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Create the Next Generation of Sanitation Technologies (Round 7)


What is the Challenge?

2.1 billion of the world’s urban population use non-piped (non-sewered) sanitation technologies such as latrines, cesspools, septic tanks, or aqua privies to capture and contain their excreta (fecal matter and urine). These types of sanitation “solutions” tend to be unsustainable and are often detrimental to public health. Water used for irrigation, bathing, household activities, and drinking is contaminated with sewage and excreta. Pathogens in uncontained fecal matter are spread throughout communities particularly in urban areas. The consequences for the poor are profound: an estimated 1.6 million children die each year from diarrheal diseases, many of which are caused by fecal-oral contamination.

The purpose of this call for proposals is to help make sanitation services truly safe and sustainable for the poor. Improving human waste containment and management technologies can help achieve this goal while growing and strengthening the sanitation service sector and providing employment.

The challenge focuses on developing solutions in four specific areas associated with non-networked sanitation for the urban poor:

  1. Hygienic and adequate pit/tank emptying and extraction;
  2. Recovery of energy from fecal sludge as a means for safe and affordable treatment and disposal;
  3. Appropriate sanitation solutions for areas challenged by an abundance of water (e.g. communities that face seasonal flooding, high groundwater tables, riparian or tidal communities, etc.); 
  4. Easy to clean, attractive and affordable latrine pan / squatting platform technologies that enhance latrines.

1. Fecal sludge extraction: Pit latrines and septic tanks are emptied either by manual laborers (family members, marginalized community members, or local craftsmen) or by mechanical emptying devices (vacuum pumps and tankers) when they fill up. Unsafe manual pit emptying thrives in many cities because mechanical emptying is unavailable or prohibitively expensive ($30-80 for a typical latrine). If available, mechanical equipment is often too large to access the latrines/septic tanks along narrow roads and alleys or the pumping distance is too long to perform the operation. Even when equipment can reach users, emptiers tend to evacuate the liquid waste fraction but leave the dense, difficult-to-remove solids that accumulate at the bottom of the pit.

2. Fecal sludge energy recovery: Fecal sludge tends to be a serious community liability despite the resource value available for energy recovery. The majority of evacuated fecal sludge is either dumped locally in nearby streets or drains or taken to dumping sites where little if any treatment takes place. The indiscriminate dumping of a truckload of fecal sludge is the public health equivalent of 5,000 incidences of open defecation. Fecal sludge, however, is a concentrate of organic material with high energetic value. Energy can be derived through digestion, extraction, or combustion, simultaneously reducing the volume of sludge that must be disposed.  Unfortunately, relatively few facilities are designed to recover the energy value from sludge and many existing facilities have fallen into disrepair.

3. Flooding and water challenges: The majority of the world’s population centers are located along coasts and rivers. The poorest communities in these cities, particularly in Asia, often live on marginal lands that are prone to water hazards or over water bodies directly. Those living in tidal, riparian, high water-table and otherwise flood-prone areas will face increasingly severe weather patterns as climate change progresses. Existing conventional or “alternative” sanitation options are inappropriate for these areas or are unaffordable for poor communities or poor governments. The result is severe contamination of the water resources that people rely on for their livelihoods and daily household activities. Chronic or seasonal flooding brings this contamination directly into neighborhoods and households.

4. Latrine pan/squatting pan: Most latrines (dry or pour flush) do not match the esthetic standards and preferences of users to make them desirable and attractive enough to be built in their living environment or used frequently. Current alternatives to ceramic squatting pans or platforms are designed with materials that are not desirable or easy to clean.  This can make latrines unusable after even a few usages, especially if the toilets are shared by several household members, schools pupils, or are in public toilet blocks. As a consequence, open defecation is often preferred to using existing latrines. Children, and particularly girls, do not use school facilities; public toilets fail to provide an adequate level of service for public hygiene.

What we are looking for:

We are seeking affordable, effective, and hygienic sanitation technology solutions that can improve the quality of sanitation services for the billions of people currently using non-piped sanitation systems.  We are specifically seeking proposals for technologies that address emptying; energy recovery; wet-area sanitation challenges; and an attractive, desirable, and affordable pour flush pan/ squatting platform for latrines as briefly described above.

Proposed ideas must ultimately be designed for low income urban settings such as slums, informal and formal peri-urban settings, or dense rural settings in Sub-Saharan Africa and Asia where demand for fecal sludge emptying and treatment are high.

Innovations can be new ideas or important improvements to existing solutions. Proposals must provide an underlying rationale, a testable hypothesis, and an associated plan for how the idea would be tested or validated.

We will NOT fund behavior change programming (e.g., implementation of community led total sanitation or related approaches), boutique technologies that cannot be scaled, or technologies with capital or operating requirements that are inappropriate for serving the urban poor in developing countries.

Areas for innovation to be considered include:

1. Hygienic manual or mechanical emptying equipment for urban areas. Technological solutions funded will enhance fecal sludge emptying business opportunities and improve quality and safety of service. Solutions/innovation should make emptying a hygienic activity with low operation and maintenance costs that allow emptying fees to be affordable to urban poor ($5-20 per latrine). Solutions should allow easy extraction of the consolidated heavy sludge accumulated in dry latrines or at the bottom of septic tanks. An advanced solution may allow safe filtration/separation of the solids fraction of fecal sludge in situ during an emptying operation. Ideally sludge transported to a designated disposal/processing site should have a high solids concentration.

Solutions should aim to meet as many of the following conditions as possible:  

  • Increases the number of pits than can be emptied per day;
  • Provides hygienic protection of the operator;
  • Allows for easy navigation and operation in narrow lanes;
  • Can be operated by maximum 2 persons;
  • Sludge can be safely emptied into receptacle suitable for at least 5-15 km of transport;
  • Removes heavy sludge/debris from the bottom of latrines/septic tanks;
  • Mechanical equipment should aim to access latrines as far as 50m away;
  • Separates solids/liquids in situ (i.e. dewatering);
  • Allows for potential on-site or “en route” treatment of evacuated liquids and/or solids for safe local disposal;
  • Based on affordable, robust, and locally available components.

2. Sludge processing for community energy generation in urban areas. Technology solutions funded will process sludge in a manner that generates energy that is ready to use for communities at a decentralized scale (bloc to district level) and that eliminates the contamination of remaining effluents and/or solids.

Solutions should aim to meet as many of the following conditions as possible:  

  • Low lifecycle costs, robust, and locally available components;
  • Easy to operate, maintain, and service during productive life;
  • Small land/space footprint at point of production and short processing/retention times (include quantitative estimates);
  • Capable of processing highly variable sludge inflow qualities and quantities;
  • Addresses odor nuisance;
  • High rate of sludge elimination, energy conversion efficiency, and effluent decontamination in the energy production process (proposals should include quantitative estimates);
  • Value of energy product generated should aim to cover operating costs of technology employed at a minimum (proposals should include quantitative estimates); 
  • Energy end-product should be market and user friendly and not require expensive or new investments at the point of use;
  • Relevant for low-security settings;
  • Safety / backup mechanism in the case of system failure;
  • Proposals must explicitly and quantitatively articulate expected advantages of the proposed work relative to existing energy recovery technologies in the field.

3. Appropriate sanitation solutions for flooded zones (e.g. communities that face seasonal flooding, high groundwater tables, riparian or tidal communities, floating communities, etc.). Technologies should improve upon or develop new sanitation technologies that cope with wet-environment conditions.

Solutions should aim to meet as many of the following conditions as possible: 

  • Prevent infiltration from surface and/or groundwater;
  • Provide robust and safe containment during heavy rain and flood events;
  • Function in tidal, riparian, or floating communities;
  • Low lifecycle costs, robust, and locally available components;
  • Easy to operate, maintain, and service during productive life; 
  • Incorporate user-centered design elements that are appropriate for women, children, and “washer” communities and that are affordable for the ultra-poor (<$1/day);
  • Proposals should articulate clearly how the innovation improves upon existing technologies for these areas in terms of reduced cost, increased community/user appropriateness, increased robustness, or other critical factors;
  • Proposals should articulate clearly the type of water-challenged environment being targeted (e.g. tidal, seasonal flooding, etc.);
  • Individual excreta bagging solutions will not be considered for this call.

4. Easy cleaning, and affordable pan / squatting platform, suitable for connection to an offset pit. Attractive technologies that enhance latrine cleanliness and that have one or more of the following features:

  • Easy to clean and smooth;
  • Attractive and offering a user experience and desirability similar to a ceramic pan;
  • Able to be mass produced;
  • Light weight and robust;
  • Durable; 
  • Affordable.

Grants will be selected on ability to create impact in the context of The Bill & Melinda Gates Foundation’s existing global health priorities. For more information on these priority global health conditions, please click here.

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