The phrase integrated constructed wetland (ICW) was invented in 1990 by Dr Rory Harrington who works for the Irish Department of Environment, Heritage and Local Government (Harrington and Ryder, 2002). The full definition of the ICW concept was published by Dr Rory Harrington in collaboration with Dr Miklas Scholz and his research group (The University of Edinburgh, UK) and Waterford County Council (Ireland) in 2007 (Scholz et al., 2007a).
Method of operation
The research consortium defines an ICW as an unlined free surface flow constructed wetland addressing the objectives of cleansing and managing water flow from farmyards and other wastewater sources, and integrating the wetland infrastructure into the landscape and enhancing its biological diversity (Scholz et al., 2007a,b). The primary objectives of the ICW Concept are the explicit integration of:
This explicit integration of ICW facilitates processing synergies, robustness, and sustainability, which are not generally available in other wetland treatment systems (Mustafa et al., 2009; Scholz et al., 2007a,b). These benefits are primarily due to the greater biological complexity and generally relatively larger land area use and associated longer hydraulic residence time of ICW in contrast to traditional constructed treatment wetlands (Carty et al., 2008).
Fundamentally, the ICW concept focuses upon the creation of an ‘ecological infrastructure’, which is largely self-managing, biologically self-designing, and of social and economic coherence. This robust, sustainable, and multi-benefit yield from ICW systems is assured by appropriate assessment, design, and construction as shown by Mustafa et al. (2009) for a representative case study. More recently, the ICW concept has been combined with advanced modelling tools to support the prediction of corresponding treatment performances (Zhang et al., 2008, 2009).
The ICW concept is frequently used by engineers, scientists and planners since 2007. Its application is widespread in northern Europe (particularly Ireland and the UK) and the US. Farm constructed wetlands (Carty et al., 2008), which are a subtype of ICW are formally promoted by the Scottish Environment Protection Agency and the Northern Ireland Environment Agency since 2008.