Water and CO2 recovery on a national scale

“The general impression is that it rains quite a lot of the time in Ireland, but two out of three hourly observations will not report any measurable rainfall.”  So says the Irish Meteorological service online, met.ie.  The fact that the service feels the need to comment at all is a measure of the myth which has grown up that it always rains in Ireland.  However, with the number of wet days averaging 150 per year on the east and south east coasts and 225 days in parts of the west it is fair to say that Ireland does get its fair share of rain.

This doesn’t mean that Ireland can afford to be complacent about its use of water.  Clean water is an increasingly expensive commodity and with little evidence of water being recovered and reused within production processes, it is one which is potentially affecting the competitiveness of Irish industry.  With this in mind FDT Consulting Engineers & Project Managers Ltd (FDT) undertook a project to assess the potential for the recovery and reuse of water and carbon dioxide from industrial waste streams in Ireland.

Part funded by the Irish Environmental Protection Agency’s Cleaner Greener Production Programme, the research not only looked at the technical aspects of recovering water and CO2 but also examined the economic implications including stress testing feasibility against future water and carbon credit prices. The project examined six sites in detail and then extrapolated the results across Ireland as a whole.

The project identified a number of opportunities to recycle water and CO2 but concluded that the costs would generally at present be outside the normal payback period of the organisations concerned.  However, this is expected to change as commodity prices rise and cheaper filtration systems arrive.  With CO2 in particular, the opportunities for recovery varied enormously from being uneconomic to a potential recover of 65%.  Potential uses for recovered CO2 were also identified including increasing crop yields in greenhouses, with a CO2 rich atmosphere estimated to boost yield by up to 15%.

When it comes to water the project concluded that it is technically possible to recover 34% of water supplied to IPPC licensed companies and if mains distribution losses are taken into account this figure could easily rise.  One of the main barriers to water reuse would be the challenge of overcoming the perception of using “dirty water”, particularly in the food and brewing industries.

Studies of this nature are vital in aiding our understanding of the costs, barriers and potential of recycling resources.  They can act as a catalyst to encourage the invention of more cost effective recycling or filtration methods as well as opening up awareness and debate on the issues.  We were therefore happy to award this project a Green Apple Award.