Types and characteristics of CWs
Constructed wetlands have developed rapidly and can be
designed and constructed in various hydrologic modes and configurations
to emphasize specific characteristics for improved
treatment performance, such as baffled flow CW, hybrid towery
CW, step feeding CWs etc (Wu et al., 2014). However, most these
variants are evolved from the basic types of CWs, which are in
relatively widespread use currently (Table 1).
Fig. 2 depicts the relationship between energy and O&M
(operation & maintenance) needs via land area requirements for
the traditional passive natural wetlands to intensified wetlands. If
an equal treatment performance is targeted, freewater surface flow
(FWS) CWs need the least energy for operation and maintenance,
but largest land area. Otherwise, the intensified wetlands such as