MSR Constructed Wetlands

Multi-Stage Recirculating Constructed Wetlands

The low-carbon, ecological option for municipal and industrial wastewater treatment and water recycling.

The Multi-Stage Recirculating Constructed Wetland (MSR Constructed Wetland) harnesses the powerful treatment capacity of natural treatment systems in an engineered environment. The MSR sub-surface flow constructed wetlands’s multiple stages and controlled recirculation rates provide a high performing, low energy and robust ecological treatment system.

4 Stages of MSR Constructed Wetlands

The Anaerobic Stage

The anaerobic stage utilizes a multiple compartment baffle tank with an option for an up flow anaerobic sludge blanket. 30% to 60% of the TSS can be removed in this stage.

The Wetland Stage

The wetland stage utilizes high surface attached growth treatment processes. Biofilms are established on both aggregate and live substrates to facilitate robust attached growth treatment processes. The majority of the BOD is removed at this stage

The Aerobic Stage

The Aerobic Stage operates to provide the necessary conditions for the nitrification of Ammonia to Nitrite and Nitrate. Denitrification takes place in the benthic zones of the Anoxic/Ecological stage. The majority of the NH3 is removed in this stage.

The Polishing Stage

The polishing stage provides a high level of final treatment by recirculating dosing through fine pore treatment media. Effluent typically passes through six cycles in this filter before flowing to UV disinfection.

HDPE Liner

Provides a long lasting UV resistant containment system.


non-woven pin dotted polypropylene provides protection above and below the liner.


Distribution manifolds and laterals provide even flow.

Plants & Gravel

Plant roots and gravel substrate provide enhanced surface area for microorganisms.


UV disinfection can be used where water is to be recycled for public areas.


Treated effluent can be recycled for irrigation of non-edible crops.


MSR Wetlands are capable of achieving high levels of treatment for BOD, TSS, nutrients and pathogens. Multiple stages perform different treatment functions. The recycle between stages provides the alternating conditions required for advanced biological nutrient removal. Each stage is sized according to process engineering calculations. The use of multiple cells allows the system to be built in stages where required. The recycle rate can be easily adjusted to respond to phases or seasonal variability in the influent flow. Each MSR Wetland is sized to meet the discharge parameters of each location.

Key Wetland Functions

1. Biological digestion and removal of organic compounds (BOD)

2. Degradation of suspended solids

3. Precipitation of metals

4. Pathogen removal

5. Nutrient removal (Nitrogen and Phosphorus)

6. Degradation of toxic compounds