Catchment News

Constructed wetlands of Ireland – new database now online

As part of an EPA-funded project, NUI Galway researchers Collette Mulkeen, Dr Mark Healy and Prof Mike Gormally identified a need for a coherent, comprehensive and an up-to-date database of constructed wetland performance in Ireland.

This will hopefully help in the development of design criteria, guidelines and operation methodology for constructed wetlands in Ireland, and provide an evidence-based reference point for constructed wetland designers, engineers, scientists and researchers.

Using a mixture of published and unpublished data from local authorities, Irish Water, and the EPA, with the help of a DCU-based web developer, Sean Healy, the NUI Galway researchers set about compiling a database that would capture these data.

It is now available at http://wetlands.nuigalway.ie

To use the database, the user first selects the county and wastewater type of interest. Three options for wastewater type are given:  municipal, agricultural and industrial. After selection of county and wastewater type, another page is presented in which the user selects a wetland location within the county. If available, the data from this wetland are presented. All of the wetland datasheets have the same format and list a range of inlet and outlet water quality parameters by sampling date. These databases may be downloaded (as an Excel worksheet) by clicking the ‘download’ button on the right hand side of the screen.

Submit your wetlands data

At the time of writing, there are over 100 wetlands in the database. However, the database is far from complete. Those involved in the monitoring of wetlands are invited to submit any further constructed wetland locations or data they may have (in whatever format they choose) by clicking on the ‘Submit wetlands data’ button at the top right-hand side of the home page. In addition, a list of Irish constructed wetlands literature is available by clicking the ‘Publications’ button on the home screen.

This database should be seen as a centralized repository of performance data from constructed wetlands in Ireland. As the data are entirely user generated, engineers, technicians, or those sampling inlet and outlet water data in constructed wetlands in Ireland are encouraged to engage with the website and submit data to it.

About constructed wetlands

The use of constructed wetlands for the treatment of domestic, municipal, agricultural and industrial wastewaters is gaining in popularity. This is due to the fact that although the domestic wastewater of approximately one third of the population of Ireland is treated by on-site domestic wastewater treatment systems, such as septic tanks, an estimated 39% of the overall proportion of the country has inadequate percolation for such treatment (EPA, 2013), and alternative treatment methods may need to be used. It is also due to the population distribution in Ireland, which outside of urban areas, is low density and diffuse. In these areas, municipal wastewater is conventionally treated using activated sludge treatment plants, which often use constructed wetlands as a polishing step. It is estimated that there are over 140 constructed wetlands used for the treatment of municipal, industrial and agricultural wastewater in Ireland.

Over the years various attempts have been made, with varying levels of success, to compile a database of the performance of constructed wetlands in Ireland (Harty and Otte, 2003; Babatunde et al., 2008; Healy and O’ Flynn, 2012). The fact that such data were not centrally compiled and were often not even available in digital format, mitigated against any potential success. Other countries in Europe and elsewhere have successfully compiled performance databases of constructed wetlands, but to date relatively little has been done in this regard in Ireland. This means that an evidence-based picture of the performance of constructed wetlands in Ireland’s temperate maritime climate has been impossible to determine. Moreover, design modifications to constructed wetlands to optimize their performance under Irish climatic conditions have not been made. This could be very significant, as constructed wetlands have traditionally been designed in accordance with empirical equations (e.g. Cooper et al., 1996) that were developed for climates quite different to Ireland’s. Therefore, there is the possibility that constructed wetlands may not be optimally sized.

 

Article by Collette Mulkeen, Mike Gormally, Sean Healy, and Mark Gerard Healy