Wastewater Infrastructure Systems DecisiOn Matrix (WISDOM)
WISDOM: Choosing the appropriate sanitation system
The WISDOM (Wastewater Infrastructure Systems DecisiOn Matrix) project aims at developing a methodology to deal with the sanitation system (SanSys) alternative selection problem.
The SanSys alternative selection problem is a complex multiple criteria group decision making (MCGDM) problem involving a large number of potential solutions, diverse conflicting criteria and different actors such as the different authorities in relation to sanitation issues and the SanSys users.
The main characteristics of the proposed multiple criteria group
decision making (MCGDM) approach can be summarized with:
- Since the different
decision makers see the problem from different perspectives and have
different interests, it is assumed that each decision maker considers his
own set of criteria which may or may not overlap with the sets of criteria
considered by the other decision makers;
- The set of appropriate
SanSys alternatives is obtained in 3 steps:
- Determination of
potential SanSys alternatives: The definition of SanSys alternative
allows the generation of the all possible and impossible SanSys
alternatives. A newly developed compatibility assessment procedure is
then applied to determine the potential (technical possible) SanSys
alternatives. This procedure allows to identify the technical
operable alternatives and to discharge the inoperable systems.
- The compatibility
assessment is based on the compatibility matrix establishing the
compatibility relationships between the different SanSys options.
- The application of the feasibility assessment procedure allows to identify feasible SanSys alternatives among potential SanSys alternatives after eliminating infeasible SanSys alternatives. The feasibility assessment is based on a set of attributes representing the main characteristics of the SanSys application case.
- Determination of
potential SanSys alternatives: The definition of SanSys alternative
allows the generation of the all possible and impossible SanSys
alternatives. A newly developed compatibility assessment procedure is
then applied to determine the potential (technical possible) SanSys
alternatives. This procedure allows to identify the technical
operable alternatives and to discharge the inoperable systems.
- The sustainability of
SanSys alternatives is accounted for through the consideration of
criteria from the economic, environmental, social, technical, and
institutional dimensions. A generic criteria list based on the
literature and expert interviews was developed for WISDOM. In a MCGDM
procedure the follwing steps need to be performed: (i) selection of
relevant criteria for a specific application case, and (ii) the weighting
of selected criteria.
- The evaluation of SanSys
alternatives involves 2 main issues: (i) handling of the different types
of data imperfection: incompleteness, uncertainty, imprecision and
subjectivity, and (ii) choice of an appropriate evaluating methodology
such as Life Cycle Assessment (LCA), Environmental Impact Assessment
(EIA), and Open Wastewater Planning (OWP).
- The individual preferences
of each decision maker are obtained through the application of a multiple
criteria decision aid (MCDA) method.
The MCGDM WISDOM approach applies mainly to settlements where no SanSys infrastructure exists yet.
It can be adapted to applications considering the extension or upgrading of existing SanSys infrastructure provided that the necessary modifications such as the consideration of the compatibility of the new SanSys options with the existing sanitation infrastructure are considered.
Related links
For more details about the WISDOM project:
- Poster AG annual
meeting 2009 [pdf]
- Compendium of
Sanitation Systems and Technologies (Tilley et al., 2008) [pdf]
Publications
Bufardi, A., Maurer, M., Tilley, E., Truffer, B., Zurbrügg, C., A multiple criteria group decision making framework for the sanitation system alternative selection problem, Submitted.
Bufardi, A., Maurer, M., Tilley, E., Truffer, B., Zurbrügg, C., Compatibility assessment procedure for generating potential sanitation system alternatives, Submitted.
Bufardi, A., Maurer, M., Tilley, E., Truffer, B., Zurbrügg, C., Feasibility assessment procedure for generating appropriate sanitation system alternatives, Submitted.
Bufardi, A., Maurer, M., Tilley, E., Truffer, B., Zurbrügg, C., A multicriteria evaluation approach for sanitation system alternatives, Submitted.