Impact of water quality parameters on the clogging
of vertical-flow constructed wetlands treating urban
wastewater

Sani, A; Scholz, M; Babatunde, A; Wang, Y

Abstract

In theory, biological and physical clogging,
induced as a result of potentially excessive formation
of biomass from degradation of pollutants and retention
of inert suspended fine particles, respectively,
should result in a decrease of treatment performance.
However, some wetlands are not prone to clogging in
practice. The aim of this study was to compare the
impact of different design (aggregate size) and operational
(contact time, empty time and chemical oxygen
demand [COD] loading) variables on the treatment
efficiency and clogging processes. Different verticalflow
constructed wetlands were constructed and operated
from June 2011 until June 2012. Data from June
2011 (setting-up period) were not used. The filter with
the highest COD loading performed the worst in terms
of outflow COD concentration (120 mg/l) but best in
terms of COD load reduction (61 %). The wetland
with the largest aggregate size had the lowest mean
nitrate-nitrogen outflow concentration of 1.2 mg/l.
However, the resultswere similar regardless of aggregate
size (10 versus 20 mm) and resting time (24 versus 48 h)
for most water quality variables. However, different
COD inflow concentrations (COD of 146 mg/l versus
COD of 312 mg/l) had a significant (p<0.05) impact
on the treatment performance for COD, ammonianitrogen,
ortho-phosphate-phosphorus and suspended
solids (SS). Serious clogging phenomena impacting
negatively on the treatment performance were not
observed for any columns. However, a small aggregate
diameter, a short contact time, a long resting
time and a low COD inflow concentration were most
beneficial in reducing SS accumulation within the
wetland filters.

Citation

wastewater. Water, Air, and Soil Pollution, 224, 1488. https://doi.org/10.1007/s11270-013-1488-2

• Journal Article Type: Article
• Acceptance Date: Feb 12, 2013
• Online Publication Date: Feb 23, 2013
• Publication Date: Mar 1, 2013
• Deposit Date: Jan 11, 2017
• Journal: Water, Air, and Soil Pollution
• Print ISSN: 0049-6979
• Electronic ISSN: 1573-2932
• Publisher: Springer Verlag
• Volume: 224
• Pages: 1488
• DOI: https://doi.org/10.1007/s11270-013-1488-2
• Publisher URL: http://dx.doi.org/10.1007/s11270-013-1488-2
• Related Public URLs: http://link.springer.com/journal/11270
• Additional Information: Funders : Nigerian Government