ZHUYi-xuan,WUZheng-qing,XUShi-rong,et al.Effect of Bio-clogging on Removal of Pollutants in Constructed Wetland[J].China Water & Wastewater,2023,39(11):69-74.
Effect of Bio-clogging on Removal of Pollutants in Constructed Wetland
China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU]
volume:
第39卷
Number:
第11期
Page:
69-74
Column:
Date of publication:
2023-06-01
- Abstract:
- To investigate the effect of bio-clogging on pollutants removal capacity of constructed wetland, three vertical flow constructed wetlands with fine (device 1), medium (device 2) and coarse (device 3) packing media was established and operated continuously to reveal the variation law of COD removal rate with permeability coefficient (k), and the seepage hydraulic characteristics of device 2 during bio-clogging was investigated by tracer experiment. With the occurrence of bio-clogging, the COD removal rate of the three devices was generally stable with the decrease of k in the early stage, and showed an obvious downward trend after 24 days of operation, in which the decreasing rates reached 18.2%, 22.8% and 22.9%, respectively. If k of 0.5 cm/s was selected as the clogging standard, the COD cumulative removal load in device 3 was the largest, while that of device 1 was the smallest. The tracer experiment results indicated that the accumulation of biofilm made the flow field more uniform and thus led to the prolong of actual hydraulic retention time (AHRT) and improvement of hydraulic efficiency in the early stage, which was beneficial to the pollutants removal. However, in the later stage, excessive bio-clogging led to local dead zone, shortened the AHRT, and significantly decreased the hydraulic efficiency of the device, leading to the decrease of COD removal rate.
Last Update:
2023-06-01