Iraq: Constructed Wetlands For Wastewater Reuse In Agriculture

Deteriorating quality and increasing scarcity of water in Iraq demands a rethink in the way wastewater is managed. We show here that a constructed wetland can assist an existing sewage treatment plan not only to be lower than actual Iraqi effluent standards, but to also meet water quality criteria for reuse in agricultural production.

Scarcity is one of several challenges to the Iraqi waters. The increasing demand from both drinking water and agriculture is overshadowed by uncertainties related to further dam construction in upstream countries. The overall aim of this study is to establish if a constructed wetland built on the available land would be sufficient to reduce the effect of wastewater effluents on the Euphrates, and meet the more stringent standards of water reuse for agriculture.

Results of a simple simulation using the actual data from operation records indicate that a 40 ha surface-water wetland would be required to bring the ca. 17,000 m3/day effluent in reach of the BOD5 and TSS water quality requirements for vegetables and fruits likely to be eaten raw.

Simulation of the effect of the constructed wetland, on daily effluent to the Euphrates River, shows a significant improvement in the capacity to meet more stringent standards. The 40 ha wetland was constructed and optimized for BOD5 and TSS removal, it would significantly help reduce eutrophication risk and bring effluent quality closer to the standards for wastewater reuse for growing vegetables and fruits likely to be eaten raw. The need to strictly adhere to existing standards and to further reduce risk of eutrophication should therefore be approached with an objective of wastewater reuse in mind. Constructed-wetlands are low-cost and effective tools already widely used for this purpose. However, they require more land then engineered solutions.