Characterization: a necessary tool in sludge management

Sludge management is one of the critical issues facing modern society due to the fast increase in its production as a result of extended sewerage, new work installations and up-grading of existing facilities. In order to (i) properly perform the utilization and disposal operations, (ii) correctly fulfil the legal requirements and (iii) build stakeholder and public confidence, it will be necessary to establish defined outlet procedures/routes and guarantee a good sludge quality. Therefore, characterization to evaluate sludge chemical, biological and physical properties is a necessary tool in sludge management. However, characterization procedures often specify different methodologies, materials and accessories; so results obtained in different places may not be fully reliable. Also comparison of the results can be problematic because they have not been obtained under standardized conditions. Consequently, the development of standardized validated characterization methods and procedures becomes necessary too. Further, the development of standardized characterization methods and procedures should be supported by the preparation of ‘guidelines’ of good practice for the different options of sludge use and disposal in order to give guidance to producers/users on how to meet legislation requirements and perform sustainable operations. In this paper the main parameters for sludge characterization are discussed and developments in European standardization outlined.