Wyniki wyszukiwania - BazTech

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Charakterystyka fizyczna i chemiczna osadów korozyjnych w rurach żelaznych eksploatowanych w obecności przepływu wody

Przywara Lucyna, Jaszczurowska Agnieszka

Polish Journal of Materials and Environmental Engineering

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2022

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Vol. 4 (24)

30--40

EN

The presented paper contains issues related to corrosion of water supply lines formed in cast iron and steel. This process can manifest in different ways, including pipe degradation, release of iron by-products, water flow restriction, microbial growth and the reduction of drinking water safety for consumers, which present a significant threat to water supply safety. The aim of the paper was to show changes that emerged in pipes formed in grey cast iron and steel as a result of potable water flow depending on the duration of their use. The corrosion scales from old water pipe lines were analyzed for their structure and composition. The description of the test methodology presents the procedure regarding, analysis of the inner and outer coating with the use of scanning equipment, and chemical analysis of the corrosion sludge. In this study, corrosion products were carefully collected from four old, corroded iron pipes made of different materials – gray cast iron and steel. It can be concluded that scale charac-teristics, including micromorphology, porosity and composition, vary significantly due to different pipe materials and times operating. Characteristics of corrosions scales sampled from different pipe segments show obvious differences, both in physical and chemical aspects. Corrosion scales were found highly amorphous. Diverse results can be observed in the case of the test of inner and outer surface of water supply pipes with the use of scanning equipment. The highest quantity of corrosion pits in the structure were present in the line formed in grey cast iron no. 2, while the deepest pits – over 14 mm – were recorded in steel pipe no. 4. Lines with the most reduced cross-section include steel pipe no. 3, which was characterized by presence of sludge sized over 26 mm. When considering the issue of the chemical composition of the formed corrosion sludge, particular attention must be drawn to the elements that may penetrate into water as a result of its flow, thus causing a considerable deterioration of its quality in chemical and physical terms. Among the major constituent elements of the deposits, iron was most prevalent followed, in the order of decreasing prevalence, by silicon, aluminum, sulfur, calcium, manganese, magnesium. Consequently, characterization of corrosion scales is indispensable to water quality protection.

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Charakterystyka mikroorganizmów biofilmów pochodzących z punktów czerpalnych wody do picia

Biedroń I., Traczewska T. M., Płaza G.

Rocznik Ochrona Środowiska

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2016

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Tom 18, cz. 2

86--99

EN

Microorganisms in the drinking water distribution system form a biofilm on the inner surfaces of the pipes. It is a life preserving strategy that provides easier access to nutrients and protects against harmful environmental factors. The biofilm is a habitat for numerous species of autochthonous microflora which contribute to the intensification of bio-corrosion and negatively affect the quality of the water supplied to the consumers. Additionally, the biofilm can consist of pathogenic species, which may pose an epidemiological hazard. Every drinking water distribution system has its own microflora, it is associated with the presence of autochthonous microorganisms that come from the raw water which despite treatment processes leaked to the network, and microbes that entered as a result of maintenance, failures and leakages. These factors contribute to the biofilm uniqueness in each water supply system, it is associated with the lack of reproducibility of the structure. In the present study characterized the microorganisms from biofilm of 17 tapping points of the water supply system for their ability to adhesion, resistance against selected antibiotics and rated their enzymatic activity. It is believed that the microorganisms with high surface affinity can play a decisive role in the early stages of biofilm formation.

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Specialized genetic operators in drinking water distribution systems control

Cimiński A., Duzinkiewicz K.

Prace Naukowe Politechniki Warszawskiej. Elektronika

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2009

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z. 169

35-42

EN

Model-based predictive control (MPC) is an effective method for control of the large scale systems. The method relying on repeating applying the first element of the calculated control sequence to the system, based on the model of the system and available system output measurements. A time duration of control calculation is a crucial criterion for applying this method. In this paper effective algorithm of control the drinking water distribution system (DWDS) is presented. Algorithm is based on genetic algorithm (GA), specialized genetic operators (SPO) and simulator Epanet. To improve the GA convergence, specialized genetic operators based on system operator knowledge of practical system control are proposed. Effectiveness of proposed specialized genetic operators on the example DWDS of the Chojnice city is presented.