Alvydas Zagorskis

Investigation of cleaning efficiency of a biofilter with an aeration chamber

Abstract The investigation was carried out using a biological air‐treatment device, i.e. a biofilter with an aeration chamber filled with water saturated with biogenic elements. To accelerate the absorption of organic compounds, air polluted with volatile organic compounds is directed to a water reservoir installed in the lower part of the filter where organic compounds are destructed. In the process of aeration, microorganisms propagate in the chamber, degrading part of pollutants to harmless products, carbon dioxide and water. Since all hydrocarbons are water‐soluble, the aeration chamber is the first phase in a hydrocarbon degradation process. Application of such a polluted air‐feeding model improves the sorption qualities of a charge. When relative air humidity reaches 100%, water‐drops evenly distribute over the entire surface area of the charge and improve the activity of microorganisms. Having passed through the aeration chamber, polluted air is filtered via charges of a different origin, composed ...

Determination of Organic Matter by UV Absorption in the Ground Water

Abstract Organic matter in drinking water is determined by applying indirect determination methods used for quantitative measurements such as total organic carbon (TOC), chemical oxygen demand (COD), and biochemical oxygen demand (BOD). These analyses require expensive devices, harmful chemical reagents, and are time consuming. Standard water quality tests are inconvenient during start-up or reconstruction of drinking water treatment plants as samples need to be transported to a laboratory and no on-line measurements on plant performing efficiency are available. For practical purposes, less sophisticated and faster methods to determine organic matter are required. One of the methods could be ultraviolet absorption of water at 254 nm wavelength (UV254). It is a technically simple and fast method for determining natural organic matter, requiring neither expensive measurement equipment nor chemical reagents. The present article aims at investigating the possibilities of practical applications of UV254 method...

Investigation of cleaning efficiency of biological air‐treatment device with activated charge of different origin

Abstract In order to carry out an experimental investigation a biological air‐treatment device was used, namely, a biofilter with a charge of a different origin composed of zeolite, foam and wood chips. When mixing foam and zeolite together with wood chips for air treatment from volatile organic compounds, not only a biological but also adsorptive air‐treatment method is used. Using complex treatment technologies the device efficiency and the charge service period are improved. The investigation has shown that microorganisms, being predominant in the bio‐treatment process, can breed in charges of on inorganic origin made of natural zeolite and foam. While cultivating spontaneous microorganism associations in the charge, biofilter treatment efficiency was determined to be dependent on the sort of the supplied pollutant, concentration and filtration period. The charge filtration function was most efficient at a velocity of 0,1 m/s when the device was supplied with acetone‐polluted air. Cleaning air from ace...

Investigation into determining the humidity of charge used for biological air treatment

Abstract Microorganisms can reproduce only in such substrata which contain a certain amount of water and dissolved nutritious substances. Therefore, it is necessary to search for such charges that are distinguished by a large filtering surface and good humidity‐retaining properties. In experiments three types of materials ‐ wood, zeolite and foam ‐ were used as a charge for the biological air‐cleaning process. The charges were mixed up to maintain humidity necessary for the microorganisms in the biofilter as long as possible. The charges were placed into three different cassettes in the biofilter. The wood charge consisted of wood chips of 10–15 mm and that of zeolite contained 10–12 mm of zeolite granules. The foam rubber was cut into separate cubes each having the dimensions of 30×30×20 mm. Dependence of the charge humidity on the airflow rate, temperature, time and charge thickness was determined in the work. During the experiments the airflow rate reached 0.1–0.6 m/sec., and the temperature ranged fro...

Research into acetone removal from air by biofiltration using a biofilter with straight structure plates

The biological air treatment method is based on the biological destruction of organic compounds using certain cultures of microorganisms. This method is simple and may be applied in many branches of industry. The main element of biological air treatment devices is a filter charge. Tests were carried out using a new-generation laboratory air purifier with a plate structure. This purifier is called biofilter. The biofilter has a special system for packing material humidification which does not require additional energy inputs. In order to extend the packing materials durability, it was composed of thermally treated birch fibre. Pollutant (acetone) biodegradation occurred on thermally treated wood fibre in this research. According to the performed tests and the received results, the process of biodestruction was highly efficient. When acetone was passed through biofilters packing material at 0.08 m s−1 rate, the efficiency of the biofiltration process was from 70% up to 90%. The species of bacteria capable of removing acetone vapour from the air, i.e. Bacillus (B. cereus, B. subtilis), Pseudomonas (P. aeruginosa, P. putida), Stapylococcus (S. aureus) and Rhodococcus sp., was identified in this study during the process of biofiltration. Their amount in the biological packing material changed from 1.6 × 107 to 3.7 × 1011 CFU g−1.

Research and analysis of biogas produced from sewage sludge using a batch bioreactor

ABSTRACT The examined equipment is a batch bioreactor intended to produce biogas from sewage sludge, vegetal and other organic wastes. The maintenance of an optimal temperature and oxygen concentration inside the devise, as well as the intensity of mixing a substrate, result in methane CH4 actively generated by methanogenic bacterial colonies. Manufacturing biotechnologies and biogas deal with environmental protection, energy and economic problems. For research purposes, considering organic loading (hereinafter, VS/L), four different types of the packing material of sewage sludge, including VS/L = 3.5 g L−1, VS/L = 5.0 g L−1, VS/L = 10.0 g L−1 and VS/L = 15.0 g L−1, were used. The highest concentration of CH4 (75.1%) and yield of biogas (36.78 L d−1) were found using a packing material, the organic loading of which made 15.0 g L−1. Throughout the experiment, the temperature of the mesophilic process reached 35–37°C, and the concentration of oxygen was 0.0–0.1%. The research carried out has disclosed the dependencies of the components of biogas on the number of the days of the performed experiment. With reference to experimental research conducted at the laboratory, a small-sized batch bioreactor can be designed and successfully used in a small farm.

Modelling of a biofiltration process of volatile organic compound mixtures in a biofilter

ABSTRACT Currently, different methods for air clean-up from chemical pollutants are applied worldwide: adsorption, absorption, and thermal and catalytic oxidation. One of the most promising methods is biological air cleaning. The aim of this study was to test the performance of a developed biofilter with packing material of activated pine bark for biological air cleaning and to mathematically model the biofiltration processes. Comparative analysis of the modelling results for individual pollutants (butyl acetate, butanol and xylene) showed strongest dependence of the efficiency of xylene removal from the air on the amount and ratio of other substances (from 20% to 70%). Thus, the process of removal of pollutants (butanol and butyl acetate) that are easier to biologically decompose was obtained to be influenced to a lesser extent by the amount and ratio (%) of other components. The results also showed that the efficiency of butyl acetate removal mostly depended on the ratio of other substances in the mixture (from 15% to 100%), whereas the efficiency of butyl acetate and xylene removal mostly depended on the amount of other substances in the mixture (from 20% to 100%). With the parameters of the biofilter (height of packing material, incoming air flow velocity) and the pollutants to be removed known, the mathematical expression of the filter efficiency was found, which would allow to make theoretical calculation and selection of the most appropriate parameters of the device as well as to achieve maximum efficiency of air cleaning.