; DGGE; DNA, Bacterial - analysis; Domestic; Domestic wastewater; Dynamical systems; Dynamics; Environmental Monitoring; Industrial Waste - analysis; Inlets; Microbial communities; Microbiology; Microorganisms; Monitoring; Nutrient removal; organic matter; Phragmites australis; planting; Poaceae - growth & development; Poaceae - metabolism; polymerase chain reaction; Portugal; recreation; RNA, Bacterial - genetics; RNA, Ribosomal, 16S - genetics; sanitation; subsurface flow; swimming; temporal variation; Time Factors; Waste Disposal, Fluid; Waste water; wastewater; Water Microbiology; Water Purification - methods; Water treatment; Wetlands
• ISSN: 1549-7879; 1522-6514; 1549-7879
• DOI: 10.1080/15226514.2010.532182

Microbial monitoring of constructed wetlands (CWs) treating domestic wastewater is generally scarce, despite the need of more knowledge about its biocenosis. The sanitation quality of a wastewater treated in a CW is a crucial aspect, mainly when the receiving water body is used as a swimming and/or recreation area. The present study was carried out in a horizontal subsurface flow CW planted with Phragmites australis receiving pre-treated domestic wastewater (mean flow 50 m³ day⁻¹), from a population of about 300 inhabitants. The monitoring programme undertaken during the first year operation, revealed removal efficiencies of 61% BOD₅, 44% COD, and 65% TSS for inlet water with ca. 90 mg L⁻¹ BOD₅, 157 mg L⁻¹ COD, and 17 mg L⁻¹ TSS. Total Coliform (TC) and Faecal Coliform (FC) bacteria were removed from wastewater (mean inlet values of 5 × 10⁶ CFU 100 mL⁻¹ TC and of 9 × 10⁵CFU 100 mL⁻¹ FC), with efficiencies of 92 and 97%, respectively. The dynamics of microbial communities established in the system assessed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), had revealed a high bacterial diversity within the system, with no relevant differences in composition at the CW inlet and outlet but exhibiting temporal differences in bacterial communities.