Hedieh Ahmadpari - M.Sc. Student of Irrigation and Drainage, Faculty of Aburaihan, University of Tehran
Seyyed Ebrahim Hashemi Garmdareh - Assistant Professor, Department of Irrigation and Drainage, Faculty of Aburaihan, University of Tehran
Mahmoud Mashal - Assistant Professor, Department of Irrigation and Drainage, Faculty of Aburaihan, University of Tehran
Maryam Varavipour - Assistant Professor, Department of Irrigation and Drainage, Faculty of Aburaihan, University of Tehran

There is not enough nitrate anion in the soil. Thus farmers are forced to meet the need for plants to use nitrogenfertilizers. Nitrate quickly washes out of the soil and enters through groundwater drainage system to surface water. Withthe influx of nitrogen compounds to the environment like rivers, environmental issues may occur such as nitrateaccumulation in the body tissues of aquatic organisms especially fish that disrupts the reproduction of them.Endangering human health and the incidence of diseases, eutrophication waters and algae growth. Therefore to increaseenvironmental sustainability of agricultural systems, it is necessary that management of nutrients would be targeted.Various methods are used to remove nitrate from waters. Due to the high volume of agricultural drainage water, onlybiological removal method is usable to remove nitrates from agricultural drainage water because of nitrate removalcosts in the Other methods are high. One of the possible strategies to biological denitrification is the use ofdenitrification beds. Denitrification beds are a cost-effective technology to remove nitrates from agricultural drainagewater. Denitrification beds are trenches that are filled with organic matter. These organic matter are source of energy forbacteria that converts nitrate to nitrogen gas. In fact, denitrification beds are a simple and relatively inexpensivetechnology where the carbon sources are used to facilitate denitrification. The denitrification intensity depends oncarbon sources that are used in the denitrification beds. The carbon materials that are used in denitrification beds mustbe compatible with the environment. The reaction product of this matter and nitrate should not have bad effect on thesurrounding environment and also should not be become a source of contamination in the future. Making the minimumcost associated with denitrification beds is important thus materials with longer durability must be selected that are notdestroyed during of the reaction and also the selected material should not cause disturbance to water movement. Thelaboratory studies must be done to determine the optimal of carbon materials. Finally among carbon materials, thematerials are selected that there is balance between availability and cost and also their reaction rate. Despite widespreadacceptance, there are still many unresolved issues in the long-term performance of denitrification beds that have beeneffective on reliability, ability to install and use them in large scale. This article discusses about of the importance ofusing denitrification beds. Research conducted on denitrification beds and factors affecting nitrate removal in these bedsare described and also the advantages and limitations of these beds are mentioned.

Nitrate, nutrients management, agricultural drainage water, biological denitrification, denitrification beds