Review of the existing evaluation criteria of sanitation technologies

prepared by MSc. Christopher Buzie (christopher.buzie-fru@tuhh.de) and MSc. Leonellha Barreto Dillon (lbarreto@ttz-bremerhaven.de)

A short consideration of current approaches (criteria and models) for assessing sanitation systems will provide points of critique and consideration for identification of new criteria. For the past years different authors have identified criteria, formulated models and other schema for assessing sanitation systems. But, the variation and range of the criteria highlight the challenge of identifying effective tools for evaluating the systems. 

Some models such as Patrick Bracken et al’s Identification of Criteria for the Sustainability of Sanitation Systems (2005) and Annelies Balkema et al’s Multi-Criteria Analysis for Sustainable wastewater Treatment (2001) focus solely on using sustainability-oriented criteria for comparing and selecting technologies. Though each of them acknowledges the need for context specific criteria (knock-out criteria), both fail to provide a framework for formulating the knock-out. Their criteria include economic, environmental, technology/functional, health and socio-cultural/institutional issues.

Katherine L. Clopeck et al’s Implementation of Appropriate Household Water Purification System in Tourou, Cameroon (2006) add a new dimension to the criteria identification process by including “service” (water availability, range of precipitation) and “human resources” as separate criteria. Their eight criteria (so-called capacity factors) and the corresponding indicators provide a frame for evaluating sanitation systems. Panesar A. et al’s Concepts for Ecologically Sustainable Sanitation in Formal and Continuing Education (2006) journeys a step further by formulating holistic criteria for comparative sustainability assessment of sanitation systems.

Other existing models place emphasis on the unique profile of host communities (characteristics, opportunities and challenges) rather than technologies. Garrick Louis’ Community Assessment for Sustainable Sanitation Services in Low-Income Communities (2004) presents a model for assessing a community’s capacity to manage and sustain sanitation systems.

The above models only present lists of criteria and indicators without proposing a methodology of evaluation. However, Hellström et al. (2000) improved on this approach by proposing a set of methods for the evaluation of selected priority criteria, including:

• Health and hygiene criterion: Microbial risk assessment, to evaluate Risk for infection 
• Social and cultural criterion: Action research and assessment scales, to evaluate Acceptance 
• Environmental criteria: Life-cycle assessment, computer-based modelling, material-flow analysis, and exergy analysis to evaluate eutrophication, spreading of toxic compounds to water and to arable soil, and use of natural resources.
• Economical criterion: Cost-benefit analysis, to evaluate total cost
• Functional and technical criterion: Functional risk analysis, to evaluate robustness.

Furthermore, the World Health Organisation (WHO) suggests in its Guidelines for the Reuse of wastewater, excreta and greywater, the application of the so-called DALYs (Disease adjusted life years) as measuring instrument for health risk, together with further risk management strategies (incl. hazard barriers and health protection measure).

Although these approaches provide seemingly reliable procedure to evaluate the indicators, they are too involving (needing a lot of time and resources), and often associated with too many assumptions. It is also well known that their application is limited to specific big scale projects or some research projects. In addition, these methodologies have been subjects of criticism, as some authors including Balkema et al. (2000) questioned the applicability of Life Cycle Assessment (LCA) when analysing the sustainability of a wastewater treatment by end users and planners. According to the author, this methodology includes some subjectivity, as there is no full consensus on the environmental impact categories.

All evaluation approaches mentioned above represent without doubt a significant step in the assessment and classification of sanitation systems, as they identify and address key sustainability criteria. However, they neither suggest a methodology for evaluating the technologies nor provide a framework for formulating locally relevant criteria. Therefore, an approach grounded in these, with deeper consideration for some of the criteria, along with new criteria and indicators need to be incorporated into current models to holistically evaluate and classify conventional and innovative low cost sanitation systems.

References:

Bracken, P., Finnson, A., Kvarnström, E., Kärrman, E., Saywell, D., Ysunza, A. (2004). A definition and identification of criteria for the sustainability of sanitation systems– 5th draft. To be published within the EcoSanRes programme.

Clopeck, Katherine L. et al. (2006). Implementation of an Appropriate Household Water Purification System in Tourou, Cameroon