Innovativeness' of the environmental innovation
Poland's water resources, including those of theSilesianProvince, are rather poor, which, coupled with relatively high water demands, can be a significant barrier limiting further development . The surface water resources of theSilesianProvinceprovide one third less water per inhabitant than the national average. Another important factor is that only a small part of the available resources can be used due to considerable contamination of surface water. Therefore, it is necessary to undertake urgent actions aimed at protecting the available water resources, including groundwater. In this context, one of the main tasks of Przedsiębiorstwo Wodociagów i Kanalizacji w Częstochowie (PWiK) as concerns environmental issues is to protect quantitatively and qualitatively exploited groundwater resources to be able to provide continuously approximately 325,000 inhabitants with potable water of high quality on one hand, and to meet the sustainability principle on the other.
In order to ensure rational water resources management, PWiK conducts a reliable quantitative monitoring of water abstracted for various purposes. To reduce losses in the process of water distribution, the Company has implemented the so-called ‘active leak control’ and conducts monitoring of the water pipe network of the exploited water supply system aimed at detecting any failures that may occur. The actions referred to here consist of detecting leaks of water pipe network that are invisible on the surface and adequately managing the water pressure of the system (the so-called ‘smart’ pressure management). The aim of this is to efficiently and successfully limit excessive, unnecessary and unjustified exploitation of the valuable water resources. Active leak control and maintaining the optimal pressure in the water supply system results in a systematic reduction of water losses from leaks in two ways: by decreasing the volume of leaks from minor, hard to detect leakages, and by reducing the number of occurring failures. The latter is of importance as removing each failure leads to an increased consumption of water necessary to rinse and disinfect the repaired part of the pipe network.
The active leak control project has been implemented since 2011. The area encompassed by the project is systematically increasing. . Until now, above 70% of the water pipe network were examined in terms of leaks. The ‘smart’ pressure management covers to-date90 kmof pipelines of the water distribution network, i.e. main distributing and connecting pipes, and including 1,600 terminal connectors (i.e. approximately 4% of the total network operated by PWiK). The implementation area was selected following an analysis of network failure indicators, and based on the values of the so-called ‘night flow levels’. The selected area was found to have the network failure factor for 2008–2010 almost two times higher than the PWiK's average. The night flow levels also exceeded the accepted standard values set in accordance with the concept of ‘Burst and Background Estimates’, as suggested by the International Water Association.
Active leak detection has been systematically broadened in the last three years, along with an increase in the number of the so-called ‘distinctive points’ in the water pipe network. Distinctive points are equipped with flow-meters, pressure transmitters and a data transmission system, which allow for selectively disconnecting sub-areas in a given zone (these are referred to as District Metered Areas, DMAs) and simultaneous observation of the indicators of measurement equipment showing the flow balance for the examined areas. In order to meet the measurement’s precision requirements, network boundary valves for the DMA are defined prior to the gradual testing, and a zero pressure test is performed to determine the water tightness of the valves. All these operations are conducted at night,
which allows for distinguishing water uptake related to its consumption by Clients from water losses due to leaks, as well as for minimizing any potential nuisance to the Clients. In the performance of these tasks, the PWiK employees also utilize electro-acoustical diagnostic equipment, such as: correlators, geophones, noise loggers, and pipe tracers. Moreover, they perform periodical examinations of pressure distribution in the specified areas using portable recorders, and measure the discharges of fire hydrants.
Gradual broadening of the monitored zones allows also for the evolution of the so- called ‘Active Leak Detection’ process and changing it into the so-called ‘Repair Speed’. This process allows to eliminate leakages in the water pipe network almost at the same time when information on a sudden increase of a night flow from a measurement point is obtained – see chart 1. Currently, due to a progressive
Chart 1. A failure in the distribution network detected thanks to flow monitoring using the TelWin system
development of the monitoring , approximately 50% of the exploited network (i.e. over1,500 km) is ubjected to continuous night flow control, which contributes to significant reducing the lasting time of failures undetectable on the surface. The remaining network is a subject of cyclic inspections conducted by employees of the PWiK’s ‘Waterworks System Diagnostics and Survey Section’.
Pressure management is another important issue in a wider approach to reducing water losses in the water pipe network. Pressure not only does pressure impacts the discharge of water from the existing leakages, but it relates directly to occurrences of new failures as well. It is, therefore, advisable to limit it in specified zones to the absolute necessary minimum, and adjust it to r daily and annual water distributions. The key pressure management equipment includes hydraulic reductors with the output pressure regulation in relation to the flow intensity. They are entirely autonomous, and require no additional external control systems, such as: drivers, flow meters, or pressure transmitters. The only purpose of the additional equipment referred to above is measurements, control, and data transmission. The lack of additional electronic equipment contributes to the reliability of the system. The operators' experiences show that the conditions in which the reductors are located (submersion, pH of the water filling the chamber, etc.) are often unfavorable for electronic circuitries. In addition, failures can be caused by lightning discharges and other factors related to electrical power fed to utilities. Usually, incorrect operation of even one of the series of elements can result in erroneous operation of the pressure regulators, which in turn usually causes interruptions in the performance of the whole system.
Application of hydraulic pressure regulators is the first implementation of this type inPoland. The research conducted for this purpose is also innovative due to its scope, which includes examining the dependencies between pressure regulation and the failure frequency of the pipes, with respect to their build material, diameter, and the seasonality of failure occurrence. As a result of this study , the reference materials for the operational conditions will be created at the regional scale, allowing for predicting the reasonability of such applications in the case of similar water distribution systems (with consideration for the freezing zone, the depth of pipeline foundation , weather conditions, etc.) in other regions.
Previous publications devoted little time to the dependence between the dynamic pressure regulation and the failure frequency of pipes, as well as to detailed analysis of the damage rates of specific groups of materials. A majority of the research into this issue has been conducted under conditions that differ very much from those common in our region (i.e. in Australia, the United Kingdom, South America). Another only partially examined factor is the seasonality of failure frequency, which is dependent on the climate and other factors, not entirely related to pressure regulation. As a result of this, the failure rates of pipes compared year over year may differ by up to several dozen percents, without any preventive actions being taken. The implementation of the activities mentioned above was based on, among other sources, the publication of J. Thornton, A. Lambert ‘Pressure: Bursts Relationships: Influence of Pipe Materials, Validation of Scheme Results, and Implications of Extended Asset Life’, IWA Water Loss 2012 Manila, 26-29 February 2012.
An exact examination of zones with the implemented dynamic pressure regulation in areas of the Silesian Province may provide the opportunity of transferring these innovations to other water supply networks in the region. and in the entire country.
Chart 2. from measurement equipments – pressure reduction at night hours.
Map generated using the GIS system – the area of the newly formed pressure reduction zone ‘Poludnie’
Head office: (34) 3655448, (34) 3773199
Secretariat: (34) 3773101
Fax: (34) 3651582
The Stand-by service: 994
E-mail: poczta@pwik.czest.pl
www.pwik.czest.pl
Przedsiębiorstwo Wodociągów i Kanalizacji Okręgu Częstochowskiego S.A. w Częstochowie
42-202 Częstochowa, ul. Jaskrowska 14/20
Sąd rejestrowy: Sąd Rejonowy w Częstochowie Wydział Gospodarczy Krajowego Rejestru Sądowego - Nr KRS 0000057953
Kraj: Polska; województwo: Śląskie; powiat: Częstochowa, gmina: Częstochowa, miejscowość: Częstochowa
NIP: PL 5730003841, REGON: 150354701
Wysokość kapitału zakładowego: 101.074.600,00zł., pokryty w całości.
e-mail: poczta@pwik.czest.pl