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Good practice Imported

Tunisia's National Wastewater Reuse & Groundwater Recharge Programme

Tunisia · Tunis · See the Tunisia profile · See the Tunis profile

Evidence: Observational / pre–post Top 89% 27/100 · Ask Evidence Copilot about this practice

Since the 1980s, Tunisia's ONAS has run a national programme reusing treated wastewater for irrigation and aquifer recharge; in 2024 it reused 64.9 million m³ (22% of treated volume) across 7,590 hectares and 9 golf courses, plus a groundwater-recharge pilot at Korba.

295 million m³
Wastewater managed by ONAS (2024)
72.5 %
Treated wastewater meeting reuse quality standards (2024)
64.9 (about 22% of treated volume) million m³
Treated wastewater actually reused (2024)
7,590 hectares
Agricultural area irrigated with treated effluent (2024)
5 (1975) to 127 (2023) stations
Treatment stations (1975-2023)
Tunisia's National Wastewater Reuse & Groundwater Recharge Programme

Details

Maturity
Established
Promoter
ONAS – Office National de l'Assainissement (Tunisia)
Period
1960s (pilot studies) – present; national policy since early 1980s
Keywords
wastewater treatment, agriculture, groundwater recharge

Context

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.

Activities

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.

Results

The 2024 figures show a mature, diversified reuse portfolio spanning agriculture, golf-course and green-space irrigation, and aquifer recharge, built on a 60-plus-year institutional track record.

Conclusions

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.

Implementation
Indicative cost
High (€500k–€5M) — A national infrastructure programme growing from 5 treatment stations in 1975 to 127 by 2023; no aggregate capital-cost figure is given in the source.
Time to results
Long (> 3 years) — Wastewater reuse studied from 1960; national policy launched in the early 1980s; 2024 figures represent the latest year of continuous operation.
Staffing & skills
ONAS (Office National de l'Assainissement) — national sanitation utility

Conditions for success

  • Decades of steady infrastructure build-out (5 stations in 1975 to 127 by 2023) across major urban centres
  • A national reuse policy framework in place since the early 1980s
  • Transparent self-reporting of quality and reuse metrics enabling accountability
  • A diversified reuse portfolio (agriculture, golf courses, green space, aquifer recharge) spreading demand

Common failure modes

  • More than a quarter (27.5%) of treated water still fails to meet reuse quality standards
  • Only about 22% of treated volume is actually reused, with the rest discharged
  • An explicit 80% quality-conformity target has not yet been met, pending further infrastructure rehabilitation

Where it fits

Governance type
national utility (ONAS) implementing state reuse policy
Scale
national, multiple cities plus the Korba aquifer-recharge site
Income level
lower-middle-income (Tunisia)

Commonly funded by

National / regional programmes

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Data sources

Where this practice's information was retrieved from, and when.

Attachments

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