A sludge treatment wetland (STW) is a specialised type of
vertical flow constructed wetland whose main function is to
reduce sludge volume by dewatering and lowering organic
matter content through mineralisation (Kim and Smith, 1997).
Treatment processes include physical retention of sludge
particles at the surface, and percolation of a fraction of the
sludge water through the wetland’s granular media (Nielsen,
2003). While pollutant concentrations are generally considered