European developments in standardisation of sludge physical parameters.

Characterisation is an important step in sludge management as it allows sludge properties to be evaluated and behaviour predicted. This is well recognised by the European Union (EU) countries which consider necessary the development of standardised sludge characterisation methods and procedures because objective and transparent regulations allow sludge management to be properly performed, legal requirements correctly fulfilled, and public confidence built. To this end, the European Committee for Standardization (CEN) established the Technical Committee 308 (TC308) whose scope is the production of Standards for sludge characterisation, and of Guides of good practice. In this field, physical properties are of great importance as they allow the prediction of sludge behaviour when handled and submitted to almost all treatment and utilisation/disposal operations. Activity of CEN/TC308 is developed in three Working Groups (WG) and several Task Groups (TG); in particular, TG3 of WG1 deals with physical parameters. In this paper developments regarding Standards for evaluation of capillary suction time, specific resistance to filtration, compressibility, settleability, thickenability, and calorific value, and Technical Reports dealing with a procedure for laboratory chemical conditioning and with sludge consistency (flowability/solidity) are briefly outlined. The results of relevant inter-laboratory tests for the validation of above standards are summarised.