Nitrogen Mass Balance and Pressure Impact Model Applied to an Urban Aquifer

Abstract

The assurance of drinking water supply is one of the biggest emerging global challenges, especially in urban areas. In this respect, groundwater and its management in the urban environment are gaining importance. This paper presents the modeling of nitrogen load from the leaky sewer system and from agriculture and the impact of this pressure on the groundwater quality (nitrate concentration) in the urban aquifer located beneath the City of Ljubljana. The estimated total nitrogen load in the model area of 58 km2 is 334 ton/year, 38% arising from the leaky sewer system and 62% from agriculture. This load was used as input into the groundwater solute transport model to simulate the distribution of nitrate concentration in the aquifer. The modeled nitrate concentrations at the observation locations were found to be on average slightly lower (2.7 mg/L) than observed, and in general reflected the observed contamination pattern. The ability of the presented model to relate and quantify the impact of pressures from different contamination sources on groundwater quality can be beneficially used for the planning and optimization of groundwater management measures for the improvement of groundwater quality.

Multi-Methodological Integrated Approach for the Assessment of Diffuse Pollution Background Levels (DPBLs) in Functional Urban Areas: The PCE Case in Milano NW Sector

“…techniques have been applied in several studies for the assessment of groundwater quality, for the analysis of groundwater geochemistry and identification of sources (Reimann and Filzmoser, 2000;Yu et al, 2014;Acikel and Ekmekci, 2018;Adhikari and Mal, 2019;Stefania et al, 2019); numerical transport models have been applied for trace main plumes for management of groundwater, remediation, and mitigation strategies (El Bouqdaoui and Aachib, 2018;Colombo et al, 2019;Guo et al, 2019;Sathe and Mahanta, 2019;Janža et al, 2020); geostatistical analysis has been applied to map some environmental variables and contamination zoning (Guadagnini et al, 2020;Hossain and Patra, 2020). Moreover, previous works mainly focused on NBLs (Matschullat et al, 2000;Molinari et al, 2012;Ducci et al, 2016;Sellerino et al, 2019) of groundwater contaminants.…”

Contaminant Trends in Urban Groundwater: Case Study from Ljubljana (Central Slovenia)

“…It mainly originates from agricultural runoff due to the excessive use of mineral and organic nitrogen fertilisers and animal manure in rural areas [30][31][32][33][34][35]. However, in urban areas, losses from sewerage systems, industrial wastewater and leachate from landfills can also contribute significantly to contamination [4,10,36,37]. Pesticides, on the other hand, have a negative impact on around 6.5% of groundwater bodies in the EU-27 region [29].…”

“…Any contamination should be kept in a downward trend, and any upward trend of new emerging synthetic organic compounds should be detected and stopped at much lower concentrations than the actual water quality standard, in the range between the limit of detection (LOD) and the limit of quantification (LOQ). The data set presented in this paper considers all available data, regardless of their different sources and time periods, and captures the transition from the era of the "nitrate and atrazine dispersed pollution" paradigm [3][4][5] to the contemporary challenges posed by "emerging organic synthetic pollutants and multipoint pollution sources" [6][7][8].…”

Assessment of Shallow Groundwater Purification Processes after the Construction of a Municipal Sewerage Network

“…Numerous studies show that, in addition to industrial and agricultural activity, one of the most significant sources of pollution is municipal wastewater, the treatment and cleaning of which is often unresolved in developing and developed countries alike [11][12][13]. In the more developed urban environment, wastewater exfiltration from the sewer system poses a threat to the subsurface water resources [14].…”