Changes

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=

 '''A Vertical Flow Constructed Wetland vertical flow constructed wetland is a planted filter bed that is planted with aquatic plantsdrained at the bottom. Wastewater is poured or dosed onto the wetland surface from above using a mechanical dosing system. The water flows vertically down through the filter matrixto the bottom of the basin where it is collected in a drainage pipe. The important difference between a vertical and horizontal wetland is not simply the direction of the flow path, but rather the aerobic conditions.'''

By intermittently dosing the wetland intermittently (four 4 to ten 10 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 During a flush phase, the previous dose of wastewater has time to percolate percolates down through the filter unsaturated bed. As the bed so that drains, air is drawn into it and the oxygen has time to diffuse through the porous media and fill the void spaces. The Vertical Flow Constructed Wetland can be designed as a shallow excavation or as an above ground construction. Each filter should have an impermeable liner and an effluent collection system. Vertical Flow Constructed Wetlands are most commonly designed to treat wastewater that has undergone primary treatment. Structurally, there is a layer of gravel for drainage (a minimum of 20cm), followed by layers of either sand and gravel (for settled effluent) or sand and fine gravel (for raw wastewater). 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. Depending on the climate, Phragmites australis, Typha cattails or Echinochloa Pyramidalis are common options. 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.

During ===Design Considerations=== The vertical flow constructed wetland can be designed as a shallow excavation or as an above ground construction. Clogging is a flush phasecommon problem. Therefore, the wastewater percolates down through influent should be well settled in a primary treatment stage before flowing into the unsaturated bed wetland. The design and size of the wetland is filtered by the sand/gravel matrix. Nutrients dependent on hydraulic and organic material are absorbed loads. Generally, a surface area of about 1 to 3 m2 per person equivalent is required. Each filter should have an impermeable liner and degraded by an effluent collection system. A ventilation pipe connected to the dense microbial populations attached drainage system can contribute to the surface of aerobic conditions in the filter media and the roots. By forcing the organisms into Structurally, there is a layer of gravel for drainage (a starvation phase between dosing phasesminimum of 20 cm), excessive biomass growth can be decreased followed by layers of sand and porosity increasedgravel. A drainage network at Depending on the base collects climate, Phragmites australis (reed), Typha sp. (cattails) or Echinochloa pyramidalis are common plant options. Testing may be required to determine the effluent. The design and size suitability of locally available plants with the wetland is dependent on hydraulic and organic loadsspecific wastewater.

Pathogen removal Due to good oxygen transfer, vertical flow wetlands have the ability to nitrify, but denitrification is accomplished by natural decay, predation by higher organismslimited. In order to create a nitrification-denitrification treatment train, this technology can be combined with a [[Free-Water Surface Constructed Wetland|Free-Water Surface]] or [[Horizontal Subsurface Flow Constructed Wetland|Horizontal Flow Wetland]] (T.7 and sedimentationT.8).

- Does not have the mosquito problems of the [[Free-Water Surface Constructed Wetland]]. <br> - Less clogging than in a [[Horizontal Subsurface Flow Constructed Wetland|Horizontal Flow Constructed Wetland]]. <br> - Requires less space than a Free-Water Surface Constructed Wetland. <br> - High reduction in BOD, suspended solids and pathogens. <br> - Construction can provide short-term employment to local labourers. | con=