Efficient carbon removal and excellent anti-clogging performance have been achieved in multilayer quartz sand horizontal subsurface flow constructed wetland for domestic sewage treatment

• Published in: Journal of environmental management 2023-06, Vol.335, p.117516-117516, Article 117516
• Main Authors: Li, Jieyue, Wang, Jiajun, Zhang, Qin, Ding, Yanli, Zhang, Yanan, Wang, Ronghua, Wang, Dunqiu, Bai, Shaoyuan
• Format: Article
• Language: English
• Subjects: adsorption; biodegradation; Brevundimonas; Carbon; chemical oxygen demand; Chitinophagaceae; Citrobacter; Clogging; Horizontal subsurface flow; Luteimonas; Microbial community; Multilayer structure; Nitrogen; Organic loading rate; organic matter; Pedobacter; pollution control; Quartz; Sand; Sewage; sewage treatment; Solids accumulation; subsurface flow; Waste Disposal, Fluid - methods; Wetlands
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2023.117516

The present study aimed to investigate the application of a multilayer quartz sand substrate horizontal subsurface flow constructed wetland (HSFCW) for campus sewage treatment. It aimed to assess the pollutant removal efficiency and anti-clogging performance under the suggested maximum organic loading rate (250 g/m2/d). The results of the multilayer HSFCW (CW6) were compared to the mololayer HSFCW (CW1) for the removal of the chemical oxygen demand (COD), solid accumulation, and microbial communities. During operation, the combination conditions of high hydraulic loading rate (HLR) with low COD concentration were better for COD removal under a high organic loading rate (OLR) of 200–300 g/m2/d. The maximum removal rate reached 80.4% in CW6 under high HLR, which was 13.8% higher than that in CW1, showing better adsorption and biodegradation ability of organic matter. Impressive clogging resistance capacity was found in CW6 due to the lower contents of the insoluble organic matter (IOM) that are prone to clogging, indicating full degradation of organic matters, particularly IOM, in CW6 under high HLR. Less abundance of unclassified Chitinophagaceae (under low HLR), Pedobacter and Saccharibacteria_genera_incertae_sedis (under high HLR) in CW6, which contributed to aerobic membrane fouling, helped to prevent clogging. Moreover, Brevundimonas, Cloacibacterium, Citrobacter, Luteimonas contributed to IOM degradation, thus further enhancing the anti-clogging performance. In view of the better clogging resistance performance, the application of CW6 operated under high HLR and low COD concentrations was recommended to achieve economical, efficient, and steady COD removal for domestic sewage treatment in long-term operation. •Build a quartz sand multilayer horizontal subsurface flow constructed wetland (CW6).•The chemical oxygen demand was removed 80.4% in CW6 under hydraulic loading rate.•Multilayer structure contributed to anti-clogging for less insoluble organic matter.•Several genus of bacteria associated with clogging in CW6 were found.•Efficient and economical CW6 could be widely applied in carbon removal of sewage.