Abstract
Wetlands are viable sinks for nitrate and have also been identified as a source of nitrous oxide, a product of two microbially regulated processes: nitrification and denitrification. Anthropogenic expansion of nitrogen is a leading cause of the eutrophication of water bodies and may also contribute to the deterioration of the ozone layer in the stratosphere. Wetlands ameliorate the quality of water percolating through them, by retaining nutrients and sequestering carbon, and simultaneously enhancing the flora and fauna diversity of these landscapes. Among the many services these wetlands provide, they also alleviate nitrate pollution by attenuating reactive nitrogen from agricultural drainage and ensure the effective reclamation of the wastewater. The literature regarding the viability of wetlands suggests a linear relationship between the removal of nitrogen and its loading rate, thereby suggesting a potential loss of nitrogen removal capacity due to the loss of wetland area. This review discusses the nitrogen removal mechanisms in existing wetlands along with the environmental variables affecting the optimum performance and management of these wetlands, in terms of greenhouse gas retention and biodiversity. Conservation of these wetlands should be contemplated to maintain the world-wide nitrogen cycle and diminish the negative repercussions of surplus nitrogen loading.
Highlights
Various aquatic ecosystems have encountered a deterioration of water quality due to surplus nutrients stacking, from both point and nonpoint sources
Lin et al [22] indicated that 4 to 11 percent of nitrogen was attenuated by wetland vegetation, while the remaining 89 to 96 percent removal was due to the process of denitrification
To improve the efficiency of nitrogen removal and ameliorate water quality in wetland systems, variables that stimulate the growth of macrophytes and certain microbes, including the concentration of dissolved oxygen, harvesting of the hydrophytes, hydraulic residence time (HRT), optimization of pH and temperature, as well as planting depth, must be scrutinized
Summary
Various aquatic ecosystems have encountered a deterioration of water quality due to surplus nutrients stacking, from both point and nonpoint sources. Numerous natural wetlands that have recently operated as wastewater disposal sites are expeditiously being altered for agricultural and infrastructure advancement, and considering the upstream treatment of wastewaters utilizing constructed wetlands is an alternative that can be exploited to establish a sustainable supply of cleansed water. Compared to conventional mechanical treatment systems, constructed wetlands productively incorporate the treatment of wastewater, as well as resource enhancement, at a cost-effective rate (60–95%). Tillage practices have been proclaimed to affect nitrate leaching to a great magnitude This nitrate leaching effect is distinctively variable, and the consequences are the highest when tillage takes place just before a high-water recharge. The significant variables that are supposed to alter the proper functioning and effectiveness of wetlands are assessed in order to identify the decisive practices for nitrogen management
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
