Application of a leakage model to assess exfiltration from sewers

2005 ◽  
Vol 52 (5) ◽  
pp. 225-231 ◽  
Author(s):  
C. Karpf ◽  
P. Krebs
Keyword(s):  
Surface Water ◽  
Urban Areas ◽  
Unsaturated Zone ◽  
Specific Model ◽  
Model Parameters ◽  
Sewer System ◽  
Leakage Model ◽  
Sewer Systems ◽  
Potential Impact ◽  
The City

The exfiltration of wastewater from sewer systems in urban areas causes a deterioration of soil and possibly groundwater quality. Beside the simulation of transport and degradation processes in the unsaturated zone and in the aquifer the analysis of the potential impact requires the estimation of quantity and temporal variation of wastewater exfiltration. Exfiltration can be assessed by the application of a leakage model. The hydrological approach was originally developed to simulate the interactions between the groundwater and surface water, it was adapted to allow for modelling of interactions between groundwater and sewer system. In order to approximate the exfiltration specific model parameters infiltration specific parameters were used as a basis. Scenario analysis of the exfiltration in the City of Dresden from 1997 to 1999 and during the flood event in August 2002 shows the variation and the extent of exfiltration rates.

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

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1171 ◽  
Author(s):  
Mitja Janža ◽  
Joerg Prestor ◽  
Simona Pestotnik ◽  
Brigita Jamnik
Keyword(s):  
Groundwater Quality ◽  
Urban Areas ◽  
Transport Model ◽  
Nitrate Concentration ◽  
Impact Model ◽  
Sewer System ◽  
Management Measures ◽  
Pressure Impact ◽  
The Impact ◽  
The City

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.

scholarly journals Microplastic Pollution in Surface Water of Urban Lakes in Changsha, China

2019 ◽  
Vol 16 (9) ◽  
pp. 1650 ◽  
Author(s):  
Lingshi Yin ◽  
Changbo Jiang ◽  
Xiaofeng Wen ◽  
Chunyan Du ◽  
Wei Zhong ◽  
...  
Keyword(s):  
Surface Water ◽  
Urban Areas ◽  
Maximum Concentration ◽  
Emerging Pollutants ◽  
Anthropogenic Factors ◽  
Dominant Type ◽  
Urban Lakes ◽  
Research Areas ◽  
The World ◽  
The City

As emerging pollutants, microplastics have attracted the attention of scholars from all over the world. However, there is a lack of research on freshwater areas, even in densely populated urban areas. This study investigated eight urban lakes in Changsha, China. It was found that microplastic concentrations ranged from 2425 ± 247.5 items/m3 to 7050 ± 1060.66 items/m3 in the surface water of research areas and the maximum concentration was found in Yuejin Lake, a tourist spot in the center of the city. Anthropogenic factors are an important reason for microplastic abundance in urban lakes. The major shape of microplastics was linear and most of the microplastics were transparent. More than 89.5% of the microplastics had a size of less than 2 mm. Polypropylene was the dominant type in the studied waters. This study can provide a valuable reference for a better understanding of microplastic pollution in urban areas of China.

scholarly journals Small cities face greater impact from automation

2018 ◽  
Vol 15 (139) ◽  
pp. 20170946 ◽  
Author(s):  
Morgan R. Frank ◽  
Lijun Sun ◽  
Manuel Cebrian ◽  
Hyejin Youn ◽  
Iyad Rahwan
Keyword(s):  
Urban Areas ◽  
Small Cities ◽  
Employment Opportunities ◽  
Worker Displacement ◽  
Large Cities ◽  
Potential Impact ◽  
Job Content ◽  
The Impact ◽  
The City ◽  
Technical Professions

The city has proved to be the most successful form of human agglomeration and provides wide employment opportunities for its dwellers. As advances in robotics and artificial intelligence revive concerns about the impact of automation on jobs, a question looms: how will automation affect employment in cities? Here, we provide a comparative picture of the impact of automation across US urban areas. Small cities will undertake greater adjustments, such as worker displacement and job content substitutions. We demonstrate that large cities exhibit increased occupational and skill specialization due to increased abundance of managerial and technical professions. These occupations are not easily automatable, and, thus, reduce the potential impact of automation in large cities. Our results pass several robustness checks including potential errors in the estimation of occupational automation and subsampling of occupations. Our study provides the first empirical law connecting two societal forces: urban agglomeration and automation's impact on employment.

scholarly journals Model predictive control based on artificial intelligence and EPA-SWMM model to reduce CSOs impacts in sewer systems

2021 ◽  
Author(s):  
Khalid El Ghazouli ◽  
Jamal El Khatabi ◽  
Aziz Soulhi ◽  
Isam Shahrour
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Control Strategies ◽  
Dynamic Control ◽  
Combined Sewer Overflows ◽  
Sewer System ◽  
Sewer Systems ◽  
Proposed Model ◽  
The Impact ◽  
The City

Abstract Urbanization and an increase in precipitation intensities due to climate change, in addition to limited urban drainage systems (UDS) capacity, are the main causes of combined sewer overflows (CSOs) that cause serious water pollution problems in many cities around the world. Model predictive control (MPC) systems offer a new approach to mitigate the impact of CSOs by generating optimal temporally and spatially varied dynamic control strategies of sewer system actuators. This paper presents a novel MPC based on neural networks for predicting flows, a stormwater management model (SWMM) for flow conveyance, and a genetic algorithm for optimizing the operation of sewer systems and defining the best control strategies. The proposed model was tested on the sewer system of the city of Casablanca in Morocco. The results have shown the efficiency of the developed MPC to reduce CSOs while considering short optimization time thanks to parallel computing.

scholarly journals CHALLENGES OF SNOW DISPOSAL AND INNOVATIVE SOLUTIONS IN THE CONDITIONS OF NUR-SULTAN

2021 ◽  
Vol 26 (1) ◽  
pp. 20-29
Author(s):  
M. T. Yermekov ◽  
◽  
O. V. Rozhkova ◽  
S. G. Sandibekova ◽  
Ye. T. Tolysbayev ◽  
...  
Keyword(s):  
Urban Areas ◽  
Sewage Treatment ◽  
Heat Pumps ◽  
Successful Implementation ◽  
Snow Melting ◽  
Sewer System ◽  
Snow Removal ◽  
Advantages And Disadvantages ◽  
The Impact ◽  
The City

Introduction. In this paper, we analyze various methods of snow removal in urban areas and consider the most cost-effective and efficient solutions for snow removal and disposal using heat from sewage drains by means of stationary snow-melting points (SMP) in Nur-Sultan. In cooperation with Astana su Arnasy specialists, responsible for the operation of the city sewer system, as well as cleaning and disinfection of urban sewage drains, we reviewed the main advantages and disadvantages. Methods. The paper looks into the possibility of utilizing heat from sewage drains with the help of heat pumps. This method has been successfully tested at a sewage treatment plant and is currently used to heat auxiliary premises. The same principle can be applied in SMPs with a separate discharge of meltwater to the storm sewer. Results. Having studied the experience of using various methods for snow removal in urban areas, we find that snow removal with the use of sewage drains through the creation of special snow-melting complexes integrated with the city sewer system is the most promising method for Nur-Sultan since it allows for reducing costs, intensifying the process of snow melting, and eliminating the hazardous impact of meltwater on the environment. Conclusion. To ensure successful implementation and use of this snow removal method in Nur-Sultan, it is required to conduct a number of additional studies on the impact of sewage treatment plants on the technological processes, as well as to test options for separating sewage drains with the help of heat pumps, and, based on the studies conducted, to determine the final configuration of snow-melting complexes.

Groundwater infiltration, surface water inflow and sewerage exfiltration considering hydrodynamic conditions in sewer systems

2011 ◽  
Vol 63 (9) ◽  
pp. 1841-1848 ◽  
Author(s):  
Christian Karpf ◽  
Stefan Hoeft ◽  
Claudia Scheffer ◽  
Lothar Fuchs ◽  
Peter Krebs
Keyword(s):  
Surface Water ◽  
High Sensitivity ◽  
Water Levels ◽  
Water Inflow ◽  
Network Modelling ◽  
Infiltration Rates ◽  
Sewer Systems ◽  
The City ◽  
Groundwater Infiltration ◽  
Modelling Approach

Sewer systems are closely interlinked with groundwater and surface water. Due to leaks and regular openings in the sewer system (e.g. combined sewer overflow structures with sometimes reverse pressure conditions), groundwater infiltration and surface water inflow as well as exfiltration of sewage take place and cannot be avoided. In the paper a new hydrodynamic sewer network modelling approach will be presented, which includes – besides precipitation – hydrographs of groundwater and surface water as essential boundary conditions. The concept of the modelling approach and the models to describe the infiltration, inflow and exfiltration fluxes are described. The model application to the sewerage system of the City of Dresden during a flood event with complex conditions shows that the processes of infiltration, exfiltration and surface water inflows can be described with a higher reliability and accuracy, showing that surface water inflow causes a pronounced system reaction. Further, according to the simulation results, a high sensitivity of exfiltration rates on the in-sewer water levels and a relatively low influence of the dynamic conditions on the infiltration rates were found.

scholarly journals Analysis of the Inflow Characteristics of Separate Sewer Systems for Rainfall Using an XP-SWMM Model and the SSOAP Toolbox

2021 ◽  
Vol 21 (5) ◽  
pp. 271-280
Author(s):  
Young Jun Lee ◽  
Chae Young Lee
Keyword(s):  
Urban Areas ◽  
Volume Data ◽  
Sewer System ◽  
Rainfall Events ◽  
Rainfall Characteristics ◽  
Sanitary Sewer ◽  
Sewer Systems ◽  
Sanitary Sewer Overflow ◽  
Sampling Intervals ◽  
Swmm Model

Even after the sewer system rehabilitation project, sewer system-related problems caused by inflow still persist. However, analysis of the characteristics of the inflow has been limited to specific rainfall events and monitoring points. This study analyzed inflow characteristics according to rainfall events using an XP-SWMM model and the Sanitary Sewer Overflow Analysis and Planning (SSOAP) Toolbox. In this study, the XP-SWMM model was built for sewers and collecting pipes in urban areas where classification projects were completed. The R, T, and K parameters were calculated using the SSOAP tool based on the sewer volume data of the study area. The calculated parameters were inputted into the XP-SWMM model and used to analyze R, T, and K of unmeasured sampling intervals. The amount of rainfall-derived inflow and infiltration (RDII) increased according to the amount of rainfall, and the correlation coefficient between the amount of rainfall and the amount of RDII was 0.9352, indicating a high correlation. The results of this study can support efficient facility planning that reflects the rainfall characteristics of specific areas, including areas where actual survey of sewage data is not possible.

Performance of partially separate sewer systems and impacts on receiving waters

2002 ◽  
Vol 45 (3) ◽  
pp. 273-279 ◽  
Author(s):  
F.M. Ferreira ◽  
J.S. Matos ◽  
A.C. Rodigues ◽  
H.M. do Monte
Keyword(s):  
Urban Areas ◽  
Oxygen Demand ◽  
First Flush ◽  
Drainage Basins ◽  
Sewer System ◽  
Sanitary Sewer ◽  
Sewer Systems ◽  
Receiving Waters ◽  
The Village ◽  
Bacteriological Contamination

The aim of this document is to present and discuss the results of the experimental work undertaken in Laje stream, in a section near the village of Oeiras in Portugal. The work was developed with the main objective of characterising stormwater quality in Portuguese drainage systems, and to predict the effects of the performance of partially separate sewer systems on receiving waters. For this purpose, volume and characteristics of stormwater carried by a partially separated sewer system were estimated, both in terms of flow and Chemical Oxygen Demand (COD) loads. The study also analyses the eventual implementation of non-conventional solutions, as a way of reducing problems of bacteriological contamination of seawaters. This aspect is particularly important in Portugal, where the population is mainly concentrated in urban areas located down-stream of important drainage basins, close to the coastline. Therefore, sanitary sewer overflows discharging directly into receiving waters are frequent, with possible consequences in terms of bacteriological contamination of bathing areas. Based on experimental research and available data it was possible to collect informations regarding stormwater average COD and overflow coliform loads, and the occurrence of first flush effects.

scholarly journals The contemporary importance of the Old Canal area for the centre of Bydgoszcz and its influence on the city’s cultural landscape

2020 ◽  
pp. 1-12
Author(s):  
Iga Grześkow
Keyword(s):  
Urban Space ◽  
Urban Areas ◽  
Cultural Landscape ◽  
Public Spaces ◽  
Specific Model ◽  
Urban Life ◽  
Economic Interests ◽  
Canal Area ◽  
The City

European cities are centuries-old connections of social and cultural interrelations in which the history and heritage of generations have formed a specific model of collective life and culture. The nature, prestige and signs of urban life in these cities are best indicated by their public spaces and their structure and inclusion in the urban tissue. Being presentable areas as well as places of social intercourse and activity, public spaces form multipurpose areas which establishe the city’s cultural landscape. Simultaneously, the game for urban areas in the city and related economic interests, and market all activities promoting the city's image and interfering with the city’s structure, pose a threat to the sensible development of the most valuable parts of the urban space. Globalisation processes contribute to the unification and standardisation of any forms of life, including space. The need for maintaining the continuity of urban tissue requires that its historical traces be cultivated. In this context, the contemporary role of the Old Canal area for downtown Bydgoszcz and its influence on the development of the city’s cultural landscape are part of the current strategies for the cultureforming regeneration of urban space.

Nowcasting of rainfall and of combined sewage flow in urban drainage systems

2009 ◽  
Vol 59 (6) ◽  
pp. 1145-1151 ◽  
Author(s):  
Stefan Achleitner ◽  
Stefan Fach ◽  
Thomas Einfalt ◽  
Wolfgang Rauch
Keyword(s):  
Spatial Scales ◽  
Radar Data ◽  
Urban Drainage ◽  
Real Time Control ◽  
Sewer System ◽  
Drainage Systems ◽  
Time Control ◽  
Sewer Systems ◽  
Urban Drainage Systems ◽  
The City

Nowcasting of rainfall may be used additionally to online rain measurements to optimize the operation of urban drainage systems. Uncertainties quoted for the rain volume are in the range of 5% to 10% mean square error (MSE), where for rain intensities 45% to 75% MSE are noted. For larger forecast periods up to 3 hours, the uncertainties will increase up to some hundred percents. Combined with the growing number of real time control concepts in sewer systems, rainfall forecast is used more and more in urban drainage systems. Therefore it is of interest how the uncertainties influence the final evaluation of a defined objective function. Uncertainty levels associated with the forecast itself are not necessarily transferable to resulting uncertainties in the catchment's flow dynamics. The aim of this paper is to analyse forecasts of rainfall and specific sewer output variables. For this study the combined sewer system of the city of Linz in the northern part of Austria located on the Danube has been selected. The city itself represents a total area of 96 km2 with 39 municipalities connected. It was found that the available weather radar data leads to large deviations in the forecast for precipitation at forecast horizons larger than 90 minutes. The same is true for sewer variables such a CSO overflow for small sub-catchments. Although the results improve for larger spatial scales, acceptable levels at forecast horizons larger than 90 minutes are not reached.

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