Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: corrosive properties

Sortuj według:

Ogranicz wyniki do:

Ocena mikrobiologiczna osadów wodociągowych, na przykładzie wybranego Systemu Zaopatrzenia w Wodę

Szuster-Janiaczyk A.

Rocznik Ochrona Środowiska

2016

Tom 18, cz. 2

815--827

The study described herein was carried out on a technical scale on a water supply system servicing approximately 350 thousand inhabitants. The total length of the water mains and distribution pipelines in the area under review approximates 1 744 km and 37 264 water supply connections. The greater part of the water supply area is compact, and a region (a maximum located to the south) is clearly separated from the rest. Because the Waterworks Company, which manages the examined SDW, does not exploit its own intakes and water treatment plants, it has to purchase the water from two external suppliers (D-1 and D-2). The studied area is supplied with water from water mains through 21 points (P1-P21) which, in many cases, are also points of water pressure reduction (reduction stations) or elevation (pumping stations). In 8 of the 21 points of purchase, through appropriate installations, phosphate corrosion inhibitors are dispensed to the water. In an article, the microbiological evaluation of deposits collected from five points in the water distribution system was conducted. The analyzed deposits were located at three different materials: cast iron, plastic, and asbestos cement, which in terms of age ranged from 3 to 40 years. Samples of deposits were collected using the same method for various months during one calendar year. Bacteriological analysis of samples included determination of: total number of mesophilic bacteria (growing at 37°C), psychrophilic (growing at 22°C), coliform, faecal coliform (thermotolerant) or E. coli, fecal streptococci, Clostridium perfingens, bacteria of the Pseudomonas genus, bacteria precipitating iron, anaerobic bacteria sulfate reducing (SRB-initiate corrosion processes), actinomycetes and fungi which are the possible contamination of the soil. Results of microbiological testing showed that the surface of the pipes developed biofilm, which is a significant reservoir of microorganisms, which is a phenomenon often occurring in water distribution systems. The analysis showed a variety of deposits in terms of microbiological, depending on the type of material which they were originally placed on. In the case of sediment samples taken from the plastic pipe, the size of the bacteria grown in the two temperatures was several times higher than in the case of samples taken from the cast iron pipe. In the case of the water sample taken from the plastic, the size of bacteria grown at both temperatures exceeded the limit values for water several times.

Wykorzystanie metody polaryzacji elektrochemicznej do opracowania syntetycznej paszy do symulowanych badań korozyjnych

Stężała S., Wieczorek S

Problemy Inżynierii Rolniczej

2000

R. 8, nr 2

51-65

Wykorzystując elektrochemiczne metody badań przy zastosowaniu polaryzacji galwanokinetycznej i potencjokinetycznej, opracowano wodny roztwór syntetycznej paszy, odpowiadający korozyjnymi właściwościami elektrochemicznymi właściwościom najbardziej agresywnych pasz naturalnych. Przeprowadzono weryfikację wyników uzyskanych na drodze elektrochemicznej, wykonując dla stali ST3 oraz czystego cynku i dwu różnych powłok cynkowych badania grawimetryczne w komorach korozyjnych. Uzyskano wyniki zbieżne z wynikami osiągniętymi w badaniach elektrochemicznych. Stanowiło to podstawę do określenia składu chemicznego roztworu syntetycznej paszy i warunków prowadzenia badań przy jego zastosowaniu. Opracowany roztwór umożliwia prowadzenie w standardowych, zawsze powtarzalnych warunkach, przyspieszonych badań korozyjnych stali konstrukcyjnych oraz nałożonych na nie powłok ochronnych, zarówno metodami elektrochemicznymi, jak i grawimetrycznymi. Uzyskane w ten sposób wyniki są wynikami porównywalnymi, czego nie gwarantują badania w paszach naturalnych.

Using electrochemical tests by application of galvano-kinetic and potentio-kinetic polarization techniques the solution of a synthetic feed was prepared. The electrochemical corrosive properties of synthetic feed solution corresponded to these properties of most aggressive natural feeds. The results obtained in electrochemical way were verified by gravimetric tests of St3 steel, pure zinc and two different zinc coatings in corrosion chambers. The results turned out nearly the same as the results obtained at electrochemical tests. Above data became the base to defining chemical composition of synthetic feed solution and the conditions of accelerated tests in this medium. Elaborated solution gave the possibilities of conducting accelerated corrosion tests under the same repeatable standard conditions, for constructive steel and protective coatings by either, electrochemical and gravimetric methods. The results obtained in such a way are comparable, what is not secured in case of tests on natural feeds.