Components  

There are small differences in constructed wetlands from place to place depending on the amount of water being treated, though the principles behind them remain the same.

  
   
Headworks  
Inorganic materials are removed by a pump and grid system.  
   
Primary clarification  
The majority of the solids are separated from the liquid. The liquid continues on to the oxidation pond while the solids proceed to the solids handling treatment structure.  
   
Solids handling (sludge disposal)  
This process uses the natural methane produced by the sewage solids to process or "digest" it until it breaks down further.  
   
Oxidation pond  
The rest of the suspended solids left after primary treatment are processed out in the oxidation pond by wetland plants and microorganisms. The water here is detained over a longer period of time to reduce the BOD (biochemical oxygen demand).  
   
Treatment marshes and enhancement marshes  
Further reduction of BOD and suspended solids occurs within these marshes. From here the waste is pumped to a disinfection basin, which uses chlorine gas to disinfect. From there, the waste is released into the enhancement marshes.  
   
Disinfection and release  
From the enhancement marshes, the waste is treated to another disinfection basin where it is treated again with chlorine gas. Following this final disinfection it is usually released into a nearby body of water.  
   
Conveyance systems  
Pipes and dikes are used as a way to convey water from one pond or marsh to the next. In some cases there has been a topographical change on site and gravity overflow has been utilized instead.  
   
Natural systems/processes within a constructed wetland  

Plants that exist in a natural wetland environment take up nitrogen and phosphorous and also send oxygen into their submerged parts. This oxygen is needed for the microorganisms that live on the submerged parts of wetland plants. Those microorganisms that exist on the soil and plants that are submerged break down the organic matter into carbon dioxide and water. Insects feed on these microorganisms, and waterfowl and other wildlife feed on those insects, moving energy up the food chain. In a constructed wetland the original plants are selected and planted by humans, but there are volunteer and emergent species that take root and grow naturally. This creates a holistic system does not appear as constructed as one might think.

Due to increased oxygen demand in a constructed wetland, which in turn creates more algae and microorganisms, it is likely an accumulation of organic matter within the pond will occur over a long period of time (years). This could potentially cause a problem in the functioning of the wetland. This accumulation is one of the only maintenance issues that makes it different from a natural wetland.