Irrigation with recycled wastewater is well established in Tunisia. The Tunisian government is pursuing wastewater reuse in agriculture as a strategic objective and is translating the objective into systematic practice. A wastewater reuse policy was launched at the beginning of the eighties.

Wastewater reuse in agriculture is regulated by the 1975 Water Code (law No. 75-16 of 31 March 1975), by the 1989 Decree No. 89-1047 (28 July 1989), by the Tunisian standard for the use of treated wastewater in agriculture (NT 106- 003 of 18 May 1989), by the list of crops than can be irrigated with treated wastewater (Decision of the Minister of Agriculture of 21 June 1994) and by the list of requirements for agricultural wastewater reuse projects (Decision of 28 September 1995). They prohibit the irrigation of vegetables that might be consumed raw. Therefore, most of the recycled wastewater is used to irrigate vineyards, citrus and other trees (olives, peaches, pears, apples, pomegranates, etc.), fodder crops (alfalfa, sorghum, etc), industrial crops (cotton, tobacco, sugar beet, etc), cereals, and golf courses (Tunis, Hammamet, Sousse, and Monastir). Some hotel gardens in Jerba and Zarzis are also irrigated with recycled wastewater.

In Tunisia, regulation of wastewater reuse in agriculture mainly relies on use restrictions. For instance, it has banned irrigation with wastewater (treated or untreated) for vegetables that are eaten uncooked. The same applies for heavily used pastures. These restrictions on allowed uses are supplemented by biological and chemical sum limit values (BOD5, COD, organic substances) and limit values for nematode eggs. Tunisia continues to permit wastewater irrigation for golf links, public parks, and the like, i.e. mainly for areas and crop types that pose little risk to consumers since the plants in question are not consumed or the crops do not come into direct contact with the wastewater used.

The 1989 decree stipulates that the use of recycled wastewater must be authorized by the Minister of Agriculture, in agreement with the Minister of Environment and Land Use Planning, and the Minister of Public Health. It sets out the precautions required to protect the health of farmers and consumers, and the Environment. Monitoring the physical-chemical and biological quality of recycled wastewater and of the irrigated crops is planned: analyses of a set of physical-chemical parameters once a month, of trace elements once every 6 months, and of helminth eggs every two weeks on 24h composite samples, etc. In areas where sprinklers are used, buffer areas must be created. Direct grazing is prohibited on fields irrigated with wastewater.

Specifications determining the terms and general conditions of recycled wastewater reuse, such as the precautions that must be taken in order to prevent any contamination (workers, residential areas, consumers, etc.), have been published. The Ministries of Interior, Environment and Land Planning, Agriculture, Economy and Public Health are in charge of the implementation and enforcement of this decree. It is interesting to note that in Tunisia, the farmers pay for the treated wastewater they use to irrigate their fields.

However, in Tunisia, where the legal, technical, and political framework for reuse is relatively favorable, only 20% of treatment plant outflows are reused. The low motivation of farmers to reuse wastewater is in fact reported to be the main obstacle to increasing the current level of reused water. One of the most important reasons for this is the legal restriction concerning the use of wastewater to irrigate vegetables. Since vegetables are the most profitable and most easy-to-market crops in Tunisia, this legal restriction is sufficient to explain the slow rate of adoption by farmers.