Constructed wetlands, as an alternative to conventional methods, are systemsdesigned on the basis of the application of natural purification processes that take placein watery and swampy overgrown habitats, with certain microbiological groups. In thewastewater treatment process various types of constructed wetlands can be combinedto achieve a higher efficiency of the purification.In this study, the removal effectiveness of the organic substances from municipalwastewater was monitored, using a horizontal pilot - scale constructed wetlandutilizing Typha latifolia and Phragmites australis. In addition to the measurement oforganic substances content through COD, BOD and KMnO4 consumption, and totaldissolved substances (TDS) in influent and effluent, microbiological sample analysis wasperformed, monitored by total number of coliform bacteria.The aim of this study was to calculate the effectiveness of removing organicsubstances from municipal wastewater, depending on the season, as well as theeffectiveness of eliminating total coliform bacteria.The results of one-year research have shown that the removal effectiveness ofthe organic substances from municipal wastewater, expressed as the chemical oxygendemand (COD), was the highest in summer - 87.82% ± 2.83%, and the lowest in thewinter - 64.51% ± 5.89%. During the study, effectiveness of elimination of total coliformbacteria was 97.88 ± 0.80% and total dissolved substances 71.27% .

Environmental care, higher requirements for quality of effluent, high cost of conventional wastewater treatment, and increased energy costs required for their work, have led scientists to more comprehensive research on a possibility of using a constructed wetland in wastewater treatment technology. Constructed wetlands are artificially shaped swamps with the aim of creating conditions conducive to the purification of wastewaters flowing through them. They are used for treatment of municipal wastewater from small settlements and a small industrial facility, as well as other types of wastewater. The educational pilot scale constructed wetland on which the research was conducted is located in the area of Bihać municipality, on a plot used by the Biotechnical Faculty in Bihać. The pilot scale constructed wetland for wastewater treatment covers an area of 20 m2 and is dimensioned for 10 equivalents of population. In this research we have examined the effectiveness of domestic wastewater treatment in the "Grmeč" Teaching Center using pilot scale constructed wetland. Plants planted in the constructed wetland were Typha latifolia and Phragmites australis, and the substrate was made of sand and pebbles of different granulations. The recipient of purified wastewater is the Drobnica stream, which is about 10 m away from the site. The research was conducted in May, with the flow varied depending on a weekly student workload. Efficiency of purification using constructed wetland depended on flow rate and organic wastewater load, ranging from 37.15% at a minimum flow of 9.89x10-6 m3/s and HPK values of 35 mgO2/L, up to 89.48% at the highest flow value of 2.51x10-5 m3/s, and HPK values of 189 mgO2/L. The highest concentration of ammonia in the influent was 145.62 mg N/L, and the lowest concentration of ammonia in the effluent was 6.31. mg N/L.

The aim of this study was to determine the polycyclic aromatic hydrocarbons (Polycyclic aromatic hydrocarbon; PAH) with a focus on benzo (a) pyrene in smoked chicken produced in controlled conditions, changing the temperature values and time at constant pressure. The technological process of thermal degradation, drying and smoking semi-dry meat products of poultry meat is done in automated thermal chambers. The current process of smoking is performed by heat treatment to make the temperature at the center of the product 72° C for 40 minutes, followed by smoke at a temperature of 65° C, to achieve certain characteristics (odor, color). First category deboned chicken meat was used for testing. It was prepared in accordance to the familiar preparing raw material procedure for process of smoking already existing process of smoking is compliant with speci€c knowledge in science as well as principles of good manufacturing practice with a special focus on the time and temperature of smoke that led to certain changes in terms of the sensory properties of smoked products like presence and said polycyclic aromatic compounds (PAHs). The product was smoked at various temperatures ranging between 52.5 and 62 °C, over 10 to 30 minutes. In determining PAH compounds (polycyclic aromatic hydrocarbons), has been allocated said benzo (a) pyrene which is an indicator of the presence of harmful substances in products. Smoked meat changed the way smoking was ranked very acceptable

: Ultrasonic flowmeter works on the principle of transmitting and returning ultrasonic waves that pass through the liquid, ie. fluid, and is used to measure the speed of fluid movement through a pipeline or some other structural form of fluid movement. By knowing the velocity of the fluid and the cross-sectional area of the pipeline or other system, the value of the volumetric or mass flow can be obtained indirectly. Fluid flow measuring device model OMNI TDI 200H owned by the laboratory of the Biotechnical Faculty was used for the first time to measure the flow of purified water at the outlet of the plant device of the training center "Grmeč", built as a pilot plant. The paper will describe the role and importance of flow measurement by the conventional method and present the results of the trial operation of an ultrasonic flow meter, model OMNI TDI 200H.