Waterless system without sludge production

These systems are preferred for this school context over VIPs because of their low O&M requirements relating to sludge management. They do not need mechanized emptying & transport services which often require truck movements, which is often impossible in slums due to the lack of access roads. The lack of emptying & transport augments their low O&M costs for schools, on top of their low capital requirements.

They can be used with urinals to enhance resource recovery initiatives where demand is available.

CBS systems

CBS systems have proved to be the most feasible solution for household sanitation in slum contexts, particularly in Africa, due to their flexibility. They can serve locations inaccessible to other safely managed sanitation systems. For this same reason, they have the potential to provide safely managed sanitation for schools in urban slums. Other reasons for their appropriateness in schools in urban slums are:

• CBS systems’ ability to overcome a myriad of physical/topographical challenges to provide safe sanitation;
• A low initial investment cost compared to how much constructing a latrine or flush toilet, for instance;
• Potential for retrofit-ability within existing school sanitation structures
• Opportunities for resource recovery for a school (depending on demand for the recovered resource and the possibility of combining CBS systems with urinals).

The main challenge for CBS in schools is the lack of a service scale large enough to handle typical school populations in slums. It remains to be seen whether CBS service providers can provide this service in a school setting.

However, if the above challenges are resolved, we can consider the following;

• CBS for a typical school setting in an urban slum may attract considerable O&M costs related to the frequent need for emptying where rates of container fill-up are likely to be high in a school
• While demonstrating success in household sanitation where excreta containers can be placed in the house, CBS in schools may need to be used with typical toilet structures to provide better user convenience.

Key Lessons for CBS:

• They are most useful when a school completely lacks sanitation facilities.
• Circular sanitation is crucial for sustainability where the collected excreta undergoes a valuable transformation with the resultant products used in such things as Eco-school programmes (gardens, etc.). A transformational centre is, therefore, key as well.
• At least 1 barrel of 55 litres per 5 learners for the faeces collection
• Provide sawdust or other dry mass for covering faeces.
• Provide urine collection through pipework to underground bio-sand filters or separate 20-litre jerry cans for reuse in the Eco-school programmes.
• Need for the school to be willing to cover operational costs of the CBS system which include the periodical manual collection of the faeces and maintenance of the containers.
• Ensure the containers are at the right height for ease of access by young learners.
• CBS in schools best housed inside safe and dignified structures (super and substructures).

Blackwater treatment with urine diversion

These novel urine-diverting water-based systems are suitable for schools in urban settings because they offer high contextual versatility.

Firstly, they apply to all typologies of wash-down toilet designs: pedestal or squat pan, cistern flush or pour flush, washers or wipers. Therefore, they do not require user behaviour change and are thus suitable for schools with learners from diverse cultural backgrounds. 

Secondly, they do not require emptying and transport and therefore offer low O&M costs. 

Thirdly, the majority of these systems have their backend system fitted above ground and therefore do not require excavation during installation, a huge advantage in slums where ground conditions are difficult. 

Lastly, they offer low-cost treatment with significant potential for resource recovery and can be used with urinals.

The caveat on these technologies is that they might be costly to acquire given the level of innovation involved. 

Waterless systems without sludge production

Waterless systems are best suited in rural settings because, unlike VIPs for example, they do not require emptying, transport and treatment services which are usually non-existent in rural areas. Furthermore, they still function effectively without a reliable water supply.
The fact that these systems cannot fill up means with proper maintenance, they can sustainably serve a rural school for many years without the need for new facilities, exhibiting exceptional cost-effectiveness. The resultant humic product from these systems can be applied as a soil amendment to the school’s or neighbouring community’s agricultural activities to boost farming. Urinals can be used with the systems to enhance resource recovery depending on the demand.

Biogas system

This system requires space for installation alongside other requirements such as animal manure as additional inputs to enhance gas production. These requirements make this system more appropriate for rural schools since ample space and animal farm activities are likely to be found in rural contexts. Besides, the lack of access to clean energy for cooking and lighting is more pronounced in rural areas than in urban areas of developing countries. This system plays a vital role in reducing the impacts of climate change, and while it may be capital-intensive to install, technology providers for digesters such as Sistema.bio have developed flexible financing options, albeit for household users, which if demand warrants may be applied to rural schools. Furthermore, it is not far-fetched to think about the potential of climate finance instruments for schools in this category following the recent increase in global interest in the nexus between sanitation and climate change.