Smart Sludge Management Audit (SSMA) concept and self-auditing tool

SSMA can be used to evaluate sludge generation, treatment with different technologies and final quality, compare the results to Baltic Sea region median values and identify possible bottlenecks and issues in the operation/equipment.

Quick guide

Smart Sludge Management Audit (SSMA) concept and self-auditing tool was developed within the INTERREG Baltic Sea region (BSR) funded Interactive Water Management (IWAMA) project by the University of Tartu. The audit concept was developed and tested in cooperation with wastewater treatment plants (WWTP) in the BSR. The aim of the SSMA is to evaluate the sludge treatment process from primary/secondary sludge generation until the final usage of the treated sludge. The evaluation includes sludge generation in biological wastewater treatment process, thickening, anaerobic digestion, dewatering, biogas utilisation, further treatment processes, treated sludge quality and final use of the treated sludge. The SSMA concept has been made into a MS Excel based tool, which interested WWTP operators and other parties could use to evaluate their WWTPs without external help needed (self-auditing process).

The necessary input into SSMA can be divided into two categories:

  1. Operation parameters of the WWTP and used process and equipment;
  2. Laboratoy data of influent, wastewater after primary clarification (if used) and effluent (COD, BOD5, TN, Ptot, SS) and sludge sample analysis after final treatment step (amoun, COD, TN, Ptot, dry matter, burn residue, Cd, Pb, Cr, Cu, Zn, Ni, Hg). If some data is not available, the SSMA can still function, albeit not all results can be generated.


The results of the SSMA are shown both as figures comparing audited WWTP data to the regional collected values and as a summary table comparing achieved values to the regional median values. Short assessments are given to explain the results provided, while longer explanations are often given in a separate supporting document called "Guidlines for using the Smart Sludge Management Audit (SSMA) tool". The SSMA tool is also supported by another separate document called the "Smart Sludge Management Audit Concept and Tool", which shows the development and results from the audited WWTPs in the IWAMA project.

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