Tunisia's National Wastewater Reuse & Groundwater Recharge Programme

Tunisia began studying treated-wastewater reuse in 1960 and launched a national reuse policy in the early 1980s, run by ONAS (Office National de l'Assainissement). The number of treatment stations grew from just 5 in 1975 to 127 by 2023, reflecting decades of steady infrastructure build-out across the country's main urban centres, including Tunis, Sousse and Sfax.
In 2024 ONAS managed 295 million m³ of wastewater, of which 72.5% met national quality standards for reuse. Of the treated volume, 64.9 million m³ (about 22%) was actually reused: 11.12 million m³ irrigated 29 agricultural perimeters covering 7,590 hectares (mainly orchards and fodder crops), 6.94 million m³ supplied 9 golf courses, and a smaller volume went to green-space irrigation. A groundwater-recharge project at Korba, in Nabeul governorate, uses treated effluent to help replenish a coastal aquifer under saline-intrusion pressure — a direct soil/aquifer nature-based mechanism alongside the irrigation reuse.
ONAS's own published figures are candid about the programme's limits: more than a quarter of treated water still fails to meet quality standards, and only about a fifth of all treated wastewater is actually put to reuse, with the rest discharged. The organisation states an explicit target of reaching 80% quality conformity through infrastructure rehabilitation. This mix of a long institutional track record with transparently reported shortfalls is reflected in the moderate rather than maximum scores below.

Read the full analysis: https://realites.com.tn/fr/eaux-usees-en-tunisie-quel-bilan-pour-lonas-en-2024/