Biologic Design

WET Systems - An Overview

A WET System is made up of a series of specially designed and constructed earth banks and ponds. As the wastewater flows through these soil banks it is both purified by microbial action and transpired by growing plants. The WET System is planted with a wide range of aquatic and marginal plants and a variety of willow types and wetland tree species.

WET Systems - sustainable wastewater purification technology

WET Systems are ‘low-entropy systems’ in that they use no fossil fuels or electricity to purify the wastewater and they are ‘solar powered’ by the ability of plants to absorb solar energy during photosynthesis.

Micro-organisms in the root-zone mineralise the nutrients found in wastewater making them available to the plants.

Low embedded energy

Unlike conventional Reedbed Treatment Systems, no gravel or plastic aeration/distribution pipes are used in their construction; thus gravel does not need to be quarried and transported to site, and because plastics are not routinely used in our designs WET Systems have a very low embedded energy - soil in the root-zone, not imported gravel, is the filtration medium and this is already on-site.

Biomass Yield of the WET System

The biomass yield from a well-managed WET System can include one-year old coppiced willow wands for basketry, two-year old willow wands for hurdle making or living willow domes and tunnels, as well as binders used for hedge-laying, and three-year old willow wands which are used for the construction of living willow structures and garden furniture.

Rapidly growing, large, biomass willow types can also be planted and when harvested and seasoned these can be used to fuel simple woodstoves and 'rocket-stoves', ceramic stoves, biomass boilers or combined heat and power (CHP) systems - and so contribute to the energy needs of the site.