This paper presents the innovative emergency Sanitation Operation System (eSOS) concept created to improve the entire emergency sanitation chain and provide decent sanitation to people in need. The eSOS kit is described including its components: eSOS smart toilets, an intelligent excreta collection vehicle-tracking system, a decentralized excreta treatment facility, an emergency sanitation coordination center, and an integrated eSOS communication and management system. The paper further deals with costs and the eSOS business model, its challenges, applicability and relevance. The first application, currently taking place in the Philippines will bring valuable insights on the future of the eSOS smart toilet. It is expected that eSOS will bring changes to traditional disaster relief management.


In general, an emergency can be considered to be the result of a man-made and/or natural disaster, whereby there is a serious, often sudden, threat to the health of the affected community which has great difficulty in coping without external assistance. Emergency sanitation intervention is a means of promoting best management practice in order to create a safer environment and minimize the spread of disease in disaster-affected areas, and of controlling and managing excreta, wastewater, solid waste, medical waste, and dead bodies. In June 2012, an international emergency sanitation conference was hosted by UNESCO-IHE in Delft where more than 200 experts from relief agencies, governments, academia and industry gathered, and discussed emergency excreta management and public health. It was confirmed that (i) emergency-specific sanitation is not at the forefront of the scientific community, (ii) current solutions are in most cases technologically and economically suboptimal, (iii) there is, in general, insufficient communication between key stakeholders, (iv) academia and practitioners are insufficiently involved, (v) emergency sanitation (technological) development is often associated with drivers such as humanitarian aid agencies or the army, (vi) emergency water supply is given much more attention than sanitation, and (vii) the smart innovative emergency sanitation management (and governance) system is lacking. This concept aims to address these deficiencies and provide sustainable, innovative, holistic, and affordable sanitation solutions for emergencies (such as floods, tsunamis, volcano eruptions, earthquakes, wars, etc.) before, during, and after disaster.


The abbreviation eSOS stands for the innovative ‘emergency Sanitation Operation System’ concept (Brdjanovic et al. 2013). This concept addresses the entire emergency sanitation chain (Figure 1). It is based on a balanced blend of innovative sanitation solutions and existing information technologies adapted to the specific conditions of emergency situations and in informal settlements. The central points of the system are the reinvented smart emergency toilet and the innovative decentralized treatment of excreta, embedded in an intelligent emergency sanitation operation system. Information and communication technologies have a unique opportunity to assist following disasters because the core of any emergency management effort is integration, sharing, communication, and collaboration, things that stakeholders involved embrace and promote.

Figure 1

eSOS concept components.

Figure 1

eSOS concept components.


The eSOS is based on different system components integrated into an easily deployable emergency sanitation kit consisting of hardware and software components. The software components include the communication chain by controlling the mobile network and the Local Area Network (LAN)/Wide Area Network (WAN) simultaneously. The routing application supports receiving data messages – from General Packet Radio Service networks and the SMS channel – from large quantities of Global System for Mobile Communications (GSM) and Code Division Multiple Access (a radio channel access method) units at the same time. Alternatively, a non-GSM-based system can be applied for disaster sites which are not covered by a GSM network (e.g. remote refugee camps) or are temporarily without GSM coverage due to a disastrous natural event. In addition, a portable navigation system is used to supplement excreta collection vehicle-tracking. Geographic Information System maps and data as well as other interactive and public domain information are used and combined into this integral eSOS, such as digital orthophotography, digital terrain maps, land-use maps, sanitary points of interest, and population density maps. It is all combined in user-friendly software with an intuitive graphic interface to allow rapid advance to expert user level.

The components of the eSOS are smart toilets, intelligent excreta collection vehicle-tracking systems, decentralized excreta treatment facilities, emergency sanitation coordination centers, and integrated eSOS communication and management systems.

eSOS® smart toilets

Sanitation facilities usually provided by relief agencies and armies have additional specifications and requirements in comparison to those regularly used in other settings. The smart eSOS toilets have the following characteristics: they are stackable and lightweight, fit a Euro-size pallet, are made of durable materials, are easy to wash and clean, are easy to empty, require minimum maintenance, are raised above the ground, do not require any excavation to install, allow more frequent use, provide excellent value for money, are easy and safe to use, provide privacy, are easily deployable, give a sense of dignity to users, look great and invite usage, etc.

Beside these aspects, the eSOS concept addresses the ‘smartness’ of the emergency sanitation toilet by incorporating unique (either as ‘built-in’ or ‘add-on’) features such as: interchangeable squatting pans or sitting toilet, delivered as a urine diversion dry toilet or flush toilet, safe and easy-to-empty storage of urine and feces, fully solar-powered with up to 7 days energy independency, GSM-based communication, GPS-based tracking, real-time information on occupancy, volume of urine collected, volume of service water and gray water and UV interior disinfection, nano-coated interior, smart card reader entry system, SOS panic button, smart software for monitoring, data collection and optimization, etc.

Beside smart data collection and communication, the eSOS toilet is subject to technological innovations from the sanitary engineering perspective. It is a urine diversion toilet with separate collection (and treatment) of urine and feces, with both ‘dry’ and ‘wet’ sanitation options. It is important to note that the eSOS toilet is not designed as an on-site treatment unit due to its high-frequency use and limited storage capacity. The rule of thumb applied by relief agencies of a maximum of 50 users per day will be evaluated during field testing and verified later by data gathered from eSOS toilets to be installed worldwide operating under different conditions. At the moment the capacities of the urine tank and feces tank in one unit is 200 and 80 L, respectively. This arrangement will be revised after experimental testing. It allows for an emptying interval of individual units of about once a week for a ‘dry’ toilet. In case the ‘community’ type of arrangement is applied (several toilets in a cluster), a common larger storage tank will replace individual units allowing for significantly larger storage, more frequent use and less frequent emptying. Longer retention times and ongoing processes in stored feces and urine will be taken into account in the design of such clustered applications at a later stage of the development of the eSOS system. Of course, the situation will change in the case where continuous or intermittent water supply system and sewer system are available where the ‘wet’ option may well be applied. As the urine tank makes up part of the toilet body, it will be possible to empty it only on-site by gravity or by a vacuum truck. For feces evacuation, several emptying options will be possible: by vacuum truck, by replacing a full tank with an empty one, and by several ways of emptying the tank manually on-site (e.g. there is an analogy with vacuum cleaner bags).

Owing to specific emergency requirements, its innovative light-weight, stackable toilet structure is proposed to be made of recycled biodegradable materials (like bio-plastic made from potato skins). Options for both on-site and centralized treatment (and their combination) of urine and fecal sludge is also investigated. Packed, a complete toilet kit occupies a volume of 2 m3 which will allow for compact and cheaper shipping (a toilet fits to one standard pallet). Owing to its modular set-up, it will be possible to quickly and simply install the toilet on the spot. Simplified instructions on how to install and use the toilet will be provided with the kit. Each part of the toilet is unique and can only be assembled in one way so as to avoid confusion. In the near future, possibilities to produce toilets locally shall be explored, also using local materials. However, in general it will not be possible to produce these toilets at the disaster location. The present version of the toilet allows for its usage by both children and adults and women and men. In addition, several variations of the eSOS toilet will be produced in a later stage of development to account for different settings and conditions and user groups including elderly citizens, people with disabilities and the injured.

Development of the eSOS smart toilet is carried out in two steps, namely: design, manufacturing, and field testing of the ‘experimental toilet’ (Figure 2) and based on the feedback from field testing and relief practitioners, the ‘design vision toilet prototype’ (Figure 3) will be manufactured. Currently, the experimental eSOS toilet is being tested at a disaster site in Tacloban City in the Philippines. During several months of testing, an extensive research program is being executed; it is expected to reveal novel information on the use of a toilet in an emergency setting and to enable useful information to be obtained that can be further correlated and used (in combination with additional sensors) for medical/health services.

Figure 2

eSOS smart experimental toilet awaiting shipment to the Philippines for field testing. The toilet's structure and electronic features have been subject to extensive testing during the manufacturing phase (photo: D. Brdjanovic; drawings: FLEX/the INNOVATIONLAB).

Figure 2

eSOS smart experimental toilet awaiting shipment to the Philippines for field testing. The toilet's structure and electronic features have been subject to extensive testing during the manufacturing phase (photo: D. Brdjanovic; drawings: FLEX/the INNOVATIONLAB).

Figure 3

eSOS smart toilet design vision prototype (images: FLEX/the INNOVATIONLAB).

Figure 3

eSOS smart toilet design vision prototype (images: FLEX/the INNOVATIONLAB).

Intelligent excreta collection vehicles tracking system

In emergency situations, due to high traffic and load to toilets, frequent emptying (of relatively fresh urine and feces) is required, which consequently creates demand for well-organized logistics for excreta collection, a feature which is regularly lacking during, by definition, rather chaotic emergency circumstances. As an emergency may last for days, months, and sometimes years, the issue of excreta management and logistics becomes extremely important in sustaining the emergency sanitation chain. For example, in the first few months after the 2010 earthquake disaster in Haiti, the costs for de-sludging toilets and latrines exceeded USD 0.5 M. The eSOS envisages the use of GPS- (or satellite-) based communication infrastructure; e.g. a real-time GPS vehicle-tracking system, where each truck and/or each trailer/cistern will be equipped with ‘easy-to-install’ GSM/GPS sensor/card (similar to those supplied with or to eSOS toilets), which will allow 24/7 information of the position (and route) of each toilet-emptying vehicle. This information will ‘feed’ the advanced, commercially available, vehicle-tracking system, and software and on-board location-based analysis, which will process data and provide much useful information (e.g. route optimizer, total amount of urine and feces collected per day, disposal location, etc.) to the user in the emergency sanitation coordination center. Efforts will be made to create the possibility to rapidly update the navigation maps with the most recent information regarding the disaster event (accessibility of roads, bridges, tunnels, etc.) and isolate sections with limited or no traffic, most likely based on physical site inspection with the eventual support of updated satellite images that can be purchased on demand as an add-on feature of the integrated eSOS.

Excreta treatment facility

Three distinctive emergency sanitation phases are generally adopted in the work of relief agencies, namely: (i) phase 1 of duration up to 2 weeks, where the main mean for sanitation provision is individual, mass-production, inexpensive kits (like biodegradable PeePoo bags), (ii) phase 2, lasting up to a few months, where substantial sanitation hardware components are supplied to the disaster site (like individual portable toilets or clusters of those, and de-sludging equipment and vehicles), and (iii) phase 3, which can last from several months up to a few years or longer where more (semi)permanent sanitation hardware is supplied such as community-based toilets and (mobile) excreta treatment facilities (more sophisticated package/containerized plants or, sometimes, on-site/land-based simplified solutions). Comparatively much higher load (increased usage per toilet), consequent requirements for more frequent emptying, and different fecal sludge characteristics (fresh biologically non-stabilized sludge and fresh non-hydrolyzed urine, with higher public health risk), are distinctive, but often overlooked features of emergency sanitation. Therefore, the current management practices in emergency sanitation need a thorough revision and re-thinking, especially from the treatment perspective, as to this aspect ‘the business as usual’ approach is applied, often not being fully aware of specific technological and social key issues of concern. Although many standard options for fecal sludge management in general already exist, their application in emergency situations is not well understood and is often lacking. To address these deficiencies, we shall conceptualize, design, manufacture, test and apply on a pilot scale an innovative, compact, and efficient treatment of emergency sanitation fecal sludge, including (separate) treatment of urine, by physical–chemical treatment-based technologies (e.g. microwave technology and/or dewatering/drying) with specific attention on public health (epidemiologic) aspects and safe disposal of treatment residuals (Figure 4). For the emergency sanitation, also due to economies of scale, it is more appropriate to apply treatment solutions in decentralized on-site settings, rather than solving the excreta issue at the level of individual toilets. However, the decentralized technology being developed here is equally applicable (with some modifications) at small scales as well. After initial testing in the Netherlands, the installation will be subject to field testing in Kenya using excrement collected from the slums of Nairobi.

Figure 4

eSOS® excreta treatment concept.

Figure 4

eSOS® excreta treatment concept.

Emergency sanitation coordination center

The emergency sanitation coordination center is the heart of eSOS concept, and should be located either on-site or at any remote location outside the disaster area. It has a high degree of automation and requires an operator/coordinator. For the immediate response, and if no skilled operator is available, remote operation is possible by an expert operator located outside the disaster area. The coordination center will be equipped with the central information processing unit (laptop or tablet) which will contain all necessary software and will receive and process all relevant information for the eSOS in the cloud. If on-site, the center will be responsible for physically inspecting and verifying some of the key information collected by remote sensing and making sure that the correct information is used (e.g. accessibility of roads and correct location of existing sanitary infrastructure used in emergency, like sanitary landfill, (decentralized wastewater treatment plant, empty industrial storage tanks, and in extreme cases, temporary discharge points to open environment, etc.).


Based on information, such as population density maps or real-time population tracking using mobile telephony and other information automatically acquired from the disaster area, in combination with the user-entered information, the operator will have a rather good understanding of where to position the emergency aids. The number of sanitation units deployed will be initially determined using rules of thumb (e.g. up to 50 people per toilet per day), but the application of eSOS will very soon provide practical feedback on these rules as much more (new) data will become available. In addition, based on the existing population density and real-time information on the population migration using mobile telephone signals, the optimal locations (density) of available sanitation units (Pee-Poo bags, for example, for the immediate response, followed by the supply of emergency toilets) will also be determined. In the case of pre-fabricated eSOS toilets, they will automatically report their location to the central system (coordination center) and will appear on the interactive disaster area map as such. In cases, where the toilet is not equipped with an eSOS kit, it can easily be retrofitted by rapid installation of the necessary sensors and electronic equipment. Also, already existing units can be upgraded with this equipment, so that the entire emergency sanitation facilities are tagged and included in the network.

The second step is to equip the excreta collection vehicles with the tracking electronic and navigation equipment. This can be done very easily and quickly by installing the removable equipment preferably inside the driver's cabin.

The third step is to mobilize the central data collection and processing unit with all the required software necessary for the operation of the eSOS and to ensure that the Internet connection or access to a cloud computing/server facility via a satellite connection is available.

After the system is up and running, the operator can use all above-described features to apply the eSOS in a rapid, more efficient, and economic fashion, with increased confidence. The eSOS system is designed as a stand-alone application, refined at the operator's emergency center. It enables the definition of the required procedure for each stage in an emergency and to react to every call within the shortest period of time. It also enables the local operator to define the unit's parameters according to both the customer's and local network demands and to create (daily, weekly, monthly) reports with statistics and performance indicators.

The authors and funding agencies plan to disseminate all useful feedback from the upcoming practical applications in a separate paper(s) and through other methods of communication. These will soon after be translated into a user manual or operational guide as a part of the eSOS emergency kit.


The current conceptual state of the development of the system does not yet allow being accurate where the costs are concerned for the following reasons. The costs and benefits will depend on many factors where the production and operations costs combined with the location-specific conditions and scale of disaster and number of people affected/served will determine the total financial picture. As both emergencies and disasters have a high degree of uncertainty associated with them and since disasters can strike anywhere in the world at any given moment and given that emergencies have different characteristics and phases, it makes the current application of standard sanitation financial models inadequate and only remotely accurate and useful. Therefore, as a part of the eSOS concept, the development of a holistic business model is demanded and is currently being developed with extended boundaries to capture aspects traditionally difficult to estimate (thus often neglected) but essential to such an assessment, such as costs (and benefits) related to public health (hospitalization, absence from work, productivity, temporary or permanent disability and casualties, quality of life, dignity, safety, etc.). The model will be interactive, adaptable to local conditions and specifics of emergency sanitation, and will also include costs for production (e.g. rotational molds, materials, ‘add-ons’, labor, etc.), costs for storage, transport and erection, costs for operation and maintenance, and costs for eventual deployment, depreciation, etc. It is expected that in the majority of emergency situations the additional unconventional features and elements of the system and associated costs will be at least compensated for if not overwhelmed by the benefits that such a system can bring. The new eSOS business model will include feedback from major relief agencies and all other key players in emergency relief, will also include demonstrations with detailed costs analyses, and will be verified on several case studies that shall provide more confidence in using it. The business model will be in the public domain.


The eSOS confirms the rule that one involved in the process of moving from invention to innovation faces a number of challenges such as how to make a product which will match its purpose at an affordable price with maximized benefits. The eSOS components are designed to satisfy specific requirements of relief operations regarding materials, durability, resistance to theft and misuse, demands of users, environmental and public health, cultural and social features of societies, and must also be attractive to people so that they make use of it in the first place. Expectedly, the eSOS concept cannot possibly be a solution for each and every emergency situation and its future will depend on acceptance, affordability, effectiveness and efficiency of operations, and the extent to which the limitations will be overcome by further development and incorporation of the feedback from practical applications.


The strength of eSOS is that it is addressing, improving, and making each component of the emergency sanitation chain smarter, taking care that innovations also take place at the level of the system. The eSOS system is globally applicable to a wide spectrum of emergency situations where external aid is needed for sanitation. The eSOS concept, with minor adaptations, can be made equally suitable for, but is not limited to (i) sanitation management under challenging conditions usually prevailing in urban-poor areas, such as slums and informal settlements, (ii) sanitation provision for visitors of major open-air events such as concerts, fairs, etc., and (iii) solid waste management.

So far, initial constructive and in general encouraging feedback from several parties, including the United Nations Children's Fund (UNICEF), United Nations Refugee Agency (UNHCR), Red Cross, Oxfam, Save the Children, Doctors without Borders (MSF) and OPEC Fund for International Development (OFID), has already been received. It is planned to have key players in relief provision more actively involved in the further development of the eSOS system. Part of the research in the Philippines and other locations will provide us with lessons and answers on how to ensure the uptake of the system. At the moment, the framework for how to commercialize the eSOS and build a business case for the new eSOS enterprise is drafted. It will also include important aspects such as after-sales services that will be very much dependent on the type of emergency, local conditions, culture, emergency setting, etc. The fate of eSOS in a post-disaster period will also be considered. If the life returns to ‘normal’ and original infrastructure is recovered, the eSOS can be cleaned, dismantled and reused elsewhere as the system allows for it. In the case where new (semi)organized settlements are created, like refugee camps, the eSOS may remain there, given that a proper governance system and the business case are in place to make it sustainable, making the eSOS of more permanent character. In the case, where the eSOS is used for non-emergency situations (events, etc.); it will be reused. In the case of its use in informal settlements (slums), it will be of permanent character. Present design takes care as much as possible that the system is theft proof (the comment on theft and costs of eSOS came up often in social media).

The potential clients/end-users are relief agencies, municipalities, water and sewerage companies, solid waste companies, army, police, fire brigades, as well as private sector companies and water supply, and sanitation vendors. The primary goal of eSOS is to save lives by providing an efficient and effective sanitation service during and after emergencies through minimizing the risk to public health of the most vulnerable members of society. The secondary goal is to reduce the investment, operation, and maintenance costs of emergency sanitation facilities and service as a pre-requisite for sustainable solutions, especially in the post-emergency period.


The innovative eSOS concept provides a sustainable, innovative, holistic, and affordable sanitation solution for emergencies before, during, and after disasters. eSOS does not only reinvent the (emergency) toilet and treatment facilities, but uses existing information and communication technology to bring innovation and potential cost savings to the entire sanitation operation and management chain, and most importantly, is expected to improve the quality of life of people in need.


The eSOS® concept is developed under the project ‘Stimulating local innovation on sanitation for the urban poor in Sub-Saharan Africa and South-East Asia’ financed by the Bill & Melinda Gates Foundation. The eSOS® smart toilet design concept is a joint effort of UNESCO-IHE, FLEX/the INNOVATIONLAB and SYSTECH. The first eSOS smart toilet testing in the Philippines is supported by the Asian Development Bank and Bill & Melinda Gates Foundation. The eSOS® concept is an invention of UNESCO-IHE Institute for Water Education.


P. M.
Y. P.
H. A.
C. M.
eSOS® – innovative emergency sanitation concept
. In:
Proceedings: 3rd IWA Development Congress and Exhibition
Nairobi, Kenya