Seasonality of water supply network failure in the aspect of water supply safety

Many phenomena are characterized by unevenness and variability in time, so-called periodic fluctuations, of which seasonal variations are a special case. In water supply systems, the failures of water pipes are also characterized by unevenness during the year. Seasonality is especially evident when the failures are analysed at particular times of the year. The main purpose of this paper is to present the problems of failures in water supply network caused by seasonal changes, to determine seasonal indicators and to give an example of the system failure analysis for the selected city of south-eastern Poland. The analysis was based on actual operational data obtained from water supply company

The Risk As a Measure of System Safety

Water supply system (WSS) is characterized by its continuous work and requires high reliability level for its operating as well as for its safety System operating is inseparably connected with the possibility that different failures (undesirable events) occur. The most often they have random character and then they can be described by the classical methods used in the reliability engineering including the probabilistic methods but sometimes they are the consequences of the events which can cause the catastrophic situation. Events of this type cause the so called domino effect that is a chain of the undesirable events which very often develops according to some definite scenarios. In many cases the consequences of such events can be very serious for water consumers as well as for water pipe companies. The basic measure describing WSS safety is risk and the elaboration of the model to analyze risk connected with WSS will allow to use the safety barriers properly. The paper presents paradigms of risk analysis in WSS in the aspect of improving safety for water consumers

Water Loss Analysis as an Element of Operation Management of Water Supply System

The aim of the study was an cause and effect analysis of water losses in the collective water supply system of the city located in south-eastern Poland. The exploitation data provided by the water supply company from 2012 - 2016 was used for the analysis. The study uses the recommendations of the IWA (International Water Association) for the water balance making and determination of water loss indicators. The values of water loss indicators were compared to international standards and the technical condition of the network was determined. In addition, failure rate analysis of the water supply network was performed based on the failure rate index λ. Based on the performed analysis, it was found that the water supply company should consider renovation or replacement of the main network pipelines to increase the safety level of water supply, reduce the amount of water losses and the company exploitation costs

Use of the CREAM Method for the Assessment of Operator Reliability in the Process of Backwashing Filters at a Water Treatment Station

The paper presents the application of the CREAM (Cognitive Reliability and Error Analysis Method) method to assess operator reliability in the backwashing of filters process at the Water Treatment Station. For this purpose, two operators were surveyed. Based on the results, the human error probability was determined, which in both cases ranges from 5∙10−5 to 1∙10−2. The results also indicate that the surveyed operators have extensive work experience and high qualifications

Seasonality analysis of water losses in a selected collective water supply system

The aim of the study is to analyse the seasonality of water losses from a collective water-supply system (CWSS) on the example of a provincial city located in south eastern Poland. The analysis was based on exploitation data obtained from the water-supply company for the period 2012–2016. For the analysis of seasonality a method based on average homogeneous sub-periods was used, with a relative seasonality index and the absolute levels of seasonal fluctuations being determined. Water losses from the analysed CWSS are also characterised using unit water-volume indicators within the water supply network. Over the research period, the volume of water produced and sold was found to decline, even as the number of inhabitants using the network increased. On the other hand, there is a growing demand for water used for own purposes by company, as related directly to their development. Water losses and values determined for the water-loss volume indicator both show a downward trend for the analysed CWSS. It is further observed that, in January, March and May, the loss of water is above average, while the volume of water lost in the other months is below average