8. SOURCE CONTROL OF POLLUTION - LOW PHOSPHORUS DETERGENTS
A challenge in Scotland is to manage and reduce excess phosphate loadings in freshwaters, which can lead to eutrophication and downgrade rivers and lochs. There are several sources of phosphate - domestic sewage, agriculture (livestock excreta and inorganic fertilisers) and detergents. The water industry adds small amounts to drinking water (to combat lead piping). A key source of phosphates is domestic cleaning products such as laundry detergents and dishwater tablets. Reducing the loading to surface waters from phosphate based detergents is necessary to reduce overall phosphate loadings from all sources.
Detergents are estimated to account for 25% of the phosphate entering waste water treatment works ( WWTW). In some WWTWs serving large populations, Scottish Water applies tertiary treatment to strip out phosphates. A reduction of phosphates in detergents would reduce Scottish Water's costs where there is such tertiary treatment.
In WWTWs without tertiary treatment, or in rural areas with dispersed populations where there is reliance on septic systems for individual households, phosphates are inevitably discharged to the water environment.
There are now alternatives to phosphates in detergents, and several countries have taken steps to ban the addition of phosphates, at least in laundry detergents, or have made an agreement with the industry not to add them.
8.1 Proposed actions
In February 2008 Defra published a consultation paper considering options for reducing phosphates in laundry detergents. It also identified taking a longer term view with respect to dishwasher detergents. Responses to the consultation had a near-universal view that regulation at a UK level was preferable to a voluntary approach, to avoid market distortions.
Scotland is committed to taking action on the use of domestic laundry cleaning products containing phosphates either along with other UK administrations or on a devolved basis.
Proposed actions for Scottish Government include:
- Support Defra in implementing any future measures on omitting phosphates from detergents in the UK.
- An education initiative on the effects of urban pollution including informing the public on the environmental benefit of, and promoting, the use of phosphate-free products.
8.2 Benefits of proposals
The reduction of phosphates from detergents would be a useful national measure to complement targeted measures for the water industry and agriculture, reducing phosphorus inputs from combined sewer overflows, misconnections and small treatment plants with no phosphorus treatment, and reducing costs of phosphorus removal at WWTWs.
It has been estimated that an 8% reduction in phosphorus concentrations in water bodies generally could result in around 50 water bodies improving their overall status. This measure, when combined with other controls on point and diffuse source pollution, will support overall improvements in water bodies. It will also prevent further deterioration in the water environment, especially those water bodies which may be at risk of deteriorating from good status.