Constructed Wetland – June 2019
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Location of the case study
Main treatment objectives
Description of the treatment process
The constructed wetland is a biological treatment unit to treat faecal sludge and wastewater. The constructed wetland has been re-engineered here to achieve primarily as separator of solid and liquid fraction of the raw faecal sludge and then the separated liquid portion undergoes to filtration media for further treatment before discharging into the environment.
The solid portion is treated biologically in mostly aerobic condition in presence of thermophilic bacteria. The presence of Cana Indica (or other available suitable plants) facilitates the nitrification and denitrification process and is responsible for NO3- removal from faecal sludge. Through the process of active bacteria inside the porous media of constructed wetland and on the surface of hay, it stimulates BOD, COD removal. The filtration media facilitates PO4- and TDS removal.
At present, final sludge is planned to be buried safely. However, it may have potential to be used as soil conditioner.
Description of the emergency context
Kutupalong camp has a natural terrain with hills and canals ﬂowing through the downhills. The forced Myanmar inhabitants have their shelters mostly at different levels of the hills, which makes it diﬃcult to desludge toilets pits.
The treatment plant will be soon decommissioned as it is set up in a flood prone area.
Contexts where the technology is applicable:
• Decentralised approach 35m2 for each unit
• Mechanical collection and gravity-fed transportation of sludge is already designed and implemented
• Can be applicable for flat terrain also with intermediate transfer station connecting with chained collection system
• Where there is adequate technical capacity on the loading and operations of constructed wetlands
Contexts where the technology is not applicable:
• Not anticipated yet as system can be reengineered according to the context
• In flood-prone locations, or hillsides prone to landslide
• In locations where surface water runoff will enter the system
• Where there is inadequate technical capacity on the loading and operations of constructed wetlands