New insights into the effects of support matrix on the removal of organic micro-pollutants and the microbial community in constructed wetlands

• Published in: Environmental pollution (1987) Vol. 240; pp. 699 - 708
• Main Authors: Zhang, Liang, Lyu, Tao, Ramírez Vargas, Carlos Andrés, Arias, Carlos A., Carvalho, Pedro N., Brix, Hans
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-09-2018
• Subjects: Adsorption; Biodegradation; Biodegradation, Environmental; Charcoal - chemistry; Community-level physiological profiling (CLPP); Ibuprofen - chemistry; Imidazoles - chemistry; Iohexol - chemistry; Nanotubes, Carbon - chemistry; Pesticides; Pharmaceuticals; Plants - metabolism; Silicon Dioxide; Triazoles - chemistry; Waste Disposal, Fluid - methods; Waste Water - analysis; Waste Water - chemistry; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - chemistry; Wetlands; Biodegradation; Adsorption; Community-level physiological profiling (CLPP); Pesticides; Pharmaceuticals
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2018.05.028

Constructed wetlands (CWs) are an eco-friendly and cost-effective technology to remove organic micro-pollutants (OMPs) from wastewater. The support matrix is an important component in CWs as it has a primary role in the growth and development of plants and microbes. However, the roles of the support matrix in CWs in removing OMPs have not been systematically studied. Therefore, in this study, six common materials (sand, zeolite, blast iron slag, petcoke, polonite and crushed autoclaved aerated concrete (CAAC)) as support matrixes were firstly investigated by batch tests to explore their adsorption capacities to selected OMPs (ibuprofen, iohexol, tebuconazole and imazalil). Results showed that the adsorption capacities of the materials were low (at the level of μg/g) compared to well-known sorbents (at the level of mg/g), such as activated carbon and carbon nanotubes. Columns packed with the six materials, respectively, were then built up to study the effects of different materials on microbial community. In the medium-term study (66 days), the removal of four OMPs in all the columns increased by 2–58% from day 25 to day 66, and was mainly attributed to microbial degradation. Furthermore, Community-level physiological profiling (CLPP) analysis indicates that material presence shaped the microbial community metabolic function not only in the interstitial water but also in the biofilm. Overall, all the findings demonstrate that although the adsorption capacities of the common materials are low, they may be a driver to improve the removal of OMPs by altering microbial community function in CWs.
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•Six common materials were tested for adsorption of organic micro-pollutants (OMPs).•The adsorption capacities of the tested materials were low.•OMP removal in material-packed columns was mainly attributed to biodegradation.•Materials shaped differently the water and biofilm microbial communities.
The adsorption capacities of the six common materials to OMPs are limited, but they can improve OMP removal in constructed wetlands via shaping microbial community.