ABSTRACT
Natural wastewater treatment systems such as constructed wetlands, biological sand filters and other decentralised solutions are becoming an increasingly relevant alternative to conventional systems when treating wastewater from small communities and dwellings due to its efficiency, low establishment costs and low operation and management requirements. In order to treat wastewater effectively, several factors have to be taken into account, e.g. the system’s capacity, the plant species used, colonization characteristics of certain microbial groups, and the interactions of biogenic compounds and particular contaminants (wastewater components) with the filter bed material (Stottmeister et al., 2003). Although filtration
is considered an important process in these removal mechanisms, additional interactions occur among media, plants and water. Many processes and relations between them take place: microbial-mediated processes, chemical networks, volatilization, sedimentation, sorption, photodegradation, plant uptake, transpiration flux and accretion (Kadlec and Wallace, 2009). The importance of microbial processes has been further studied as many reactions are microbiologically mediated (Stottmeister et al., 2003 and Kadlec and Wallace, 2009).
