scholarly journals A Literature Review of Wetland Treatment Systems Used to Treat Runoff Mixtures Containing Antibiotics and Pesticides from Urban and Agricultural Landscapes

Water ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 3631
Author(s):  
Emily R. Nottingham ◽  
Tiffany L. Messer
Keyword(s):  
Point Source ◽  
Nitrogen Removal ◽  
Nitrate Nitrogen ◽  
Agricultural Landscapes ◽  
Emerging Contaminant ◽  
Wetland Ecosystems ◽  
Contaminant Mixtures ◽  
Wetland Treatment ◽  
Removal Processes ◽  
The Impact

Wetland treatment systems are used extensively across the world to mitigate surface runoff. While wetland treatment for nitrogen mitigation has been comprehensively reviewed, the implications of common-use pesticides and antibiotics on nitrogen reduction remain relatively unreviewed. Therefore, this review seeks to comprehensively assess the removal of commonly used pesticides and antibiotics and their implications for nitrogen removal in wetland treatment systems receiving non-point source runoff from urban and agricultural landscapes. A total of 181 primary studies were identified spanning 37 countries. Most of the reviewed publications studied pesticides (n = 153) entering wetlands systems, while antibiotics (n = 29) had fewer publications. Even fewer publications reviewed the impact of influent mixtures on nitrogen removal processes in wetlands (n = 16). Removal efficiencies for antibiotics (35–100%), pesticides (−619–100%), and nitrate-nitrogen (−113–100%) varied widely across the studies, with pesticides and antibiotics impacting microbial communities, the presence and type of vegetation, timing, and hydrology in wetland ecosystems. However, implications for the nitrogen cycle were dependent on the specific emerging contaminant present. A significant knowledge gap remains in how wetland treatment systems are used to treat non-point source mixtures that contain nutrients, pesticides, and antibiotics, resulting in an unknown regarding nitrogen removal efficiency as runoff contaminant mixtures evolve.

Model-based evaluation of mechanisms and benefits of mainstream shortcut nitrogen removal processes

2015 ◽  
Vol 71 (6) ◽  
pp. 840-847 ◽  
Author(s):  
Ahmed Al-Omari ◽  
Bernhard Wett ◽  
Ingmar Nopens ◽  
Haydee De Clippeleir ◽  
Mofei Han ◽  
...  
Keyword(s):  
Nitrogen Removal ◽  
Control Strategies ◽  
Model Based ◽  
Main Challenge ◽  
Nitrite Oxidizing Bacteria ◽  
Shortcut Nitrogen Removal ◽  
Target Ratio ◽  
Removal Processes ◽  
Selection Mechanisms ◽  
The Impact

The main challenge in implementing shortcut nitrogen removal processes for mainstream wastewater treatment is the out-selection of nitrite oxidizing bacteria (NOB) to limit nitrate production. A model-based approach was utilized to simulate the impact of individual features of process control strategies to achieve NO−2-N shunt via NOB out-selection. Simulations were conducted using a two-step nitrogen removal model from the literature. Nitrogen shortcut removal processes from two case studies were modeled to illustrate the contribution of NOB out-selection mechanisms. The paper highlights a comparison between two control schemes; one was based on online measured ammonia and the other was based on a target ratio of 1 for ammonia vs. NOx (nitrate + nitrite) (AVN). Results indicated that the AVN controller possesses unique features to nitrify only that amount of nitrogen that can be denitrified, which promotes better management of incoming organics and bicarbonate for a more efficient NOB out-selection. Finally, the model was used in a scenario analysis, simulating hypothetical optimized performance of the pilot process. An estimated potential saving of 60% in carbon addition for nitrogen removal by implementing full-scale mainstream deammonification was predicted.

scholarly journals A comprehensive sensitivity and uncertainty analysis for discharge and nitrate-nitrogen loads involving multiple discrete model inputs under future changing conditions

2019 ◽  
Vol 23 (3) ◽  
pp. 1211-1244 ◽  
Author(s):  
Christoph Schürz ◽  
Brigitta Hollosi ◽  
Christoph Matulla ◽  
Alexander Pressl ◽  
Thomas Ertl ◽  
...  
Keyword(s):  
Land Use ◽  
Point Source ◽  
Case Studies ◽  
Environmental Variables ◽  
Nitrate Nitrogen ◽  
Swat Model ◽  
Sources Of Uncertainty ◽  
Environmental Systems ◽  
Model Setup ◽  
The Impact

Abstract. Environmental modeling studies aim to infer the impacts on environmental variables that are caused by natural and human-induced changes in environmental systems. Changes in environmental systems are typically implemented as discrete scenarios in environmental models to simulate environmental variables under changing conditions. The scenario development of a model input usually involves several data sources and perhaps other models, which are potential sources of uncertainty. The setup and the parametrization of the implemented environmental model are additional sources of uncertainty for the simulation of environmental variables. Yet to draw well-informed conclusions from the model simulations it is essential to identify the dominant sources of uncertainty. In impact studies in two Austrian catchments the eco-hydrological model Soil and Water Assessment Tool (SWAT) was applied to simulate discharge and nitrate-nitrogen (NO3--N) loads under future changing conditions. For both catchments the SWAT model was set up with different spatial aggregations. Non-unique model parameter sets were identified that adequately reproduced observations of discharge and NO3--N loads. We developed scenarios of future changes for land use, point source emissions, and climate and implemented the scenario realizations in the different SWAT model setups with different model parametrizations, which resulted in 7000 combinations of scenarios and model setups for both catchments. With all model combinations we simulated daily discharge and NO3--N loads at the catchment outlets. The analysis of the 7000 generated model combinations of both case studies had two main goals: (i) to identify the dominant controls on the simulation of discharge and NO3--N loads in the two case studies and (ii) to assess how the considered inputs control the simulation of discharge and NO3--N loads. To assess the impact of the input scenarios, the model setup, and the parametrization on the simulation of discharge and NO3--N loads, we employed methods of global sensitivity analysis (GSA). The uncertainties in the simulation of discharge and NO3--N loads that resulted from the 7000 SWAT model combinations were evaluated visually. We present approaches for the visualization of the simulation uncertainties that support the diagnosis of how the analyzed inputs affected the simulation of discharge and NO3--N loads. Based on the GSA we identified climate change and the model parametrization as being the most influential model inputs for the simulation of discharge and NO3--N loads in both case studies. In contrast, the impact of the model setup on the simulation of discharge and NO3--N loads was low, and the changes in land use and point source emissions were found to have the lowest impact on the simulated discharge and NO3--N loads. The visual analysis of the uncertainty bands illustrated that the deviations in precipitation of the different climate scenarios to historic records dominated the changes in simulation outputs, while the differences in air temperature showed no considerable impact.

scholarly journals A comprehensive sensitivity and uncertainty analysis for discharge and nitrate-nitrogen loads involving multiple discrete model inputs under future changing conditions

2018 ◽  
Author(s):  
Christoph Schürz ◽  
Brigitta Hollosi ◽  
Christoph Matulla ◽  
Alexander Pressl ◽  
Thomas Ertl ◽  
...  
Keyword(s):  
Land Use ◽  
Point Source ◽  
Case Studies ◽  
Environmental Variables ◽  
Visual Analysis ◽  
Nitrate Nitrogen ◽  
Swat Model ◽  
Sources Of Uncertainty ◽  
Model Setup ◽  
The Impact

Abstract. Environmental modeling studies aim to infer the impacts on environmental variables that are caused by natural and human-induced changes in environmental systems. Changes in environmental systems are typically implemented as discrete scenarios in environmental models to simulate environmental variables under changing conditions. The scenario development of a model input usually involves several data sources and perhaps other models, that are potential sources of uncertainty. The setup and the parametrization of the implemented environmental model are additional sources of uncertainty for the simulation of environmental variables. Yet, to draw well-informed conclusions from the model simulations it is essential to identify the dominant sources of uncertainty. In two Austrian impact studies the eco-hydrological model Soil and Water Assessment Tool (SWAT) was applied to simulate discharge and nitrate-nitrogen (NO3−-N) loads under future changing conditions. For both catchments the SWAT model was set up with different spatial aggregations and non-unique model parameter sets were identified that adequately reproduced observations of discharge and NO3−-N loads. We developed scenarios of future changes for land use, point source emissions, and climate and implemented the scenario realizations in the different SWAT model setups with different model parametrizations, which resulted in 7000 combinations of scenarios and model setups for both catchments. With all model combinations we simulated daily discharge and NO3−-N loads at the catchment outlets. In both case studies we employed global sensitivity analysis (GSA) to identify the impact of the scenario inputs, the model setup and the parametrization on the simulation of discharge and NO3−-N loads. We accompanied the GSA with a visual analysis of the simulation outputs and their associated uncertainties that resulted from the simulations of the 7000 SWAT model combinations. We present visualizations of the results of the GSA and the simulation uncertainty bands that proved to be powerful diagnostic tools in this study. Based on the GSA we identified climate change and the model parametrization to be the most sensitive model inputs for the simulation of discharge and NO3−-N loads in both case studies. In contrast, the impact of the model setup on the simulation of discharge and NO3−-N loads was low and the changes in land use and point source emissions were found to have the least impact on the simulated discharge and NO3−-N loads. Additionally, the visual analysis of the uncertainty bands illustrated that the precipitation of the climate scenarios dominated the changes in simulation outputs, rather than changes in air temperature in both case studies.

Enhancement of nitrogen removal in subsurface flow constructed wetlands employing a 2-stage configuration, an unsaturated zone, and recirculation

1995 ◽  
Vol 32 (3) ◽  
pp. 59-67 ◽  
Author(s):  
Kevin D. White
Keyword(s):  
Constructed Wetlands ◽  
Nitrogen Removal ◽  
Constructed Wetland ◽  
Subsurface Flow ◽  
Great Promise ◽  
Effluent Recirculation ◽  
Wetland Treatment ◽  
Subsurface Flow Constructed Wetlands ◽  
Inlet Zone ◽  
Bod Removal

Constructed wetland technology is currently evolving into an acceptable, economically competitive alternative for many wastewater treatment applications. Although showing great promise for removing carbonaceous materials from wastewater, wetland systems have not been as successful at nitrification. This is primarily due to oxygen limitations. Nitrification does occur in conventional wetland treatment systems, but typically requires long hydraulic retention times. This paper describes a study that first evaluated the capability of subsurface flow constructed wetlands to treat a high strength seafood processor wastewater and then evaluated passive aeration configurations and effluent recirculation with respect to nitrogen treatment efficiency. The first stage of a 2-stage wetland treatment system exhibited a relatively short hydraulic retention time and was designed for BOD removal only. The second stage wetland employed an unsaturated inlet zone and effluent recirculation to enhance nitrification. Results indicate that organic loading, and thus BOD removal, in the first stage wetland is key to optimal nitrification. Passive aeration through an unsaturated inlet zone and recirculation achieved up to 65-70 per cent ammonia nitrogen removal at hydraulic retention times of about 3.5 days. Inlet zone configuration and effluent recirculation is shown to enhance the nitrogen removal capability of constructed wetland treatment systems.

Nitrogen removal from wastewater treatment lagoons

1999 ◽  
Vol 39 (6) ◽  
pp. 191-198 ◽  
Author(s):  
Timothy J. Hurse ◽  
Michael A. Connor
Keyword(s):  
Wastewater Treatment ◽  
Nitrogen Removal ◽  
Treatment Plant ◽  
Ammonia Removal ◽  
Contour Plot ◽  
Removal Mechanism ◽  
Dissolved Oxygen Concentration ◽  
Physical Processes ◽  
Contour Plots ◽  
Removal Processes

In an attempt to gain a better understanding of ammonia and nitrogen removal processes in multi-pond wastewater treatment lagoons, an analysis was carried out of data obtained during regular monitoring of Lagoon 115E at the Western Treatment Plant in Melbourne. To do this, a contour plot approach was developed that enables the data to be displayed as a function of pond number and date. Superimposition of contour plots for different parameters enabled the dependence of ammonia and nitrogen removal rates on various lagoon characteristics to be readily assessed. The importance of nitrification as an ammonia removal mechanism was confirmed. Temperature, dissolved oxygen concentration and algal concentration all had a significant influence on whether or not sizeable nitrifier populations developed and persisted in lagoon waters. The analysis made it evident that a better understanding of microbial, chemical and physical processes in lagoons is needed before their nitrogen removal capabilities can be predicted with confidence.

scholarly journals Study on the Causes of Water Environmental Pollution of Important Rivers in Haihe River Basin and Countermeasures

2021 ◽  
Vol 261 ◽  
pp. 04023
Author(s):  
Xu He ◽  
Hou Siyan
Keyword(s):  
Water Quality ◽  
Point Source ◽  
Environmental Pollution ◽  
River Basin ◽  
River Regulation ◽  
Haihe River Basin ◽  
Point Source Pollution ◽  
Haihe River ◽  
The Impact

The water quality of six important rivers in Haihe River Basin, including Yongding River, Luanhe River, North Canal, Daqing River, South Canal and Chaobai River, was evaluated. The influence of point source and non-point source on water quality was analyzed. The causes of water environmental pollution in the major rivers were preliminarily revealed. The results show that the water quality of Chaobai River is good, and the impact of point source and non-point source discharge on the water body is small. Other rivers are affected by different degrees of point source and non-point source pollution. Based on the analysis results, the engineering measures and management countermeasures for river regulation are put forward.

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