Search results for "Sewer"

Accounting for service quality to customers in the efficiency of water companies: evidence from England and Wales

2015

This paper investigates the role of service quality to customers in the efficiency assessment of water companies in England and Wales. To achieve this, data envelopment analysis techniques are employed to compute the technical efficiency of the water companies following two approaches: (i) traditional assessment based on quantity variables (without the inclusion of service quality variables) and (ii) alternative assessment considering quantity and service quality variables as undesirable outputs. The analysis covers 22 water and sewerage companies and water only companies providing drinking water services. The results indicate that the traditional efficiency assessment reveals a high level …

Development of an early warning system to predict sewer overflow

Flash flooding in our city is still a fairly common phenomenon.Unfortunately, the development of a flash flood forecasting system in urban areas is not a simple and unambiguous procedure.While attending the PhD course in Civil and Environmental Engineering, research activity has been given to realize an urban overflowing prediction system that was best as possible suited to the drainage network of the city of Palermo. With the support of radar data and hybrid hydraulic model for drainage network has been possible to demonstrate the effectiveness of this instrument, while the reduction of residual flood risk has been supported by modern resilience measures.

Notes about urban drainage systems in the ancient Rome

2012

The magnificence of Roman buildings is very well-known from historical books, notes etc.. In contraposition to this, generally speaking, less is known about the majesty of Roman sewer systems in terms of structures, facilities and the very advanced as well as rudimental complexity. The Roman sewers have been over-praised. Indeed, despite their longevity, they ignored basic sanitary principles as well as design rules. The Roman Empire is in many ways the highest point of sewage management in the ancient world. Famous for public baths and latrines with quite complex engineering, Rome also excelled in the use of covered drains for stormwater and waste-sewage, with some houses directly connecte…

Changes in the total costs of the English and Welsh water and sewerage industry: The decomposed effect of price and quantity inputs on efficiency

2020

Abstract Understanding what drives changes in regulated water companies' costs is of great relevance to water regulators. This study decomposes and estimates the change in total costs for a sample of ten water and sewerage companies in England and Wales from 1993 to 2016. The results demonstrate that companies' total costs increased over time due to increases in input prices and input quantity. Any gains obtained from the efficient allocation of resources and technical progress were lost due to mergers and technical inefficiency. Finally, we link our results with the regulatory cycle to evaluate the impact of the regulatory regime on companies' costs and discuss some policy implications.

Separate and combined sewer systems: a long-term modelling approach

2009

Sewer systems convey mostly dry weather flow, coming from domestic and industrial sanitary sewage as well as infiltration flow, and stormwater due to meteoric precipitations. Traditionally, in urban drainage two types of sewer systems are adopted: separate and combined sewers. The former convey dry and wet weather flow separately into two different networks, while the latter convey dry and wet weather flow together. Which is the best solution in terms of cost-benefit analysis still remains a controversial subject. The present study was aimed at comparing the pollution loads discharged to receiving bodies by Wastewater Treatment Plant (WWTP) and Combined Sewer Overflow (CSO) for different ki…

A preliminary investigation of total organic carbon variation in influent and effluent of Isfahan (Iran) water treatment plant, urban network and Fel…

2006

In this work a series of total organic carbon (TOC) analyses were carried out to analyse the influent and the effluent of a water treatment plant providing Isfahan city in Iran. Other analyses were focused on the determination of TOC in the urban network and Fellman wells (in Isfahan and Dehaghan cities), in order to compare the water quality soon after the treatment with that of circulating water in the city network. Since it supplies water treatment plant, TOC content of Zayandehrood River was also compared with the treated water. The obtained results revealed that there were significant differences between TOC content of effluent of water treatment plant and that of the urban network (ma…

Assessing the efficiency of Chilean water and sewerage companies accounting for uncertainty

2016

Abstract Efficiency assessment of water and sewerage companies (WaSCs) has attracted considerable attention both for water company managers and water regulators. Within the methodological approaches that can be applied to estimate efficiency scores, data envelopment analysis (DEA) is the most widely applied technique. In spite of the positive features of DEA, it presents a major drawback which is its deterministic nature. In other words, conventional DEA models do not account for uncertainty in the data. To overcome this limitation, we assess, for the first time, the efficiency of a sample of Chilean WaSCs by using a DEA model with statistical tolerance in the data. Hence, 81 efficiency sco…

Comparison between a detailed and a simplified integrated model for the assessment of urban drainage environmental impact on an ephemeral river

2008

The benefit of integrated analysis has been demonstrated in technical literature and it is also required by the EU Water Framework Directive 60/2000, which proposes a water-quality-orientated view of the whole urban drainage system and oversees new ways of assessing its performance. Integrated models, such as any complex modelling approach, often have prohibitive data availability requirements that reduce their applicability. Moreover, widely different approaches can be applied, ranging from simple conceptual models to complex physically based ones. In the present paper, two approaches have been compared using data from an experimental catchment in Bologna ( Italy), which consists of a part…

Strategies for Improving Optimal Positioning of Quality Sensors in Urban Drainage Systems for Non-Conservative Contaminants

2021

In the urban drainage sector, the problem of polluting discharges in sewers may act on the proper functioning of the sewer system, on the wastewater treatment plant reliability and on the receiving water body preservation. Therefore, the implementation of a chemical monitoring network is necessary to promptly detect and contain the event of contamination. Sensor location is usually an optimization exercise that is based on probabilistic or black-box methods and their efficiency is usually dependent on the initial assumption made on possible eligibility of nodes to become a monitoring point. It is a common practice to establish an initial non-informative assumption by considering all network…

Evaluation of rehabilitation impact on hydraulic and environmental performance of sewer systems (WP3 CARE-S Project)

2005

The research project CARE-S (Computer Aided RE-habilitation of Sewer Networks) deals with public sewer and storm water networks of any dimension. CARE-S aims to analyse the structural and functional reliability of wastewater networks at minimum cost and disturbance. The ultimate product will be a Decision Support System (DSS) that will enable municipal engineers to establish and maintain effective management of their sewer networks. The project work plan follows a logical structure for the necessary work. It is divided in 10 Work Packages (WP) and each WP is distributed among several partners. The present paper presents the structure and the final results of WP 3 .The work package aim is th…