How Do Floating Treatment Wetlands Work?

July 6, 2017

Maintaining compliance under stricter regulations with aging equipment and limited budgets is a continuous juggling act for communities around the world. This challenge lends to the desire to find cost-effective solutions for wastewater treatment.

Floating Treatment Wetlands (FTW) are an innovative solution engineered to enhance the natural processes that occur between water, plants, and micro organisms in order to remove contaminants from wastewater and stormwater in a passive and natural way.

Floating Treatment Wetlands provide a foundation for plants to grow. The matrix is open and porous in structure, which enables the plants’ roots to spread throughout ultimately creating a vast activated surface area for microbes and bacteria to live. The microbes and bacteria attach to the roots, the microscopic root hairs of the plants and on the fibers of the matrix. The microbes and bacteria secrete a sticky film called biofilm, where total suspended solids (TSS) are either trapped or settle. The microbes and bacteria digest the organic matter and nutrients, including biochemical oxygen demand (BOD), nitrogen and phosphorus through a process called bioremediation.

Biological Treatment takes place below

the water where hanging root systems grow.

There are 3 Critical Elements for Effective Biological Water Treatment:

1. Surface Area

The fibrous matrix along with the roots of the hydroponically grown vegetation create an extensive network of surface area for pollutant eating microbes and bacteria to live.

  • 1 ft2 of planted Floating Treatment Wetland has approximately 3300 ft2 of surface area.

2. Hydraulic Retention Time (HRT)

Through the use of attached flow curtains Floating Treatment Wetlands control water flow thereby maximizing retention time. This allows for more treatment time.

3. Vegetation

Through photosynthesis plant roots secrete sugar and oxygen for microbes and bacteria to feed on. The microbes and bacteria in return, give the plants food such as nitrogen, phosphorous and ammonia through a process called phytoremediation.

Floating Treatment Wetlands are Effective for:

  • Anaerobic Digestion
  • Nitrification Processes
  • De-nitrification and Polishing
  • Removal of Total Suspended Solids (TSS)
  • Reduction in Biochemical Oxygen Demand (BOD)
  • Reduction in Fecal Coliforms
  • Reduction in Phosphorus
  • Reduction in Turbidity

Close-up view of plant roots.