Sustainable Sanitation
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Sustainable Sanitation

Compiled by:
Katharina Conradin (seecon international gmbh)

Sustainable sanitation recognizes that in order to be sustainable, a sanitation approach must be socially acceptable and economically viable. In this way, sustainable sanitation is a loop-based approach that differs fundamentally from the current linear concepts of wastewater management, and that does not only recognize technology, but also social, environmental and economic aspects. Sustainable sanitation is an approach that considers sanitation holistically. It recognises that human excreta and wastewater are not waste product, but a valuable resource. This view is based on the fact that wastewater and excreta contain significant amount of energy, plant nutrients and also water that can be recycled and reused, thus protecting natural resources.

Problems with Current Approaches to Sanitation

On-site sanitation systems, such as pit latrines, or septic tanks etc. do form an incomplete barrier between users and the environment. Nutrients and pathogens infiltrate and contaminate water sources, hence posing a health risks (Source: CONRADIN 2007, adapted from WERNER).

On-site sanitation systems, such as pit latrines, or septic tanks etc. do form an incomplete barrier between users and the environment. Nutrients and pathogens infiltrate and contaminate water sources, hence posing a health risks. Source: CONRADIN (2007, adapted from WERNER)

Present conventional forms of wastewater management and sanitation fall either under the category of conventional waterborne or dry (pit) systems. In both cases, the design is based on the premise that excreta are waste, and that this waste should be disposed of. It is also assumed that the environment can safely assimilate this waste. These assumptions lead to linear flows of resources and wastes and often cause severe environmental pollution (see also water pollution). The technological developments that were once designed to solve the sanitation problem have become part of the problem, not the answer to it (ESREY 2000).


Conventional Centralised Systems

Linear end-of-pipe system, mixing all different kinds of wastewater. Source: WINBLAD and ESREY 2004

Linear end-of-pipe system, mixing all different kinds of wastewater. Source: WINBLAD and ESREY (2004)

On-Site Systems

In pit systems, which are abundant in many parts of the world, the toilet does form a barrier between human beings and excreta. Yet, this barrier is incomplete. Pit latrines are mostly designed to retain solids and infiltrate liquids. When liquids infiltrate, nutrients, and worse, pathogens also infiltrate. If there are large settlements, or if the toilets are built too close to water sources, this can lead to a severe pollution of ground and surface waters, as shown above. Consequences are a high prevalence of waterborne diseases.

Also conventional waterborne systems have their drawbacks. One of the largest is probably that they are linear “end-of-pipe” systems, which are constructed on the assumption that a treatment will take place at the end of the pipe. Yet, worldwide, more than 90% of the wastewater does not receive any treatment at all (CORCORAN et al. 2010), thus polluting an even larger amount of water. There are several other important drawbacks of centralised water-based sewerage (see also water pollution). Some of the most important are: 

 

 

What is Sustainable Sanitation?

Conventional approaches to wastewater management that regard wastewater as a waste, and often are dysfunctional, have serious drawbacks (Source: CONRADIN 2010).

Conventional approaches to wastewater management that regard wastewater as a waste, and often are dysfunctional, have serious drawbacks. Source: CONRADIN (2010)

Sustainable sanitation aims at overcoming these drawbacks. It is not a certain technology, but an approach with certain underlying principles. There are a number of technologies (see for instance sanitation systems) that can be used to make sanitation and wastewater management more sustainable. The term “sustainable sanitation” in principle denominates the same as ecological sanitation, though the latter has a stronger focus on source separation.

The first and foremost principle is probably the one to recognise that excreta and wastewater are not a waste, but a valuable resource that can be reused and recycled. This is actually — to speak in a simplified way — the very basis of sustainability: to use resources wisely and without impairing the possibilities of future generations to meet their own needs.

Sustainable sanitation can be defined more precisely (adapted from SUSANA 2008):

The main objective of any sanitation system is to protect and promote human health by providing a clean environment and breaking the cycle of disease. In order to be sustainable a sanitation system has to do this, and additionally be economically viable, socially acceptable, and technically and institutionally appropriate, and it should also protect the environment and the natural resources. This implies the following criteria:

 

 

Most sanitation systems have been designed with these aspects in mind, but in practice they are failing far too often because some of the criteria are not met. In fact, there is probably no system that is absolutely sustainable. The concept of sustainability is more of a direction rather than a stage to reach. Nevertheless, it is crucial, that sanitation systems are evaluated carefully with regard to all dimensions of sustainability. Since there is no one-for-all sanitation solution, which fulfils the sustainability criteria in different circumstances to the same extent, this system evaluation will depend on the local framework and has to take into consideration existing environmental, technical, socio-cultural and economic conditions.

Taking into consideration the entire range of sustainability criteria, it is important to observe some basic principles when planning and implementing a sanitation system. These were already developed some years ago by a group of experts and were endorsed by the members of the Water Supply and Sanitation Collaborative Council as the “Bellagio Principles for Sustainable Sanitation” during its 5th Global Forum in November 2000 (EAWAG/SANDEC & WSSCC 2000):

 

  1. Human dignity, quality of life and environmental security at household level should be at the centre of any sanitation approach (see also sociocultural issues).
  2. In line with good governance principles, decision-making should involve participation of all stakeholders, especially the consumers and providers of services (see also creating an enabling environment).
  3. Waste should be considered a resource, and its management should be holistic and form part of integrated water resources, nutrient flow and waste management processes (see also IWRM).
  4. The domain in which environmental sanitation problems are resolved should be kept to the minimum practicable size (household, neighbourhood, community, town, district, catchments, and city) (see also Community Led Urban Environmental Sanitation, CLUES).

Conclusion

To summarise, sustainable sanitation is a simple approach: the most basic principle is that it considers wastewater and excreta not as a waste, but as a resource, that sanitation has to be socially acceptable and should be as economically viable as possible. There is no “one-fits-all” approach, much rather, the most adequate solution has to be found from case to case, considering climate and water availability, agricultural practices, socio-cultural preferences, affordability, safety, and technical prerequisites — just to name a few. 

References

CONRADIN, K. (2007): Ecological Sanitation in the Khuvsgul Area, Northern Mongolia: Socio-Cultural Parameters and Acceptance. Unpublished Master Thesis. Basel: University of Basel. URL [Accessed: 19.01.2011].

CORCORAN, E. (Editor); NELLEMANN, C. (Editor); BAKER, E. (Editor); BOS, R. (Editor); OSBORN, D. (Editor); SAVELLI, H. (Editor) (2010): Sick Water? The central role of wastewater management in sustainable development. A Rapid Response Assessment. United Nations Environment Programme (UNEP), UN-HABITAT, GRID-Arendal. URL [Accessed: 05.05.2010].

EAWAG (Editor); SANDEC (Editor); WSSCC (Editor) (2000): Summary Report of Bellagio Expert Consultation on Environmental Sanitation in the 21st Century. Duebendorf & Geneva: Swiss Federal Institute for Aquatic Science and Technology EAWAG & Water Supply and Sanitation Collaborative Council. URL [Accessed: 04.08.2010].

ESREY, S. A. (2000): Towards a Recycling Society. Ecological Sanitation – Closing the Loop to Food Security. In: Proceedings of the 1st Int. Symposium on Ecological Sanitation in Bonn 30th – 31st October 2000.

GALLATI, M. (2007): Ozonierung modernisiert die Abwasserreinigung. In: Schweizer Gemeinde 44, 19-20.

OTIS, R. (1996): Small diameter gravity sewers: experience in the United States. In: Low-Cost Sewerage , 123-133.

SUSANA (Editor) (2008): Towards more Sustainable Sanitation Solutions. (= Version 1). Eschborn: Sustainable Sanitation Alliance (SuSanA). URL [Accessed: 21.04.2012].

UNDP – UNITED NATION’S DEVELOPMENT PROGRAMME (Editor) (2006): Human Development Report 2006. Beyond scarcity: Power, poverty and the global water crisis. New York, Palgrave Macmillan: United Nations Development Programme (UNDP). URL [Accessed: 17.04.2012].

WINBLAD, U.; SIMPSON-HERBERT, M. (2004): Ecological Sanitation - revised and enlarged edition. (pdf presentation). Sweden: Stockholm Environment Institute. URL [Accessed: 04.08.2010].

For further readings, case studies, awareness raising material, training material, important weblinks or the related powerpoint presentation, see www.sswm.info/category/concept/sustainable-sanitation