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 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.

scholarly journals River water intrusion as a source of inflow into the sanitary sewer system

2020 ◽  
Vol 82 (11) ◽  
pp. 2472-2481
Author(s):  
Shuai Guo ◽  
Xiang Shi ◽  
Xujia Luo ◽  
Haoming Yang
Keyword(s):  
River Water ◽  
Field Experiments ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Sewer System ◽  
Water Intrusion ◽  
Sanitary Sewer ◽  
Sewer Systems ◽  
Water Problem ◽  
Groundwater Infiltration

Abstract Previous studies on the extraneous water problem (or infiltration/inflow) in sanitary sewer systems assumed that the wastewater flow is mainly composed of foul sewage (FS), groundwater infiltration (GWI) and rainfall-derived inflow and infiltration (RDII). Most existing assessment methods are based on this assumption. In 2018, China initiated the ‘Protection of the Yangtze River Program’, and the two-year research data showed that it was neither the GWI nor the RDII but the direct surface water intrusion (DSWI), which has rarely been reported in literatures, that serves as the main source of the extraneous water in many local sewer systems. The discovery has enriched the understanding of the extraneous water in sewer systems. Meanwhile, it brings new challenges for the assessment of extraneous water. In this study, starting from the analysis of the low influent concentration of chemical oxygen demand (COD) of the wastewater treatment plant in a southeastern city in China, a river water intrusion point was successfully localized and the volume of river water intrusion was quantified by a series of field experiments. The methodology used in this study can also be applied in other areas with DSWI.

Estimating rainfall-induced inflow and infiltration in a sanitary sewer system based on water quality modelling: which parameter to use?

2018 ◽  
Vol 4 (3) ◽  
pp. 385-393 ◽  
Author(s):  
Mingkai Zhang ◽  
Yanchen Liu ◽  
Qian Dong ◽  
Yi Hong ◽  
Xia Huang ◽  
...  
Keyword(s):  
Public Health ◽  
Water Quality ◽  
Water Quality Modelling ◽  
Sewer System ◽  
Sanitary Sewer ◽  
Sewer Systems ◽  
Management Issues

Rainfall-derived inflow and infiltration (RDII) of urban sanitary sewer systems poses serious challenges for public health and management issues.

Settleable Solids from Combined Sewers: Settling, Stormwater Treatment, and Sedimentation Rates in Rivers

1994 ◽  
Vol 29 (1-2) ◽  
pp. 95-102
Author(s):  
S. Michelbach ◽  
C. Wöhrle
Keyword(s):  
River Sediments ◽  
Oxygen Demand ◽  
Stormwater Treatment ◽  
Organic Micropollutants ◽  
Sewer Systems ◽  
Settling Behaviour ◽  
Combined Sewer ◽  
Important Pathway ◽  
Receiving Waters ◽  
The Relationship

Settleable solids are an important pathway for pollutants found in river sediments. To study settling behaviour of settleable solids, settling velocity was measured by a settling apparatus. Special measurements were undertaken to determine the relationship between the settling distribution of settleable solids and their pollutant load - organic mass, chemical oxygen demand, heavy metals and organic micropollutants. To calculate where settleable solids from combined sewer systems will settle in receiving waters, the settling distribution is also useful. The results of a three-year research indicate that stormwater treatment by settling is effective in preventing adverse environmental impacts of combined sewage pollutants.

Urban Drainage Systems: Design and Operation

1993 ◽  
Vol 27 (12) ◽  
pp. 31-70 ◽  
Author(s):  
J. Marsalek ◽  
T. O. Barnwell ◽  
W. Geiger ◽  
M. Grottker ◽  
W. C. Huber ◽  
...  
Keyword(s):  
Sewage Treatment ◽  
Systems Design ◽  
Urban Drainage ◽  
Sewer System ◽  
Drainage Systems ◽  
Planning And Design ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Urban Drainage Systems ◽  
Receiving Waters

Design and operation of urban drainage systems are addressed in the context of the urban water system comprising drainage, sewage treatment plants and receiving waters. The planning and design of storm sewers are reviewed with reference to planning objectives, design objectives, flows and pollutant loads, sewer system structures and urban runoff control and treatment. The discussion of combined sewers focuses on hydraulic design of combined sewer systems, including combined sewer overflow (CSO) structures, and the use of CSO structures and storage in control of CSOs. The section on operation of sewer systems focuses on real time control, its feasibility, planning, design, operation and applications. Sewer system planning and design are generally conducted using computer modelling tools and procedures which are reviewed in the last section. A brief listing of selected models focuses on internationally used models. Finally, it was concluded that further improvements in environmental and ecological protection of urban waters is feasible only by consideration of urban drainage systems in conjunctions with sewage treatment and water quality in the receiving waters.

Infiltration in Sewer Systems: Multi-Criteria Comparison of Investment / Rehabilitation Strategies

2007 ◽  
Vol 2 (1) ◽  
Author(s):  
J.-L. Bertrand-Krajewski ◽  
S. Barraud ◽  
P. Le Gauffre ◽  
E. Baer
Keyword(s):  
Investment Strategy ◽  
Final Decision ◽  
Specific Information ◽  
Sewer System ◽  
Site Specific ◽  
Infiltration Rates ◽  
Sewer Systems ◽  
Receiving Waters ◽  
Rehabilitation Strategies

Within the FP5 European APUSS project (Assessing infiltration and exfiltration on the Performance of Urban Sewer Systems), a methodology has been proposed to account for environmental, technical and economic impacts of infiltration or exfiltration on sewer systems, treatment plants and receiving waters, and to evaluate the consequences of possible investment / rehabilitation strategies. The multi-criteria method Electre III is used to compare and to rank the various strategies, as this method has a high potential adaptability to diverse contexts and objectives. An example of application of the proposed methodology is given for a 245 ha residential catchment equipped with a combined sewer system, including scenarios with different infiltration rates. It shows that the methodology is applicable, but also that validated and site specific information (data, measurements, calibrated models, etc.) is necessary in order to carry out a valuable analysis. Results shall be reviewed carefully and the final decision making process should take into account the context of the study. There is no unique best investment strategy, but several options may be considered depending on priorities and criteria of the sewer operator. The methodology is general, but results of the case study are site specific and cannot be extrapolated.

A conceptual CSO emission model: SEWSIM

1998 ◽  
Vol 37 (1) ◽  
pp. 259-267
Author(s):  
Mingchuan Ruan ◽  
Jan. B. M. Wiggers
Keyword(s):  
Urban Areas ◽  
Pollution Source ◽  
Emission Model ◽  
Rainfall Runoff ◽  
Deterministic Models ◽  
Sewer System ◽  
Erosion And Deposition ◽  
Receiving Waters ◽  
Event Based ◽  
Programming Package

CSO emission is widely considered a significant pollution source to receiving waters in urban areas. The existing deterministic sewer models are not able to predict CSO emission effectively. In this study, a conceptual CSO emission model SEWSIM has been developed using a powerful programming package MATLAB and SIMULINK. A sewer system consisting of an impervious catchment and a sewer network is schematised as two linear dynamic reservoirs. The following physical processes are conceptually modelled: rainfall-runoff; surface solids buildup and washoff; sewer sediment erosion and deposition. The model is suitable for both event-based and continuous simulations. Some simulation results demonstrate that SEWSIM predicts pollution load of CSO emission more effectively than deterministic models.

scholarly journals Comparative Study of AI-Based Methods—Application of Analyzing Inflow and Infiltration in Sanitary Sewer Subcatchments

2020 ◽  
Vol 12 (15) ◽  
pp. 6254
Author(s):  
Zhe Zhang ◽  
Tuija Laakso ◽  
Zeyu Wang ◽  
Seppo Pulkkinen ◽  
Suvi Ahopelto ◽  
...  
Keyword(s):  
Situation Awareness ◽  
Structural Condition ◽  
Sewer System ◽  
Important Indicator ◽  
Inference System ◽  
Sanitary Sewer ◽  
Sewer Systems ◽  
Pumping Stations ◽  
Spatial Decision Making ◽  
Using Data

Inflow and infiltration (I/I) is a common problem in sanitary sewer systems. The I/I rate is also considered to be an important indicator of the operational and structural condition of the sewer system. Situation awareness in sanitary sewer systems requires accurate wastewater-flow information at a fine spatiotemporal scale. This study aims to develop artificial intelligence (AI)-based models (adaptive neurofuzzy inference system (ANFIS) and multilayer perceptron neural network (MLPNN)) and to compare their performance for identifying the potential inflow and infiltration of the sanitary sewer subcatchment of two pumping stations. We tested the performance of these AI models by using data gathered from two pumping stations through a supervisory control and data acquisition (SCADA) system. As a result, these two AI models produced similar inflow and infiltration patterns—both subcatchments experienced inflow and infiltration. On the other hand, the ANFIS had overall higher performance than that of the MLPNN model for modelling the I/I situation for the catchments. The results of the research can be used to support spatial decision making in sewer system maintenance.

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.

Design of self-cleansing sanitary sewer systems with the use of flushing devices

2009 ◽  
Vol 60 (4) ◽  
pp. 901-908 ◽  
Author(s):  
T. Goormans ◽  
D. Engelen ◽  
R. Bouteligier ◽  
P. Willems ◽  
J. Berlamont
Keyword(s):  
Surface Waters ◽  
Sewer System ◽  
Sewer Pipes ◽  
Hydrodynamic Simulations ◽  
Sanitary Sewer ◽  
Sewer Systems ◽  
Increased Risk ◽  
Combined Sewer ◽  
Maintenance Requirements

Many European countries tend to shift from constructing combined sewer systems to separate ones, in order to optimise wastewater treatment efficiency and reduce CSO impact on surface waters. An economic design minimises maintenance requirements by aiming at self-cleansing pipes. However, providing the necessary slopes for self-cleansing sanitary sewer pipes often is unfeasible in flat regions, resulting in an increased risk of loss of hydraulic capacity or blocking. To reduce these risks, flushing tanks can be installed in the sewer system. Where most other researchers contribute to a better understanding of the hydraulics of flushing, this paper rather tries to formulate a methodology to design and test flushing devices in sanitary sewer systems using standards and hydrodynamic simulations. Therefore, several aspects that require consideration when incorporating flushing devices into a sanitary sewer system are discussed. For instance, when flushing sanitary sewers the increase in discharge has to be explicitly considered. A Belgian case study is used to investigate the suitability of the developed methodology. Although the pipe slopes in the methodology are derived assuming uniform flow, the simulation results comply with it. Furthermore, pressurisation of the conduits due to multiple flushing waves remains within acceptable limits.

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