Constructed wetland for water quality improvement: a case study from Taiwan

2010 ◽  
Vol 62 (10) ◽  
pp. 2408-2418 ◽  
Author(s):  
C. Y. Wu ◽  
J. K. Liu ◽  
S. H. Cheng ◽  
D. E. Surampalli ◽  
C. W. Chen ◽  
...  
Keyword(s):  
Water Quality ◽  
Wastewater Treatment ◽  
Constructed Wetlands ◽  
Constructed Wetland ◽  
Water Reuse ◽  
Oxygen Demand ◽  
Sediment Oxygen Demand ◽  
Nucleotide Sequence Analysis ◽  
Sediment Samples ◽  
Wetland System

In Taiwan, more than 20% of the major rivers are mildly to heavily polluted by domestic, industrial, and agricultural wastewaters due to the low percentage of sewers connected to wastewater treatment plants. Thus, constructed or engineered wetlands have been adopted as the major alternatives to clean up polluted rivers. Constructed wetlands are also applied as the tertiary wastewater treatment systems for the wastewater polishment to meet water reuse standards with lower operational costs. The studied Kaoping River Rail Bridge Constructed Wetland (KRRBCW) is the largest constructed wetland in Taiwan. It is a multi-function wetland and is used for polluted creek water purification and secondary wastewater polishment before it is discharged into the Kaoping River. Although constructed wetlands are feasible for contaminated water treatment, wetland sediments are usually the sinks for organics and metals. In this study, water and sediment samples were collected from the major wetland basins in KRRBCW. The investigation results show that more than 97% of total coliforms (TC), 55% of biochemical oxygen demand (BOD), and 30% of nutrients [e.g. total nitrogen (TN), total phosphorus (TP)] were removed via the constructed wetland system. However, results from the sediment analyses show that wetland sediments contained high concentrations of metals (e.g. Cu, Fe, Zn, Cr, and Mn), organic contents (sediment oxygen demand = 1.7 to 7.6 g O2/m2 d), and nutrients (up to 18.7 g/kg of TN and 1.22 g/kg of TN). Thus, sediments should be excavated periodically to prevent the release the pollutants into the wetland system and causing the deterioration of wetland water quality. Results of polymerase chain reaction (PCR), denaturing gradient gel electrophoresis (DGGE), and nucleotide sequence analysis reveal that a variation in microbial diversity in the wetland systems was observed. Results from the DGGE analysis indicate that all sediment samples contained significant amounts of microbial ribospecies, which might contribute to the carbon degradation and nitrogen removal. Gradual disappearance of E. coli was also observed along the flow courses through natural attenuation mechanisms.

Using a constructed wetland for non-point source pollution control and river water quality purification: a case study in Taiwan

2010 ◽  
Vol 61 (10) ◽  
pp. 2549-2555 ◽  
Author(s):  
C. Y. Wu ◽  
C. M. Kao ◽  
C. E. Lin ◽  
C. W. Chen ◽  
Y. C. Lai
Keyword(s):  
Water Quality ◽  
Wastewater Treatment ◽  
Quality Improvement ◽  
Point Source ◽  
River Water ◽  
Constructed Wetlands ◽  
Constructed Wetland ◽  
River Water Quality ◽  
Water Quality Improvement ◽  
Wetland System

The Kaoping River Rail Bridge Constructed Wetland, which was commissioned in 2004, is one of the largest constructed wetlands in Taiwan. This multi-function wetland has been designed for the purposes of non-point source (NPS) pollutant removal, wastewater treatment, wildlife habitat, recreation, and education. The major influents of this wetland came from the local drainage trench containing domestic, agricultural, and industrial wastewaters, and effluents from the wastewater treatment plant of a paper mill. Based on the quarterly investigation results from 2007 to 2009, more than 96% of total coliforms (TC), 48% of biochemical oxygen demand (BOD), and 40% of nutrients (e.g. total nitrogen, total phosphorus) were removed via the constructed wetland system. Thus, the wetland system has a significant effect on water quality improvement and is capable of removing most of the pollutants from the local drainage system before they are discharged into the downgradient water body. Other accomplishments of this constructed wetland system include the following: providing more green areas along the riversides, offering more water assessable eco-ponds and eco-gardens for the public, and rehabilitating the natural ecosystem. The Kaoping River Rail Bridge Constructed Wetland has become one of the most successful multi-function constructed wetlands in Taiwan. The experience obtained from this study will be helpful in designing similar natural treatment systems for river water quality improvement and wastewater treatment.

scholarly journals EFFICACY OF PHRAGMITE KARKA PLANT IN CONSTRUCTED WETLAND SYSTEM

2015 ◽  
Vol 3 (9SE) ◽  
pp. 1-5
Author(s):  
Shalini Saxena
Keyword(s):  
Water Quality ◽  
Wastewater Treatment ◽  
Quality Improvement ◽  
Constructed Wetland ◽  
Flood Control ◽  
Water Quality Improvement ◽  
The Past ◽  
Wetland Treatment ◽  
Natural Wetlands ◽  
Wetland System

Wetlands, either constructed or natural, offer a cheaper and low-cost alternative technology for wastewater treatment. A constructed wetland system that is specifically engineered for water quality improvement as a primary purpose is termed as a ‘Constructed Wetland Treatment System’ (CWTS). In the past, many such systems were constructed to treat low volumes of wastewater loaded with easily degradable organic matter for isolated populations in urban areas. However, widespread demand for improved receiving water quality, and water reclamation and reuse, is currently the driving force for the implementation of CWTS all over the world. Recent concerns over wetland losses have generated a need for the creation of wetlands, which are intended to emulate the functions and values of natural wetlands that have been destroyed. Natural characteristics are applied to CWTS with emergent macrophyte stands that duplicate the physical, chemical and biological processes of natural wetland systems. The number of CWTS in use has very much increased in the past few years. The use of constructed wetlands is gaining rapid interest. Most of these systems cater for tertiary treatment from towns and cities. They are larger in size, usually using surface-flow system to remove low concentration of nutrient (N and P) and suspended solids. However, in some countries, these constructed wetland treatment systems are usually used to provide secondary treatment of domestic sewage for village populations. These constructed wetland systems have been seen as an economically attractive, energy-efficient way of providing high standards of wastewater treatment by the help of Phragmite karka plant. Typically, wetlands are constructed for one or more of four primary purposes: creation of habitat to compensate for natural wetlands converted for agriculture and urban development, water quality improvement, flood control, and production of food and fiber.

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>

Removal efficiency of the constructed wetland wastewater treatment system at Bainikeng, Shenzhen

1995 ◽  
Vol 32 (3) ◽  
pp. 31-40 ◽  
Author(s):  
Yang Yang ◽  
Zhencheng Xu ◽  
Kangping Hu ◽  
Junsan Wang ◽  
Guizhi Wang
Keyword(s):  
Wastewater Treatment ◽  
Removal Efficiency ◽  
Constructed Wetland ◽  
Suspended Solids ◽  
Oxygen Demand ◽  
Design Flow ◽  
Treatment System ◽  
Wastewater Treatment System ◽  
Tennessee Valley ◽  
Wetland System

In this paper, three years study on a constructed wetland wastewater treatment system at Bainikeng, Shenzhen, is reviewed and summarized. The wetland system under study occupies an area of 8400m2, with a design flow of 3100 m3 per day. The study was conducted to understand removal efficiencies of constructed wetland systems for municipal wastewaters from small or medium scale towns in the sub-tropics. Such parameters as biological oxygen demand, chemical oxygen demand, suspended solids, total nitrogen, and total phosphorus in the influent and effluent of the wetland system are examined, and their removal rates are determined. It is shown that the system is very effective in removing organic pollutants and suspended solids and its removal efficiency is much similar to those of the constructed wetlands at Tennessee Valley Authority (TVA) (Choate et al., 1990) while better than those of conventional secondary biochemical treatments.

scholarly journals Integrating MFT-qPCR techniques in constructed wetland faecal bacterial purification monitoring; a case of a typical tropical hybrid constructed wetland system

2018 ◽  
Vol 78 (9) ◽  
pp. 2008-2018 ◽  
Author(s):  
Donde Oscar Omondi ◽  
Muia Anastasia Wairimu ◽  
Makindi Stanley Maingi ◽  
Onyango Godfrey Otieno ◽  
Kibet Caroline Jepkorir ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Constructed Wetlands ◽  
Constructed Wetland ◽  
Membrane Filtration ◽  
Pathogenic Bacteria ◽  
Quantitative Polymerase Chain Reaction ◽  
Health Concern ◽  
Human Pathogens ◽  
Purification Efficiency ◽  
Wetland System

Abstract The sanitation control of pathogens in the tropical effluents needs much more attention to ensure ecosystem health integrity and the safety of human health. The common use of chemicals in achieving this in wastewater treatment has remained unsustainable due to much health concern. Indeed, based on the numerous challenges associated with faecal pathogenic bacteria in wastewaters, the focus is now on achieving higher purification efficiencies in the elimination of the human pathogens from wastewater through eco-sustainable systems such as constructed wetlands (CWs). Hence, the need to explore the application of constructed wetlands in wastewater treatment under specific local environmental conditions for accurate understanding and improved treatment efficiency. This study therefore aimed at monitoring constructed wetlands faecal bacteria purification efficiency through integrated non-molecular membrane filtration technique and molecular quantitative polymerase chain reaction (MFT-qPCR) technique. The results showed some shortfall in the treatment system and also proved that integrating MFT-qPCR in faecal bacterial purification monitoring within a constructed wetland system provides a more accurate and reliable outcome. Additionally, the wetland purification efficiency was low (<80%) with the dissolved oxygen posing the strongest influence on faecal pathogenic bacterial purification trend across the wetland. Hence, the need to regularly carry out dredging and macrophyte harvesting as well as the use of holistic and more integrative approaches such as MFT-qPCR in managing and monitoring the performance of CWs in faecal pathogen eradication for improved CWs purification efficiency.

scholarly journals Hybrid constructed wetlands system with intermittent feeding applied for urban wastewater treatment in South Brazil

2019 ◽  
Vol 9 (3) ◽  
pp. 559-570 ◽  
Author(s):  
Benny Zuse Rousso ◽  
Catiane Pelissari ◽  
Mayara Oliveira dos Santos ◽  
Pablo Heleno Sezerino
Keyword(s):  
Wastewater Treatment ◽  
Constructed Wetlands ◽  
Hybrid System ◽  
Constructed Wetland ◽  
Oxygen Demand ◽  
Urban Wastewater ◽  
Treatment Technology ◽  
State Regulations ◽  
Intermittent Feeding ◽  
Pollutants Removal

Abstract Hybrid constructed wetlands composed by vertical flow constructed wetland (VFCW) followed by horizontal subsurface flow constructed wetland (HFCW) are a wastewater treatment technology employed worldwide. However, there are few studies of their application in Brazil. Treatment performance is not achieved directly after the start of operation and may change according to external conditions over time. This paper evaluated a VFCW–HFCW hybrid system applied to treat urban wastewater in southern Brazil during the first 70 operational weeks. The system was operated with cycles of rest and feed periods. The results point to the first 10 weeks of operation as a transitioning period, especially for VFCW, after which chemical oxygen demand (COD) (from 77% to 90%) and total suspended solids (TSS) (from 90% to 100%) removal performances stabilized and reached their peak rates. Factors such as rainfall precipitation, macrophytes' adaptation, and time of operation affected pollutants' removal. Regardless of the fluctuations throughout the period, the hybrid system presented resilience by generating excellent average removal rates. It showed a mean removal efficiency of 99% for TSS, 98% for COD, 69% for total nitrogen (TN), 91% for NH4+-N, and 96% for P-PO43−. Moreover, the effluent was always suitable to be discharged into the environment according to Brazilian national and state regulations.

Application of a constructed wetland for non-point source pollution control

2001 ◽  
Vol 44 (11-12) ◽  
pp. 585-590 ◽  
Author(s):  
C.M. Kao ◽  
J.Y. Wang ◽  
H.Y. Lee ◽  
C.K. Wen
Keyword(s):  
Water Quality ◽  
Point Source ◽  
Constructed Wetlands ◽  
Constructed Wetland ◽  
Pollution Control ◽  
Pistia Stratiotes ◽  
Storm Event ◽  
Untreated Wastewater ◽  
Nps Pollution ◽  
Wetland System

In Taiwan, non-point source (NPS) pollution is one of the major causes of impairment of surface waters. The main objective of this study was to evaluate the efficacy of using constructed wetlands on NPS pollutant removal and water quality improvements. A field-scale constructed wetland system was built inside the campus of National Sun Yat-Sen University (located in southern Taiwan) to remove (1) NPS pollutants due to the stormwater runoff, and (2) part of the untreated wastewater from school drains. The constructed wetland was 40 m (L) × 30 m (W) × 1 m (D), which received approximately 85 m3 per day of untreated wastewater from school drainage pipes. The plants grown on the wetland included floating (Pistia stratiotes L.) and emergent (Phragmites communis L.) species. One major storm event and baseline water quality samples were analyzed during the monitoring period. Analytical results indicate that the constructed wetland removed a significant amount of NPS pollutants and wastewater constituents. More than 88% of nitrogen, 81% of chemical oxygen demand (COD), 85% of heavy metals, and 60% of the total suspended solids (TSS) caused by the storm runoff were removed by the wetland system before discharging. Results from this study may be applied to the design of constructed wetlands for NPS pollution control and water quality improvement.

Construction and maintenance cost analyzing of constructed wetland systems

2011 ◽  
Vol 6 (3) ◽  
Author(s):  
K. Gunes ◽  
B. Tuncsiper ◽  
F. Masi ◽  
S. Ayaz ◽  
D. Leszczynska ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Constructed Wetlands ◽  
Constructed Wetland ◽  
Rural Areas ◽  
Subsurface Flow ◽  
Maintenance Cost ◽  
Operational Costs ◽  
Subsurface Flow Constructed Wetland ◽  
Wetland System ◽  
Horizontal Subsurface Flow

Nowadays, use of constructed wetlands for wastewater treatment especially in rural areas has become increasingly preferable. The most important reason behind this fact is its relatively low investment cost over other treatment options depending on economical conditions of the country. Nonetheless, due to lower operational costs of constructed wetlands than other conventional wastewater treatment systems, investment costs could be regarded secondary as of importance. Investment costs could show differences even at regional scale in a country. Choosing a constructed wetland system among “Subsurface Horizontal Flow”, “Subsurface Vertical Flow” or “Free Water Surface Flow”; or designing a hybrid system using concurrent systems plays important role when defining costs of the constructed wetland systems. Due to increasing interest for constructed wetlands since 2003, so many constructed wetland systems have been built in rural parts of Turkey and most of these systems have been designed as horizontal subsurface flow constructed wetland system. As a fact, the cost of horizontal subsurface flow constructed wetlands is comparatively higher than other wetland systems. When different applications in the world are examined, it is observed that mostly horizontal subsurface flow constructed wetland systems are preferred in rural areas. According to the studies within the extent of this work, different constructed wetland types which are built in different regions of Turkey and their expected and realized costs are analyzed and compared with other countries. Moreover, operational costs have been calculated. Consequently, a work to be taken as reference for further scientific studies has been prepared with presented wetland analyses which could be used by especially decision makers and researchers.

scholarly journals Community Wastewater Treatment with Attached Growth Assisted Constructed Wetland Reactor

2017 ◽  
Vol 7 (2 (S)) ◽  
pp. 327
Author(s):  
Nitin Ingole ◽  
Mangesh Gulhane
Keyword(s):  
Wastewater Treatment ◽  
Constructed Wetlands ◽  
Constructed Wetland ◽  
Operating Conditions ◽  
Laboratory Scale ◽  
Scale Model ◽  
Reactor Model ◽  
Attached Growth ◽  
Growth System ◽  
Wetland System

Constructed wetlands are systems of artificial wastewater treatment which consists of shallow ponds or channels that have been planted with aquatic plants. The treatment is based on the natural, biological, physical and chemical treatment of wastewater. The technique is reported to be cost effective as compared to other methods. The constructed wetlands have impermeable clay or synthetic coatings and artificial structures for controlling the direction of flow, liquid retention time and the water level. However, there are certain limitations of constructed wetland system, which need improvement for its wide adoptability. As such the effort was made to assist the constructed wetland system with attached growth system with the aim to design an economical and user friendly waste water treatment option for the small community. The laboratory scale model was fabricated using GI sheet of thickness 0.5 mm. The overall capacity of the model was 275 L. The laboratory scale reactor model consisted of four compartments out of which first three compartments were based on attached growth system and the fourth compartment acted as constructed wetland reactor. All the three compartments were packed with different types of artificial, semi-artificial and natural media. The fourth compartment consisted of media packed from bottom as aerocon stone layers 03 in numbers followed by snail shell, followed by a soil layer of 80 mm thick which holds the plants in rows. The reactor was operated as continuous flow reactor with varying detention time and change of different type of media packed in the reactor. The performance of Customized Constructed Wetland reactor was observed under various operating conditions for removal of BOD, COD and TS parameters. The paper presents the details regarding the development of the reactor model, operation of the reactor model and results obtained during the course of study. The paper also cover the discussion regarding the improved performance of reactor noted during the study and adoptability of the developed reactor model for community waste treatment.

scholarly journals Enhanced removal of nutrients and heavy metals from domestic-industrial wastewater in an academic campus of Hanoi using modified hybrid constructed wetlands

2020 ◽  
Vol 82 (10) ◽  
pp. 1995-2006
Author(s):  
Mai Huong ◽  
Dan-Tam Costa ◽  
Bui Van Hoi
Keyword(s):  
Heavy Metals ◽  
Water Quality ◽  
Constructed Wetlands ◽  
Constructed Wetland ◽  
Aquatic Ecosystems ◽  
Industrial Wastewater ◽  
Oxygen Demand ◽  
Outdoor Experiment ◽  
Removal Efficiencies ◽  
Cyperus Alternifolius

Abstract Vietnam, like many developing countries, is facing serious water quality issues due to discharging wastewaters without treatment or with improper treatment, which can constitute a potential risk for aquatic ecosystems, food safety and human health. Hybrid constructed wetlands with four substrate layers (HCW) and modified hybrid constructed wetland (MHCW-1 and MHCW-2) with seven substrate layers were designed to evaluate the enhanced treatment capacity for wastewaters. To this end, we carried out an outdoor experiment at the Vietnam Academy of Science and Technology, Vietnam to treat its wastewaters from April to August 2019. All constructed wetland units were planted with reed Phragmites australis and cyperus Cyperus alternifolius; and specifically wetland MHCW-2 was cultured with earthworm Perionys excavates. Results indicated that MHCW-1 and MHCW-2 with seven substrate layers had higher removal efficiencies of -N, TKN and TP than HCW system. More substrate layers in MHCW-1 and MHCW-2 also resulted in increase of Cu and Pb removal efficiencies, with 73.5%, 79.4%, 71.5% and 67.8%, respectively. Particularly, earthworm addition in MHCW-2 was more efficient in decreasing the concentrations of biochemical oxygen demand (BOD5), with removal efficiency over 70%.

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