Petras Vaitiekūnas

Mathematical simulation of solid particle dispersion in the air of Vilnius city

Abstract One of the main methods for the air quality assessment and forecast is mathematical simulation of pollutants. In order to simulate the dispersion of solid particles (SP) in the air, there may be applied the package of “Phoenics” software in which the proximity methods of equation solution are used, because an accurate analytic solution of movement equations is not possible to be applied. The software was used in Žverynas district of Vilnius city in which the exact values of SP were selected. The paper presents the technique of mathematical simulation of SP dispersion in the air, the Algebraic Slip Model is described which is used for the solution of the problem; the model uses calculation‐based formulas. Based on the results of the experiment (the values of SP concentration) and the obtained results by applying “Phoenics” mathematical simulation program, the feasibility of the simulation program for modeling the SP concentration dispersion is determined. The results of simulation are submitted in...

Investigation of volatile organic compound (VOC) emission in oil terminal storage tank parks

Abstract The problem of VOC volatilization into the atmosphere from oil terminals is discussed in the paper. Investigation of VOC concentration in an oil terminal was performed in characterized spots of the main pollutant concentration ‐ in storage tank parks of light and heavy oil products. A complex analysis of the impact of meteorological elements, oil‐product‐storage tank construction, the level of filling storage tanks with oil products on the emissions of VOCs in oil terminals and adjacent territories is provided in the paper. The dependence of VOC concentration on the following parameters of the construction of storage tanks was analysed: the capacity of storage tanks, the insulation between the wall of a storage tank and peculiarities of the pontoon construction (single, double, triple insulation). The results of the investigation may be applied for the development and improvement of the VOC calculation method (LAND 31–2007/M‐11), reduction of VOC emissions in the existing oil terminals and when d...

Modeling of motor transport exhaust pollutant dispersion

Abstract Pollution is a major problem in all countries, even developed ones. It is the major environmental negative impact of anthropogenic activities affecting ecology. There are two major ways for assessment of negative impact of motor transport flow intensity and pollution level: monitoring the air or modeling pollutant dispersion. It is very important to estimate different unknown air modeling programs. In this work modeling is to be executed by the US EPA (United States Environmental Protection Agency) the so‐called “the best possible existing software for strategic environmental assessment”. That is also recommended by the Ministry of Environment of the Republic of Lithuania. In this work pollution modeling was executed for the northern part of Vilnius (the network of streets Geležinis Vilkas ‐ Ozas ‐ Kalvarijos). For motor vehicle pollution mathematical modeling, it is necessary to evaluate meteorological parameters like temperature, humidity, the wind direction and speed. Modeling software can als...

Modelling of motor transport exhaust gas influence on the atmosphere

Santrauka Pagrindiniai atmosferos tarsos saltiniai miestuose yra mobilūs (automobiliu transportas), taip pat ir pramones bei energetikos tarsos saltiniai. Automobiliu transporto ismetami tersalai duoda didžiausia emisija i aplinka. Tyrimais nustatyta, kad daugiausia tersalu yra ismetama rytinio ir vakarinio piko valandomis, kai automobiliu transporto eismo intensyvumas mieste yra pats didžiausias. Automobiliu transporto ismetalai yra ypac dideli intensyvaus eismo miesto gatvese ir 2–5 m atstumu nuo važiuojamosios kelio dangos, o esant 6–10 m atstumui ju kiekiai staigiai sumažeja. Nustatyta, kad CO, NOx, CHx, SO2 koncentracijos tiesiogiai priklauso nuo automobiliu transporto eismo intensyvumo. Koncentracija tolygiai mažeja didejant atstumui nuo gatves važiuojamosios dalies. Tyrimai atlikti Vilniaus mieste 14 Žirmūnu gatviu vietu, kur skaiciuotas važiuojancio automobiliu transporto (lengvuju, vidutinio lengvumo, sunkiuju automobiliu) skaicius, pagal tai su COPERT programa nustatytos rytinio ir vakarinio pik...

Study of Gas–Solid Flow in a Multichannel Cyclone

Abstract This paper aims to analyse the problem of the gas–solid particle (SP) flow in the multichannel cyclone (three rings) with tangential inlet (KDG – equipment for separation of solid particles from gaseous fluid flow). It provides a review of experimental and theoretical papers that describe cyclones with a very complex swirling flow. The paper describes the experimental study and numerical modelling of the flow in the multichannel cyclone, the height of which is 0.72 m and the diameter – 0.50 m; with the height of the cylindrical part amounting to 0.29 m, the height of the conical part – 0.43 m, and the inlet area – 0.29×0.034 m2. The multi-functional measuring instrument Testo 400, intended for measuring the flow velocity in the inlet and outlet of the multichannel cyclone was used in experimental studies of the cyclone. Three-dimensional transport differential equations (Reynolds) for incompressible turbulent flow inside a cyclone are solved numerically using finite volume-based numerical method ...

Investigation of volatile organic compounds (VOCs) emission beyond the territory of oil terminals during different seasons

Abstract The present paper deals with an important environmental issue: air pollution with volatile organic compounds (VOCs) in oil terminals. In attempt to determine the dependence of VOCs concentration in the air on the wind speed and oil loading intensity analyses were carried out during shorter time intervals, when the fluctuations of ambient temperature are minimal (1−3) °C. VOCs concentrations were analysed by gas chromatography method in different chosen observation posts during different seasons. A complex analysis of experimental study and impact of meteorological conditions on the air pollution was performed taking into account the oil loading intensity in oil terminals and the types of loaded oil products. A new indicator was introduced for the analysis of the obtained results—a loading indicator that characterizes the amount and type of handled products as well as the number and type of operations carried out in the terminal. The dependence of the change of VOCs concentration on the loading in...

Geležinkelio transporto taršos sunkiaisiais metalais dirvožemyje tyrimai ir ivertinimas

Santrauka Vienas is pagrindiniu dirvožemio tersikliu yra transportas. Jam Lietuvoje priskiriama 75 % tersalu. Pastaruoju metu mokslineje ir žemes ūkio literatūroje itin dažnai minimi sunkieji metalai. Tai grupe cheminiu elementu, kuriutankis didesnis kaip 5 g/cm3. Paprastai sunkieji metalai aptinkami ne elementu, o drusku ir kitu junginiu formos. Is 100 ar dau‐giau elementu apie 80 galima priskirti metalams, o 3/4 ju‐ sunkiesiems metalams. Biologiskai svarbūs ir tirti metalai yra kadmis, gyvsidabris, svinas, cinkas, chromas ir varis. Dirvožemio užterstumas ‐ tai rimta geležinkeliu sistemos aplinkos apsaugos problema. Geležinkelio transportas gali tureti itakos dirvožemio užtarsai naftos produktais, nedideliais kancero‐geniniu medžiagu kiekiais, sunkiaisiais metalais. Tyrimai atlikti geležinkelio ruožuose: Vilnius ‐ Naujoji Vilnia (Pavilnio regioninis parkas), Ignalina ‐ Svencioneliai Aukstaitijos nacionaliniame parke, misko teritorijoje netoli Svencioneliu, Radviliskyje ir vienas Melnrages gyvenvietes ter...

Determination of cadmium in a municipal sewage sludge based compost by spectrophotometric method

Abstract An experimental investigation on cadmium detection in the municipal sewage sludge (MSS) based compost by spectrophotometric method, has been carried out in a scientific laboratory of the Department of Environmental Protection of Vilnius Gediminas Technical University. For this purpose a reagent of 5, 7 dibromo — 8 — hydroxyquinoline (DBHQ) has been used. In reaction of the reagent with cadmium a leach of greenish‐yellow has been produced and absorption wavelength of spectrophotometer has been chosen at visible UV length, about 396 nm. The method is simple to use and sensitive enough for the detection of cadmium amounts in solid samples. The investigation has been carried out in two ways of samples preparation: mineralization, for the total cadmium amounts investigation in the compost and investigation of 24 h batch leach of compost for soluble cadmium values detection.

Modelling the noise generated by railway transport: statistical analysis of modelling results applying CADNAA and IMMI programs

Abstract To avoid a negative impact on human health, Lithuania, alike other countries, pays full attention to reducing noise in the environment. One of the implemented actions against noise sources and the way to reduce it is a composition of strategic maps. Research focuses on the performance of modelling noise dispersion employing CadnaA and IMMI software and proposes the analysis of the actuarial reliability of the above-mentioned programs. The dispersion of the noise generated by railway transport has been modelled in the dwelling area of Klaipeda railway station. The chosen zone covers a sector of 500 m in length and is situated at the distance of 150–200 m from this sector. Modelling noise dispersion maps applying both programs displayed that the maximum level of noise caused by day and night railway transport was registered near railway during both periods of time and varied from 75 to 80 dBA, whereas at the locations of 150–200 m that are more distant from the railway line, the level of noise grad...

Dispersion modelling of solid particles from vehicle exhaust into the atmosphere@@@Autotransporto į atmosferą išskiriamų kietųjų dalelių sklaidos modeliavimas

Department of Environmental Protection, Vilnius Gediminas Technical University, Saulėtekio al. 11, LT-10223, Vilnius, Lithuania E-mail: vaitiek@ap.vgtu.lt Th e research carried out in major towns has revealed that the highest level of pollution is registered during the morning and aft ernoon rush hours when traffi c intensity is the greatest. Traffi c pollutant emissions are very concentrated in streets of high traffi c intensity, but at a distance of 1–2 meters and especially 4–6 meters from the carriageway their amount is sharply reduced. Th e concentration of aerosol particles is directly dependent on the intensity of the traffi c fl ow. Th eir concentration is evenly reduces with the distance from the carriageway, and at a distance of 300 m particles tend to deposit on the ground surface. Th e research was carried out at 14 selected points of Vilnius, Žirmūnai neighbourhood streets, where the number of vehicles passing by (light, medium, heavy traffi c) has been counted. Th e obtained results have been applied to determine the mean concentrations of solid particles (SP) in the morning and aft ernoon rush hours. Th e data were used for the mathematical modelling of solid particle dispersion in Žirmūnai neighbourhood. In some cases, the maximum allowable concentration (MAC) of solid particles was exceeded.