Sanitation Learning Exchange Visit to Simplified and Decentralised Sanitation Systems in Tanzania

by James Tayler


Group photo at Mabatini pilot project, Mwanza, Tanzania.

In early February, the Water, Sanitation & Energy (WSE) Consortium of the Mukuru SPA project in Nairobi, Kenya traveled to Tanzania for a learning exchange to visit simplified and decentralised sanitation systems. The Water Sanitation and Energy consortium is one of the eight consortia, contributing to the Mukuru integrated development plan and its implementation through the development of water, sanitation and energy sectorial plan.

In readiness for this phase, the consortium planned a learning exchange visit to learn from the experience of others who have solved similar challenges. The WSE identified Tanzania as a country that has achieved significant social indicators on access to hygiene and sanitation services. Together with the host facilitators: Centre for Community Initiatives (CCI), Mwanza Urban Water Sewerage Authority (MWAUSA), Dar es Salaam Water and Sewerage Authority (DAWASA) and BORDA, the group held workshops and field visits. The learning exchange visit participants included representatives from: Nairobi City Water & Sewerage Company (NCWSC), Nairobi City County Government (NCCG), Caritas Switzerland, Akiba Mashinani Trust (AMT), Water & Sanitation for the Urban Poor (WSUP) and Sanergy.

Objectives for the learning exchange visit

The main purpose of this learning exchange visit was to:

  • increase learning and exposure on how sustainable decentralized sanitation systems have been operationalized by water utilities in informal settlements;
  • Increase the exposure of the team to sustainable sanitation options particularly decentralized sanitation systems in informal settlement;
  • learn about the successes and challenges of decentralized sanitation systems for informal settlements which will be instrumental as the WSE consortium develops the WSE sector plans for Mukuru informal settlement, Nairobi Kenya;

Field Visit to Vingunguti Simplified Sewerage System, Dar es Salaam  

The pilot project at Vingunguti was carried out by CCI & the Tanzania urban poor federation. CCI is a local based non-profit organization which supports urban poor communities with housing and shelter; community savings and credits and informal settlements upgrading. CCI has developed different approaches as interventions for the challenge of sanitation in urban areas, i.e. construction of simplified sewerage system and toilets for individual households.

Highlights of the visit:

  • The simplified sewerage system at Vingunguti is an alternative sanitation option in the informal settlement that collects all household wastewater in small diameter pipes laid at fairly flat gradients.
  • This system allows more flexible design and reduces construction and maintenance costs by up to 50% compared to a conventional system.
  • Community participation in the planning process of simplified sewerage system is a fundamental requirement to achieve higher household connection rates.
  • Meetings are carried out at the housing block level for information, discussions, and clarification required for a joint group decision on network design, community contributions during construction and maintenance responsibilities
  • Crucial to have management arrangements in place to remove blockages which are more frequent with convention sewers.
  • Simplified sewer diameters are 4inch, laid at a gradient of 1 in 200
  • Simple block or plastic chambers are used.
  • The main constrain for application is existing conservative design and construction standards linked to conventional systems.

Sanitation Workshop at Dar es Salaam Water & Sewerage Authority 

The Acting Director of Dar Es Salaam Water Supply and Sanitation Authority (DAWASA), Eng. Aaron, welcomed the participants and officially opened the workshop. The workshop main agenda was presentations from DAWASA, CCI, BORDA and WSE consortium. The presentations were followed by group discussions, questions, brainstorming and the way forward for each group present.

Highlights of the Workshop:

  • The purpose of visit by the WSE consortium, WSE consortium role in SPA and how the visit will help the consortium fulfil its mandate was discussed.
  • DAWASA shared successful approaches in provision of water and sanitation services through construction of off-grid water systems and simplified sewerage systems.
  • Discussions on how hygiene and sanitation has improved in the service areas
  • DAWASA decentralised wastewater treatment solution (DEWATS) pilot projects, the construction process, treatment process, maintenance process, community participation, and the challenges.
  • How to increase trust and create stronger relationship between public and private sector for improved sanitation services.
  • Learning about approaches to setting up transformative policy and legislation, formalizing institutional arrangements for strengthened delivery, and creating behavioural change among citizens with the involvement of the private sector.

BORDA & Mburahati site visit

BORDA welcomed the group at their office in Mikocheni, Dar Es Salaam. BORDA was founded in 1977 as non-for-profit organization in Bremen. Since 2001 BORDA exclusively facilitates a network of development cooperation that focus on providing basic need services (BNS) to disadvantaged segments of society.

BORDA is facilitating the BNS Network in Africa (Tanzania, Zambia, Lesotho, Mali and South Africa) and has played a big role in solving sanitation challenges in Tanzania through decentralized wastewater treatment system (DEWATS).

Highlights of BORDA visit:

  • DEWATS convey, treat and dispose or reuse wastewater from small communities, buildings, and dwellings in remote areas, individual, public, or private properties.
  • We learned that DEWATS protect public health and the natural environment by reducing  health and environmental hazards substantially.
  • Decentralization to the neighborhood level includes clusters of homes, gated communities, and small areas which are served by vacuum sewers.
  • DEWATS technology applies anaerobic treatment processes, including anaerobic baffled reactors and anaerobic filters, followed by aerobic treatment in ponds or  constructed wetlands.
  • DEWATS works without electric energy, is built using local materials, easy to operate and manage, water re-use and resource recovery e.g. biogas generation.


Group meeting with community members in Kilimahewa. 

Visit to Mwanza

The Mwanza Urban Water Sewerage Authority (MWAUWASA) team hosted the WSE consortium for the two days spent in Mwanza. The MD gave brief welcoming remarks and invited both teams from Kenya and MWAUWASA to share ideas around the ways that we can make our cities better in terms of improved water and sanitation services, mainly focusing on long term solutions.

MWAUWASA was established in July 1996 with legal mandate to supply portable water and sanitation services to Mwanza city. MWAUWASA has constructed two major simplified sewerage pilot projects in Kilimahewa and Mabatini area through support from government of Tanzania, UN-Habitat, and European investment bank. The two projects that started as pilot projects has now been scaled up to nine other on-going projects majorly funded by the Government of Tanzania and other donors.

Highlights of the visit:

  • The aim of the projects was to contribute to the reduction of pollution flowing into the lake by improving sustainable water supply and sanitation infrastructure in areas around the lake.
  • The densely populated informal settlements are built on granite rocks and steep slopes.
  • The sanitation program in Mwanza has provided many residents in informal settlements of Kilimahewa and Mabatini with access to sanitation through the simplified sewerage systems, as well as access to clean water
  • Before the interventions, sanitation in the areas was very poor. The residents couldn’t achieve enough depth for their latrines due to the rocky nature of the land.
  • The project has also significantly improved residents’ access to clean and safe water.
  • Noted; the aim of the project was to provide access to sanitation and clean water to the informal settlements, but it has also made accessibility of residents to their homes easier and better through the stairway up the rocky hills.
  • Community support, involvement and participation before, during and after implementation of the project, was key factor in implementation process.


The visit to simplified sanitation schemes in Dar Es Salaam and in Mwanza exposed WSE members to new and feasible options of sanitation and increased their knowledge on how wastewater can be sufficiently managed where conventional sewerage systems do not exist or are difficult to construct. Lessons learnt during the visit will contribute and advise the WSE consortium as they plan to develop the water and sanitation sector plans for Mukuru informal settlement. Lessons learnt on approaches used to promote community engagement, participation and empowerment for sustainability of these initiatives will also be considered and incorporated in the plan.