Due to the natural energy sources used in constructed wetlands, minimal energy and chemicals are required for wastewater treatment. For the successful wastewater treatment via constructed wetlands, adequate pretreatment and a sufficient amount of oxygen are crucial. Constructed wetlands can be used to treat industrial wastewater, such as wastewater from the dairy industry, with prior degreasing. This study was conducted on a horizontal flow pilot constructed wetland located on a plot of land used by the Biotechnical Faculty in Bihać. The constructed wetland consisted of two fields planted with rushes (Typha latifolia) and reeds (Phragmites australis). The substrate and plants were not changed during the experimental period. We monitored the efficiency of industrial wastewater treatment (wastewater from the dairy industry) by season, varying the flow rate as well as the hydraulic retention time of the water in the device. The quality of the influent and effluent was monitored by determining analytical parameters. The constructed wetland showed the highest efficiency in the summer period, with a hydraulic retention time of 6 days, with removal efficiencies of 98.03% for ammonia, 98.19% for total nitrogen, 95.27% for total phosphorous, 94.50% for COD and 97.73% for BOD5. The organic substance removal efficiency across all four seasons was 94.68%.

Rapid population growth requires more intense production of food industry, with two major consequences: significant amount of food processing residues and more sewage sludge originating from biological wastewater treatment plant. Sludge is a big concern for the disposal for wastewater treatment plant. The European Union makes an effort regarding the reduction of organic fractions disposed at a landfill. Composting is a cost-effective and ecological-friendly alternative for managing biodegradable organic fractions. Experiments of co-composting of sewage sludge, green waste and food waste, at carbon/nitrogen ratios 8.75, 18.00 and 24.90, were performed during three months by monitoring temperature, pH, moisture, carbon and nitrogen proportion, carbon/nitrogen ratio, and germination index. The results showed that co-composting of sewage sludge, green waste, and food waste is effective and results in the production of quality compost.

Heavy metal pollution is a significant environmental problem and has a negative impact on human health and agriculture. Phytoremediation has recently emerged as an efficient heavy metal remediation technology. To examine the phytoremediation potential, an experiment was conducted, where the influence of high and low concentrations of heavy metals, lead, cadmium and zinc (Pb, Cd and Zn) on the phenological characteristics of corn (Zea mays), as well as their accumulation in the underground and aboveground part was monitored. The experiment was carried out in outdoor conditions in pots in which corn was planted and the soil was contaminated with heavy metals in concentrations below and above the maximum allowable concentration prescribed by the Ordinance. The experiment lasted 45 days. By processing the results, statistically significant differences in plant development were determined.The highest concentration of Zn was recorded in the aboveground part of the plant, the stem in the amount of 24.443 mg/kg, and the lowest concentration in the leaf 0.216 mg/kg. The highest concentrations of Cd and Pb were recorded in the root, for lead 26.610 mg/kg and in the stem for cadmium 30.490 mg/kg, which is a statistically significantly higher established value compared to other parts of the plant.

Phytoremediation has proven to be a suitable method for removing heavy metals from the soil with the help of plants. To examine the phytoremediation potential, the experimental study monitored the influence of high and low concentrations of heavy metals (Pb, Cd, and Zn) on Helianthus annuus L., as well as their accumulation in seeds, roots, stems and leaves. The experiment was carried out during one growing season in outdoor conditions, in pots with a volume of 5L in which Helianthus annuus L. was planted, and the soil was contaminated with these heavy metals in concentrations below and above the maximum allowable concentration prescribed by the Rulebook on Determining Permissible Quantities of Harmful and Dangerous Substances in Soil and Methods of Their Testing. After growth and development of the plant, the experimental research examined the accumulation potential of the plant, the growth of the plant itself and its ability to survive depending on different concentrations of heavy metals. By processing the obtained results, statistically significant differences of heavy metals were determined in individual parts of the plants, depending on the applied concentration. The highest concentration of Zn was recorded in the leaves of the plant in the amount of 18.21 mg/kg, and the lowest concentration in the stem, 3.92 mg/kg. The measured values of heavy metals Cd and Pb differ from the above because the lowest concentrations of these heavy metals were recorded in the seed, and were 12.02 mg/kg for Pb and 9.20 mg/kg for Cd, which is a statistically significantly lower determined value relative to other parts of the plant.

The biological performance of flocculent sludge in sequencing batch reactor for the treatment of fish canning wastewater was evaluated in terms of organic matter and nutrient removal by gradual increase of salt concentration in the nitritation-denitritation process. Salinity negatively affected the biological system performance in a way that reduced organic and nutrient removal. The removal efficiency of organic matter and nitrogen showed good performance below 20 g NaCl/L, while phosphate accumulating organisms activity was deteriorated and declined during whole experiment. Nitrogen removal occurred as ammonium oxidation with nitrite accumulation. Nitrite reduction was not affected by salt concentration.

The accumulation of organochlorines (OCs) in mussel tissue depends on the physiological and biochemical status of the organism and its interaction with the environment. Mytilus galloprovincialis, 2- and 1-year-old mussels, sampled from Mali Ston Bay, a reference area, and transplanted to Kaštela Bay in cages, were used for the assessment of OC levels and influence of biological parameters on accumulation. Results of bimonthly exposures during one year highlighted that OC accumulation decreases with increasing mussel age. Polychlorinated biphenyls (PCBs) and p,p′-dichlorodiphenyltrichloroethane (p,p′-DDTs) increased, while organochlorine pesticide (OCP; i.e., HCB, lindane, heptachlor, and aldrin) variations were very low. Statistical analysis generally did not confirm the significant effect of lipid content on the accumulation of OCs in mussel tissue. OC levels in mussels were below the maximum permitted levels for human consumption (European Commission).

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% .

s As a result of globalization, entry of foreign capital and the need to achieve greater competitiveness of companies, interest in understanding the organisational culture in Bosnia and Herzegovina in recent years is growing. In an era characterized by rapid adaptation of organisational performance to changes imposed by the market environment, organisational culture and economic performance are becoming an indispensable factor of success. Managers who want to achieve superior business results are required to be familiar with the national culture and to be able to create an organisational culture in their companies as this can have a significant impact on improving the economic performance but also on many other organisational outcomes. The aim of this paper is by giving explanation on the relation of dimensions of organisational culture and economic performances, provide guidelines to top managers in companies in Bosnia and Herzegovina for initiation of appropriate actions to change the organisational culture in your company in order to improve various organisational outcomes. The research included 334 middle managers, employees in companies in Bosnia and Herzegovina. Results of the research have found existence of statistically significant relationship between organisational culture and the economic performance of the companies in Bosnia and Herzegovina.

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.

In this work was used activated sludge from the WWTP (wastewater treatment plant), in which with technique accumulation nitrificants and denitrificants, were prepared mixed bacterial cultures which showed the ability nitrification of ammonia- nitrogen to nitrate, as well as the ability of denitrification of nitrate nitrogen to gaseous nitrogen in municipal wastewater. As carbon source in the process of biological denitrification was used sodium acetate, in the ratio C/N=1 and C/N=2. Activity of mixed microbial cultures for removal components with nitrogen was determined by measuring the concentration of organic matter, expressed as COD, ammonia-nitrogen, nitrite, nitrate, pH, concentration dissolved oxygen, and the concentration of microbial biomass. Keywords: municipal water, activated sludge, nitrogen removal

The aim of this work was to investigate the efficiency of nitrogen removal from municipal landfill leachate with a microbial culture in 3 L batch bioreactor. The microbial culture, originating from landfill leachate, was prepared by an enrichment culture technique. Organic compounds measured as chemical oxygen demand (COD) of 400–600 mg L–1 and high concentrations of ammonium nitrogen (NH4 +-N) 270–312 mg L–1 characterized the landfill leachate as a mature leachate. The rate of ammonium nitrogen removal was 24.5 mg NH4 +-N L–1 h–1. Nitrification rate was 20.1 mg NOx–-N L–1 h–1. Denitrification was performed with the addition of sodium acetate as external carbon source in ratio C/N 2 and 4. Sodium acetate was insufficient for complete denitrification at C/N 2. Complete denitrification at C/N 4 was performed at denitrification rate 8.3 mg NO3–-N L–1 h–1.