scholarly journals Risk of root intrusion by tree and shrub species into sewer pipes in Swedish urban areas

2012 ◽  
Vol 11 (1) ◽  
pp. 65-71 ◽  
Author(s):  
Johan Östberg ◽  
Max Martinsson ◽  
Örjan Stål ◽  
Ann-Mari Fransson
Keyword(s):  
Urban Areas ◽  
Shrub Species ◽  
Sewer Pipes

scholarly journals A Novel Buffer Tank to Attenuate the Peak Flow of Runoff

2019 ◽  
Vol 5 (12) ◽  
pp. 2525-2534 ◽  
Author(s):  
Yinghong Qin ◽  
Zhengce Huang ◽  
Zebin Yu ◽  
Zhikui Liu ◽  
Lei Wang
Keyword(s):  
Urban Areas ◽  
Peak Flow ◽  
Heavy Rain ◽  
Green Roofs ◽  
Sewer Pipes ◽  
Rainfall Depth ◽  
Dead Storage ◽  
Buffer Tank ◽  
Edge Side ◽  
Outlet Orifice

Impermeable pavements and roofs in urban areas convert most rainfall to runoff, which is commonly discharged to local sewers pipes and finally to the nearby streams and rivers. In case of heavy rain, the peak flow of runoff usually exceeds the carrying capacity of the local sewer pipes, leading to urban flooding. Traditional facilities, such as green roofs, permeable pavements, soakaways, rainwater tanks, rain barrels, and others reduce the runoff volume in case of a small rain but fail in case of a heavy rain. Here we propose a novel rainwater buffer tank to detain runoff from the nearby sealed surfaces in case of heavy rain and then to discharge rainwater from an orifice at the tank’s bottom. We found that considering a 100m2 rooftop with 0.80 runoff coefficient and a 10cm rainfall depth for an hour, a cubic tank with internal edge side of a square of 2 m attenuates the peak flow about 45%. To reduce a desirable peak flow, the outlet orifice of the buffer tank must be optimized according to site-specific conditions. The orifice can be set at an elevation from the tank’s bottom to create a dead storage for harvesting rainwater.

Experimental and numerical investigation of interactions between above and below ground drainage systems

2013 ◽  
Vol 67 (3) ◽  
pp. 535-542 ◽  
Author(s):  
Slobodan Djordjević ◽  
Adrian J. Saul ◽  
Gavin R. Tabor ◽  
John Blanksby ◽  
Istvan Galambos ◽  
...  
Keyword(s):  
Numerical Investigation ◽  
Urban Areas ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Sewer Pipes ◽  
Drainage Systems ◽  
Flow Features ◽  
Below Ground ◽  
Set Up ◽  
Flood Flow

This paper presents the results of the experimental and numerical investigation of interactions between surface flood flow in urban areas and the flow in below ground drainage systems (sewer pipes and manholes). An experimental rig has been set up at the Water Engineering Laboratory at the University of Sheffield. It consists of a full scale gully structure with inlet grating, which connects the 8 m2 surface area with the pipe underneath that can function as an outfall and is also further connected to a tank so that it can come under surcharging conditions and cause outflow from the gully. A three-dimensional CFD (Computational Fluid Dynamics) model has been set up to investigate the hydraulic performance of this type of gully inlet during the interactions between surface flood flow and surcharged pipe flow. Preliminary results show that the numerical model can replicate various complex 3D flow features observed in laboratory conditions. This agreement is overall better in the case of water entering the gully than for the outflow conditions. The influence of the surface transverse slope on flow characteristics has been demonstrated. It is shown that re-circulation zones can form downstream from the gully. The number and size of these zones is influenced by the transverse terrain slope.

scholarly journals Development of a Partial Repair Process for Sewer Lines to Prevent Ground Subsidence in Urban Areas

2020 ◽  
Vol 20 (4) ◽  
pp. 43-50
Author(s):  
Seok In Hong ◽  
Won Jik Yang
Keyword(s):  
Urban Areas ◽  
Local Governments ◽  
Repair Process ◽  
Ground Subsidence ◽  
Similar Process ◽  
Sewer Pipe ◽  
Sewer Pipes ◽  
Repair Method ◽  
Partial Repair ◽  
Urban Problem

Ground subsidence and pollutant runoff due to old sewer lines have been considered a major urban problem. Accordingly, the central and local governments are continuously making efforts to repair the sewage lines. In this study, an economical sewage line repair method based on glass fiber was developed, and its performance was evaluated. In the case of physical characteristics, it was found that the new method can secure more stability and strength compared to the existing sewer pipe repair method. In addition, it was found that economic efficiency was effectively improved by more than 10% in sewage pipes of 300 mm or more and 28%, which is the maximum value in 900 mm pipes, compared to the existing, similar process. In particular, since 70% of domestic sewer pipes are composed of pipes with a diameter of 300 mm or more, the partial repair method developed through this study is expected to be economically beneficial for sewer pipe repairs in the future.

scholarly journals Potential influence of sewer heat recovery on in-sewer processes

2019 ◽  
Vol 80 (12) ◽  
pp. 2344-2351 ◽  
Author(s):  
Mohamad Abdel-Aal ◽  
Raffaella Villa ◽  
Natalia Jawiarczyk ◽  
Luca Alibardi ◽  
Henriette Jensen ◽  
...  
Keyword(s):  
Hydrogen Sulphide ◽  
Urban Areas ◽  
Heat Recovery ◽  
Heat Extraction ◽  
Heat Sources ◽  
Sewer Pipes ◽  
Biochemical Processes ◽  
Study Approach ◽  
Heat Demand

Abstract Heat recovery from combined sewers has a significant potential for practical renewable energy provision as sources of heat demand and sewer pipes are spread across urban areas. Sewers are continuously recharged with relatively hot wastewater, as well as interacting with heat sources from surrounding air and soil. However, the potential effects of modifying sewage temperature on in-sewer processes have received little attention. The deposition of fats, oils and greases (FOGs) and hydrogen sulphide formation are biochemical processes and are thus influenced by temperature. This paper utilises a case study approach to simulate anticipated temperature reductions in a sewer network due to heat recovery. A laboratory investigation into the formation of FOG deposits at temperatures varying between 5 °C and 20 °C provided mixed results, with only a weak temperature influence, highlighting the need for more research to fully understand the influence of the wastewater composition as well as temperature on FOG deposit formation. A separate modelling investigation into the formation of hydrogen sulphide when inflow temperature is varied between 5 °C and 20 °C showed considerable reductions in hydrogen sulphide formation. Hence, heat extraction from sewers could be a promising method for managing some in-sewer processes, combined with traditional methods such as chemical dosing.

scholarly journals Groundwater-Sewer Interaction in Urban Coastal Areas

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1774 ◽  
Author(s):  
Ting Liu ◽  
Xin Su ◽  
Valentina Prigiobbe
Keyword(s):  
Surface Water ◽  
Water Table ◽  
Urban Areas ◽  
Weather Conditions ◽  
Rain Event ◽  
Combined Sewer Overflows ◽  
High Concentration ◽  
Sewer Pipes ◽  
Model Combining ◽  
One Year

In this paper, a study of the potential causes of the occurrence of high concentration of Enterococcus Faecalis in surface water within urban areas in dry-weather conditions (DWCs) is presented. Two hypotheses were formulated: (1) undersized sewer system; and (2) groundwater infiltration into damaged sewer pipes. In both cases, more frequent combined sewer overflows (CSOs) may occur discharging untreated sewage into surface water. To evaluate the first hypothesis, a hydraulic model of a sewer was developed assuming a water-tight system. The simulation results show that CSOs never occur in DWCs but a rain event of intensity equal to 1/3 of one-year return period may trigger them. To evaluate the second hypothesis, a model combining sewer failure with groundwater level was developed to identify the sections of damaged sewer below the water table and, therefore, potentially affected by infiltration. The risk of infiltration exceeds 50% in almost half of the entire network even at the lowest calculated water table. Considering 50% of infiltration distributed throughout that part of the network, CSOs can occur also in DWCs.

The characteristics of odor substances in sewer pipes in urban areas

2020 ◽  
Vol 19 (2) ◽  
pp. 157-165
Author(s):  
Sang-Su An ◽  
Jeong-Won Jang ◽  
Min-Cheol Cho ◽  
Min-Jin Kim ◽  
Hwan-Gi Kim ◽  
...  
Keyword(s):  
Urban Areas ◽  
Sewer Pipes

scholarly journals Carbon Uptake and Air Pollution Mitigation of Different Evergreen Shrub Species

2016 ◽  
Vol 42 (5) ◽  
Author(s):  
Jacopo Mori ◽  
Alessio Fini ◽  
Gianluca Burchi ◽  
Francesco Ferrini
Keyword(s):  
Air Pollution ◽  
Water Availability ◽  
Urban Areas ◽  
Carbon Allocation ◽  
Co2 Assimilation ◽  
Shrub Species ◽  
Evergreen Shrub ◽  
Pollution Mitigation ◽  
Potted Plants ◽  
Drought Tolerant

Three independent experiments assessed CO2 assimilation and metals leaf deposition of seven evergreen shrub species (Arbutus unedo L., Elaeagnus × ebbingei L., Laurus nobilis L., Ligustrum japonicum Thunb., Photinia × fraseri Dress., Viburnum tinus subsp. lucidum L., and Viburnum tinus subsp. tinus L.). CO2 assimilation and carbon allocation were determined in 2011 (Exp. 1) under optimal water availability and in 2012 (Exp. 2) under drought on potted plants. A third experiment (Exp. 3) measured seasonal leaf depositions of Cd, Cu, Ni, Pb, and Zn in 2011 on plants transplanted in proximity of a four-lane road. E. × ebbingei showed the highest CO2 assimilation under optimal water availability but one of the lowest under drought (Exp. 1, 2). Conversely, P. × fraseri had intermediate CO2 assimilation but it declined less during drought compared to the other species. In Experiment 3, E. × ebbingei showed the highest metal deposition, mainly due to its greater leaf area. Greater rainfall and RH% decreased metal depositions, whilst greater wind velocity and air temperature increased leaf depositions. Species which drastically reduce CO2 assimilation under drought (V. tinus subsp. lucidum, L. japonicum, E. × ebbingei) are not recommended in droughtprone environments, where drought-tolerant “mesic” species (P. × fraseri), should be preferred. E. × ebbingei could be used to optimize deposition of metals. The three experiments provide useful insights especially about CO2 assimilation (Exp. 1, 2) and air pollution mitigation (Exp. 3) of widely used shrubs for application in urban areas and planning of roadside greening in southern Europe.

Estimation of sediments in urban drainage areas and relation analysis between sediments and inundation risk using GIS

2008 ◽  
Vol 58 (4) ◽  
pp. 811-817 ◽  
Author(s):  
Park Moojong ◽  
Jun Hwandon ◽  
Shin Minchul
Keyword(s):  
Urban Area ◽  
Sediment Yield ◽  
Urban Areas ◽  
Unit Area ◽  
Higher Order ◽  
Complex Nature ◽  
Urban Drainage ◽  
Sewer Pipes ◽  
Sediment Yields ◽  
Relation Analysis

Sediments entering the sewer in urban areas reduce the conveyance in sewer pipes, which increases inundation risk. To estimate sediment yields, individual landuse areas in each sub-basin should be obtained. However, because of the complex nature of an urban area, this is almost impossible to obtain manually. Thus, a methodology to obtain individual landuse areas for each sub-basin has been suggested for estimating sediment yields. Using GIS, an urban area is divided into sub-basins with respect to the sewer layout, with the area of individual landuse estimated for each sub-basin. The sediment yield per unit area for each sub-basin is then calculated. The suggested method was applied to the GunJa basin in Seoul. For a relation analysis between sediments and inundation risk, sub-basins were ordered by the sediment yields per unit area and compared with historical inundation areas. From this analysis, sub-basins with higher order were found to match the historical inundation areas.

Management of minor ailments in primary schoolchildren in rural and urban areas

1996 ◽  
Vol 22 (3) ◽  
pp. 167-174
Author(s):  
J A Cantrill ◽  
B Johannesson ◽  
M Nicholson ◽  
P R Noyce
Keyword(s):  
Urban Areas ◽  
Rural And Urban Areas ◽  
Rural And Urban ◽  
Primary Schoolchildren ◽  
Minor Ailments

Cannabis use in Switzerland: The role of attribution of drug use to friends, urbanization and repression 1The study was supported by the Swiss Federal Office of Public Health (Bundesamt für Gesundheit BAG) Grant 316.96.5980.

2001 ◽  
Vol 60 (2) ◽  
pp. 99-107 ◽  
Author(s):  
Holger Schmid
Keyword(s):  
Drug Use ◽  
Urban Areas ◽  
Hierarchical Linear Model ◽  
Cannabis Use ◽  
School Aged Children ◽  
Structural Variables ◽  
Hbsc Study ◽  
Nationally Representative ◽  
Highly Correlated ◽  
Individual Use

Cannabis use does not show homogeneous patterns in a country. In particular, urbanization appears to influence prevalence rates, with higher rates in urban areas. A hierarchical linear model (HLM) was employed to analyze these structural influences on individuals in Switzerland. Data for this analysis were taken from the Switzerland survey of Health Behavior in School-Aged Children (HBSC) Study, the most recent survey to assess drug use in a nationally representative sample of 3473 15-year-olds. A total of 1487 male and 1620 female students indicated their cannabis use and their attributions of drug use to friends. As second level variables we included address density in the 26 Swiss Cantons as an indicator of urbanization and officially recorded offences of cannabis use in the Cantons as an indicator of repressive policy. Attribution of drug use to friends is highly correlated with cannabis use. The correlation is even more pronounced in urban Cantons. However, no association between recorded offences and cannabis use was found. The results suggest that structural variables influence individuals. Living in an urban area effects the attribution of drug use to friends. On the other hand repressive policy does not affect individual use.

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