Treatment of baseflow from an urban catchment by a floating wetland system
This study investigated the performance of a floating wetlands system (FWS) planted with Chrysopogon zizanioides (Vetiver grass), Typha angustifolia and Polygonum barbatum as treatment units to remove nutrients contained in the baseflow to the Kranji reservoir in Singapore. Phase 1 of the study co...
| Main Authors: | , , , |
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| Other Authors: | |
| Format: | Journal Article |
| Language: | English |
| Published: |
2013
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| Online Access: | https://hdl.handle.net/10356/98080 http://hdl.handle.net/10220/13245 |
| _version_ | 1811686205850386432 |
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| author | Sim, C. H. Chua, Lloyd Hock Chye Tan, Stephen Boon Kean Goyal, Manish Kumar |
| author2 | School of Civil and Environmental Engineering |
| author_facet | School of Civil and Environmental Engineering Sim, C. H. Chua, Lloyd Hock Chye Tan, Stephen Boon Kean Goyal, Manish Kumar |
| author_sort | Sim, C. H. |
| collection | NTU |
| description | This study investigated the performance of a floating wetlands system (FWS) planted with Chrysopogon
zizanioides (Vetiver grass), Typha angustifolia and Polygonum barbatum as treatment units to remove nutrients
contained in the baseflow to the Kranji reservoir in Singapore. Phase 1 of the study consisted of
controlled experiments with a perspex floating wetland test cell of dimensions 2.5 m
×2 m
×1 m. Separate
experiments were carried out using the inflows from Sungei Kangkar, Sungei Tengah and Sungei
Peng Siang, which drain into Kranji reservoir. Tests were conducted for each plant species using water
taken from each of the tributaries in turn. Water samples were collected from the experimental and
control tanks during the experiment and analysed for total nitrogen, TN (mg/L), total phosphorus, TP
(mg/L), orthophosphate, OP (mg/L) as PO4 and ammoniacal nitrogen, AN (mg/L) as NH4+. The net nutrient
reduction (%) for Vetiver, Typha and Polygonum were 19.1, 39.2 and 46.0 for TP, and 40.8, 67.5, 7.8 for TN,
respectively. The rate of decrease of nutrients was found to be significant within the first few days and
reached steady state after approximately 10 days. The removal coefficient (day−1) for Vetiver, Typha and
Polygonum were 0.66, 0.87 and 1.06 for TP and 0.64, 0.68, 0.87 for TN, respectively. The removals of OP and
AN could not be ascertained due to the low concentrations of these parameters contained in the waters
tested. In Phase 2, field experiments were carried out with the FWS installed in Sungei Peng Siang with
the same plant species that were used in the controlled experiments. The growth of Vetiver and Typha was
monitored while all three plant species were tested for plant nutrient content. Plant TN and TP content
increased rapidly during the initial rapid growth stage, reached a maximum after approximately 1 month
and decreased. Typha achieved the highest rate of increase in nutrient content compared to Vetiver and
Polygonum. The uptake of TN by Typha, Vetiver and Polygonum was estimated to be 16.2, 1.74 and 2.82
(mg/day m2). The corresponding uptake for TP was 1.57, 0.16 and 0.4 (mg/day m2). For Typha, the mat
size required for 50% removal of TN and TP from the baseflow was estimated to be 0.056 and 0.031 ha of
mat/ha of catchment area. This is a conservative estimate since nutrient uptake by the root system was
ignored. |
| first_indexed | 2024-10-01T04:56:43Z |
| format | Journal Article |
| id | ntu-10356/98080 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T04:56:43Z |
| publishDate | 2013 |
| record_format | dspace |
| spelling | ntu-10356/980802020-03-07T11:43:45Z Treatment of baseflow from an urban catchment by a floating wetland system Sim, C. H. Chua, Lloyd Hock Chye Tan, Stephen Boon Kean Goyal, Manish Kumar School of Civil and Environmental Engineering This study investigated the performance of a floating wetlands system (FWS) planted with Chrysopogon zizanioides (Vetiver grass), Typha angustifolia and Polygonum barbatum as treatment units to remove nutrients contained in the baseflow to the Kranji reservoir in Singapore. Phase 1 of the study consisted of controlled experiments with a perspex floating wetland test cell of dimensions 2.5 m ×2 m ×1 m. Separate experiments were carried out using the inflows from Sungei Kangkar, Sungei Tengah and Sungei Peng Siang, which drain into Kranji reservoir. Tests were conducted for each plant species using water taken from each of the tributaries in turn. Water samples were collected from the experimental and control tanks during the experiment and analysed for total nitrogen, TN (mg/L), total phosphorus, TP (mg/L), orthophosphate, OP (mg/L) as PO4 and ammoniacal nitrogen, AN (mg/L) as NH4+. The net nutrient reduction (%) for Vetiver, Typha and Polygonum were 19.1, 39.2 and 46.0 for TP, and 40.8, 67.5, 7.8 for TN, respectively. The rate of decrease of nutrients was found to be significant within the first few days and reached steady state after approximately 10 days. The removal coefficient (day−1) for Vetiver, Typha and Polygonum were 0.66, 0.87 and 1.06 for TP and 0.64, 0.68, 0.87 for TN, respectively. The removals of OP and AN could not be ascertained due to the low concentrations of these parameters contained in the waters tested. In Phase 2, field experiments were carried out with the FWS installed in Sungei Peng Siang with the same plant species that were used in the controlled experiments. The growth of Vetiver and Typha was monitored while all three plant species were tested for plant nutrient content. Plant TN and TP content increased rapidly during the initial rapid growth stage, reached a maximum after approximately 1 month and decreased. Typha achieved the highest rate of increase in nutrient content compared to Vetiver and Polygonum. The uptake of TN by Typha, Vetiver and Polygonum was estimated to be 16.2, 1.74 and 2.82 (mg/day m2). The corresponding uptake for TP was 1.57, 0.16 and 0.4 (mg/day m2). For Typha, the mat size required for 50% removal of TN and TP from the baseflow was estimated to be 0.056 and 0.031 ha of mat/ha of catchment area. This is a conservative estimate since nutrient uptake by the root system was ignored. 2013-08-27T08:10:28Z 2019-12-06T19:50:20Z 2013-08-27T08:10:28Z 2019-12-06T19:50:20Z 2012 2012 Journal Article Chua, L. H., Tan, S. B., Sim, C., & Goyal, M. K. (2012). Treatment of baseflow from an urban catchment by a floating wetland system. Ecological Engineering, 49, 170-180. 0925-8574 https://hdl.handle.net/10356/98080 http://hdl.handle.net/10220/13245 10.1016/j.ecoleng.2012.08.031 en Ecological engineering |
| spellingShingle | Sim, C. H. Chua, Lloyd Hock Chye Tan, Stephen Boon Kean Goyal, Manish Kumar Treatment of baseflow from an urban catchment by a floating wetland system |
| title | Treatment of baseflow from an urban catchment by a floating wetland system |
| title_full | Treatment of baseflow from an urban catchment by a floating wetland system |
| title_fullStr | Treatment of baseflow from an urban catchment by a floating wetland system |
| title_full_unstemmed | Treatment of baseflow from an urban catchment by a floating wetland system |
| title_short | Treatment of baseflow from an urban catchment by a floating wetland system |
| title_sort | treatment of baseflow from an urban catchment by a floating wetland system |
| url | https://hdl.handle.net/10356/98080 http://hdl.handle.net/10220/13245 |
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