**4. Conclusions**

The SOWATT tool was successfully used for the case of Limbe market in the city of Blantyre, Malawi. The structured decision support process involved participation of different local stakeholder groups to consider seven technology alternatives for biowaste treatment: windrow composting, in-vessel composting, vermicomposting, anaerobic digestion, slow pyrolysis, black soldier fly processing, and wet-biomass-briquetting. Together with the stakeholders, the main and sub-objectives were defined, preferences for each were elicited, and technology performances were assessed. Scores for the technology alternatives were then calculated using weights and performance indicators. The results provide an evidence base for the planning and implementation of a full-scale biowaste treatment facility at LM. The results indicate (without limiting the choice) that the most appropriate technology in this context is vermicomposting. While conducting the study, certain limitations of the process became evident: the SOWATT tool requires detailed cost and performance estimations for each of the alternatives, which, for Blantyre, proved difficult, as there was limited local evidence. Estimations had to be obtained through literature from applications in similar geographic and socio-economic conditions. Although such estimations were possible, the respondents felt insecure about how well to trust this information, as there were no local implementation experiences, and therefore they could not accurately judge how such technologies might perform in Blantyre. Going through all the steps of the SOWATT procedure in a structured way proved to be quite demanding for many of the stakeholders involved, who have very seldom been confronted with such methods of evaluation. Some stakeholders, mainly vendors, found the preference elicitation method (swing and reverse swing) to be complicated. Given this experience, we therefore sugges<sup>t</sup> that further studies are necessary to determine how to simplify the preference elicitation exercise for non-experts. In spite of the limitations, the Limbe Market study stimulated the stakeholders to think about different alternatives. Conducting the study also triggered their involvement and the debate on biowaste managemen<sup>t</sup> and gave them the opportunity to reflect on the challenges and opportunities in biowaste managemen<sup>t</sup> in Blantyre in a structured way. This assessment is also an opportunity for stakeholders to reflect on technological attributes that they might otherwise overlook when making decisions.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/2313-4321/3/4/55/s1, Table S1: The Swing Questionnaire: points given to each scenario were used in the calculation of the stakeholder's preference weight for the objective pointed by an arrow in the respective scenario; Table S2: The Reverse Swing Questionnaire: points given to each scenario were used in the calculation of the stakeholder's preference weight for the objective pointed by an arrow in the respective scenario.

**Author Contributions:** The following bullets specify the individual contributions of each author: Conceptualization: I.Z. and C.Z., E.T.; Methodology: I.Z. and C.Z.; Validation: W.M., E.T. and I.Z.; Formal Analysis: W.M. and E.T.; Investigation: W.M. and E.T.; Resources: E.T. and C.Z.; Data Curation: W.M. and E.T.; Writing-Original Draft Preparation: W.M.; Writing-Review & Editing: W.M., E.T., I.Z. and C.Z.; Visualization: W.M.; Supervision: E.T. and I.Z.; Project Administration: E.T. and C.Z.; Funding Acquisition: E.T. and C.Z.

**Funding:** This research was funded by the Swiss Agency for Development and Cooperation (grant no. 7F-04463.03.01) and Eawag: Swiss Federal Institute of Aquatic Science and Technology.

**Acknowledgments:** The study was accomplished through funding from Sandec/Eawag. Special thanks to the WASHTED Centre at University of Malawi's Polytechnic for providing intellectual support and a workstation during the study. Utmost gratitude to the BCC officials, NGO representatives (CCODE, Crown, Water for People, and Pump Aid), and market chairpersons and vendors for dedicating their time by willingly participating in the study. Special recognition and thanks to the experts from Eawag, University of Malawi, Crown Financial Ministries, Malawi Industrial Research and Technology Development Centre, Green Malata, Saunders' Estate, Sustainable Development Solutions Organisation, and other individuals for their input in the technology performance estimation phase.

**Conflicts of Interest:** The authors declare no conflict of interest.
