Performance of a pilot showcase of different wetland systems in an urban setting in Singapore

2015 ◽  
Vol 71 (8) ◽  
pp. 1158-1164 ◽  
Author(s):  
B. S. Quek ◽  
Q. H. He ◽  
C. H. Sim
Keyword(s):  
Water Quality ◽  
Suspended Solids ◽  
Water Quality Monitoring ◽  
Surface Flow ◽  
Urban Setting ◽  
Feed Water ◽  
Urban Drainage ◽  
Stormwater Treatment ◽  
Canal Water ◽  
Satisfactory Performance

The Alexandra Wetlands, part of PUB's Active, Beautiful, Clean Waters (ABC Waters) Programme, showcase a surface flow wetland, an aquatic pond and a sub-surface flow wetland on a 200 m deck built over an urban drainage canal. Water from the canal is pumped to a sedimentation basin, before flowing in parallel to the three wetlands. Water quality monitoring was carried out monthly from April 2011 to December 2012. The order of removal efficiency is sub-surface flow (81.3%) >aquatic pond (58.5%) >surface flow (50.7%) for total suspended solids (TSS); sub-surface (44.9%) >surface flow (31.9%) >aquatic pond (22.0%) for total nitrogen (TN); and surface flow (56.7%) >aquatic pond (39.8%) >sub-surface flow (5.4%) for total phosphorus (TP). All three wetlands achieved the Singapore stormwater treatment objectives (STO) for TP removal, but only the sub-surface flow wetland met the STO for TSS, and none met the STO for TN. Challenges in achieving satisfactory performance include inconsistent feed water quality, undesirable behaviour such as fishing, release of pets and feeding of animals in the wetlands, and canal dredging during part of the monitoring period. As a pilot showcase, the Alexandra Wetlands provide useful lessons for implementing multi-objective wetlands in an urban setting.

Statistical and Data Mining Techniques for Understanding Water Quality Profiles in a Mining-Affected River Basin

2018 ◽  
Vol 9 (2) ◽  
pp. 1-19 ◽  
Author(s):  
Jose Simmonds ◽  
Juan A. Gómez ◽  
Agapito Ledezma
Keyword(s):  
Data Mining ◽  
Water Quality ◽  
River Basin ◽  
Suspended Solids ◽  
Water Quality Monitoring ◽  
High Flow ◽  
Quality Monitoring ◽  
Low Flow ◽  
Inverse Relation

This article contains a multivariate analysis (MV), data mining (DM) techniques and water quality index (WQI) metrics which were applied to a water quality dataset from three water quality monitoring stations in the Petaquilla River Basin, Panama, to understand the environmental stress on the river and to assess the feasibility for drinking. Principal Components and Factor Analysis (PCA/FA), indicated that the factors which changed the quality of the water for the two seasons differed. During the low flow season, water quality showed to be influenced by turbidity (NTU) and total suspended solids (TSS). For the high flow season, main changes on water quality were characterized by an inverse relation of NTU and TSS with electrical conductivity (EC) and chlorides (Cl), followed by sources of agricultural pollution. To complement the MV analysis, DM techniques like cluster analysis (CA) and classification (CLA) was applied and to assess the quality of the water for drinking, a WQI.

The improvement of water quality indicators in constructed wetland treatment systems in Latvia

2020 ◽  
Author(s):  
Linda Grinberga ◽  
Ainis Lagzdins
Keyword(s):  
Water Quality ◽  
Constructed Wetlands ◽  
Constructed Wetland ◽  
Catchment Area ◽  
Suspended Solids ◽  
Subsurface Flow ◽  
Oxygen Demand ◽  
Total Suspended Solids ◽  
Surface Flow ◽  
Subsurface Flow Constructed Wetland

<p>This study includes water quality monitoring data obtained since June, 2014 at the farm located in the middle part of Latvia. The water treatment system with two separate constructed wetlands was established to improve water quality in agricultural area. A surface flow constructed wetland received drainage runoff from the agricultural catchment basin. A subsurface flow constructed wetland was implemented to retain nutrients from the surface runoff collected in the area of impermeable pavements of the farmyard. As there are no other specific calculations recommended for the designing of constructed wetlands in Latvia, both wetlands were calculated basing on the surface area of the constructed wetland/catchment area ratio. The surface area of the subsurface flow constructed wetland was deigned by 1.2% of the catchment area and the ratio was 0.5 % for the surface flow constructed wetland.</p><p>Water samples were collected manually by grab sampling method once or twice per month basing on a flowrate. Water quality parameters such as total suspended solids (TSS), nitrate-nitrogen (NO3-N), ammonium-nitrogen (NH4-N), total nitrogen (TN), orthophosphate-phosphorus (PO4-P), and total phosphorus (TP), biochemical oxygen demand (BOD) and chemical oxygen demand (COD) were analysed to monitor the performance of both wetlands. The concentrations at the inlet and outlet were compared to evaluate the efficiency of the water treatment.</p><p>The concentrations of NO3-N, NH4-N and TN were reduced on average by 21 %, 35 % and 20 %, respectively for the surface flow constructed wetland. PO4-P and TP concentrations were reduced on average by 31 % and 45 %, respectively for the surface flow constructed wetland. Total suspended solids were reduced by 17% at the outlet of the surface flow constructed wetland. However, in some cases, an increase in nutrient concentrations in water leaving the wetland was observed. The study showed the constant reduction of the PO4-P and TP concentrations 82 % and 83 %, respectively in the subsurface flow constructed wetland. The concentrations of NO3-N, NH4-N and TN were reduced on average by 14 %, 66 % and 53 %, respectively for the subsurface flow constructed wetland. BOD and COD reduction on average by 93 % and 83 %, respectively in for the subsurface flow constructed wetland indicated the ability of the treatment system to be adapted for wastewater treatment with high content of organic matter under the given climate conditions. This study outlined that the farmyards should receive a special attention regarding surface runoff management.</p>

scholarly journals A Rapid UV/Vis Spectrophotometric Method for the Water Quality Monitoring at On-Farm Root Vegetable Pack Houses

2020 ◽  
Vol 10 (24) ◽  
pp. 9072
Author(s):  
Algirdas Radzevičius ◽  
Midona Dapkienė ◽  
Nomeda Sabienė ◽  
Justyna Dzięcioł
Keyword(s):  
Water Quality ◽  
Suspended Solids ◽  
Principal Component ◽  
Water Quality Monitoring ◽  
Quality Monitoring ◽  
Coliform Bacteria ◽  
Limit Values ◽  
Root Vegetable ◽  
Quality Of Water ◽  
On Farm

Our research aim was to apply UV/Vis spectrophotometric techniques for the rapid monitoring of the quality of water sourced from on-farm root vegetable washing processes. To achieve this goal, the quality assessment of the washing water and wastewater at different stages of the technological processes was performed using physicochemical, biological, and UV/Vis absorbance measurements as well as statistical methods, such as principal component analysis (PCA) and partial least squares (PLS) regression. Limit values of UV/Vis absorbance at specific wavelengths were predicted in order to adapt them for routine testing and water quality monitoring at the farm packhouses. Results of the lab analyses showed, that the main problems of the water quality were caused by suspended solids (470–3400 mg L−1), organic substances (BOD5 215–2718 mg L−1; COD 540–3229 mg L−1), nitrogen (3–52 mg L−1), phosphorus (1–6 mg L−1), and pathogenic microorganisms (TVC > 300 cfu mL−1, E. coli 5.5 × 103–1.0 × 104 cfu mL−1, intestinal enterococci 2.8 × 102–1.5 × 104 cfu mL−1, coliform bacteria 1.6 × 103–2.0 × 104 cfu mL−1). Suspended solids exceeded the limit values by 10–50 times, organic matter by 10–25 times, dissolved organic carbon by 3–5 times, nitrogen by 3–7 times, total phosphorus by 3–12 times, and microorganisms by 3–10 times. UV/Vis limit values calculated were as follows: A210 nm—3.997–4.009 cm−1, A 240 nm—5.193–5.235 cm−1, A254 nm—4.042–4.047 cm−1, A320 nm—7.387–7.406 cm−1, and A 660 nm—3.937–3.946 cm−1. UV/Vis measurements at A320 nm are proposed for the routine water quality monitoring.

scholarly journals Polycyclic Aromatic Hydrocarbons and Suspended Materials in a Semi-urbanized Tidal Creek after an Historic Flood Event and Implications for Water Quality Monitoring

2017 ◽  
pp. 3-11 ◽  
Author(s):  
Barbara A. Beckingham ◽  
Michael Shahin ◽  
Kathryn Ellis ◽  
Timothy J. Callahan
Keyword(s):  
Water Quality ◽  
Aromatic Hydrocarbons ◽  
Suspended Solids ◽  
Tidal Creek ◽  
Water Quality Monitoring ◽  
Quality Monitoring ◽  
Storm Event ◽  
Tidal Creeks ◽  
Polycyclic Aromatic ◽  
Bull Creek

Tidal creeks transport both dissolved and particulate natural organic carbon materials and contaminants, connecting land-based activities with estuarine surface waters. It is important to characterize these materials in tidal creeks because it provides insights as to their origins and potential for ecosystem impacts. Surface water samples were collected from Bull Creek, Charleston, SC, a semi-urbanized tidal creek wetland, on five sampling dates from fall 2015 to spring 2016 to measure total suspended solids (TSS), turbidity, dissolved organic carbon (DOC), SUVA254 (specific absorbance as an indicator of aromaticity of DOC), and total water concentrations of polycyclic aromatic hydrocarbons (PAHs), a ubiquitous class of hydrophobic organic contaminants of concern. Stream discharge was also measured to allow an estimation of material flux. One of the sampling dates captured these parameters following a historic rainfall related to Hurricane Joaquin in October 2015, and therefore the aim of the present study is to characterize the sources and to quantify the transport of carbonaceous materials and PAHs in Bull Creek, with a focus on the response to this storm event. The quality of suspended solids and DOC were different following the October storm event in comparison to the other sampling dates, and they were more terrestrially derived as shown by shifts in SUVA254 and correlations between TSS and turbidity. Elevated levels of PAHs were detected in Bull Creek after the storm, and diagnostic ratios indicated that additional mixed sources were mobilized by the event. Combining the measures of both carbonaceous material quality and PAH profile contributed to a better understanding of the sources to the tidal creek. Shifts in PAH sources and suspended materials have implications for PAH toxicity to aquatic life, as well as for the appropriate approach to water quality monitoring. Future work should aim to develop relationships between discharge, suspended materials, and PAHs to facilitate more continuous monitoring of material transport in tidal creeks, especially during storm events, which have a strong influence on water quality.

scholarly journals NUTRIENT RETENTION IN SURFACE FLOW CONSTRUCTED WETLAND IN AGRICULTURAL LAND IN LATVIA

2018 ◽  
Author(s):  
Linda GRINBERGA ◽  
Ainis LAGZDINS
Keyword(s):  
Water Quality ◽  
Constructed Wetland ◽  
Suspended Solids ◽  
Agricultural Land ◽  
Nutrient Retention ◽  
Total Suspended Solids ◽  
Quality Parameters ◽  
Surface Flow ◽  
Water Quality Parameters ◽  
Nutrient Concentrations

The research site consists of a pilot-scale surface flow constructed wetland at the farm Mezaciruli located in Zalenieki County, Jelgava Region, in the middle part of Latvia. The constructed wetland was installed in June 2014 to improve water quality in agricultural catchment and examine nutrient retention at the constructed wetland receiving surface and drainage runoff. The constructed wetland’s surface area of 0.37 ha corresponds to 0.5 % of the total catchment area. During the observation period of 32 months (2014-2017) water quality parameters such as total suspended solids (TSS), nitrate-nitrogen (NO3-N), ammonium-nitrogen (NH4-N), total nitrogen (TN), orthophosphate-phosphorus (PO4-P), and total phosphorus (TP) were monitored twice a month using a grab sample approach. Retention efficiency for monitored water quality parameters was calculated based on their concentrations at the inlet and outlet. The monitoring results obtained during this study showed a reduction within the constructed wetland for all examined parameters. The concentrations of NO3-N, NH4-N and TN were reduced on average by 13 %, 15 % and 16 %, respectively. PO4-P and TP concentrations were reduced on average by 38 % and 36 %, respectively. Total suspended solids were reduced by 31% at the outlet of the constructed wetland. However, in some cases, an increase in nutrient concentrations in water leaving the constructed wetland was observed. Therefore, there is a need for further research to investigate causes of such increase.

scholarly journals Untangling Microbiota Diversity and Assembly Patterns in the World's Largest Water Diversion Canal

2021 ◽  
Author(s):  
Lu Zhang ◽  
Wei Yin ◽  
Chao Wang ◽  
Aijing Zhang ◽  
Hong Zhang ◽  
...  
Keyword(s):  
Water Quality ◽  
Water Environment ◽  
Null Model ◽  
Water Quality Monitoring ◽  
Water Diversion ◽  
Ecological Knowledge ◽  
Canal Water ◽  
Long Distance ◽  
Environmental Selection ◽  
Microbial Proliferation

Large water diversion projects are important constructions for reallocation of human-essential water resources. Deciphering microbiota dynamics and assembly mechanisms underlying canal water ecosystem services especially during long-distance diversion is the prerequisite for water quality monitoring, biohazard warning and sustainable management. Using a 1432-km canal of the South-to-North Water Diversion Projects as a model system, we answer three central questions: how bacterial and micro-eukaryotic communities spatio-temporally develop, how much ecological stochasticity contributes to microbiota assembly, and which immigrating populations better survive and navigate across the canal. We applied quantitative ribosomal RNA gene sequence analyses to investigate canal water microbial communities sampled over a year, as well as null model- and neutral model-based approaches to disentangle the microbiota assembly processes. Our results showed clear microbiota dynamics in community composition driven by seasonality more than geographic location, and seasonally dependent influence of environmental parameters. Overall, bacterial community was largely shaped by deterministic processes, whereas stochasticity dominated micro-eukaryotic community assembly. We defined a local growth factor (LGF) and demonstrated its innovative use to quantitatively infer microbial proliferation, unraveling taxonomically dependent population response to local environmental selection across canal sections. Using LGF as a quantitative indicator of immigrating capacities, we also found that most micro-eukaryotic populations (82%) from the source lake water sustained growth in the canal and better acclimated to the hydrodynamical water environment than bacteria (67%). Taxa inferred to largely propagate include Limnohabitans sp. and Cryptophyceae, potentially contributing to water auto-purification. Combined, our work poses first and unique insights into the microbiota assembly patterns and dynamics in the world's largest water diversion canal, providing important ecological knowledge for long-term sustainable water quality maintenance in such a giant engineered system.

scholarly journals Application of Compact Piping Sedimentation Unit as Pretreatment for Ultrafiltration Plant

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Amira Mohamed Nagy ◽  
Mohamed ElHosseiny El-Nadi ◽  
Nany Ali Hassan Nasr ◽  
Hossam Mostafa Hussien
Keyword(s):  
Water Quality ◽  
Retention Time ◽  
Suspended Solids ◽  
Total Suspended Solids ◽  
Water Source ◽  
Water Sources ◽  
Feed Water ◽  
Removal Efficiencies ◽  
Inclined Plates

Abstract The study aimed to create a compact pretreatment unit before the ultrafiltration modules. This unit targeted to improve the inlet water quality to meet the average values of the feed water quality required for the ultrafiltration plants according to the manufacturer. The used unit in this study was a pipe worked as a sedimentation unit with inclined plates to apply the plate settler technology. The suitability of using this unit was determined by using varied water sources with different Total Suspended Solids (TSS) concentrations and different retention times. The removal efficiencies for the low TSS water source reached 96.47 %, 82.94 %, 64.80 % & 30.59 % with retention time 30 minutes, 15 minutes, 5 minutes & 20 seconds respectively. For the medium TSS water source at the same retention times, the removal efficiencies reached 97.33 %, 92.87 %, 86.10 % & 63.89 %. For the high TSS water source, the removal efficiencies reached 98.64 %, 93.86 %, 87.51 % & 76.23 %. These results make the sedimentation unit able to work as an effective pretreatment unit for the ultrafiltration units for all water sources.

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