Abstract on the theme: "The rationale the structure of the instrument for measuring the concentration of dissolved oxygen in wastewater"
Content
- Introduction
- 1. Actuality of the theme
- 2. The aim and Objectives
- 2.1 Planned practical results
- 2.2 Alleged scientific innovation
- Literature
The end of the twentieth century was characterized by a powerful jerk of scientific and technological progress, the growth of social contradictions, rapid population explosion, environmental degradation. The water is characterized by physical and chemical properties, one of which is oxygen. Natural water always contains dissolved salts in it of various chemical elements, a large amount of suspended particles of mineral and organic origin, which determine the degree of transparency.
Current status of the aquatic environment does not meet health standards. But the level of automation in modern instrumentation allows for the operational control of these parameters in different environments. There is also a problem and need for control of dissolved oxygen in rivers, lakes and the waters are not suitable for use.
Oxygen is one of the major dissolved gases are constantly present in surface waters, the regime which largely determines the chemical and biological condition of water bodies. It is proved that in the atmosphere, water, and accessible to direct chemical study of the solid crust, we find that the share of oxygen accounts for about 50% of their total mass. The main sources of oxygen in surface waters are the processes of absorption from the atmosphere. Dissolved oxygen in surface waters is in the form of O2 molecules. Its solubility increases with decreasing temperature, salinity and pressure increases.
Versatile use of oxygen due to its properties: non toxic, non explosive, non flammable, has no color, taste and smell, refers to oxidants, thereby burning various materials. The high strength of chemical bonds between atoms in a molecule of O2 leads to the fact that at room temperature, gaseous oxygen is chemically quite maloaktiven. Oxygen concentration determines the amount of oxidation - reduction potential and to a large extent the direction and speed of the processes of chemical and biochemical oxidation of organic and inorganic compounds [1]. As a rule, changes in oxygen concentration in the discharge of its spending is caused by the oxidation of easily oxidized substances in the water. However, water – insoluble oily substances, petroleum products, create a film on the water surface, which prevents the dissolution of oxygen, causing a decrease in its concentration. In this regard, all the water, which is involved in the process, is purified [2].
The process of cleaning all water is accompanied by the constant control of dissolved oxygen concentration, since it is an indicator of water quality. As a result, a variety of oxidation processes oxygen is constantly moving from free to bound states. However, the amount of free oxygen remains virtually unchanged since its quantitative offset by the vital activity of plants. In order to determine the dissolved oxygen in the water developed special equipment oxygen analyzers (oximeters), designed to measure the concentration of dissolved oxygen. Not all, but most of them have a small measurement range and low threshold, so the main goal of master's work is to develop an instrument for measuring dissolved oxygen, which will be Kmet low cost and improved performance accuracy. An important parameter is the duration of the analysis, linearity and repeatability as a percentage of the measurement range.
Some oxygen analyzers are the elements that react with oxygen and prevent the accurate assessment of its concentration in a given substance. Therefore, the instrument designed to meet modern technological demands of aesthetics and ergonomics, and will also be convenient and easy to maintain, have low weight and dimensions, which should allow it to operate in a variety of challenging conditions. Thus, in the implementation of the thesis will address the existing prototype instruments for measuring oxygen in the water, the analysis of the advantages and disadvantages of these prototypes and conclusions on improving the processes of measurement and processing of the results.
There will also be developed block diagram of the apparatus for measuring the concentration of dissolved oxygen in the water.
All oximeters will be able to generate uniform signals with their subsequent transfer to a standardized protocol to the controller and operator consoles will be developed microprocessors to implement the transfer of records in the memory of the measurement results, communicate with other devices, as well as monitoring and analysis process.
2.2 Alleged scientific innovation
Despite the fact that there are many methods for determining the concentration of dissolved oxygen in water, used only a few. These are methods that do not require cumbersome equipment and qualified personnel. Sensors based on luminescence method has several advantages over traditional electrochemical sensors. They are:
– the selectivity of oxygen that can measure extremely low concentrations of oxygen in the presence of unknown impurities;
– lack of oxygen consumption during operation;
– high performance and small temperature dependence;
– short response time, a high mechanical stability;
– no need to replace the membrane and the electrolyte;
– do not need a gauge brow;
– no need to flow;
1. Ìóðàâéîâ À.Ã. Êåð³âíèöòâî ç âèçíà÷åííÿ ïîêàçíèê³â ÿêîñò³ âîäè ïîëüîâèìè ìåòîäàìè. 2 – å âèä., Ïåðåðàá. ³ äîïîâí. ÑÏá.: "Êð³ñìàñ 1999. – 232 ñ.
2. Ñòåïàíþê ².À. Îêåàíîëîã³÷í³ âèì³ðþâàëüí³ ïåðåòâîðþâà÷³ / ².À. Ñòåïàíþê - Ë.:óäðîìåòåîâèäàâí, 1986. – 269 ñ.
Note: While writing this essay, Master's work is not completed yet. Final date: December 2012. Full text of all materials on the subject can be obtained from the author or his manager after that date.