40
O. Mahjoub et al.
effluents (Gharbi 2012). It is estimated that for the sanitation sector, greenhouse gas
emissions from the production and management of wastewater and sludge contribute
about 84% of the methane, while 16% is due to energy consumption related to sanitation services. Moreover, it is estimated that 0.79 million tCO 2 will be emitted
by the sanitation sector in 2020 and 0.94 million tCO 2 are expected for the year
2030. Tunisia is planning to stabilize greenhouse gas by 2050. These measures are
included under the program, “Nationally Appropriate Mitigation Action” (NAMA),
supported by Germany (Fadhel 2017). Of the existing 119 wastewater treatment
plants (WWTPs), only 30 WWTPs are supplying 31 irrigated areas with water for
agricultural reuse. Taking into account the rate of intensification, the percentage of
reuse for agricultural irrigation and municipal purposes (golf and garden irrigation)
is around 9%, while the five-year National Development Plan (2016–2020) targeted
a rate of reuse of 50%. Today, about 8100 ha of fruit trees and fodder crops, and
1490 ha of landscape (1040 ha of golf course and 450 ha of green areas) are irrigated
by secondarily treated effluent (Gharbi 2012). The regulatory framework and the
Tunisian National Quality Standards (NT 106.03) were set in 1989, and may also
have to be revised to account for actual use. In the meantime, a decree was passed
in 2018 with more relaxed standards related to the discharge of effluents in water
bodies.
In addition to agricultural reuse, aquifer recharge using reclaimed water is being
adopted to replenish depleted aquifers and to counterbalance the decline in groundwater level caused by over-pumping, especially in the coastal areas. Over-pumping
is expected to increase in the coming years due to climate change. Because of the
uneven distribution of rainfall over time and the increasing trend of extreme events,
there are seasonal excesses of surface water. The availability of treated effluents on
the supply side, including Managed Aquifer Recharge (MAR), can protect, prolong,
sustain, or augment groundwater supplies. As one of a suite of IWRM strategies,
this expands local water resources, reduces evaporation loss, and helps to replenish
depleted aquifers (Dillon et al. 2014).
In 2018, a National Action Plan on reuse was launched within the Water Partnership Program, supported by the World Bank, to promote reuse as an integral
part of water resource management in Tunisia (SCP 2017). The plan was developed
because the country has undergone several extreme events,, i.e., drought and flash
floods, between 2016 and 2018, resulting in considerable damage to the agricultural
sector and infrastructure. Indeed, the 30 main dams in the country were filled to
only 28% of capacity in November 2017, and 32% in November 2018. This water
shortage has forced the government to restrict use of irrigation water and growing
certain crops that require high water consumption (ONAGRI 2018).
Egypt has progressed in integrating wastewater reuse in its water policy. Since
the Nile provides Egypt with 97% of its agricultural irrigation requirements, a huge
amount of drainage water coming from agriculture is considered to be wastewater
and is reused indirectly by mixing it with treated and untreated domestic wastewater,
as well as with industrial effluents disposed in agricultural drainage canals (Abdel
Wahaab and Omar 2011). However, the Nile Basin is already forecast to undergo
wetter conditions and an increase of up to 4.2 °C in temperature by 2099. As of 2011,
O. Mahjoub et al.
effluents (Gharbi 2012). It is estimated that for the sanitation sector, greenhouse gas
emissions from the production and management of wastewater and sludge contribute
about 84% of the methane, while 16% is due to energy consumption related to sanitation services. Moreover, it is estimated that 0.79 million tCO 2 will be emitted
by the sanitation sector in 2020 and 0.94 million tCO 2 are expected for the year
2030. Tunisia is planning to stabilize greenhouse gas by 2050. These measures are
included under the program, “Nationally Appropriate Mitigation Action” (NAMA),
supported by Germany (Fadhel 2017). Of the existing 119 wastewater treatment
plants (WWTPs), only 30 WWTPs are supplying 31 irrigated areas with water for
agricultural reuse. Taking into account the rate of intensification, the percentage of
reuse for agricultural irrigation and municipal purposes (golf and garden irrigation)
is around 9%, while the five-year National Development Plan (2016–2020) targeted
a rate of reuse of 50%. Today, about 8100 ha of fruit trees and fodder crops, and
1490 ha of landscape (1040 ha of golf course and 450 ha of green areas) are irrigated
by secondarily treated effluent (Gharbi 2012). The regulatory framework and the
Tunisian National Quality Standards (NT 106.03) were set in 1989, and may also
have to be revised to account for actual use. In the meantime, a decree was passed
in 2018 with more relaxed standards related to the discharge of effluents in water
bodies.
In addition to agricultural reuse, aquifer recharge using reclaimed water is being
adopted to replenish depleted aquifers and to counterbalance the decline in groundwater level caused by over-pumping, especially in the coastal areas. Over-pumping
is expected to increase in the coming years due to climate change. Because of the
uneven distribution of rainfall over time and the increasing trend of extreme events,
there are seasonal excesses of surface water. The availability of treated effluents on
the supply side, including Managed Aquifer Recharge (MAR), can protect, prolong,
sustain, or augment groundwater supplies. As one of a suite of IWRM strategies,
this expands local water resources, reduces evaporation loss, and helps to replenish
depleted aquifers (Dillon et al. 2014).
In 2018, a National Action Plan on reuse was launched within the Water Partnership Program, supported by the World Bank, to promote reuse as an integral
part of water resource management in Tunisia (SCP 2017). The plan was developed
because the country has undergone several extreme events,, i.e., drought and flash
floods, between 2016 and 2018, resulting in considerable damage to the agricultural
sector and infrastructure. Indeed, the 30 main dams in the country were filled to
only 28% of capacity in November 2017, and 32% in November 2018. This water
shortage has forced the government to restrict use of irrigation water and growing
certain crops that require high water consumption (ONAGRI 2018).
Egypt has progressed in integrating wastewater reuse in its water policy. Since
the Nile provides Egypt with 97% of its agricultural irrigation requirements, a huge
amount of drainage water coming from agriculture is considered to be wastewater
and is reused indirectly by mixing it with treated and untreated domestic wastewater,
as well as with industrial effluents disposed in agricultural drainage canals (Abdel
Wahaab and Omar 2011). However, the Nile Basin is already forecast to undergo
wetter conditions and an increase of up to 4.2 °C in temperature by 2099. As of 2011,