Treatment of high-strength wastewater in tropical vertical flow constructed wetlands planted with Typha angustifolia and Cyperus involucratus

The ability of vertical flow (VF) constructed wetland systems to treat high-strength (ca. 300 mg L-1of COD and ca. 300 mg L-1total-nitrogen) wastewater under tropical climatic conditions was studied during a 5-month period. Nine 0.8-m diameter experimental VF units (depth 0.6 m) were used: three uni...

Full description

Saved in:
Bibliographic Details
Main Authors: Suwasa Kantawanichkul, Supreeya Kladprasert, Hans Brix
Format: Journal
Published: 2018
Subjects:
Online Access:https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=59149085037&origin=inward
http://cmuir.cmu.ac.th/jspui/handle/6653943832/49111
Tags: Add Tag
No Tags, Be the first to tag this record!
Institution: Chiang Mai University
id th-cmuir.6653943832-49111
record_format dspace
spelling th-cmuir.6653943832-491112018-08-16T02:10:16Z Treatment of high-strength wastewater in tropical vertical flow constructed wetlands planted with Typha angustifolia and Cyperus involucratus Suwasa Kantawanichkul Supreeya Kladprasert Hans Brix Environmental Science The ability of vertical flow (VF) constructed wetland systems to treat high-strength (ca. 300 mg L-1of COD and ca. 300 mg L-1total-nitrogen) wastewater under tropical climatic conditions was studied during a 5-month period. Nine 0.8-m diameter experimental VF units (depth 0.6 m) were used: three units were planted with Typha angustifolia L., another three units were planted with Cyperus involucratus Rottb and three units were unplanted. Each set of units were operated at hydraulic loading rates (HLRs) of 20, 50 and 80 mm d-1. Cyperus produced more shoots and biomass than the Typha, which was probably stressed because of lack of water. The high evapotranspirative water loss from the Cyperus systems resulted in higher effluent concentrations of COD and total-P, but the mass removal of COD did not differ significantly between planted and unplanted systems. Average mass removal rates of COD, TKN and total-P at a HLR of 80 mm d-1were 17.8, 15.4 and 0.69 g m-2d-1. The first-order removal rate constants at a HLR of 80 mm d-1for COD, TKN and total-P were 49.8, 30.1 and 13.5 m year-1, respectively, which is in the higher range of k-values reported in the literature. The oxygen transfer rates were ca. 80 g m-2d-1in the planted systems as opposed to ca. 60 g m-2d-1in the unplanted systems. The number of Nitrosomonas was two to three orders of magnitude higher in the planted systems compared to the unplanted systems. Planted systems thus had significantly higher removal rates of nitrogen and phosphorus, higher oxygen transfer rates, and higher quantities of ammonia-oxidizing bacteria. None of the systems did, however, fully nitrify the wastewater, even at low loading rates. The vertical filters did not provide sufficient contact time between the wastewater and the biofilm on the gravel medium of the filters probably because of the shallow bed depth (0.6 m) and the coarse texture of the gravel. It is concluded that vertical flow constructed wetland systems have a high capacity to treat high-strength wastewater in tropical climates. The gravel and sand matrix of the vertical filter must, however, be designed in a way so that the pulse-loaded wastewater can pass through the filter medium at a speed that will allow the water to drain before the next dose arrives whilst at the same time holding the water back long enough to allow sufficient contact with the biofilm on the filter medium. © 2008 Elsevier B.V. All rights reserved. 2018-08-16T02:10:16Z 2018-08-16T02:10:16Z 2009-02-09 Journal 09258574 2-s2.0-59149085037 10.1016/j.ecoleng.2008.06.002 https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=59149085037&origin=inward http://cmuir.cmu.ac.th/jspui/handle/6653943832/49111
institution Chiang Mai University
building Chiang Mai University Library
country Thailand
collection CMU Intellectual Repository
topic Environmental Science
spellingShingle Environmental Science
Suwasa Kantawanichkul
Supreeya Kladprasert
Hans Brix
Treatment of high-strength wastewater in tropical vertical flow constructed wetlands planted with Typha angustifolia and Cyperus involucratus
description The ability of vertical flow (VF) constructed wetland systems to treat high-strength (ca. 300 mg L-1of COD and ca. 300 mg L-1total-nitrogen) wastewater under tropical climatic conditions was studied during a 5-month period. Nine 0.8-m diameter experimental VF units (depth 0.6 m) were used: three units were planted with Typha angustifolia L., another three units were planted with Cyperus involucratus Rottb and three units were unplanted. Each set of units were operated at hydraulic loading rates (HLRs) of 20, 50 and 80 mm d-1. Cyperus produced more shoots and biomass than the Typha, which was probably stressed because of lack of water. The high evapotranspirative water loss from the Cyperus systems resulted in higher effluent concentrations of COD and total-P, but the mass removal of COD did not differ significantly between planted and unplanted systems. Average mass removal rates of COD, TKN and total-P at a HLR of 80 mm d-1were 17.8, 15.4 and 0.69 g m-2d-1. The first-order removal rate constants at a HLR of 80 mm d-1for COD, TKN and total-P were 49.8, 30.1 and 13.5 m year-1, respectively, which is in the higher range of k-values reported in the literature. The oxygen transfer rates were ca. 80 g m-2d-1in the planted systems as opposed to ca. 60 g m-2d-1in the unplanted systems. The number of Nitrosomonas was two to three orders of magnitude higher in the planted systems compared to the unplanted systems. Planted systems thus had significantly higher removal rates of nitrogen and phosphorus, higher oxygen transfer rates, and higher quantities of ammonia-oxidizing bacteria. None of the systems did, however, fully nitrify the wastewater, even at low loading rates. The vertical filters did not provide sufficient contact time between the wastewater and the biofilm on the gravel medium of the filters probably because of the shallow bed depth (0.6 m) and the coarse texture of the gravel. It is concluded that vertical flow constructed wetland systems have a high capacity to treat high-strength wastewater in tropical climates. The gravel and sand matrix of the vertical filter must, however, be designed in a way so that the pulse-loaded wastewater can pass through the filter medium at a speed that will allow the water to drain before the next dose arrives whilst at the same time holding the water back long enough to allow sufficient contact with the biofilm on the filter medium. © 2008 Elsevier B.V. All rights reserved.
format Journal
author Suwasa Kantawanichkul
Supreeya Kladprasert
Hans Brix
author_facet Suwasa Kantawanichkul
Supreeya Kladprasert
Hans Brix
author_sort Suwasa Kantawanichkul
title Treatment of high-strength wastewater in tropical vertical flow constructed wetlands planted with Typha angustifolia and Cyperus involucratus
title_short Treatment of high-strength wastewater in tropical vertical flow constructed wetlands planted with Typha angustifolia and Cyperus involucratus
title_full Treatment of high-strength wastewater in tropical vertical flow constructed wetlands planted with Typha angustifolia and Cyperus involucratus
title_fullStr Treatment of high-strength wastewater in tropical vertical flow constructed wetlands planted with Typha angustifolia and Cyperus involucratus
title_full_unstemmed Treatment of high-strength wastewater in tropical vertical flow constructed wetlands planted with Typha angustifolia and Cyperus involucratus
title_sort treatment of high-strength wastewater in tropical vertical flow constructed wetlands planted with typha angustifolia and cyperus involucratus
publishDate 2018
url https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=59149085037&origin=inward
http://cmuir.cmu.ac.th/jspui/handle/6653943832/49111
_version_ 1681423351211360256