Reuse and Disposal of Sewage Sludge in the UK

CoronCo.on.ca/wacer/proceccing qualicy/biosolids/recyclable. 

In the case of de-watered sludge that is not stored in a container or lagoon it must be stored securely and in a way as to prevent pollution. Uncovered stockpiles will be exposed to rainfall and the decision where to locate the storage area should take into account that run-off or leachate may be produced, which could enter a watercourse or groundwater. 

The main inputs and outputs of land spreading are shown in Fig. 11.6. Inputs are related to the sludge itself, the additional resources such as petrol for transportation and application and room for storage. The main outputs are the yield improvement and fertiliser substitution. In addition, the emission of pollutants to soil, and indirect emissions to air and water. Other emissions to air are exhaust gases from transportation and application vehicles. Dried sludge may also be emitted to the air during transportation when trucks are not covered. 

Land spreading also involves the application to soil of the pollutants contained in sludge. Those pollutants undergo different transformations and transfer processes, including leaching, runoff, volatilisation, which could enable the transfer of the compounds into the air and water, and their introduction into the food chain. Disamenities may take place because of land spreading operation odour. 

Possible solutions include the use of inorganic fertilisers or imported topsoil, which can be very expensive depending on location and availability. An alternative solution is the use of organic wastes such as sewage sludge, which is already used in the UK as well as Sweden and Finland. 

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Figure 11.4 Reuse and disposal of sewage sludge in the UK between 1991 and 2004. Source http //www.environment-agency.gov.uk/.

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