Sewage Sludge Disposal: Operational and Environmental Issues
FR/R0001
Revised and Updated Dec 2002

The sewage sludge ROCK was the first title in FWR's Reviews Of Current Knowledge (ROCKs). The first edition was prepared by Alan Bruce and published in June 1999. In December 2002 it was comprehensively revised and updated by Tim Evans to take account of developments. ROCKS focus on water-environment topics that are of broad interest; they are intended to be comprehensive, authoritative and independent.

The ROCK explains why sewage sludge is an inevitable consequence of sewage treatment and how much is produced by each person. The quantity produced has increased in response to society's demand for increasing volumes to be treated and also for treating the water to higher standards. The urban drainage system serves domestic and non-domestic premises; it often carries surface drainage as well. Sewage treatment separates water from solids and sediment. Plant nutrients are separated from the water so that it is fit for release back into the aquatic environment without feeding water plants excessively because doing so would harm the quality of that environment and reduce its amenity value and the number of species it would support. Sludge comprises the remainder. The various ways in which it can be treated and used or disposed are discussed as well as the measures that can be taken to ensure no adverse environmental or health effects.

The ROCK reviews the potential benefits and hazards associated with the use or disposal of sludge. Some of the potential benefits are contributions to renewable energy, replacement of mineral fertilisers and soil structural improvement; hazards could include chemical pollutants and dissemination of disease organisms. There has been a massive amount of scientific research into these matters; the ROCK provides an objective review with 30 references and 6 suggestions for further reading.

Governments support the use of sludge on land where this is practicable and they have enacted legislation to prevent harm. Other means of use or disposal are controlled by other legislation. The ROCK reviews these controls and the succession of independent reviews to which they have been subjected.

One of the challenges for society is the communication of technical information in order that public attitudes are informed by objective information rather than swayed by miss-information and emotion. The ROCK discusses initiatives to exchange information.

Contents: 34 pages A5 format; 6 tables; 2 figures; 6 pictures; 36 references

December 2002

This report is available from the Foundation price £10.00, less 20% discount for members, or as a printable download in Adobe Acrobat pdf format.