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Performance of a 10000 m3/day Constructed Wetland for Treating Polluted River Water

The Wu-Luo River located in the Ping-Tong County of southern
Taiwan has long been polluted by untreated domestic and partially treated
poultry wastewaters and is among the most polluted rivers in Taiwan. A
full-scale constructed wetland (CW) has been in operation since January
of 2005 for cleaning a part of the polluted river water. The purpose of
this study was to investigate the specifications of the CW and its
performance for removing both organic and inorganic pollutants form the
influent water.
Results indicate that during the investigation period of April 2006 to
February 2007, the CW had channel widths of 86-112 m (average 100 m)
and a zone-type length of 1,600 m. It occupied a total area of 18
hectares in which around 9 hectares were wetted by the introduced river
water. Around 4.7 hectares of the CW was flooded by the river water
and 1.9 hectares were occupied by emergent and floating plants such as
cattail, water lettuce, reed, water celery, and bara grass. A total water
volume of around 6,800 m3 was estimated. In the period, 10,000-20,000
m3/day (CMD) (average 10,800 CMD) of the polluted river water was
introduced to the CW and a hydraulic retention time (HRT) of 0.63 day
was estimated for the flowing water in the through the water body.
Results also indicated that the influent water has the following
qualities (unit in mg/L except pH and number in parentheses indicates the
average value): total COD (CODt) 10-121 (52), BOD 6-36 (21),
suspended solids (SS) 10-165 (70), pH 5.4-8.1 (7.4), ammonia-N 2-22
V
(13), nitrate-N 0-9.4 (2.5), nitrite-N 0-1.8 (0.2), total-N (TN) 9.9-41.3
(22.6), phosphate-P 0-3.1 (0.9), total-P (TP) 1.2-36.7 (5.2), Cu 0.022-0.60
(0.071), and Zn 0.01-0.36 (0.13). It was found that water sampled from
nearly the middle point of the CW got better clarification results than that
from the effluent end. Pollutant removal efficacies were 60, 60, and
67%, respectively, for CODt, BOD, and SS at the middle point, while 56,
54, and 45%, respectively, for CODt, BOD, and SS at the effluent end.
Organics, N, and P released from rotten plants were responsible for the
poor water qualities at the end. The CW had only a TN removal
efficacy of around 18% and no TP removal effect.

Identiferoai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0713107-020217
Date13 July 2007
CreatorsTsai, Shiang-an
ContributorsLei Yang, Ming-Shean Chou, Ju-Sheng Huang
PublisherNSYSU
Source SetsNSYSU Electronic Thesis and Dissertation Archive
LanguageCholon
Detected LanguageEnglish
Typetext
Formatapplication/pdf
Sourcehttp://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0713107-020217
Rightsrestricted, Copyright information available at source archive

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