Luka Traven

The biodrying process is a well-established method in solid waste management for reducing the moisture content of municipal solid waste (MSW), facilitating its mechanical treatment, enhancing energy recovery efficiency, and simplifying disposal. However, challenges such as variability in drying efficiency, seasonal fluctuations, and operational inconsistencies limit its optimization and broader applicability. This study undertakes a detailed evaluation of biodrying operations using Statistical Process Control (SPC) techniques to improve process stability and identify key factors influencing efficiency. Data collected over a one-year period from a waste management facility employing Herhoff Rotteboxes^® reveal an average drying efficiency of 28%, with notable seasonal trends showing reduced efficiency during summer and fall. A regression model analyzing waste load, operational parameters, and seasonal effects accounted for 25% of the variability in drying efficiency, suggesting additional factors like waste composition and microbial activity significantly impact the process. This study highlights the value of SPC tools in monitoring process stability and demonstrates how targeted optimization strategies—such as seasonal adjustments and refined loading practices—can enhance biodrying outcomes. By addressing gaps in current practices, these findings contribute to the advancement of waste management technologies and support the development of more efficient and sustainable systems for handling municipal solid waste.

We investigated the effectiveness of high-density polyethylene (HDPE) covers in reducing landfill emissions of hydrogen sulphide (H ₂ S), ammonia (NH ₃ ), and inhalable particulate matter smaller than 10 μm in diameter (PM ₁₀ ) at the Waste Management Centre Marišćina (Croatia) by comparing air quality data from 2018, prior to the installation of the HDPE cover, with data from 2021, post-installation. The results demonstrate a significant reduction in H ₂ S and PM ₁₀ concentrations (36.76 % and 24.18 %, respectively). However, NH ₃ levels unexpectedly increased by 20.48 %, suggesting the presence of additional sources of ammonia in the vicinity of the centre or changes in landfill microenvironment. Our findings highlight the effectiveness of HDPE covers in controlling specific landfill emissions and the need for a comprehensive environmental management strategy to address all pollutants. Future research should also investigate the long-term effects of HDPE cover on landfill emissions and how they could contribute to broader environmental goals, such as reducing greenhouse gas emissions and improving air quality.

Emissions of odorous compounds are major contributors to public opposition when siting waste management facilities. Thus, it is essential to understand how to minimise the concentration of odour-causing chemicals in ambient air surrounding such facilities. Although the concentration of pollutants in the atmosphere is a function of meteorology, there is limited data on the atmospheric parameters that drive ambient air concentrations of odour-causing substances in settlements near waste management facilities. Here, we analysed how temperature, wind direction, wind speed, atmospheric pressure and humidity impact the concentrations of hydrogen sulphide (H₂S) in the ambient air, a potentially toxic chemical and a chief contributor to noxious odours. The relative contribution of each variable was assessed using multivariate statistical analysis applied to an extensive data set of over 7,000 data points collected during 2021. Our results show that all tested atmospheric parameters significantly affected H₂S concentrations in ambient air. Wind direction had the greatest impact on H₂S concentrations, followed by temperature, humidity, atmospheric pressure and wind speed. Specifically, the concentration of H₂S was positively correlated with humidity and atmospheric pressure and had a U-shaped correlation with temperature. Atmospheric variables were able to explain 15% of variation in H₂S concentrations (R² = 15%), indicating the presence of other factors affecting H₂S ambient air concentrations. Our study shows that proper consideration of atmospheric parameters, especially wind direction and temperatures, is of uttermost importance when siting waste management facilities. The conclusions are broadly applicable to odorous compounds near waste management facilities, so adverse effects to human health and the environment can be minimised.

For some sound sources, the function of the square of sound pressure amplitudes on the sphere in the far field is an integrable function or can be integrated with geometrical simplifications, so an exact or approximated analytical expression for the sound power can be calculated. However, often the sound pressure on the sphere in the far field can only be defined in discrete points, for which a numerical integration is required for the calculation of the sound power. In this paper, two new algorithms, Anchored Radially Projected Integration on Spherical Triangles (ARPIST) and Spherical Quadrature Radial Basis Function (SQRBF), for surface numerical integration are used to calculate the sound power from the sound pressures on the sphere surface in the far field, and their solutions are compared with the analytical and the finite element method solution. If function values are available at any location on a sphere, ARPIST has a greater accuracy and stability than SQRBF while being faster and easier to implement. If function values are available only at user-prescribed locations, SQRBF can directly calculate weights while ARPIST needs data interpolation to obtain function values at predefined node locations, which reduces the accuracy and increases the calculation time.

The increasing exchange of goods by sea is contributing significantly to pollution in port areas. Although several methods have been developed to assess the environmental performance of ports, most of them have shortcomings including a qualitative-only approach and self-assessment of environmental performance. Therefore, there is a pressing need to develop a different approach based on quantitative measurements obtained through measurements at ports. In this paper we present the Port Environmental Index (PEI), a quantitative composite index of port environmental performance driven by IoT. The index allows for environmental measurements to be collected in real time or close to real time through sensors providing an assessment of a port’s environmental performance in real time. In addition, since the methodology for creating the index is standardised, the index makes it possible to compare different ports and rank them in terms of their environmental performance. As a proof of concept (PoC) this paper also describes the application of the index to the port of Thessaloniki (Greece).

The following study aims at assessing the health risks associated with the consumption of the most commonly consumed seafood in the north-western part of Croatia due to the presence of heavy metals. Samples of seafood were collected and analysed for lead (Pb), cadmium (Cd), and mercury (Hg) content. Analyses of Cd and Pb were carried out by inductively coupled plasma mass spectrometry (ICP-MS) whereas Hg content was measured using atomic absorption spectrometry (AAS). Metal concentrations were in the following order Hg > Pb > Cd for the gilthead seabream, European hake, sardines, and tuna fish whereas in the Patagonian squid cadmium (Cd) was the heavy metal with the highest concentration, with the order of other metals being Cd > Hg > Pb. The heavy metal concentrations have been used to address the health risks using the Estimated Weekly Intake (EWI), Target Hazard Quotients (THQ), and Hazard Indices (HI). The findings revealed that the concentrations of the tested heavy metals, expressed on a per wet weight basis, did not exceed the Maximum Residue Levels (MRL) for those compounds mandated by national Croatian legislation. However, the HI for Hg was above 1, indicating a risk of adverse health effects due to the presence of this heavy metal in the consumed seafood. We conclude that the consumption of certain type of seafood such as the tuna fish should be limited when sensitive segments of the population such as children, elderly and pregnant women are concerned. Our results strongly advocate for a more stringent seafood quality control in the region.

With this study we challenge the widely held assumption that sulphur-containing compounds in ambient air are good indicators of the presence noxious odours near waste management facilities. We analysed an extensive set of olfactometric data and data on the concentrations of hydrogen sulphide and trace sulphur compounds (TSCs) near a waste management facility in Croatia in 2021. The results show that the presence of noxious odours significantly correlates only with the concentrations of hydrogen sulphide and methyl mercaptan in ambient air but not with other measured TSCs. Thus, in addition to the measurement of pollutants in ambient air, Integrated Pollution and Prevention Control (IPPC) permits should mandate olfactometric measurements to detect and mitigate noxious odours near waste management facilities.