This article deals with the analysis of particle sedimentation velocity in water media with application of video information and pictures management. Kinetics of particles sedimentation in model suspensions and in wastewater were studied by gravimetric method and also by method of video recording of sedimentation with digital photo camera and pictures processing in computer program Adobe Photoshop CS3. In the result of research it was found that analyses of histograms of brightness make it possible to determine particles sedimentation velocity in water media with less time and labor expenditures than in gravimetric method

Ignatenko, A. V.

Sazanovets, M. A.

Belarusian State Technological University

ISSN 1683-0377. Proceedings of BSTU. 2013. No. 4. Chemistry, Organic Substances Technology and Biotechnology 40 УДК 541.18 M. A. Sazanovets, PhD student (BSTU); A. V. Ignatenko, PhD (Biology), assistant professor (BSTU). METHOD OF ANALYSIS OF PARTICLE  SEDIMENTATION RATE IN AQUEOUS MEDIA  This article deals with the analysis of particle sedimentation velocity in water media with applica-tion of video information and pictures management. Kinetics of particles sedimentation in model sus-pensions and in wastewater were studied by gravimetric method and also by method of video recording of sedimentation with digital photo camera and pictures processing in computer program Adobe Photo-shop CS3. In the result of research it was found that analyses of histograms of brightness make it possi-ble to determine particles sedimentation velocity in water media with less time and labor expenditures than in gravimetric method.  Introduction. Determination of parameters of the particle granulometric composition is an impor-tant task in various fields of science and industry [1, 2]. Sedimentation analysis of suspended parti-cles is widely used to characterize the level of sewage pollution and assess the effectiveness of cleaning them [3].  Wastewater is a complex heterogeneous sys-tem consisting of aqueous solutions, colloidal mixtures, suspended solids, various forms of liv-ing organisms: viruses, bacteria, yeasts, filamen-tous fungi, micro-algae, protozoa, and their asso-ciates [3, 4]. The dispersed particles of wastewater are sepa-rated into groups according to the size:  – molecular dispersions with particle size less than 10-7 cm. They include homogeneous molecu-lar and ionic solutions of organic and inorganic substances. Their content in the urban wastewater treatment facilities is 10–50 mg / l; – colloidal systems with a particle size of 10–7–10–5 cm as solutions of substances have kinetic stability and are not stratified in the water. Their content in the wastewater can reach hundreds of milligrams per liter; – suspensions, emulsions (particles larger than 10–5cm) (oil products: mazut, mineral oil, solvents, etc.) which are present in wastewater at a concen-tration of 50–300 mg / l; – coarse dispersions with a particle size of more than 10–3 cm (fibers, sand, clay, etc.) may be in the waste waters at concentrations from 200–400 to 1000–3000 mg / l; – microorganisms and parasites: their sizes are from 10–6 to 10–1 cm and by disperse characteris-tics they are referred to biological colloids and suspensions.  Total microbial count of microorganisms in wastewater is estimated in the range 106 – 108 CFU/cm3.  Pollution o wastewater with parasites is deter-mined by the number of viable lamblia cysts and helminth per unit volume of water and changes in the interval 100–102 particles /dm3 [4]. According to L. A. Kulski’s classification [5], weighted components of waste water are divided into settling and not settling ones. Knowing the velocity sedimentation of suspended particles it is possible to determine their disperse and sorption properties, reactivity.  Since large particles oxidized slowly by micro-organisms, it is better to eliminate them at the early stage of water purification. Sedimentation is the easiest way to discharge from the wastewater particulate pollutants, which settle on the bottom of the settler under the influ-ence of gravitation or float on its surface in for two-hour. To examine the particulate composition of the wastewater gravimetric and optical methods of analysis are widely used [2]. The disadvantage of gravimetric method ap-plies is its high complexity. Particle light scattering method is less labor intensive than the gravimetric method, but it requires special equipment and doesn’t allow analyzing too turbid media. Main part. This work aims at the development of not labor-intensive rapid method of the sedi-mentation rate analysis of particles in aqueous me-dia using video and digital image processing. Aqueous suspensions of bentonite and soil with concentration C = 1 – 10 g / l, and also wastewater with suspended solid concentration 0.1 – 0.5 g / l determined by weighing the dry residue were the objects of research. Kinetics of particle sedimentation was studied by gravimetric method based on measuring the mass of sediment deposited on the scale in liquid [2], as well as by video recording of deposition process of particles in aqueous suspensions using a digital camera Canon Power Shot A3300 IS with further image processing by a computer program Adobe Photoshop CS3. Digital image is a matrix of pixels having dif-ferent brightness depending on the radiation fell on them. Each pixel is a photosensitive element having specific dimensions depending on the method of Chemistry, Technology of Organic Substances, Materials and Goods 41matrix preparation and has a minimum pixel value 10 × 10 µm [6–8]. This paper deals with the method of digital photography to analyze particle sedimentation ve-locity of wastewater and water model systems. Black and white (achromatic) digital image is characterized by a number of parameters: light-ness, brightness, etc. [7].  Lightness is determined by the proportion of white light in the image.  Image brightness of non-reflection objects from the physical point of view is characterized by the intensity of the reflected or scattered light fell on the photocell matrix camera from the object being analyzed. Digital image histogram characterizes the de-pendence of the number of pixels on their level of brightness. It is determined by the values of a total number of pixels in the image, the average bright-ness, the percentage of the number of pixels of the selected brightness, etc. Fig. 1 shows a digital image of the soil sam-ples in aqueous suspension, depending on its set-tling time.               Fig. 1. Photos of the sedimentation  of soil suspension particles in cylinder (C = 4 g / l):  1 – 0.5 min, 2 – 2 min.; 3 – 5 min.  As it can be seen, lightening of the suspension is observed when particles deposit.  The fundamental quantity to characterize im-ages in sedimentation analysis can be pixel brightness, which reflects the change in the light-ness image during the sedimentation of suspended particles. Histograms of image brightness changes in soil suspension from the time of settling particles are shown in fig. 2. As one can see from it, initially the pixels with brightness of black predominated in the image. Then, during the sedimentation of suspended particles the proportion of pixels decreased and the maximum of the histogram shifted toward white. As it can be seen, the brightness of light pixels in the image increases in the course of time.                         Fig. 2. Image brightness histogram  of soil suspension from the sedimentation time:  a – 0 ; b – 2 min ; c – 5 min; P – number of pixels  of a certain level of brightness; I – brightness level Fig. 3 shows changing kinetics of the image bright-ness in the deposition of soil suspension particles. 80901001101201301401501601700 10 20 30Средняя яркость, усл. ед.t, мин  Fig. 3. Dependence of the brightness  of soil suspension images (C = 0.4%)  on settling time of the particles  This is due to the fact that the soil particles are black and readily absorb the emission of all colors. As a result, dark colors predominate in the histo-gram of the image at the initial time. The content of light colors increases with the deposition of sus-pended particles in the image. The table shows the results of analysis of depo-sition rate of particles in an aqueous medium, de-              1                       2                      3       а    b   с РР Р I I I                                       2                   37060504030201101009080Medium brightness, units t, min ISSN 1683-0377. Proceedings of BSTU. 2013. No. 4. Chemistry, Organic Substances Technology and Biotechnology 42 fined by the gravimetric method and according to changes in the brightness of digital images. Table Characteristic of particle sedimentation rate  by gravimetric method  and by analyzing the image brightness Particle sedimentation rate, min-1 Subject gravimetric method change  in the bright-ness of digital images Correlation coefficient 1. Soil suspension υ1 0.180 0.709 υ2 0.092 0.412 υ3 0.046 0.310 υ4 0.016 0.018 0.966 2. Wastewater υ1 0.044 0.022 υ2 0.038 0.014 υ3 0.018 0.006 0.955 The rate of change of image brightness was determined from the slope of the curves obtained for various fractions with different particle sedi-mentation rates. As it can be seen from the table, there is a strong direct correlation between the indications of the gravimetric method and data analysis of image brightness, indicating the reliability of the results and the possibility of their use for the analysis of the sedimentation properties of suspended waste-water solids. Conclusion. The digital image analysis of the sedimentation of suspended particles was carried out and rapid test is proposed for the rate estima-  tion of deposition according to the change bright-ness of images. The method is characterized by high efficiency, low labor and accuracy matching with the gravimetric method of analysis. The method can be used to control the level of pollution in wastewater, as well as evaluating the effectiveness of their purification from suspended particles. References 1. Романовский, С. И. Физическая седимен-тология / С. И. Романовский. – Л.: Недра, 1988. – 240 с. 2. Порошки металлические. Методы седимен-тационного анализа: ГОСТ 22662–77. – Введ. 01.01.79. – М.: Изд-во стандартов, 1977. – 8 с. 3. Очистка производственных сточных вод / С. В. Яковлев [и др.]. – М.: Стройиздат, 1979. – 320 с. 4. Жмур, Н. С. Технологические и биохими-ческие процессы очистки сточных вод на со-оружениях с аэротенками / Н. С. Жмур. – М.: АКВАРОС, 2003. – 512 с. 5. Справочник по свойствам, методам ана-лиза и очистки воды / Л. А. Кульский [и др.]. – Киев: Наукова думка, 1980. – 1206 с. 6. Прэт, У. Цифровая обработка изображе-ний: в 2 т. / У. Прэт. – М.: Мир, 1982. – Т. 1. – 317 с.; Т. 2. – 479 с. 7. Кэлби, С. Цифровая фотография: в 2 т. / С. Кэлби. – Вильямс, 2011. – Т. 1. – 224 с.;  Т. 2. – 258 с.  8. 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Method of analysis of particle sedimentation rate in aqueous media

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Method of analysis of particle sedimentation rate in aqueous media

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