Joint analyses of nitrate transit time distributions and legacy effects in catchments with contrasting physical settings in Germany

2020 ◽  
Author(s):  
Sophie Ehrhardt ◽  
Andreas Musolff ◽  
Michael Weber ◽  
Pia Ebeling ◽  
Rohini Kumar
Keyword(s):  
Waste Water Treatment ◽  
Organic N ◽  
Time Lags ◽  
Topographic Wetness Index ◽  
N Budget ◽  
Temporal Dimension ◽  
N Accumulation ◽  
Federal States ◽  
Wide Range ◽  
N Input

<p>Increased anthropogenic inputs of nitrogen (N) to the biosphere during the last decades have resulted in increased groundwater and surface water concentrations of N (primarily as nitrate), posing a global problem. Although measures have been implemented to reduce N inputs, they have rarely led to decreasing riverine nitrate concentrations and loads. This limited response to the measures can either be caused by the accumulation of organic N in the soils (biogeochemical legacy) –or by long travel times (TTs) of inorganic N to the streams (hydrological legacy). Both legacy types determine the temporal dimension of catchment response on the one hand and the quantitative dimension on the other hand.</p><p>Here we analyze several decades of N input, water quality and discharge observations from 62 catchments in 8 federal states in Germany. The selection of catchments represents a wide range of land use, geology and soils, topography and hydroclimate. In an input-output assessment, N input from atmospheric deposition, waste water treatment and agriculture is compared with riverine N concentrations (nitrate-N) as N output. We assess jointly the N budget and the effective TTs of N through the soil and groundwater compartments. In combination with long-term trajectories of the C–Q relationships, we evaluate the potential for and the characteristics of an N legacy.</p><p>Our data-driven approach shows a mean legacy of 73 % (spanning 0 – 90 %), cumulating to a total missing mass of 4270 kg N/ha a. Log-normal distributed TTs have a mean of 6 years (0.8 – 34 years) with an R<sup>2</sup> of 89 % between the convolved N input and N output. Due to the chemostatic export regime (mean CV<sub>C</sub>/CV<sub>Q</sub>: 0.36 < 0.5) and relatively short TTs in most of the catchments, the biogeochemical legacy seems to dominate the catchment responses nowadays. Further analyses aim to investigate the controlling parameters determining the N time lags and legacies type. A correlation analyses hint to topographic parameters, mainly slope and topographic wetness index, as main controls of the legacy i.e. that flat catchments have the tendency to higher legacies or retention.</p><p>Legacies of almost ¾ of the N input pose a challenge to the limited denitrification potential of soils and aquifers or indicate a massive N accumulation in the catchment. Latter can cause elevated N concentrations for the next decades explaining at the same time a limited response to measures. The dominant biogeochemical legacy suggests that management needs to address both a longer-term reduction of N inputs and shorter-term mitigation of past high N loads by favoring denitrification.</p>

Assessing Nitrogen Legacies in Western Europe

2021 ◽  
Author(s):  
Andreas Musolff ◽  
Sophie Ehrhardt ◽  
Rémi Dupas ◽  
Rohini Kumar ◽  
Pia Ebeling ◽  
...  
Keyword(s):  
Time Series ◽  
Agricultural Land ◽  
Time Lags ◽  
Water Safety ◽  
Biological Fixation ◽  
Nitrogen Inputs ◽  
Wide Range ◽  
N Input ◽  
Nitrate Concentrations ◽  
Input Time

<p>Intensive agricultural land use have introduced vast quantities of nutrients such as reactive nitrogen (N) to soils and subsequently to groundwater and surface waters. High nitrate concentrations are still a pressing issue for drinking water safety and aquatic ecosystem health e.g. in Europe, although fertilizer inputs have been significantly lowered in the last decades. This is partly due to a slow response of riverine nitrate concentrations to changes in nitrogen inputs attributed to N legacies in catchments. N can be stored organically bound as a biogeochemical legacy in soils or can be slowly transported as nitrate in groundwater forming a hydrologic legacy. Legacy can thus lead to a net retention of N in catchments and to substantial time lags in the response to input changes. Here, we systematically explore legacy effects over a wide range of catchment in the Western European countries France and Germany. We are making use of long observational time series of nitrate concentration in 238 catchments covering 40% of the total area of France and Germany. We apply a Weighted Regression on Time, Discharge, and Season (WRTDS) to derive continuous daily flow-normalized concentrations and loads. The temporal pattern of concentration and loads at the catchment outlet is compared to the N input time series evolving from agricultural N surplus, atmospheric deposition and biological fixation. We found that on long-term catchments retain on average 72% of the N input. Time lags between input and output were successfully explained by a lognormal transport time distribution. The modes of these distributions were found to be rather short with a median mode of 5.4 years across all catchments. Based on this data-driven assessment only the fate of N in the catchments is hard to assess as denitrification in soil and groundwater can lead to similar observations as the storage of N in legacies. Focusing on the mobile part of N that is exported by catchments, we estimate that a substantial amount of N is still stored in the subsurface that will be released in the coming years. We therefore analyzed how catchment nitrate export will evolve under the scenario of a total cut down, reduced or constant future N inputs. We report the expected timescale of reaction to implemented measures to help tackling this pressing water quality problem.</p>

scholarly journals Trajectories of nitrate input and output in three nested catchments along a land use gradient

2019 ◽  
Vol 23 (9) ◽  
pp. 3503-3524 ◽  
Author(s):  
Sophie Ehrhardt ◽  
Rohini Kumar ◽  
Jan H. Fleckenstein ◽  
Sabine Attinger ◽  
Andreas Musolff
Keyword(s):  
Land Use ◽  
Low Flow ◽  
Organic N ◽  
Catchment Management ◽  
N Fixation ◽  
Time Lags ◽  
Input And Output ◽  
N Input ◽  
Nitrate Concentrations

Abstract. Increased anthropogenic inputs of nitrogen (N) to the biosphere during the last few decades have resulted in increased groundwater and surface water concentrations of N (primarily as nitrate), posing a global problem. Although measures have been implemented to reduce N inputs, they have not always led to decreasing riverine nitrate concentrations and loads. This limited response to the measures can either be caused by the accumulation of organic N in the soils (biogeochemical legacy) – or by long travel times (TTs) of inorganic N to the streams (hydrological legacy). Here, we compare atmospheric and agricultural N inputs with long-term observations (1970–2016) of riverine nitrate concentrations and loads in a central German mesoscale catchment with three nested subcatchments of increasing agricultural land use. Based on a data-driven approach, we assess jointly the N budget and the effective TTs of N through the soil and groundwater compartments. In combination with long-term trajectories of the C–Q relationships, we evaluate the potential for and the characteristics of an N legacy. We show that in the 40-year-long observation period, the catchment (270 km2) with 60 % agricultural area received an N input of 53 437 t, while it exported 6592 t, indicating an overall retention of 88 %. Removal of N by denitrification could not sufficiently explain this imbalance. Log-normal travel time distributions (TTDs) that link the N input history to the riverine export differed seasonally, with modes spanning 7–22 years and the mean TTs being systematically shorter during the high-flow season as compared to low-flow conditions. Systematic shifts in the C–Q relationships were noticed over time that could be attributed to strong changes in N inputs resulting from agricultural intensification before 1989, the break-down of East German agriculture after 1989 and the seasonal differences in TTs. A chemostatic export regime of nitrate was only found after several years of stabilized N inputs. The changes in C–Q relationships suggest a dominance of the hydrological N legacy over the biogeochemical N fixation in the soils, as we expected to observe a stronger and even increasing dampening of the riverine N concentrations after sustained high N inputs. Our analyses reveal an imbalance between N input and output, long time-lags and a lack of significant denitrification in the catchment. All these suggest that catchment management needs to address both a longer-term reduction of N inputs and shorter-term mitigation of today's high N loads. The latter may be covered by interventions triggering denitrification, such as hedgerows around agricultural fields, riparian buffers zones or constructed wetlands. Further joint analyses of N budgets and TTs covering a higher variety of catchments will provide a deeper insight into N trajectories and their controlling parameters.

scholarly journals Decadal trajectories of nitrate input and output in three nested catchments along a land use gradient

2018 ◽  
Author(s):  
Sophie Ehrhardt ◽  
Rohini Kumar ◽  
Jan H. Fleckenstein ◽  
Sabine Attinger ◽  
Andreas Musolff
Keyword(s):  
Land Use ◽  
Agricultural Land ◽  
Organic N ◽  
Agricultural Land Use ◽  
Catchment Management ◽  
Time Lags ◽  
Travel Times ◽  
N Input ◽  
Nitrate Concentrations

Abstract. Increased anthropogenic inputs of nitrogen (N) to the biosphere during the last decades have resulted in increased groundwater and surface water concentrations of N (primarily as nitrate) posing a global problem. Although measures have been implemented to reduce N-inputs especially from agricultural sources, they have not always led to decreasing riverine nitrate concentrations and loads. The limited response to the measures can either be caused by the accumulation of slowly mineralized organic N in the soils acting as a biogeochemical legacy or by long travel times (TTs) of inorganic N to the streams forming a hydrological legacy. Both types of legacy are hard to distinguish from the TTs and N budgets alone. Here we jointly analyze atmospheric and agricultural N inputs with long-term observations of nitrate concentrations and discharge in a mesoscale catchment in Central Germany. For three nested sub-catchments with increasing agricultural land use, we assess the catchment scale N budget, the effective TT of N. In combination with long-term trajectories of C-Q relationships we finally evaluate the potential for and the characteristics of an N-legacy. We show that in the 42-year-long observation period, the catchment received an N-input of 42 758 t, of which 97 % derived from agricultural sources. The riverine N-export sums up to 6 592 t indicating that the catchment retained 85 % of the N-input. Removal of N by denitrification could not fully explain this imbalance. Log-normal travel time distributions (TTD) for N that link the input history to the riverine export differed seasonally, with modes spanning 8–17 years. Under low-flow conditions, TTs were found to be systematically longer than during high discharges. Systematic shifts in the C-Q relationships could be attributed to significant changes in N-inputs resulting from agricultural intensification and the break-down of the East German agriculture after 1989 and to the longer travel times of nitrate during low flows compared to high flows. A chemostatic export regime of nitrate was only found after several years of stabilized N-inputs. We explain these observations by the vertical migration of the N-input and the seasonally changing contribution of subsurface flow paths with differing ages and thus differing N-loads. The changes in C-Q relationships suggest a dominance of hydrological N-legacy rather than a biogeochemical N-fixation in the soils, which should result in a stronger and even increasing dampening of riverine N-concentrations after sustained high N-inputs. Despite the strong N-legacy, a chemostatic nitrate export regime is not necessarily a persistent endpoint of intense agricultural land use, but rather depends on a steady replenishment of the mass of N propagating through the catchments subsurface. The input-output imbalance, the long time-lags and the lack of significant denitrification in the catchment let us conclude that catchment management needs to address both, a longer-term reduction of N-inputs and shorter-term mitigation of today’s high N-loads.

Stirring and aeration system for the upgrading of small waste water treatment plants

1994 ◽  
Vol 29 (12) ◽  
pp. 149-156 ◽  
Author(s):  
Marcus Höfken ◽  
Katharina Zähringer ◽  
Franz Bischof
Keyword(s):  
Waste Water ◽  
Water Treatment ◽  
Large Scale ◽  
Waste Water Treatment ◽  
Water Treatment Plants ◽  
Waste Water Treatment Plants ◽  
Basic Fluid ◽  
Aeration System ◽  
Technical Realization ◽  
Wide Range

A novel agitating system has been developed which allows for individual or combined operation of stirring and aeration processes. Basic fluid mechanical considerations led to the innovative hyperboloid design of the stirrer body, which ensures high efficiencies in the stirring and the aeration mode, gentle circulation with low shear forces, excellent controllability, and a wide range of applications. This paper presents the basic considerations which led to the operating principle, the technical realization of the system and experimental results in a large-scale plant. The characteristics of the system and the differences to other stirring and aeration systems are illustrated. Details of the technical realization are shown, which conform to the specific demands of applications in the biological treatment of waste water. Special regard is given to applications in the upgrading of small compact waste water treatment plants.

Danube River Basin: Progress with the Environmental Programme

1999 ◽  
Vol 40 (10) ◽  
pp. 1-8 ◽  
Author(s):  
T. Botterweg ◽  
D. W. Rodda
Keyword(s):  
River Basin ◽  
Action Plan ◽  
Waste Water Treatment ◽  
Warning System ◽  
Danube River ◽  
The Black Sea ◽  
Research Activity ◽  
Global Environment Facility ◽  
Major Activity ◽  
Wide Range

An Internationally funded Programme, involving the European Commission, the Global Environment Facility managed by UN Development Programme, the World Bank and the European Bank for Reconstruction and Development, is addressing river basin problems in a unique situation. The solution of these should lead to the prevention of pollution and better water quality, protected ecosystems, sustainable water resources and more efficient sewerage and waste water treatment facilities for the 90 million population living in the region and the reduction of pollution impact on the Black Sea into which the Danube River flows. The paper introduces current Programme activities, the challenges being met and progress. Work is described for implementing a monitoring strategy, an accident emergency warning system and implementation of the 1994 Strategic Action Plan. The applied research activity is explained. The Programme is a major activity with many elements addressing a wide range of environmental problems in the catchment of a major international waterway.

The EU as an “enforcement patchwork”: the impact of national enforcement for compliance with EU water law in Spain and Britain

2013 ◽  
Vol 34 (2) ◽  
pp. 331-353 ◽  
Author(s):  
Mónica García Quesada
Keyword(s):  
Waste Water Treatment ◽  
National Level ◽  
State Level ◽  
Detailed Examination ◽  
Deterrent Effect ◽  
Eu Law ◽  
Wide Range ◽  
The Uk ◽  
The Impact ◽  
The Eu

AbstractFailures of compliance with European Union (EU) directives have revealed the EU as a political system capable of enacting laws in a wide range of different policy areas, but facing difficulties to ensure their actual implementation. Although the EU relies on national enforcement agencies to ensure compliance with the EU legislation, there is scarce analysis of the differential deterrent effect of national enforcement in EU law compliance. This article examines the enforcement of an EU water directive, the Urban Waste Water Treatment Directive, in Spain and the UK. It focuses on the existing national sanctions for disciplining actors in charge of complying with EU requirements, and on the actual use of punitive sanctions. The analysis shows that a more comprehensive and active disciplinary regime at the national level contributes to explain a higher degree of compliance with EU law. The article calls for a detailed examination of the national administrative and criminal sanction system for a more comprehensive understanding of the incentives and disincentives to comply with EU law at the national state level.

Dynamics of nitrogen and dry-matter partitioning and accumulation in broccoli (Brassica oleracea var. italica) in relation to extractable soil inorganic nitrogen

1999 ◽  
Vol 79 (2) ◽  
pp. 277-286 ◽  
Author(s):  
P. A. Bowen ◽  
B. J. Zebarth ◽  
P. M. A. Toivonen
Keyword(s):  
Dry Matter ◽  
N Fertilization ◽  
N Fertilizer ◽  
Organic N ◽  
Soil N ◽  
Inorganic N ◽  
N Accumulation ◽  
Spring Planting ◽  
Extractable Soil ◽  
Soil Inorganic

The effects of six rates of N fertilization (0, 125, 250, 375, 500 and 625 kg N ha−1) on the dynamics of N utilization relative to extractable inorganic N in the soil profile were determined for broccoli in three growing seasons. The amount of pre-existing extractable inorganic N in the soil was lowest for the spring planting, followed by the early-summer then late-summer plantings. During the first 2 wk after transplanting, plant dry-matter (DM) and N accumulation rates were low, and because of the mineralization of soil organic N the extractable soil inorganic N increased over that added as fertilizer, especially in the top 30 cm. From 4 wk after transplanting until harvest, DM and N accumulation in the plants was rapid and corresponded to a rapid depletion of extractable inorganic N from the soil. At high N-fertilization rates, leaf and stem DM and N accumulations at harvest were similar among the three plantings. However, the rates of accumulation in the two summer plantings were higher before and lower after inflorescence initiation than those in the spring planting. Under N treatments of 0 and 125 kg ha−1, total N in leaf tissue and the rate of leaf DM accumulation decreased while inflorescences developed. There was little extractable inorganic soil-N during inflorescence development in plots receiving no N fertilizer, yet inflorescence dry weights and N contents were ≥50 and ≥30%, respectively, of the maxima achieved with N fertilization. These results indicate that substantial N is translocated from leaves to support broccoli inflorescence growth under conditions of low soil-N availability. Key words: N translocation, N fertilizer

scholarly journals Recovery of Phosphorus from Waste Water Profiting from Biological Nitrogen Treatment: Upstream, Concomitant or Downstream Precipitation Alternatives

Agronomy ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1039
Author(s):  
Albert Magrí ◽  
Mar Carreras-Sempere ◽  
Carmen Biel ◽  
Jesús Colprim
Keyword(s):  
Waste Water ◽  
Water Treatment ◽  
Waste Water Treatment ◽  
N Recovery ◽  
Ammonium Oxidation ◽  
Chemically Induced ◽  
Wide Range ◽  
N Treatment ◽  
Phosphate Salts ◽  
Biological Nitrogen

Mined phosphate rock is the largest source of phosphorus (P) for use in agriculture and agro-industry, but it also is a finite resource irregularly distributed around the world. Alternatively, waste water is a renewable source of P, available at the local scale. In waste water treatment, biological nitrogen (N) removal is applied according to a wide range of variants targeting the abatement of the ammonium content. Ammonium oxidation to nitrate can also be considered to mitigate ammonia emission, while enabling N recovery. This review focuses on the analysis of alternatives for coupling biological N treatment and phosphate precipitation when treating waste water in view of producing P-rich materials easily usable as fertilisers. Phosphate precipitation can be applied before (upstream configuration), together with (concomitant configuration), and after (downstream configuration) N treatment; i.e., chemically induced as a conditioning pre-treatment, biologically induced inside the reactor, and chemically induced as a refining post-treatment. Characteristics of the recovered products differ significantly depending on the case studied. Currently, precipitated phosphate salts are not typified in the European fertiliser regulation, and this fact limits marketability. Nonetheless, this topic is in progress. The potential requirements to be complied by these materials to be covered by the regulation are overviewed. The insights given will help in identifying enhanced integrated approaches for waste water treatment, pointing out significant needs for subsequent agronomic valorisation of the recovered phosphate salts, according to the paradigms of the circular economy, sustainability, and environmental protection.

scholarly journals A note on the Hybrid Soil Moisture Deficit Model v2.0

2015 ◽  
Vol 54 (2) ◽  
pp. 126-131 ◽  
Author(s):  
Rogier P.O. Schulte ◽  
Iolanda Simo ◽  
Rachel E. Creamer ◽  
Nicholas M. Holden
Keyword(s):  
Information System ◽  
Soil Moisture ◽  
Short Note ◽  
Soil Drainage ◽  
Topographic Wetness Index ◽  
Soil Moisture Deficit ◽  
Nutrient Emissions ◽  
Moisture Deficit ◽  
Wide Range ◽  
Soil Information

Abstract The Hybrid Soil Moisture Deficit (HSMD) model has been used for a wide range of applications, including modelling of grassland productivity and utilisation, assessment of agricultural management opportunities such as slurry spreading, predicting nutrient emissions to the environment and risks of pathogen transfer to water. In the decade since its publication, various ad hoc modifications have been developed and the recent publication of the Irish Soil Information System has facilitated improved assessment of the spatial soil moisture dynamics. In this short note, we formally present a new version of the model (HSMD2.0), which includes two new soil drainage classes, as well as an optional module to account for the topographic wetness index at any location. In addition, we present a new Indicative Soil Drainage Map for Ireland, based on the Irish Soil Classification system, developed as part of the Irish Soil Information System.

scholarly journals Application of flotation in the decontamination of sediments from the Cerny prikop stream

2009 ◽  
Vol 11 (1) ◽  
pp. 8-11
Author(s):  
Peter Fečko ◽  
Iva Janakova ◽  
Helena Raclavská ◽  
Barbara Tora
Keyword(s):  
Waste Water ◽  
Water Treatment ◽  
Waste Water Treatment ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Waste Water Treatment Plant ◽  
Wide Range ◽  
Odra River ◽  
Coking Plant ◽  
The Given

Application of flotation in the decontamination of sediments from the Cerny prikop stream The stream Cerny prikop is located in the Ostrava city districts of Marianske Hory, Moravska Ostrava and Privoz. This locality belongs to the most polluted areas in Ostrava as it is unbearably polluted by the Coking Plant of Jan Sverma, company BorsodChem MCHZ (the chemical plant), City Waste Water Treatment Plant and a number of other companies in the given territory, all the way to its mouth to the Odra River. Moreover, the area is also affected by the construction of the D 47 motorway. The sediments of Cerny prikop represent a significant ecological burden within the Ostrava urban area. They are contaminated by a wide range of organic pollutants which have never been exactly identified.

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