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 acetone, when the original concentration of the pollutant was 103 mg/m 3 , the filter treatment efficiency reached 95%. When the concentration of pollutants supplied into the biofilter is reduced and the filtration period is increased, the device treatment efficiency increases as well.

Studies were conducted by employing a new generation lamellar structure laboratory air purification device -a biofilter, capable of purifying airflow, polluted with gaseous pollutants. The internal structure of the biofilter is unique in that the bioload, upon which microorganisms dwell and propagate, is fitted onto uprightly arranged wavy lamellas -a layout that creates a capillary moistening effect. Thermally treated birch wood fibers and non-woven caulked materials were used as the bioload in order to increase durability of the load. This paper discusses the results of studies, performed to determine the efficiency of acetone, xylene and ammonia's biological breakdown processes. The conducted research revealed high efficiency of biological breakdown processes. With the acetone fumes concentration of 0,3 g m -3 running through the biofilter load at the velocity of 0,08 m s -1 and with the number of self-contained microorganisms 1,28·10 10 CFU/cm 2 , the biodegradation efficiency of the contaminant was 94%, with the xylene fumes concentration of 0,3 g m -3 running through the biofilter load and the number of self-contained microorganisms 2,45·10 8 cfu/cm 2 , the efficiency was 87%, and running 0,3 g m -3 concentration of ammonia fumes the efficiency was 88% with the number of self-contained microorganisms of 4,4·10 8 CFU/cm 2 . Using wavy lamellas with fastened load allows a longer contact time between the pollutant and the bioload compared to flat lamellas.

The aim of experimental tests is to determine aerodynamic characteristics in an improved multichannel cyclone with a spiral shell. This device was developed in order to improve the separation of ultra-fine solid particles from a polluted air (gas) flow. The purification device was designed at the Department of Environmental Protection (DEP) of Vilnius Gediminas Technical University (VGTU). Since the quality of air (gas) flow cleaning process is largely dependent on aerodynamic characteristics (air flow velocity and device's resistance), air (gas) flow velocity in a multichannel cyclone with a spiral shell and the overall resistance of the cyclone device depending on the number of channels and the positioning of curvilinear semi-rings were determined during experimental tests.