Hedieh Ahmadpari - M.Sc. Student of Irrigation and Drainage, Faculty of Aburaihan, University of Tehran
Behnam Behnam Rigi Ladez - M.Sc. Student of Irrigation and Drainage, Department of Water Engineering, University of Zabol
Efat Mohamadi - M.Sc. Student of Water Resources Engineering, Department of Water Engineering, University of Zabol

Subsurface tile drainage is critical for crop production agriculture and the playability of managed, recreational turfgrass (i.e., golf courses and athletic playing fields). Tile drainage is primarily designed to rapidly convey water from a site, especially in the case of a storm event. Drainage networks rapidly, efficiently, and economically remove excess water from a site, thus permitting traffic for planting, harvest, and recreation. However, the environmental impacts attributed to subsurface drainage may outweigh the economic benefits. Identifying, testing, and implementing practices or strategies that reduce the environmental impacts of subsurface drainage are required to maintain a balance of productivity and environmental services. Discharge from subsurface tile drains is known to carry elevated levels of dissolved pollutants such as phosphor, nitrogen, and pesticides. Moreover, subsurface drainage that conveys discharge directly into streams and ponds bypasses natural and managed filter processes, including upland and riparian buffer zones. As a consequence, excess NO3‐N discharged into the Mississippi River has led to a growing hypoxic area downstream in the Gulf of Mexico. So agriculture is the most extensive source of nitrate-N to groundwater and increases in nitrate-N within shallow groundwater due to modern agricultural practices have been well documented. The efficiency of N applied and ultimately consumed by humans or livestock is generally low, with approximately 33% of all N added to agroecosystems consumed by humans or livestock, while 65% is lost to the atmosphere or aquatic ecosystems. Additionally it has been estimated that in the US, farmers typically over fertilize with N by 24 to 38%. As a result of this low efficiency, nitrate-N concentrations in shallow groundwater underneath agricultural lands exceed the maximum contaminant level (MCL = 10 mg L−1) in 19% of samples nationwide. In addition to fertilizer efficiency improvements, edge of field remediation processes can help achieve water quality standards for N. Since the nitrate is a stable and highly soluble ion with low potential for coprecipitation or adsorption. Thus conventional treatment technologies cannot be used. In this study, application of various adsorbents in nitrate removal from water it was discussed.

Tile drainage, Environmental impacts, Nitrate, conventional treatment