Phytoremediation applications for waste water and improved water quality

Abstract

Macrophytes play an important role in natural and constructed wetlands (CWs). Their most important function is removal of excessive levels of some substances, such as nutrients, total suspended solids, trace elements, etc. CWs are widely used all around the world to treat many types of wastewater, with relatively high removal efficiency (5-day biochemical oxygen demand [BOD5]-around 80 %, total nutrients-approx. 40 % in the case of domestic sewage). Considering the purpose of CWs application, a few types were created with several variants in certain environmental conditions and for many effluent types with various loads of many substances. Two main types of flow through CWs are considered-surface and subsurface flow. The latter is further divided into horizontal and vertical flow. The most popular use of CWs is for domestic and municipal wastewater as secondary and tertiary treatment stages. Among macrophytes applied for phytoremediation, great diversity of plant species has been observed, especially native species and a wide range of ubiquitous species, such as Phragmites australis and Typha spp. Most macrophyte species also play an important role in natural ecosystems in improvement of surface water quality. Many species are utilized as indicators of water quality, even when low pollutant levels occur, while others are important for phytoextraction or phytostabilization.