There is a trend in ...

There is a trend in developing countries to use "natural" attenuation systems for treating wastewater and sludge using Constructed Wetlands and Reed Beds. These are low energy technologies and they can be configured to produce tertiary quality water and Class A biosolids. Plants are selected for their ability to have rhizomes that are durable for the region and are usually selected from native species, e.g. Vertiver, Phragmities, etc.  They have even been installed on remote islands like the Galapagos (Ecuador) to protect the environment from using western construction brick and mortar techniques that would otherwise destroy native habitat in a World Heritage Site.