Results of Estonian LIFE project - willow for wastewater purification

Short rotation willow plantation for wastewater purification: case study at Aarike, Estonia
V. Kuusemets, K. Heinsoo, E. Sild & A. Koppel
University of Tartu, Institute of Botany and Zoology

A small pilot willow plantation was established to study the possibilities of usage of willows for biomass production and wastewater purification. The wastewater from a dwelling house (25 p.e.) is treated on an 180 m surface - subsurface flow constructed wetland.
The wastewater is flowing in serpentine ditches through three basins on which beds with filter media are planted with willows (Salix viminalis and Salix dasydados).
The system showed high wood productivity and also high wastewater purification efficiency.
The average annual plant wood dry matter production for the second rotation period was 1,16 kg, which exceeded the productivity in the fertilized lantations in the same region (0,71 kg). During the study period (1995-2000) average purification efficiency of BOD7, total N and total P was 75, 32 and 14%, respectively.