Sustainable sanitation
Sustainable sanitation is a sanitation system designed to meet certain criteria and to work well over the long-term. The Sustainable Sanitation Alliance includes five features in its definition of "sustainable sanitation." Systems need to be economically and socially acceptable, technically and institutionally appropriate and protect the environment and natural resources.
The purpose of sustainable sanitation is the same as sanitation in general: to protect human health. However, "sustainable sanitation" attends to all processes of the system. This includes methods of collecting, transporting, treating and the disposal of waste.
Terminology
Comparison with "improved sanitation"
The Joint Monitoring Programme for Water Supply and Sanitation of the WHO and UNICEF was responsible for monitoring progress towards the Millennium Development Goal for drinking water and sanitation. For reasons of simplicity—being able to monitor the sanitation situation with household surveys—the JMP had to find a simple differentiation between "improved" sanitation and "unimproved" sanitation.According to the JMP definition, improved sanitation facilities include facilities which are:
- not shared or public; and
- which are one of the following toilet types: flush or pour-flush to piped sewer system, septic tank or pit latrine, ventilated improved pit latrine, pit latrine with slab or a composting toilet.
- flush or pour-flush to elsewhere
- pit latrine without slab or open pit;
- bucket toilet; hanging toilet or hanging latrine, or no facilities or bush or field.
Comparison with ecosan
Sustainable sanitation, defined with the five sustainability measures, may or may not have an focus on reuse of excreta, because the criterion of "protecting the natural resources" is only one of several that need to be aimed towards. In comparison, ecological sanitation has a strong focus on the reuse of waste.Sustainability criteria
The main objective of a 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 be not only economically viable, socially acceptable, and technically and institutionally appropriate, but it should also protect the environment and the natural resources. According to the Sustainable Sanitation Alliance, when improving an existing and/or designing a new sanitation system, sustainability criteria related to the following aspects should be considered:Health
Health aspects include the risk of exposure to pathogens and hazardous substances that could affect public health at all points of the sanitation system from the toilet via the collection and treatment system to the point of reuse or disposal. The topic also covers aspects such as hygiene, nutrition and the improvement of livelihood achieved by the application of a certain sanitation system, as well as downstream effects.Environment and natural resources
Environment and natural resources aspects involve the required energy, water and other natural resources for construction, operation and maintenance of the system, as well as the potential emissions to the environment resulting from use. It also includes the degree of recycling and reuse of excreta practiced and the effects of these, for example reusing the wastewater, returning nutrients and organic material to agriculture, and the protecting of other non-renewable resources, for example through the production of renewable energy.Technology and operation
Technology and operation aspects incorporate the functionality and the ease with which the system can be constructed, operated and monitored using the available human resources. It also concerns the suitability to achieve an efficient substance flow management from a technical point of view. Furthermore, it evaluates the robustness of the system, its vulnerability towards disasters, and the flexibility and adaptability of its technical elements to the existing infrastructure, to demographic and socio-economic developments and climate change.Finance and economics
Financial and economic issues relate to the capacity of households and communities to pay for sanitation, including the construction, maintenance and depreciation of the system. Besides the evaluation of investment, operation and maintenance costs, the topic also takes into account the economic benefits that can be obtained in “productive” sanitation systems, including benefits from the production of the recyclables, employment creation, increased productivity through improved health and the reduction of environmental and public health costs.Socio-cultural and institutional aspects
Socio-cultural and institutional aspects take into account the socio-cultural acceptance and appropriateness of the system, convenience, system perceptions, gender issues and impacts on human dignity, the contribution to subsistence economies and food security, and legal and institutional aspects.Planning for sustainable sanitation
Most sanitation systems have been designed with the five aspects in mind, but in practice they are failing far too often because some of the criteria are not met. Since there is no one-for-all sanitation solution which fulfils the sustainability criteria, evaluation will depend on the local framework and will have to take into consideration the existing environmental, technical, socio-cultural and economic conditions.Some basic principles to be observed when planning and implementing a sustainable sanitation system were endorsed by the members of the Water Supply and Sanitation Collaborative Council during its 5th Global Forum in November 2000:
- Human dignity, quality of life and environmental security at household level should be at the centre of any sanitation approach.
- In line with good governance principles, decision-making should involve participation of all stakeholders, especially the consumers and providers of services.
- Waste should be considered a resource, and its management should be holistic and form part of integrated water resource, nutrient flow and waste management processes.
- The domain in which environmental sanitation problems are resolved should be kept to the minimum practicable size.
Examples
Some examples for improving present sanitation practices in the short-term, purely from a technology perspective, are listed below:- Pit latrines could be modified to be soil-composting latrines, thus requiring some wall reinforcement, made shallow and maintained using daily soil additions: the pits would be periodically closed and covered with soil in order to allow for sanitization and composting prior to emptying and reuse in agriculture.
- Simple urinals with separate collector systems could be installed instead of using toilets and pit latrines for urination
- Flush toilets could be modified to use less water or reuse greywater.
- Greywater could be source-separated from the blackwater from toilets thus simplifying its treatment and providing opportunities for reuse.
- Blackwater from toilets could be held in conservancy tanks instead of open septic tanks and cess pits and then emptied and transported to biogas reactors; alternatively the toilets could be connected to biogas reactors.
- Cess pits e.g. from pour-flush toilets could be equipped with a safety zone of additional filter material to prevent contamination of ground water.
- Above ground dry toilets with urine diversion could be installed in dry areas lacking water, rocky areas where pits are expensive to dig and areas with high water tables and flooding.