The appropriateness of sanitation technologies for the local context will directly influence the effectiveness and sustainability of an intervention. Appropriateness needs to be assessed through technical, geophysical, socio-cultural, financial and institutional factors as well as aspects related to skills and capacities. As well as selecting appropriate technologies along the sanitation service chain, their combination into entire systems needs to be appropriate. A wide variety of different technologies and systems exist, making rapid decision-making difficult. In the acute response, the focus is on appropriate community latrines (i.e. the user interface and on-site storage) to eliminate open defecation. Over time, the aim is to move to shared or household latrines and, when pits start filling up, to identify appropriate technologies for conveyance, treatment and safe disposal along the entire sanitation service chain.
- Assess the initial situation including the identification of the WASH practices and preferences of the user groups to be served, the geographical conditions, the existing WASH infrastructure and services in the area and the institutional and regulatory environment
- Find out what sanitation practices the target communities are used to and evaluate if these are appropriate and can be implemented
- Focus on the safe containment of faeces to protect human health in the immediate response
- Get an overview of available technologies: refer to the Compendium of Sanitation Technologies in Emergencies, Excreta Disposal in Emergencies, or Generation and Evaluation of Sanitation Options for Urban Planning
- Identify technologies that are potentially appropriate for each of the functional groups. Parts of a sanitation system may already exist and can be integrated
- Gather minimum information to check if technologies are appropriate. Include the number of users, water availability, special requirements for children, women and elderly people, space availability, soil conditions and the risk of flooding. Use simple guides and checklists such as those provided in OXFAM (2022) and Harvey (2007) or MacMahon et al. (2019)
- Move as fast as possible from open defection to using shared latrines and on-site containments appropriate for the local context (e.g. shallow or deep trench latrines)
- Consider raised latrines or container-based solutions that are water-tight if there is a risk of flooding, the groundwater table is high or the soil conditions do not allow pits
- Consider single and double pits, cesspits, twin-pits for pour-flush or septic tanks as potential water-based sanitation solutions. These technologies are designed for solid-liquid separation and require a strategy for emptying. Effluent can be infiltrated locally if there is no nearby drinking water source. If not, emptying must take place more frequently
- Consider Inclusive Design (women, children, elderly people) and socio-cultural aspects when designing latrines (‘washers’ versus ‘wipers’)
- Use urinals to reduce the volume of liquid entering on-site containments. Urine usually does not contain pathogens and hence some infiltration is acceptable
- Think about greywater and how to manage it. The aim is to keep the volume of products that are faecally contaminated as small as possible
- Consider solid waste management to avoid its disposal in the pits
- Identify Emptying and Transport technologies (as pits are filling up and desludging is required) that are appropriate for local skills and financial resources
- Take account of subsequent phases when selecting technologies for each phase and develop a corresponding Exit Strategy. Key considerations include vehicular access to on-site facilities, the availability of vehicles and, most importantly, the designation of land to accommodate treatment facilities (see also Site Planning). Communities must be involved in the selection of land as early as possible: land is expensive, locations are controversial (nobody wants to live close to a faecal sludge treatment plant) and transportation distances should be optimised
- Consider potential synergies with the sanitation systems of host communities
The type of sanitation technology and the system implemented will influence its long-term sustainability: user acceptance, availability of skills and resources for long-term Operation and Maintenance as well as long-term environmental and health protection and the potential for resource recovery.
There are various technologies that can be combined into dry or wet, on-site, decentralised or centralised systems. Using a clear framework to systematically match potential technology solutions with the relevant decision criteria makes technology selection easier. The Compendium of Sanitation Technologies in Emergencies or SaniChoice are tools that support technology identification and selection.
During the acute phase, the focus is on the user interface and on-site storage for community latrines to eliminate open defecation and contain the excreta safely. In the stabilisation phase, community latrines can be replaced by improved shared or household toilets and storage solutions. The next step is to plan and implement services for the emptying, collection, treatment and safe reuse and/or disposal of faecal sludge along the entire sanitation service chain to ensure public health and environmental protection. Greywater and Solid Waste Management should also be considered to avoid the mixing of greywater with excreta and to ensure that solid waste does not end up in pits or clog drains.
Types of sanitation technologies and systems
Sanitation systems and their associated technologies can be broadly divided into dry or water-based/wet (see also How to Select Appropriate Technologies?). Dry technologies do not use water for the transport and treatment of human excreta. Depending on the technology, they may rely on on-site storage, source separation, composting or dehydration, among others, to treat and stabilise human excreta or sludge products. They can produce valuable by-products such as compost or pit humus. Dry technologies can be particularly useful in areas where water is scarce or where water-based sanitation systems are not feasible due to geographical or environmental constraints. Wet systems instead use water for flushing and as a transport medium; they require treatment of faecal sludge or blackwater.
Sanitation systems can also be broadly divided into on-site and off-site systems (see also What Different Sanitation Systems Exist?). On-site systems allow for the storage and/or treatment and safe disposal of excreta, sludge and effluents on-site. Dry on-site storage technologies include, among others, Single Pit Latrines and Twin Pit Latrines, Ventilated Improved Pits (VIPs), Raised Latrines, Urine Diversion Dry Toilets or Container-Based Toilets. Common water-based on-site storage technologies include single or double pits, ventilated improved pits or Twin-Pits for Pour-Flush connected to e.g. a Septic Tank. For off-site systems, faecal sludge or human excreta are usually transported either using Manual or Motorised Emptying and Transport, while wastewater or blackwater are commonly transported through sewers (such as a Simplified Sewer or a Conventional Gravity Sewer). Sewers usually cost more and require large amounts of water; they are not usually relevant for a humanitarian response unless an existing system can be rehabilitated or expanded.
The sanitation service chain and sustainable sanitation
Combining technologies into entire systems builds a sanitation service chain from the user through to the final use or disposal. The sanitation service chain can be divided into five steps: the user interface (U), on-site storage and/or treatment (S), transportation or conveyance (C), treatment (T) and disposal or reuse (D) (see the table below).
In the acute response phase, the focus is always on the user interface and on-site storage and safe disposal, while the aim during the stabilisation and recovery phases is to have a full sanitation system in place. The long-term goal (beyond the humanitarian response) is to establish sustainable sanitation systems – systems that protect human health and the environment, that are technically appropriate, financially viable, socio-culturally and institutionally accepted and allow for resource recovery and reuse (SuSanA 2008).
Selecting appropriate technology and system options
The table below summarises the most common technological options as well as the key decision criteria to consider in each of the five functional groups in the three response phases. For more details on how to select locally appropriate technologies, refer to How to Select Appropriate Technologies?.
The focus of the stabilisation phase is to move from communal to shared latrines and then to household latrines. It is advisable to consider design options for the superstructure and the slab (user interface) and the pit (on-site storage) separately and to use locally available materials for each component where possible. Decisions about whether to integrate bathing units are taken in this phase and about how to deal with greywater in general. If desludging is needed, treatment focuses on safe containment and pathogen removal. In places where a system already exists but is damaged, the focus is on providing temporary emergency solutions while trying to rehabilitate the existing one. Often when the stabilisation phase is reached, there is hardly any budget remaining. Hence the best that can be achieved is simple pit latrines with household participation. However, using the table above to plan for sanitation infrastructure along the entire sanitation value chain from the beginning can support additional fund-raising or handover to other providers.
In the recovery phase, the objective is full coverage with household latrines, infrastructure and management practices along the entire sanitation chain. In this phase, the focus is on the selection of appropriate Emptying and Transport, Treatment and Safe Disposal or Use Technologies considering the Quantities of Faecal Sludge or compost/ pit humus. It is important to develop Management Plans and Financial Plans according to the locally available budget, skills, and capacities.
The development of an Exit Strategy is crucial to guarantee the services for the future. Here, it is important to consider potential synergies with host communities, space for on-site storage and off-site treatment and burial versus treatment according to commonly agreed Standards.
In some circumstances, reuse might be an option if demand exists. Simple reuse options include the application of Compost or Stabilised Sludge as soil conditioner, the Use of Stored Urine as fertiliser, pellets made from Dried Faeces for cooking stoves or controlled Irrigation with greywater of trees or other crops (see also How to Ensure Safe Disposal and Reuse?).
Excreta Disposal in Emergencies: A Field Manual
Preparing to be Unprepared - Decision Making and the Use of Guidance on Sanitation Systems and Faecal Sludge Management in the First Phase of Rapid-Onset Emergencies
Generation and Evaluation of Sanitation Options for Urban Planning: Systematic Consideration of Technology Innovations and Sustainability Criteria
Towards more Sustainable Sanitation Solutions - SuSanA Vision Document
Sani Tweaks. Best Practices in Sanitation
Decision Tree for Excreta Disposal in Refugee Camps
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