1988

The aim of this Manual of Good Practice is to provide advice to those involved in soil injection of sewage sludge to farmland so that the operation is carried out effectively to the benefit of both the farmer and the water industry. This advice is based on research and water industry experiences and attempts to cover the wide range of operating conditions that will be encountered.

The principal reason for injecting sludge into soil is to eliminate where necessary the potential odour and visual problems associated with surface spreading. If carried out successfully there are additional benefits in that land currently barred to surface spreading, because of its proximity to housing, may become available offering potential savings in transport costs. Injection of untreated sludge may also in certain circumstances be a cheaper option than dewatering or digestion and surface spreading. Benefits to the farmer include soil loosening, control of surface run-off, better nutrient management and improved pasture hygiene.

The new DOE Code of Practice and the EC Directive on the use of sludge on agricultural land prohibit the use of untreated sludges unless incorporated as soon as possible or injected. This means that soil injection carried out according to good practices is now the only method available for applying untreated sludges to grassland.

The benefits of soil injection will not be fully realised unless due care is taken during the injection operation and this Manual of Good Practice addresses the following main aspects where special attention is required:

• Avoidance of sludge spillage
• Minimising soil and sward damage
• Maintainin sward hygiene and crop response

The Manual of Good Practice is divided into four main sections; description of equipment, general considerations aimed at eliminating sludge spillage and separate sections on specific advice for minimising sward and soil damage in grassland and arable situations.

Copies of this report are available from FWR, price £15.00, less 20% to Members.