THE USE OF SUBSURFACE-FLOW CONSTRUCTED WETLANDS FOR WASTE-WATER TREATMENT IN THE CZECH-REPUBLIC

The use of constructed wetlands for wastewater treatment is an emergin g technology in the Czech Republic. The inventory survey in 1993 revea led that 28 systems have been built and put into operation or are unde r construction since 1989. In addition, it was found that 54 systems a re in the design stage. The survey was conducted to identify the major design parameters of existing and planned constructed wetlands. All e xisting constructed wetlands surveyed were subsurface horizontal-flow systems that treat predominantly mechanically pretreated municipal or domestic sewage. The treatment area of operational systems ranges betw een 20 and 6000 m(2) and population equivalent ranges from 4 to 1200. Common reed (Phragmites australis (Cav.) Trin. ex Steud.) is the most frequently used plant and gravel, sand and associated mixtures are use d as media. The treatment efficiency is high in terms of BOD, and susp ended solids while nutrient removal is low.