Master thesis

Muhammad Muqeet Iqbal (2019)
Assessing the denitrification potential of managed aquifer recharge (MAR). Master thesis, Technische Universität Dresden, September 2019
(joint supervision with the International Groundwater Resources Assessment Center)

Abstract

Nitrate (NO₃) is a common contaminant in groundwater and surface water worldwide which has to be treated from the public water supply systems. Several techniques are already in use for the removal of nitrates such as reverse osmosis and ion exchange. However, they result in brine production and the associated capital and operational costs are usually high. One of the cheapest and effective methods for nitrate removal is denitrification in which dissolved nitrates are reduced to nitrogen gas. However, this process is time-consuming. Research has shown that Managed Aquifer Recharge (MAR) can enhance natural attenuation of nitrates by accelerating denitrification that occurs during groundwater recharge and groundwater flow. Therefore, this study aims at assessing the potential for denitrification through MAR, taking into consideration international practices for nitrate removal through MAR. Based on the literature review, an inventory of case studies was developed which identifies suitable MAR techniques and significant factors for denitrification. A conceptual model was designed for a modified infiltration basin for denitrification. Feasible sites are then identified in the Free State of Saxony using multi-criteria decision analysis. Results show that 43% of the total area of Saxony is feasible to implement the proposed design. Characterization of optimal conditions for denitrification through MAR as a nature-based solution for treating nitrates and their spatial distribution can provide a focus for future field studies and ultimately assist practitioners and policy-makers to reduce nitrate contamination in aquifers of the Free State of Saxony and in the nitrate vulnerable zones of Europe.