A method of turning farmyard waste water into water fit to bathe in has been developed by Edinburgh University engineers. The eco-friendly system allows for safe storage and treatment of farm dirty water and requires very little maintenance.
The method was developed in cooperation with the Irish government and backed by the Scottish government and the Scottish Environment Protection Agency. It involves storing the liquids – manure traces and farmyard runoff – in a linked series of outdoor shallow ponds.
Effluents are channelled downhill into the ponds, in which water-borne plants filter out solid particles. Over time, the waste breaks down into its component minerals and other materials – some is taken up by the plants for nutrition. Other solid particles settle on the bottom of the pond.
Over several days or weeks, the water travels between each of the ponds and becomes clean enough to meet bathing quality standards. In most cases, water can be discharged from the final pond to a local river, stream, ditch or woodland.
The system, known as an integrated constructed wetland, provides a cheaper and safer alternative to the common practice of spreading dirty water on farmland. It also prevents loss of contaminants to rivers and lakes, where they may be detrimental to animal or human health.
‘Wetlands offer a safer alternative to spreading dirty water on fields, and are effective and easy to maintain. It’s a back-to-basics approach of dealing with farmyard waste water,’ said Dr Miklas Scholz from Edinburgh University’s School of Engineering and Electronics.