Greywater irrigation as a source of organic micro-pollutants to shallow groundwater and nearby surface water

Increased water demands due to population growth and increased urbanisation have driven adoption of various water reuse practices. The irrigation of greywater (water from all household uses, except toilets) has been proposed as one potential sustainable practice. Research has clearly identified environmental harm from the presence of micro-pollutants in soils, groundwater and surface water. Greywater contains a range of micro pollutants yet very little is known about their potential environmental fate when greywater is irrigated to soil. Therefore, this study assessed whether organic micro-pollutants in irrigated greywater were transferred to shallow groundwater and an adjacent surface waterway. A total of 22 organic micro-pollutants were detected in greywater. Six of these (acesulfame, caffeine, DEET, paracetamol, salicylic acid and triclosan) were selected as potential tracers of greywater contamination. Three of these chemicals (acesulfame, caffeine, DEET) were detected in the groundwater, while salicylic acid was also detected in adjacent surface water. Caffeine and DEET in surface water were directly attributable to greywater irrigation. Thus the practice of greywater irrigation can act as a source of organic micro-pollutants to shallow groundwater and nearby surface water. The full list of micro-pollutants that could be introduced via greywater and the risk they pose to aquatic ecosystems is not yet known

Developing resilience to England's future droughts: time for cap and trade?

Much of England is seriously water stressed and future droughts will present major challenges to the water industry if socially and economically damaging supply restrictions are to be avoided. Demand management is seen as a key mechanism for alleviating water stress, yet there are no truly effective incentives to encourage widespread adoption of the behavioural and technological demand management practices available. Water pricing could promote conservation, but on its own it is an inefficient tool for dealing with short term restriction in water supply. Raising prices over the short term in response to a drought is likely to be ineffectual in lowering demand sufficiently; conversely, maintaining high prices over the long term implies costs to the consumer which are needlessly high most of the time. We propose a system for developing resilience to drought in highly water stressed areas, based on a cap and trade (C&T) model. The system would represent a significant innovation in England's water market. However, international experience shows that C&T is successful in other sectors, and need not be overly complex. Here, we open the debate on how a C&T system might work in England