Key vocabulary & definitions:
- DAWASA: Dar es Salaam Water and Sanitation Authority
- Connection box: connects between a latrine and the network
- Junction box: connects pipes in the route
- Latrine: a toilet
The network team comprises 5 members, all volunteers of Kite DSM: 4 final year students (all studying Environmental Engineering) and a second year student, studying Water Resources and Irrigation Engineering.
This is the first year there have been no UK volunteers working on the simplified sewerage network team: this area of the project is being handed over completely to the Tanzanian team.
Vingunguti is an administrative ward in the Ilala district of Dar es Salaam, Tanzania. According to a 2012 census, the population of Vingunguti is 106,946. Nearly all the settlements in Vingunguti are informal and the area is largely dependent on pit latrines. CDI works in an area close to the Spenco waste settlement ponds.
These waste settlement ponds are the exit points for the sewage from our simplified sewerage routes. Waste from industry and households throughout the city is also treated here.
The concept: Simplified Sewerage
Simplified sewerage is a widely used sanitation technology throughout Pakistan and Brazil. It is based on the idea that conventional sewerage systems are overly conservative in many of their design features, and therefore unnecessarily expensive and technically complex. Traditional sewerage systems haven’t been able to keep up with the phenomenal rate at which informal settlements like Vingunguti are growing, and would be impossible to retrospectively install around the unplanned housing layout. Simplified sewerage uses smaller diameter pipes than conventional sewerage systems. These pipes are placed at shallower depths, reducing the required excavation volume as well as the cost and complexity of repairs.
In previous years, a new simplified sewerage route was constructed every summer. The first route was built in 2014. CDI have facilitated the construction of a further three routes.
The plan for this year:
The network construction team’s aims for this summer are to facilitate the construction of a further ten latrines and to connect them into existing network routes from previous years, in order to continue satisfying demand from the community. Beyond the summer, the team plans to continue facilitating the construction and connection of more latrines into the pre-existing network routes.
So far, surveys have been conducted to identify the number of houses which will be joined to the network, the number of people served and the technical complexity of each connection to the existing route. The team will carry out design work of the new connections, supervise construction (which will be contracted out to local technicians) and conduct maintenance due to operational failures.
The team is also in charge of collating documents for a proposal to DAWASA. A large part of this is preparing a budget estimate to submit to DAWASA for funding. At the end of the summer, when the latrines are finished, the total actual spending will be calculated and DAWASA reimbursed for any initial overestimation. However, the application to DAWASA is to fund the central network pipes and junction boxes only – the cost of the latrine construction will be paid back by the households in the route. This financing model will be explored further in the Spotlight on Community Engagement.
The goal is for an “alumni team” to be formed from up to four graduates of the network team and one graduate from the community engagement team. The importance of the alumni team lies in the rapidity of expansion: at the moment, network expansion happens at about 10 to 15 new connections each year, as the team only works for 2 months during the summer. However, a dedicated year-round network team will enable the rate of expansion to increase significantly, allowing more community members to gain access to safe and affordable sanitation in the near future.