Online load measurement in combined sewer systems – possibilities of an integrated management of waste water transportation and treatment

2002 ◽  
Vol 45 (4-5) ◽  
pp. 421-428 ◽  
Author(s):  
M. Häck ◽  
U. Lorenz
Keyword(s):  
Waste Water ◽  
Municipal Wastewater ◽  
Control Strategies ◽  
Integrated Management ◽  
Organic Load ◽  
Sewer System ◽  
Water Transportation ◽  
Sewer Systems ◽  
Hydraulic Conditions ◽  
Pre Treatment

To obtain a further appreciable reduction of discharges in the area of sewage disposal, besides waste water purification at our treatment plants, discharge of wastewater through the sewer system has to be taken into account. Today, control strategies pursuing this aim are mainly based on hydraulic conditions like level or flow rate. They all neglect the wastewater organic load as an essential parameter. The main reasons are the expensive methods used to continuously measure traditional organic sum parameters like COD or TOC. A meaningful alternative to those parameters is the spectral absorption coefficient at λ = 254 nm (SAC), defined in DIN 38402 by the German Institute for Standardisation. As a purely physical parameter, the SAC shows a good correlation to organic sum parameters like COD and TOC, especially if municipal wastewater is considered. By using an UV-process probe, it is possible to measure the SAC and infer the organic load of raw wastewater continuously without any sample pre-treatment. By the use of this instrument numerous possibilities arise, in order to control the sewers discharge load depend.

Origins and characteristics of urban wet weather pollution in combined sewer systems: the experimental urban catchment “Le Marais” in Paris

1998 ◽  
Vol 37 (1) ◽  
pp. 35-43 ◽  
Author(s):  
Marie-Christine Gromaire-Mertz ◽  
Ghassan Chebbo ◽  
Mohamed Saad
Keyword(s):  
Waste Water ◽  
Sewer System ◽  
Urban Catchment ◽  
Rainfall Events ◽  
Sources Of Pollution ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Wet Weather ◽  
Wet Weather Flow ◽  
Different Sources

An experimental urban catchment has been created in the centre of Paris, in order to obtain a description of the pollution of urban wet weather flows at different levels of the combined sewer system, and to estimate the contribution of runoff, waste water and sewer sediments to this pollution. Twenty-two rainfall events were studied from May to October 1996. Dry weather flow was monitored for one week. Roof, street and yard runoff, total flow at the catchment outlet and waste water were analysed for SS, VSS, COD and BOD5, on both total and dissolved fraction. Results show an evolution in the characteristics of wet weather flow from up to downstream: concentrations increase from the catchment entry to the outlet, as well as the proportion of particle-bound pollutants and the part of organic matter. A first evaluation of the different sources of pollution establishes that a major part of wet weather flow pollution originates from inside the combined sewer, probably through erosion of sewer sediments.

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.

Anaerobic hydrolysis of a municipal wastewater in a pilot-scale digester

2003 ◽  
Vol 47 (12) ◽  
pp. 223-230 ◽  
Author(s):  
J.A. Álvarez ◽  
C.A. Zapico ◽  
M. Gómez ◽  
J. Presas ◽  
M. Soto
Keyword(s):  
Volatile Fatty Acids ◽  
Municipal Wastewater ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Pilot Scale ◽  
Organic Load ◽  
Active Volume ◽  
Santiago De Compostela ◽  
Load Rate ◽  
Pre Treatment

Raw domestic wastewater from the city of Santiago de Compostela (Northwest Spain) was fed into a pilot-scale hydrolytic up flow sludge bed (HUSB) digester with an active volume of 25.5 m3. The total influent chemical oxygen demand (COD) ranged from 360 to 470 mg/l, the influent SS varied from 190 to 370 mg/l, and the temperature was between 17° and 20°C. The organic load rate (OLR) applied increased step by step from 1.2 to 3.9 kgCOD/m3.d, while the hydraulic retention time (HRT) decreased from 7.1 h to 2.9 h. A high suspended solids (SS) removal of about 82-85% from the influent was reached, most of which (81 to 88%) was eliminated by hydrolysis, while the rest remained in the purge stream. The total COD removal ranged from 46 to 59%. On the other hand, a high acidification of the COD remaining in the effluent was obtained, so the percent COD in the form of volatile fatty acids (VFACOD) with respect to total effluent COD was about 43% for the highest HRT applied, and about 27% for the lowest HRT. The soluble to total COD ratio (CODs/CODt) increased from 25-32% for the influent to 71-86% for the effluent. The results obtained confirm the viability and interest of direct anaerobic hydrolytic pre-treatment of domestic wastewater.

Model Based On-Line Control of Sewer Systems

1993 ◽  
Vol 28 (11-12) ◽  
pp. 87-98
Author(s):  
Jörgen Bo Nielsen ◽  
Sten Lindberg ◽  
Poul Harremöes
Keyword(s):  
Real Time ◽  
Software Package ◽  
Control Strategies ◽  
Forecast Model ◽  
Central Feature ◽  
Real Time Control ◽  
Sewer System ◽  
Model Based ◽  
Sewer Systems ◽  
On Line

A new software package has been developed for use in real-time control of the flow in combined sewer systems (CSS). A central feature of the new package is forecast modelling of the flows and volumes in the sewer system. Based upon the forecast model predictions, an expert system or an optimisation module determines the set-points for all regulators in the system. The new software package includes a comprehensive tool-set for use in the design of on-line control systems, including a model-based real-time simulator, which can be applied in the testing of control strategies. The first practical application of the software package for a sewer system in the city of Aalborg is described.

Vacuum Sewer Systems and their Possible Canadian Applications

1974 ◽  
Vol 1 (1) ◽  
pp. 50-61
Author(s):  
D. W. Averill ◽  
G. W. Heinke
Keyword(s):  
Waste Water ◽  
Small Diameter ◽  
Vacuum Pump ◽  
Pressure Differential ◽  
Water Usage ◽  
Sewer System ◽  
Basic Principles ◽  
Air Gaps ◽  
Sewer Systems ◽  
Gravity System

This paper reviews the basic principles of vacuum sewer systems and the introduction of vacuum sewers to Canada. A vacuum sewer uses air pressure instead of gravity as the driving force for waste water transport. Waste water is moved in plugs, separated by air gaps, at high velocities through small diameter pipes. The pressure differential of about one-half atmosphere is created by a central vacuum pump. Specially designed vacuum toilets, valves, and a central collection tank complete the system. The advantages of a vacuum sewer system over a conventional gravity system are its ability to transport waste water horizontally and to a certain extent upgrade, its much lower water usage, and its lower capital cost. However the length, capacity, and lift potential of vacuum sewers are limited by the available pressure differential, which precludes their use in many cases.

A conceptual model for sediment transport in combined sewer systems

1999 ◽  
Vol 39 (9) ◽  
pp. 39-46 ◽  
Author(s):  
Flemming Schlütter
Keyword(s):  
Sensitivity Analysis ◽  
Sediment Transport ◽  
Conceptual Model ◽  
Qualitative Information ◽  
Sewer System ◽  
Erosion And Deposition ◽  
Sewer Systems ◽  
Hydraulic Conditions ◽  
Combined Sewer

This paper presents a numerical model capable of simulating sediment transport in combined sewer systems. The main objectives of the model are to model mass transport rates at the outlet from a catchment and at the same time obtaining qualitative information on erosion and deposition going on at different locations in the sewer system. The model is conceptual but based on deterministic computations of hydraulic conditions. The formulations used in the conceptual model (STSim) are presented as well as results from a sensitivity analysis. Finally, an example is given of a calibration event from a case study.

scholarly journals The efficiency of urban combined sewer systems during wet weather

2018 ◽  
Vol 45 ◽  
pp. 00017 ◽  
Author(s):  
Ewa Burszta-Adamiak ◽  
Justyna Stańczyk ◽  
Janusz Łomotowski ◽  
Tomasz Konieczny
Keyword(s):  
Urban Areas ◽  
Hydraulic Parameters ◽  
Test Results ◽  
Sewer System ◽  
Transient Flows ◽  
Sewer Systems ◽  
Hydraulic Conditions ◽  
Combined Sewer ◽  
Artificial Neural ◽  
Accuracy Of Prediction

The intensive development of urban areas results in the sealing of increasingly large areas. In such conditions the existing sewer systems are quite often unable to simultaneously collect sewage along with the additional volume of rainwater. These systems require control of the hydraulic parameters in order to recognize the hydraulic conditions that occur in different operational states. Nowadays, such control may be exercised through the use of models that are capable of prediction as a result of the process of learning from a database of historical events. The study presents the possibilities of using Artificial Neural Networks (ANNs) for the analyses of the time series of waste-water depth and flows in a combined sewer system. The measurement campaign organized in Wrocław (Poland) enabled obtaining data on the hydraulic parameters of the flow of sewage in the sewer systems, and rainfall of various characteristics. The test results demonstrate that algorithms of the MLP (Multi-Layered Perceptron) Artificial Neural Network may be implemented to predict the flow rate in the system. The method presented in the paper may be applied to the daily operation of sewer systems to predict transient flows. The obtained results demonstrate a good and very good accuracy of prediction model.

Distribution of heterotrophic and autotrophic organisms in a biological aerated filter

2008 ◽  
Vol 3 (3) ◽  
Author(s):  
O. González-Barceló ◽  
S. González-Martínez
Keyword(s):  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Low Cost ◽  
Ammonia Nitrogen ◽  
Organic Load ◽  
Homogeneous Distribution ◽  
Municipal Wastewater Treatment ◽  
Filter Media ◽  
Aerated Filter ◽  
Secondary Settling

Biological aerated filtration is a viable option for small municipal wastewater treatment plants. A low cost filter media was obtained by triturating volcanic rock. An apparent porosity of 46 % and a specific surface area of 395 m2/m3·d were obtained once the filter was packed by using a grain size of 8.2 mm. The performance of the system, operated as a biological filter, was evaluated under an average organic load of 2.6±0.4 kgCODT/m3·d (6.7±1.1 gCODT/m2·d) without primary and secondary settling. The average CODT decreased from 220 mg/l in the influent to 88 mg/l in the effluent and the CODD was decreased from 148 mg/l in the influent to 50 mg/l in the effluent. The filter media, in combination with the biofilm, allowed a 75 % TSS removal. The ammonia nitrogen decreased from 51 mg/l in the influent to 33 mg/l in the effluent. The maximum flux coefficients of 9.3gCODdissolved/m2·d and 2.9gNH4-N/m2·d at the biofilm surface were used to simulate, with the Michaelis-Menten model, the profiles of dissolved COD, ammonium and nitrates through the aerated filter. It was possible to conclude that the backwashing procedure removed the excess biomass and was responsible for a homogeneous distribution of heterotrophic and autotrophic microorganisms along the filter depth.

Total Discharges Taken into Account for Comprehensive Planning of Urban Drainage and Waste Water Treatment

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2609-2612
Author(s):  
D.-Th. Kollatsch
Keyword(s):  
Waste Water ◽  
Water Treatment ◽  
Waste Water Treatment ◽  
Simulation Models ◽  
Urban Drainage ◽  
Comprehensive Planning ◽  
Environmental Care ◽  
Sewer Systems ◽  
Treatment Facilities ◽  
Receiving Waters

The most important task of urban drainage and waste water treatment in the future is the environmental care of rivers and receiving waters. For this it is necessary to have a look at all discharges of sewer systems and treatment facilities. With simulation models the interactions between surface, sewer systems, overflow structures and treatment facilities can be shown. With these models the efficiency of upgrading measures can be proved in all parts of urban water systems.

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