Changes

<!{|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}}|}{|width="100%"|style="width:50%;"|{{santablesantable_new|

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:Icon_vertical_flow_constructed_wetland.png |right|95px80px]]'''A Vertical Flow Constructed Wetland is a filter bed that is planted with aquatic plants. Wastewater is poured or dosed onto the wetland surface from above using a mechanical dosing system. The water flows vertically down through the filter matrix. The important difference between a vertical and horizontal wetland is not simply the direction of the flow path, but rather the aerobic conditions.'''

By dosing the '''A vertical flow constructed wetland intermittently (four to ten times is a day), planted filter bed that is drained at the bottom. Wastewater is poured or dosed onto the filter goes through stages of being saturated and unsaturated, and accordingly, different phases of aerobic and anaerobic conditionssurface from above using a mechanical dosing system. The frequency of dosing should be timed such that the previous dose of wastewater has time to percolate water flows vertically down through the filter bed so that oxygen has time matrix to diffuse through the media bottom of the basin where it is collected in a drainage pipe. The important difference between a vertical and fill horizontal wetland is not simply the void spacesdirection of the flow path, but rather the aerobic conditions.'''

The Vertical Flow Constructed Wetland can be designed as <br>By intermittently dosing the wetland (4 to 10 times a shallow excavation or as an above ground construction. Each day), the filter should have an impermeable liner goes through stages of being saturated and unsaturated, and, accordingly, different phases of aerobic and an effluent collection systemanaerobic conditions. Vertical Flow Constructed Wetlands are most commonly designed to treat During a flush phase, the wastewater that percolates down through the unsaturated bed. As the bed drains, air is drawn into it and the oxygen has undergone primary treatmenttime to diffuse through the porous media. StructurallyThe filter media acts as a filter for removing solids, there is a fixed surface upon which bacteria can attach and a base for the vegetation. The top layer of gravel for drainage (is planted and the vegetation is allowed to develop deep, wide roots, which permeate the filter media. The vegetation transfers a minimum small amount of 20cm)oxygen to the root zone so that aerobic bacteria can colonize the area and degrade organics. However, followed by layers the primary role of either sand vegetation is to maintain permeability in the filter and gravel (provide habitat for settled effluent) or sand 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 fine gravel (for raw wastewater)porosity increased.

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