The ratio of concentrations of total nitrogen and five-day biochemical oxygen demand in the sanitary wastewater of an energy infrastructure facility in Serbia is many times higher than usual, resulting in only half of the total nitrogen being eliminated in wastewater treatment plants (membrane bioreactor with anoxic and aerobic reactors) by denitrification. The first step of analysis was mathematical modelling of the composition and origins of the input wastewater. The model was developed based on the scientific literature data on composition of human excrement and the data on composition of water used for sanitary purposes. Next, it was successfully verified by comparisons to the experimental data of the wastewater composition. In the next step, a model for wastewater treatment simulation was created by using the BioWin software (Envirosim Associates, USA) in order to examine functioning of the plant and test the effects of several possible modifications of the process. A good agreement with the qualities of the influent and effluent determined by laboratory analyses was achieved after model calibration. The results of simulations showed a tenfold decrease in the total nitrogen concentration and a fortyfold decrease in the total phosphorous concentration in the effluent after introducing the following modifications to the simulated process: ferric chloride dosing, increasing dosing of acetate in the anoxic reactor by a factor of seven, increasing of the waste activated sludge rate by a factor of four and increasing the recirculation flow rate by a factor of three.

The evolution of wireless communication technologies has been marked by significant advancements, with 5G and its successor, 6G, at the forefront of this transformative journey. 5G, the fifth generation of wireless technology, can revolutionize connectivity by delivering ultra-fast data speeds and low latency, enabling a plethora of applications, from augmented reality to autonomous vehicles. The integration of mobile edge computing (MEC) in 5G networks can further augment network performance by bringing computation closer to the data source, facilitating real-time data processing and minimizing latency. Network slicing, a key feature of 5G, allows the creation of customized virtual network segments to segregate traffic based upon user requirements. Most publicly available 5G and private 5G systems do not implement these features. This work provides an example implementation of high performance 5G Standalone (SA) and key 6G features in the context of modern drone operations. Unparalleled data rates will be available soon and MEC will play a pivotal role in 6G. Moreover, 6G will introduce radio access network slicing, allowing for even more granular customization of network resources. Key 5G and 6G features coupled with mobile edge computing, network slicing, and radio access network slicing, represent an evolution that promises to reshape the way we connect, communicate, and compute in an increasingly digital world.

This paper describes the two-step method used to analyse the factors and aspects influencing human error during the maintenance of mining machines. The first step is the cause-effect analysis, supported by brainstorming, where five factors and 21 aspects are identified. During the second step, the group fuzzy analytic hierarchy process is used to rank the identified factors and aspects. A case study is done on mining companies in Serbia. The key aspects are ranked according to an analysis that included experts who assess risks in mining companies (a maintenance engineer, a technologist, an ergonomist, a psychologist, and an organisational scientist). Failure to follow technical maintenance instructions, poor organisation of the training process, inadequate diagnostic equipment, and a lack of understanding of the work process are identified as the most important causes of human error.

This work gives a model of OH&S risk assessment for the workplace driller in the process of implementation the geological exploratory works. Model of OH&S risk assessment for the workplace driller is based on ISO 31010 Standard and fulfilling the requirements of OHSAS 18001 and legal regulations. In this case, a partially adjusted and optimized Kinny method was used. Model of OH&S risk assessment provides a reasonable basis for development and implementation the system of occupational health and safety management in accordance with BS OHSAS 18001: 2008, since it is practically applied and tested in the organizations dealing with geological exploratory drilling, such as 'Geops Balkan Drilling Services' Ltd., Drillex International Ltd., International Drilling Service Ltd. and Stara Planina Resources Ltd.

This paper points out the opportunities and needs for integration the maintenance function with other management systems in accordance with the requirements of ISO 9001, ISO 14001, OHSAS 18001 as well as the new Standard ISO 55001. It defines the flowchart of risk assessment in the procedure of mining equipment maintenance as well as the methodological framework for risk assessment in the procedure of mining equipment maintenance. The proposed risk assessment model defines the criteria for probability of occurrence the hazardous events as the consequences that may arise, as well as the mechanisms for control the assessed risk. This risk assessment model can be also put in the context of integrated risk management.

This work presents a methodological approach to the identification of aspects and evaluation the environmental impact, in order to optimize the model of risk assessment of environmental pollution for the mining projects, in order to improve and advance this process on the example of the project 'Magnesite Mining in the Deposit Cavlovac - Masnica' in the area of the municipality Cajetina. .