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<!{|style="float: left;"|{{Language-- table at top of page with logo, picture, Application level, Management level, and input-output tables -->box|english_link=Vertical_Flow_Constructed_Wetland|french_link=Filtre_planté_à_écoulement_vertical|spanish_link=Humedal_Artificial_de_Flujo_Vertical|hindi_link=coming soon|malayalam_link=coming soon|tamil_link=coming soon | korean_link=coming soon | chinese_link=Coming soon | indonesian_link=Coming soon | japanese_link=Coming soon}}|}

sys2=[[Blackwater Treatment System with Infiltration|56]]|sys3=[[Blackwater Treatment System with SewerageEffluent Transport|67]]|sys4=[[Blackwater Transport to (Semi-) Centralized Treatment System |78]]|sys5=[[Sewerage System with Urine Diversion |89]]|

Input1=Blackwater|Input2=Greywater |Input3= Brownwater | Input4= Effluent |Input5=|Output1= Effluent | Output2= Biomass | Output3= | Output4= | Output5=|english_link=Vertical_Flow_Constructed_Wetland|french_link=Filtre_planté_à_écoulement_vertical|spanish_link=Humedal_Artificial_de_Flujo_Vertical

|[[Image:Vertical_flow_constructed_wetland.png |right|300px500px]]

By dosing the wetland intermittently (four to ten times a day), the filter goes through stages of being saturated and unsaturated, and accordingly, different phases of aerobic and anaerobic conditions. The frequency of dosing should be timed such that the previous dose of wastewater has time to percolate through the filter bed so that oxygen has time to diffuse through the media and fill the void spaces[[Image:Icon_vertical_flow_constructed_wetland.png |right|80px]]

The Vertical Flow Constructed Wetland can be designed as '''A vertical flow constructed wetland is a shallow excavation planted filter bed that is drained at the bottom. Wastewater is poured or as an dosed onto the surface from above ground constructionusing a mechanical dosing system. Each The water flows vertically down through the filter should have an impermeable liner and an effluent collection system. Vertical Flow Constructed Wetlands are most commonly designed matrix to treat wastewater that has undergone primary treatment. Structurally, there the bottom of the basin where it is collected in a layer of gravel for drainage (pipe. The important difference between a minimum vertical and horizontal wetland is not simply the direction of 20cm)the flow path, followed by layers of either sand and gravel (for settled effluent) or sand and fine gravel (for raw wastewater)but rather the aerobic conditions.'''

<br>By intermittently dosing the wetland (4 to 10 times a day), the filter goes through stages of being saturated and unsaturated, and, accordingly, different phases of aerobic and anaerobic conditions. During a flush phase, the wastewater percolates down through the unsaturated bed. As the bed drains, air is drawn into it and the oxygen has time to diffuse through the porous media. The filter media acts as both a filter for removing solids, a fixed surface upon which bacteria can attach and a base for the vegetation. The top layer is planted and the vegetation is allowed to develop deep, wide roots , which permeate the filter media. The vegetation transfers a small amount of oxygen to the root zone so that aerobic bacteria can colonize the area and degrade organics. However, the primary role of vegetation is to maintain permeability in the filter and provide habitat for microorganisms. Nutrients and organic material are absorbed and degraded by the dense microbial populations. By forcing the organisms into a starvation phase between dosing phases, excessive biomass growth can be decreased and porosity increased.

Depending on the climate, Phragmites australis, Typha cattails ===Design Considerations=== The vertical flow constructed wetland can be designed as a shallow excavation or Echinochloa Pyramidalis are common optionsas an above ground construction. The vegetation transfers Clogging is a small amount of oxygen to the root zone so that aerobic bacteria can colonize the area and degrade organicscommon problem. HoweverTherefore, the primary role of vegetation is to maintain permeability influent should be well settled in the filter and provide habitat for microorganisms. During a flush phase, the wastewater percolates down through the unsaturated bed and is filtered by the sand/gravel matrix. Nutrients and organic material are absorbed and degraded by the dense microbial populations attached to the surface of the filter media and the roots. By forcing the organisms primary treatment stage before flowing into a starvation phase between dosing phases, excessive biomass growth can be decreased and porosity increased. A drainage network at the base collects the effluentwetland. The design and size of the wetland is dependent on hydraulic and organic loads. Pathogen removal Generally, a surface area of about 1 to 3 m2 per person equivalent is required. Each filter should have an impermeable liner and an effluent collection system. A ventilation pipe connected to the drainage system can contribute to aerobic conditions in the filter. Structurally, there is accomplished a layer of gravel for drainage (a minimum of 20 cm), followed by natural decaylayers of sand and gravel. Depending on the climate, predation by higher organismsPhragmites australis (reed), and sedimentationTypha sp. (cattails) or Echinochloa pyramidalis are common plant options. Testing may be required to determine the suitability of locally available plants with the specific wastewater.

- High reduction of BOD, suspended solids and pathogens <br>- Ability to nitrify due to good oxygen transfer <br>- Does not have the mosquito problems of the [[Free-Water Surface Constructed Wetland|Free-Water Surface Constructed Wetland]]. <br> - Less clogging than in a [[Horizontal Subsurface Flow Constructed Wetland|Horizontal Subsurface Flow Constructed Wetland]]. <br> - Requires less space than a Free-Water Surface Constructed or Horizontal Flow Wetland. <br> - High reduction in BODLow operating costs | con=- Requires expert design and construction, particularly, suspended solids and pathogens. the dosing system <br> - Construction can provide short-term employment to local labourers. | con=Requires more frequent maintenance than a Horizontal Subsurface Flow Constructed Wetland <br>- Constant A constant source of electrical energy may be required. <br> - Long startup time to work at full capacity <br>- Not all parts and materials may be locally available locally. <br> - Requires expert design and supervision. <br> - Moderate capital cost depending on land, liner, etc.; low operating costs. <br> - Pre-treatment is required to prevent clogging. <br> - Dosing system requires more complex engineering.

==Adequacy=Health Aspects/Acceptance=== Pathogen removal is accomplished by natural decay, predation by higher organisms, and filtration. The risk of mosquito breeding is low since there is no standing water. The system is generally aesthetic and can be integrated into wild areas or parklands. Care should be taken to ensure that people do not come in contact with the influent because of the risk of infection.

Clogging ===Operation & Maintenance=== During the first growing season, it is important to remove weeds that can compete with the planted wetland vegetation. Distribution pipes should be cleaned once a common problemyear to remove sludge and biofilm that might block the holes. ThereforeWith time, the influent gravel will become clogged by accumulated solids and bacterial film. Resting intervals may restore the hydraulic conductivity of the bed. If this does not help, the accumulated material has to be removed and clogged parts of the filter material replaced. Maintenance activities should be well settled with focus on ensuring that primary treatment is effective at reducing the concentration of solids in the wastewater before flowing into it enters the wetland. This technology is Maintenanceshould also ensure that trees do not appropriate for untreated domestic wastewater (i.e. blackwater)grow in the area as the roots can harm the liner.

There are many complex processes at work* Brix, H. and accordinglyArias, there is a significant reduction in BOD, solids and pathogensC. A. (2005). [http://ocfpathplanning. In many cases, the effluent will be adequate for discharge without further treatmentorg/graywater/BrixDanishGWguidelines. Because pdf The Use of the mechanical dosing system, this technology is most appropriate Vertical Flow Constructed Wetlands for communities with trained maintenance staff, constant power supply, and spare partson-Site Treatment of Domestic Wastewater: New Danish Guidelines]. Ecological Engineering 25 (5): 491-500.

Vertical Flow Constructed Wetlands are best suited to warm climates but can be designed to tolerate some freezing * Crites, R. and Tchobanoglous, G. (1998). Small and periods of low biological activityDecentralized Wastewater Management Systems. WCB/McGraw- Hill, New York, US. pp. 599-609.(Book; Comprehensive summary chapter including solved problems)

==Health Aspects* Kadlec, R. H. and Wallace, S. D. (2009). [https:/Acceptance==/sswm.info/sites/default/files/reference_attachments/KADLEC%20WALLACE%202009%20Treatment%20Wetlands%202nd%20Edition_0.pdf Treatment Wetlands, 2nd Ed]. CRC Press, Taylor & Francis Group, Boca Raton, US.

The risk of mosquito breeding is low since there is no standing water* UN-HABITAT (2008). The system is generally aesthetic and can be integrated into wild areas or parklands[https://unhabitat. Care should be taken to ensure that people do not come in contact with the influent because of the risk of infectionorg/constructed-wetlands-manual Constructed Wetlands Manual]. UN-HABITAT Water for Asian Cities Programme. Kathmandu, NP.

* U.S. EPA (2000). [https://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=64144&Lab=Maintenance==NRMRL Constructed Wetlands Treatment of Municipal Wastewaters]. EPA/625/R-99/010. U.S. Environmental Protection Agency, Washington, D.C., US.

With time, the gravel will become clogged with accumulated solids and bacterial film. The material may have to be replaced every 8 to 15 or more years. Maintenance activities should focus on ensuring that primary treatment effectively lowers organics and solids concentrations before entering the wetland. Testing may be required to determine the suitability of locally available plants with the specific wastewater. The vertical system requires more maintenance and technical expertise than other wetland technologies. ===Acknowledgements===