scholarly journals Ecohydrological modelling of water discharge and nitrate loads in a mesoscale lowland catchment, Germany

2009 ◽  
Vol 21 ◽  
pp. 49-55 ◽  
Author(s):  
Q. D. Lam ◽  
B. Schmalz ◽  
N. Fohrer

Abstract. The aims of this study are to identify the capacities of applying an ecohydrological model for simulating flow and to assess the impact of point and non-point source pollution on nitrate loads in a complex lowland catchment, which has special hydrological characteristics in comparison with those of other catchments. The study area Kielstau catchment has a size of approximately 50 km2 and is located in the North German lowlands. The water quality is not only influenced by the predominating agricultural land use in the catchment as cropland and pasture, but also by six municipal wastewater treatment plants. Ecohydrological models like the SWAT model (Soil and Water Assessment Tool) are useful tools for simulating nutrient loads in river catchments. Diffuse entries from the agriculture resulting from fertilizers as well as punctual entries from the wastewater treatment plants are implemented in the model set-up. The results of this study show good agreement between simulated and measured daily discharges with a Nash-Sutcliffe efficiency and a correlation coefficient of 0.76 and 0.88 for the calibration period (November 1998 to October 2004); 0.75 and 0.92 for the validation period (November 2004 to December 2007). The model efficiency for daily nitrate loads is 0.64 and 0.5 for the calibration period (June 2005 to May 2007) and the validation period (June 2007 to December 2007), respectively. The study revealed that SWAT performed satisfactorily in simulating daily flow and nitrate loads at the lowland catchment in Northern Germany.

Author(s):  
Moh Sholichin ◽  
Tri Budi Prayogo

Lake Tondano is the largest natural lake in North Sulawesi, Indonesia, which functions as a provider of clean water, hydroelectric power, rice field irrigation, inland fisheries, and tourism. This research aims to determine the effect of land cover types from the Tondano watershed on the lake water quality. The Soil and Water Assessment Tool (SWAT) model was used to evaluate the rate of soil erosion and the pollutant load of various land types in the watershed during the last ten years. Rainfall data is obtained from two rainfall stations, namely Paleloan Station and Noonan Station. The model is calibrated and validated before being used for analysis. We use climatological data from 2014 to 2019. The process of the SWAT model calibration and validation was carried out with the statistical formulas of the coefficient of determination (R2) and Nash-Sutcliffe efficiency (NSE). The results show that the potential for pollution load from the Tondao watershed is organic N of 0.039 kg/ha and organic P of 0.006 kg/ha coming from the agricultural land. The results of this study conclude that the fertility conditions of Lake Tondano are at the eutrophic level, where the pollutant inflow is collected in the lake waters, especially for the parameters of total N (1503697.44kg/year) and total P (144831.36kg/year). The SWAT simulation results show deviation between the modeling and field data collected with the value of R2 = 0.9303, and the significant level ≤ 10.


2019 ◽  
Vol 43 (1) ◽  
pp. 76-89 ◽  
Author(s):  
Zakaria Kateb ◽  
Hamid Bouchelkia ◽  
Abdelhalim Benmansour ◽  
Fadila Belarbi

AbstractThe dam of Beni Haroun is the largest in Algeria, and its transfer structures feed seven provinces (wilayas) in the eastern part of Algeria. Due to its importance in the region, it has now become urgent to study its watershed as well as all the parameters that can influence the water and solid intakes that come into the dam. The Soil and Water Assessment Tool (SWAT) model is used to quantify the water yields and identify the vulnerable spots using two scenarios. The first one uses worldwide data (GlobCover and HWSD), and the second one employs remote sensing and digital soil mapping in order to determine the most suitable data to obtain the best results. The SWAT model can be used to reproduce the hydrological cycle within the watershed. Concerning the first scenario, during the calibration period, R2 was found between 0.45 and 0.69, and the Nash–Sutcliffe efficiency (NSE) coefficient was within the interval from 0.63 to 0.80; in the validation period, R2 lied between 0.47 and 0.59, and the NSE coefficient ranged from 0.58 to 0.64. As for the second scenario, during the calibration period, R2 was between 0.60 and 0.66, and the NSE coefficient was between 0.55 and 0.75; however, during the validation period, R2 was in the interval from 0.56 to 0.70, and the NSE coefficient within the range 0.64–0.70. These findings indicate that the data obtained using remote sensing and digital soil mapping provide a better representation of the watershed and give a better hydrological modelling.


2010 ◽  
Vol 61 (5) ◽  
pp. 1349-1354
Author(s):  
H. Saveyn ◽  
D. Curvers ◽  
J. Pelicaen ◽  
J. Cauwenberghs ◽  
C. Thoeye ◽  
...  

The present paper outlines the impact of hydrolysis occurring in DMAEA-Q type polymers in the dewatering facilities of municipal wastewater treatment plants. Laboratory studies of polymer hydrolysis kinetics were combined with full-scale dewatering experiments to investigate the influence of polymer charge loss on polymer consumption and cake dry matter yields. The results indicate that prolonged polymer storage leads to important charge loss effects, resulting in increased dosage requirements for satisfactory dewatering performance. Fortunately, charge loss effects due to hydrolysis upon polymer storage could be minimized by acidifying the polymer batches. Furthermore, cake dry matter contents obtained from dewatering tests with freshly prepared polymer batches suggested that acidification of the polymer batch also had a beneficial effect on the conditioning efficiency of the polymer solution. The results from this study thus stress the influence of pH on the shelf life and efficiency of polymer solutions in wastewater treatment plants. As a consequence, polymer preparation and storage procedures should be adapted to the polymer consumption pattern and pH of the medium used for polymer batch production.


2014 ◽  
Vol 69 (7) ◽  
pp. 1359-1372 ◽  
Author(s):  
Oskar Modin ◽  
David J. I. Gustavsson

Microbial bioelectrochemical systems (BESs) utilize living microorganisms to drive oxidation and reduction reactions at solid electrodes. BESs could potentially be used at municipal wastewater treatment plants (WWTPs) to recover the energy content of organic matter, to produce chemicals useful at the site, or to monitor and control biological treatment processes. In this paper, we review bioelectrochemical technologies that could be applied for municipal wastewater treatment. Sjölunda WWTP in Malmö, Sweden, is used as an example to illustrate how the different technologies potentially could be integrated into an existing treatment plant and the impact they could have on the plant's utilization of energy and chemicals.


2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Tewodros Getu Engida ◽  
Tewodros Assefa Nigussie ◽  
Abreham Berta Aneseyee ◽  
John Barnabas

Understanding the hydrological process associated with Land Use/Land Cover (LU/LC) change is vital for decision-makers in improving human wellbeing. LU/LC change significantly affects the hydrology of the landscape, caused by anthropogenic activities. The scope of this study is to investigate the impact of LU/LC change on the hydrological process of Upper Baro Basin for the years 1987, 2002, and 2017. The Soil Water Assessment Tool (SWAT) model was used for the simulation of the streamflow. The required data for the SWAT model are soils obtained from the Food and Agriculture Organization; Digital Elevation Model (DEM) and LU/LC were obtained from the United States Geological Survey (USGS). The meteorological data such as Rainfall, Temperature, Sunshine, Humidity, and Wind Speeds were obtained from the Ethiopian National Meteorological Agency. Data on discharge were obtained from Ministry of Water, Irrigation and Electricity. Ecosystems are deemed vital. Landsat images were used to classify the LU/LC pattern using ERDAS Imagine 2014 software and the LU/LC were classified using the Maximum Likelihood Algorithm of Supervised Classification. The Sequential Uncertainty Fitting (SUFI-2) global sensitivity method within SWAT Calibration and Uncertainty Procedures (SWAT-CUP) was used to identify the most sensitive streamflow parameters. The calibration was carried out using observed streamflow data from 01 January 1990 to 31 December 2002 and a validation period from 01 January 2003 to 31 December 2009. LU/LC analysis shows that there was a drastic decrease of grassland by 15.64% and shrubland by 9.56% while an increase of agricultural land and settlement by 18.01% and 13.01%, respectively, for 30 years. The evaluation of the SWAT model presented that the annual surface runoff increased by 43.53 mm, groundwater flow declined by 27.58 mm, and lateral flow declined by 5.63 mm. The model results showed that the streamflow characteristics changed due to the LU/LC change during the study periods 1987–2017 such as change of flood frequency, increased peak flows, base flow, soil erosion, and annual mean discharge. Curve number, an available water capacity of the soil layer, and soil evaporation composition factor were the most sensitive parameters identified for the streamflow. Both the calibration and validation results disclosed a good agreement between measured and simulated streamflow. The performance of the model statistical test shows the coefficient of determination (R2) and Nash–Sutcliffe (NS) efficiency values 0.87 and 0.81 for calibration periods of 1990–2002 and 0.84 and 0.76 for the validation period of 2003 to 2009, respectively. Overall, LU/LC significantly affected the hydrological condition of the watershed. Therefore, different conservation strategies to maintain the stability and resilience of the ecosystem are vital.


Author(s):  
Paweł Marcinkowski ◽  
Mikołaj Piniewski ◽  
Ignacy Kardel ◽  
Marek Giełczewski ◽  
Tomasz Okruszko

AbstractModelling of discharge, nitrate and phosphate loads from the Reda catchment to the Puck Lagoon using SWAT. This study presents an application of the SWAT model (Soil and Water Assessment Tool) in an agricultural, coastal catchment situated in northern Poland, draining an area of 482 km2 (the Reda catchment). The main objective of this study was calibration and validation of the model against daily discharge and water quality parameters (bi-monthly total suspended solids [TSS], nitrate nitrogen [N-NO3] and phosphate phosphorus [P-PO4] loads). Calibration and validation were conducted using the SWAT-CUP program and SUFI-2 (Sequential Uncertainty Fitting Version 2) algorithm. The Nash- -Sutcliffe efficiency, which was set as an objective function in calibration of all variables, was equal for discharge to 0.75 and 0.61 for calibration and validation periods, respectively. For TSS, N-NO3 and P-PO4 loads NSE was equal to 0.56, 0.62 and 0.53 in calibration period, and 0.22, 0.64 and -1.78 in validation period, respectively. For the calibration period all the results are satisfactory or good, while for the validation period the results for TSS and P-PO4 loads are rather poor, which is related mainly to the lack of homogeneity between calibration and validation periods. These results demonstrate that SWAT is an appropriate tool for quantification of nutrient loads in Polish agricultural catchments, in particular for N-NO3. The model can therefore be applied for water resources management, for quantification of scenarios of climate and land use change, and for estimation of the Best Management Practices efficiency


1994 ◽  
Vol 30 (4) ◽  
pp. 17-23 ◽  
Author(s):  
B. Evans ◽  
P. Laughton

The province of Ontario is Canada's most populous province with over 8 million residents out of a total population of 27 million. The Province is situated in the eastern portion of North America and stretches from 41°N to 50° N. All the Great Lakes fall within Ontario's boundaries and the Province is estimated to have over 280,000 lakes. The area along Lake Ontario is home to 5 million of the residents who are serviced by 11 large sewage treatment plants. The remaining 403 treatment plants are scattered throughout the province. with an average size of 20 000 m3/d. Ontario Hydro commissioned a study of the wastewater treatment plants to identify the main power users at the various types of sewage treatment plants, as well as potential areas within each plant where significant energy savings could be generated. By using this information, Ontario Hydro hoped to assess the potential to reduce the load and identify any electrical efficiency improvements, fuel switching and load shifting opportunities that may exist as well as the impact of environmental regulations on power saving initiatives. It was found that several major opportunities existed. These included:■ that up to 25% of power currently used can be reduced by introducing energy efficient measures■ of all the unit operations in wastewater treatment plants, aeration accounts for 42% of the power usage, influent and effluent pumping - 20%, and dewatering - 6%. Of this influent and effluent pumping, specifically influent represented the best target area as significant aeration system upgrade had already taken place.


2006 ◽  
Vol 53 (4-5) ◽  
pp. 357-366 ◽  
Author(s):  
Y. Okayasu ◽  
H. Tanaka ◽  
T. Inui ◽  
Y. Tanaka

The effect of potassium cyanide (KCN) on nitrification processes in municipal wastewater treatment plants was studied by batch nitrification tests, which indicated that nitrification processes tend to be inhibited at a lower KCN concentration than the present discharge standard to sewerage. The experiment of the biosensor using nitrifying bacteria was also conducted for continuous monitoring of nitrification inhibitor in influent wastewater, and demonstrated that the biosensor can detect KCN at as low as EC10 of the abovementioned batch nitrification test. Moreover, to determine the effectiveness of application of the biosensor to avoid the impact of KCN due to an accidental spillage in a sewerage system, KCN was intentionally injected into the experimental models of activated sludge process equipped both with and without the biosensor. The model with the biosensor that could detect KCN could divert the wastewater including KCN to a refuge tank, which resulted in the avoidance of upset of the activated sludge process. On the other hand, the model without the biosensor was upset in the nitrification process due to KCN. Such differences demonstrate the effectiveness of the biosensor applied to countermeasures of an accidental spillage of toxic chemicals to avoid upset of nitrification in municipal wastewater treatment plants.


2019 ◽  
Vol 79 (2) ◽  
pp. 334-341 ◽  
Author(s):  
Y. S. Cao ◽  
J. G. Tang ◽  
M. Henze ◽  
X. P. Yang ◽  
Y. P. Gan ◽  
...  

Abstract China has achieved significant progress on wastewater treatment and aquatic environmental protection. However, leakage (in- and exfiltration) of sewer systems is still an issue. By using the statistical data of water and wastewater in 2016 in China, and the person loads (PLs) of water and wastewater in Singapore, the leakage fractions of hydraulic flow, organic carbon (COD), nitrogen (N) and phosphorus (P) mass loading, and in-sewer COD biological removal in the sewer systems of China (except Hong Kong, Macau and Taiwan), Shanghai, Guangzhou and Beijing were reported for the first time. The fractions of hydraulic flow infiltration (13%, Shanghai and Guangzhou) and exfiltration (39%, China) were calculated. Except Beijing, whose sewer networks are under appropriate management with small leakage fractions, the exfiltration fractions of COD (including in-sewer biological COD removal) ranged from 41% (Shanghai) to 66% (China) and averaged 55%; N ranged from 18% (Shanghai) to 48% (China) and averaged 33%; and P ranged from 23% (Shanghai and Guangzhou) to 44% (China) and averaged 30%. The exfiltrated sewage, COD, N and P not only wastes resources, but also contaminates the aquatic environment (especially groundwater) and contributes to ‘black and odorous water bodies’. In- and exfiltration in the sewer network leads to low influent COD concentration, C/N ratio and high inorganic solids and inert particulate COD concentrations of many municipal wastewater treatment plants (WWTPs) causing high cost for nutrient removal, poor resource recovery, additional reactor/settler volume requirement and other operational problems. Therefore, tackling sewer leakage is of primary importance to today's environment in China. Recommendations for the inspection of sewer systems and the rehabilitation of damaged sewers as well as the development of design and operation guidelines of municipal WWTPs tailored to the specific local sewage characteristics and other conditions are proposed.


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