Project Description

2014 – 2018

Setting up a sewer network GIS for the  Greater Tunis area

Operational web-based GIS

16 900 km of sewer networks
119 treatment plants
788 pumping stations



Through this project, ONAS’s objective is to deploy a GIS in coordination with the operational information system for its business activities on the Grand Tunis area: 7 million inhabitants, 1,910,000 customers, 176 communes, 16,900 km of sewer networks, 119 treatment plants, 788 pumping stations, 263 Mm³ of waste water.

Among ONAS’s business activities are geolocation of clients, operating sanitation infrastructure, management of water quality and re-use, control of industrial waste, network maintenance, studies and projects and related activities in the social, economic and statistical domains.

To meet such requirements and scale, Altereo implements a Web-based geographic information system with an N-tier architecture.


Project Description

  • Construction of the GIS project and the data model
  • Supplying information for this model through continuous updates and upgrades through the GIS application.
  • Deeper knowledge base on network and network behaviour
  • Pedagogic and participative approach for Technical Assistance for an advanced level GIS-Sanitation project.

ONAS now has an operational Web-based GIS shared by all departements with a geolocalised and updated database of all Grand Tunis sanitation assets. The GIS is interfaced with other ONAS IT systems.

The implementation of the sewer network GIS for the Grand Tunis Area should significantly improve the waste water public service : drainage and treatment, quality of outflows to the natural environment, prevention of incidents such as obstructions and overflows which cause nuisance and pollution.