The Copenhagen Accord has agreed the need to keep global temperature rises to no more than 2C and, although avoiding binding targets, has said that the world’s rich countries will commit to cutting greenhouse gases. Despite the lack of binding targets from Copenhagen, it seems likely that the UK government will continue with its own challenging targets to reduce emissions to 80-% of their 1990 level, by 2050. As such the water industry will have an important role to play in helping deliver these targets as it emits as much greenhouse gas as the aviation industry. Wastewater treatment is a major user of energy and this use continues to increase in a linear way as the industry seeks to deliver tougher discharge consents. As a result a modern wastewater treatment plants is able to produce an effluent that has a negligible impact on the receiving watercourse. The efficacy of such treatment is evidenced by the continuous improvement in the quality of our rivers which the Environment Agency acknowledges as being the best on record.

But many commentators now consider that climate change is the biggest global threat to public health of the 21st Century and if this is the case then water quality improvements must be balanced against climate change impacts. There are many examples of costly enhancements to wastewater treatment that deliver questionable environmental benefits, inter alia: a spot compliance regime, effluent disinfection, odour control, nitrogen removal and sludge pasteurisation. If the water industry is to take seriously the threats of climate change, the challenge for both the regulators and the water companies is to balance the environmental costs and benefits of wastewater treatment in a manner that considers the wider environmental impacts and not solely the aquatic environment.

Therefore it is the aim of this event to consider:

i) What are the relative environmental impacts and benefits of our current treatment regime and which consented parameters deliver negligible measurable benefits?
ii) What is the scope for relaxing consents, where this can be shown to demonstrate negligible adverse impacts but large reductions in GHG emissions?
iii) What low-carbon treatment alternatives are available, but held back by the consenting regime?
iv) What limits on GHG emissions should water companies strive towards for its wastewater treatment activities?