A decision support tool for selecting the optimal sewage sludge treatment

Ville Turunen, Jaana Sorvari, Anna Mikola

Research output: Contribution to journalArticleScientificpeer-review

40 Citations (Scopus)


Sewage sludge contains significant amounts of resources, such as nutrients and organic matter. At the same time, the organic contaminants (OC) found in sewage sludge are of growing concern. Consequently, in many European countries incineration is currently favored over recycling in agriculture. This study presents a Multi-Attribute Value Theory (MAVT)-based decision support tool (DST) for facilitating sludge treatment decisions. Essential decision criteria were recognized and prioritized, i.e., weighted, by experts from water
utilities. Since the fate of organic contaminants was in focus, a simple scoring method was developed to take into account their environmental risks. The final DST assigns each sludge treatment method a preference score expressing its superiority compared to alternative methods. The DST was validated by testing it with data from two Finnish municipal wastewater treatment plants (WWTP). The validation results of the first case study preferred sludge pyrolysis (preference score: 0.629) to other alternatives: composting and incineration (score 0.580, and 0.484 respectively). The preference scores were influenced by WWTP dependent factors, i.e., the operating environment and the weighting of the criteria. A lack of data emerged as the main practical limitation. Therefore, not all of the relevant criteria could be included in the value tree. More data are needed on the effects of treatment methods on the availability of nutrients, the quality of organic matter and sludge-borne OCs. Despite these shortcomings, the DST proved useful and adaptable in decision-making. It can also help achieve a more transparent, understandable and comprehensive decision-making process.
Original languageEnglish
Pages (from-to)521-529
Number of pages9
Publication statusPublished - Feb 2018
MoE publication typeA1 Journal article-refereed


  • sludge treatment
  • nutrient recycling
  • environmental risk
  • MCDA


Dive into the research topics of 'A decision support tool for selecting the optimal sewage sludge treatment'. Together they form a unique fingerprint.

Cite this