An end to point source pollution?
Dr Paul Fogg of ADAS, the UK's largest provider of rural and environmental solutions and policy advice, and one of the UK's pioneers of biobed development explains why their use could soon be widespread.Around 40% of pesticides in water courses originates from point source pollution caused by agriculture. This is a huge problem for the water industry and agriculture, but there is a solution: biobeds. Although capable of capturing up to 99 per cent of pesticides from point source contamination, at present, there are less than 20 biobeds in use in the UK. However, imminent changes to waste regulations to include agriculture will make biobeds a far more viable option for farmers and will result in their use becoming widespread.
A little history
The early 1990s saw concerns raised about the amount of pesticide in water, a problem which was costing water companies huge amounts of money to rectify. Then, in 1998 came the Cherwell study, a study designed to identify exactly what was causing point source pollution. The study recognised on-farm pesticide use as the cause - namely the small drips and spills associated with filling sprayer and the decontamination practices performed on the same site year on year, due to the relative locations of the farm pesticide store and a clean water supply. The problem is further intensified by the fact that most farmyards are concrete, so any spilt pesticide simply runs off the surface, potentially reaching yard drains and surface water.
Set against this background and keen to avoid enforced legislation, the Crop Protection Agency brought in the Voluntary Initiative in 2001 - a series of measures designed to help reduce the problem of pesticides. The Initiative put the emphasis on spray contractors and farmers to follow best practice in water protection issues and reduce point source pollution.
So what can agriculture do to tackle this issue? Better training of sprayer operators and good machinery maintenance can reduce the number of accidental releases. However, due to time constraints and other pressures small drips and spills are still likely to occur. Direct inputs from the decontamination of tractors and sprayers, and residues that remain in the sprayer sump after infield tank rinsing are also an unavoidable feature of the spraying operation.
To supplement good handling practices contaminated run-off may be collected for subsequent treatment. One option, which has been in existence for sometime, is the Sentinel system. This is a waste water treatment facility designed for the agrochemical industry. However, the key downfalls of this system are that it is very expensive and high-tech. The other solution is the biobed.
Originally pioneered in Sweden, the biobed is a purpose-built sprayer loading and washing area designed to soak up spillages. The biobed should be lined, fitted with a drain and at least 1m deep. The surface area is determined by the volume of pesticide-contaminated run-off water and rainfall being directed through the biobed, but as a guide, 1.0sqm is required for every 1000 litres. Within the biobed is a mixture of 50% straw, 25% compost and 25% topsoil which absorbs the pesticides. A drive-over biobed system can be established, or alternatively, a filling area can be off-set from the biobed.
Apart from the fact that biobeds are almost 100 per cent effective, the other important benefit of these systems is the fact that they are relatively inexpensive and straightforward to develop. Construction costs are put at between £1500 and £3000. However, what has impeded the take-up of biobeds in this country is the lack of clear guidelines as to the acceptability of the biobed system by regulators.
Both the Scottish Environment Protection Agency and more recently the Environment Agency have issued regulatory guidance on the use of biobeds. Lined biobeds are acceptable for treating the pesticide waste and washings associated with the use of agrochemicals. However, "lined biobeds will be regarded as waste treatment systems when the Agricultural Waste Regulations are introduced. Within a year of the Agricultural Waste Regulations coming into force, the operator of existing biobeds will need to register an exemption for the biobed under the Waste Management Licensing Regulations.
This is dependent on an appropriate exemption for biobeds under the Waste Management Licensing Regulations being provided (the Environment Agency is recommending there should be). Any biobed constructed (and used) after the Agricultural Waste Regulations come into force (and before the exemption under the Waste Management Licensing Regulations is available) will not benefit from this one year transitional period and, strictly speaking, would require a waste management licence immediately. The Environment Agency is reviewing our enforcement policy for these circumstances".
The clear guidance that is now available on the use of biobeds, in particular how the Agricultural Waste Regulations are likely to impact on the use of biobeds is likely to catalyse uptake of the technology. Biobeds offer a far more viable and practicable solution, in terms of affordability and convenience, relative to other treatment systems and it is likely that biobeds will become a common feature on farms. Currently, there are very few working biobeds in the UK. However, the number of systems used in agriculture could increase dramatically which will impact positively on water pollution.
To find out more about biobeds, contact Paul Fogg on 01623 844331