Box 5: Integrated wastewater treatment and reuse in Tunisia
In Tunisia, most residents of large urban centres have access to various adequate sanitation systems
and wastewater treatment facilities. The sanitation coverage is 87% for all the population –
96% in the urban areas and 65% in the rural areas. Industries have to comply with the Tunisian
standards (INNORPI, 1989) prior to discharging their wastewater into the sewerage system. They
are given subsidies to equip their industrial units with pre-treatment processes. Of the 287 Mm3
of wastewater collected annually, 224 Mm3 (78%) are treated in 98 treatment plants (mainly secondary
biological treatment).
About 30-43% of the treated wastewater is used for agricultural and landscape irrigation. Reusing
wastewater for irrigation is viewed as a way to increase water resources, provide supplemental
nutrients, and protect coastal areas, water resources and sensitive receiving water bodies.
Reclaimed water is used on 8,100 ha to irrigate industrial and fodder crops, cereals, vineyards,
citrus and other fruit trees. Regulations allow the use of secondary-treated effluent on all crops
except vegetables, whether eaten raw or cooked. Regional agricultural departments supervise the
water reuse decree enforcement and collect charges (about $0.02 m3). Golf courses are also irrigated
with treated effluent.
Tunisia launched its national water reuse program in the early 1980s. Treatment and reuse needs
are combined and considered at the planning stage. Some pilot projects have been launched or
are under study for industrial use and groundwater recharge, irrigation of forests and highways
and wetlands development (Bahri, 2000). The annual volume of reclaimed water is expected to
reach 290 Mm3 in the year 2020. At that point, the expected amount of reclaimed water will then
be approximately equal to 18% of the available groundwater resources and could be used where
excessive groundwater mining is causing seawater intrusion in coastal aquifers