Constructed Wetland Open Day at Greenmount Campus, CAFRE

An Open Day aimed at farmers and growers who wish to learn more about the potential of Constructed Wetlands to treat farmyard dirty water is being organised for Wednesday 15 September 2010 at the Greenmount Campus of CAFRE, outside Antrim.

Starting at 10.00 am, attendees can join tours of the Greenmount Wetland. Each tour will last approximately 45 minutes and tours will run at 30 minute intervals. The last one starts at 3.00 pm. The tour aims to demonstrate the main sources of dirty water generated by the dairy unit at Greenmount and how dirty water is being treated to a required standard by the Wetland.

Dirty water has minimal value as a source of fertiliser but it is a highly polluting waste so that its management requires particular care. The volumes produced can be large. On dairy farms, for example, run-off from yard areas contaminated by the daily movement of cattle, generate large volumes that augment “wash water” from milking parlours and dairies.

Farmers who could benefit most from using wetland technology include those considering increasing stock numbers and who currently store large volumes of dirty water in slurry tanks. However, a key requirement is the availability of suitable land close to the farmyard. This has to be of sufficient size to accommodate the wetland and have the necessary soil type, topography and a suitable discharge outlet.

The Greenmount wetland consists of five ponds constructed and planted in 2004 and has been operational since late in 2005.  It treats dirty water from the Campus dairy unit with three main sources of dirty water:

Performance Various aspects of the performance of the Wetland have been monitored by staff from the Agri-Food and Biosciences Institute (AFBI), Greenmount Campus, (CAFRE), Northern Ireland Environment Agency (NIEA) and students from Queens University of Belfast.  These investigations have shown generally high treatment performances and the Wetland has been able to meet the requirements for the discharge consent limit of 40 mg/l BOD set by NIEA. Nutrient retention within the wetland was of a very high level, and consistently higher than reported in studies of many other wetlands.

The extensive growth of Phragmites australis 'reed' plants in the Greenmount Campus Constructed Wetland facilitates the treatment of dirty water by a combination of biological, chemical and physical processes