Selecting the most appropriate set of sanitation technologies for a specific context is a challenging task and requires considerable experience. The key decision criteria below aim to give the eCompendium user general guidance in the technology selection process and in the overall design of a sanitation system. The decision criteria are featured in each of the technology information sheets.
1. Phase of Emergency
Technologies are either or less appropriate depending on the phase of the emergency. As such, their suitability is characterised for the three emergency phases: Acute Response, Stabilisation, Recovery. An indication of whether or not a technology is suitable in the different emergency phases is given using asterisks (two asterisks: suitable, one asterisk: less suitable, no asterisk: unsuitable). The level of appropriateness is decided on a comparative level between the different technologies, mainly based on applicability, speed of implementation and material requirements. It is up to the eCompendium user to decide on the emergency phase for the specific situation in which he/she is working.
2. Application Level
The application level describes the different spatial levels for which the technology is most appropriate. It is subdivided into the following levels:
Household (one unit serving one up to several individual households)
Neighbourhood (one unit serving a few to several hundred households)
City (one unit serving an entire settlement, camp or district)
An indication of whether a technology is suitable at a specific spatial level is given using asterisks (two asterisks: suitable, one asterisk: less suitable, no asterisk: unsuitable). It is up to the eCompendium user to decide on the appropriate level for the specific situation in which he/she is working.
3. Management Level
The management level describes where the main responsibility for operation and maintenance (O&M) for a specific technology lies:
Household (all O & M related tasks can be managed by the individual household)
Shared (group of users are responsible for O & M by ensuring that a person or a committee is in charge on behalf of all users. Shared facilities refer to a self-defined group of users who decide who is allowed to use the facility and what their responsibilities are)
Public (government, institutional or privately run facilities: all O & M is assumed by the entity operating the facility)
An indication regarding the appropriateness of each management level is given using zero to two asterisks, with two asterisks meaning that the technology can be well handled at the respective level.
4. Objectives/Key Features
This section gives a concise indication of the main features and functions of specific technologies. It also provides general guidance for the immediate evaluation and classification of technologies and their suitability for an envisioned sanitation system or context.
5. Space Required
This section gives a qualitative estimate of the space required for each technology, meaning the area or spatial footprint required by the technology. This can help planning in areas where space is a limiting factor. Asterisks are used to indicate how much space is needed for the given technology (three asterisks: much space required, two asterisks: medium space required, and one asterisk: little space required). The categorisation is based on a comparative approach between the different technologies and not in absolute terms, e.g. a Single Pit Latrine needs little space compared to a Constructed Wetland. The space required is indicated for one typical unit and not per user. The amount of space required for each technology can heavily depend on the number of users connected to this technology and on other design criteria. For this assessment, it does not matter if a technology can be constructed underground and therefore the space above can potentially be used, e.g. an Anaerobic Baffled Reactor requires medium space, but as it can be constructed underground, part of its surface can be used for other purposes.
6. Technical Complexity
This section gives an overview of the technical complexity of each technology, meaning the level of technical expertise needed to implement, operate and maintain the given technology. This can help planning where skills and capacities are limited or temporarily unavailable. Asterisks are used to indicate the technical complexity for the given technology (three asterisks: high complexity, two asterisks: medium complexity, and one asterisk: low complexity). Low technical complexity means that no or minimal technical skills are required to implement, operate and maintain a technology. This can be done by non-professionals and artisans. Medium technical complexity means that certain skills are required for either implementation or O & M. Skilled artisans or engineers are required for the design and O & M of such a technology. High technical complexity means that an experienced expert, such as a trained engineer, is required to implement, operate and maintain a technology in a sustainable manner. The categorisation is based on a comparative approach between the different technologies and not in absolute terms, e.g. Manual Emptying and Transport is less technically complex than a Conventional Gravity Sewer.
7. Inputs/Outputs
Different technologies are required for the management of different inputs and the generation of specific outputs. Therefore, when selecting technologies, one must consider the input products that have to be dealt with and the desired output products. Through reverse engineering technologies can be selected from the end of the sanitation chain based on a desired output product. For example, if the goal of the sanitation chain is to produce compost as an end product, a technology can be selected with compost as an output product. Upstream technology components would support this goal. Keeping in mind the safety and quality of the desired output products at each step of the system helps to internalise the system approach, and supports the selection of a combination of technologies that creates end-products that can be safely used or disposed of into the environment.
Inputs refer to the products that flow into the given technology. The products shown without parentheses are the regular inputs that typically go into a technology. Products shown with parentheses represent alternatives or options of which not all are necessary, depending on the design or context. Where a product should be used in conjunction with another product, this is indicated by the plus (+). The product following the plus is mixed with the preceding product(s).
Outputs refer to the products that flow out of the given technology. The products shown without parentheses are the regular outputs that typically come out of a technology. Products in parentheses () are additional (optional) products that may or may not occur as output products, depending on the design or context. When these products occur mixed with another product, this is indicated by the plus (+). The product following the plus is mixed with the preceding product(s).
8. Design Considerations
In this section, general and key design considerations are described, including general sizing, space requirements and other features. This section does not describe the detailed design parameters to allow the complete construction of a technology, but gives an idea on dimension features to consider, the retention times, as well as the main potential pitfalls to be aware of when designing the technology. This section helps the compendium user understand the technical design and complexity of a given technology.
9. Materials
This section lists the different materials and equipment required for the construction, operation and maintenance of a given technology. It indicates whether materials are likely to be locally available or producible, e.g. wood and bricks or whether materials will need to be imported or require special manufacturing, which will considerably delay implementation during an emergency. The materials section also indicates whether a technology can be prefabricated as a unit to speed up implementation.
10. Applicability
Applicability describes the contexts in which a technology is most appropriate. This section indicates a technology’s applicability in terms of type of setting, distinguishing between rural or urban, short-term or a longer-term settlement. The section describes the phases of an emergency in which a technology can be implemented. Other physical considerations of applicability are listed here, including soil conditions required, water availability needed, ground water table considerations, etc. This section also gives information on the potential for replicability, scalability and the speed of implementation.
11. Operation and Maintenance
Every technology requires operation and maintenance (O & M), more so if it is used over a prolonged period of time. The O & M implications of each technology must be considered during initial planning. Many technologies fail due to the lack of appropriate O & M. In this section, the main operation tasks that need to be considered and the maintenance that is required to guarantee longer-term operation are listed. This section differentiates between different O & M skills and provides an indication of frequency of O & M tasks and the time required to operate and maintain a technology. A list of potential misuses and pitfalls to be aware of is also provided.
12. Health and Safety
All sanitation technologies have health and safety implications. The health implications or risks described in this section should be considered during planning to reduce health risks in the local community and among sanitation personnel and staff. The health and safety section also describes overall risk management procedures, which can lead to decisions to exclude a technology if safety cannot be guaranteed. Where relevant, the personal protective equipment needed to guarantee personal safety is listed.
13. Costs
Costs are another key decision criterion to consider. Each technology has costs associated with construction, operation, maintenance and management. In addition, each technology has cost implications for other technologies in the sanitation chain. For example, a Septic Tank will require regular desludging and therefore equipment and time is needed for the task of desludging, which is usually not accounted for in the Septic Tank. Costs are geographically dependent and are not absolute. Hence, this section presents the main cost elements associated with a technology, allowing for a first approximation.
14. Social Considerations
Social considerations are a crucial element when deciding on specific sanitation technologies, especially at the user interface level, or an entire sanitation system. There are potential cultural taboos, user preferences and habits as well as local capacities that may be challenging, impossible or inappropriate to change. A sanitation technology needs to be accepted by the users as well as the personnel operating and maintaining it.
15. Strengths and Weaknesses
This section concisely summarises main strengths and weaknesses and thereby supports the decision-making process. The weaknesses of a technology might indicate that an exclusion criterion is fulfilled and a technology is not suitable for a specific context. Both strengths and weaknesses can be effectively used to inform decisions of users and all involved in the planning and implementation of the sanitation system.
16. References and Further Readings
This section refers users to relevant publications and further reading materials related to a specific technology including a short description for each listed publication. Users can use the publication list to find additional relevant information (e.g. design guidelines, research papers, case studies) on specific technologies.
