This paper presents the findings of an experimental investigation on the performance of a laboratory-scale spray dryer involving flue gas desulfurization. Using commercial hydrated lime as a sorbent, a systematic set of experiments were performed to evaluate SO₂ absorption capacity of the spray dryer. The experimentation involved accurate measurement of the spray drying characteristics, such as temperature and SO₂ concentration along the spray chamber, by varying the input and output variables. Tests were done to investigate the effects of spray characteristics, i.e., inlet gas phase temperature (120–180 ℃) and calcium-to-sulfur ratio (1–2.5), on SO₂ removal efficiency. The performance of the spray dryer was further evaluated based on the degree of conversion of calcium (sorbent utilization) after SO₂ absorption. Results indicated an increase in SO₂ removal efficiency by increasing the stoichiometric ratio and decreasing the temperature. Absorption efficiency of SO₂ beyond 90% was achieved at a stoichiometric ratio of 2.5. A high degree of conversion of calcium was realized at low stoichiometric ratios, with a maximum utilization of 94% obtained at a stoichiometric ratio of 1.5. The analysis of the final desulfurization product revealed the presence of sulfite with better conversion achieved at a stoichiometric molar ratio of 1.5. A significant amount of unreacted sorbent (63.43%) was observed at a stoichiometric ratio of 2, while samples collected at a stoichiometric ratio of 1.5 had the lowest concentration of unreacted Ca[OH]₂ (41.23%).

Long-term exposure to pollution from particulate matter in palm oil mills can result in chronic respiratory diseases, cardiovascular diseases and mortality. Particulate matter with a size of less than 2.5 µm (PM_2.5) has a greater impact than one with a size of 10 µm. The current PM cleaning equipment in palm oil mills consists of cyclones that are incapable of optimally filtering PM_2.5. For this reason, it is necessary to design cyclone applications for fine particle separation in palm oil mills. Normal cyclones are incapable of segregating particles smaller than 2.5 µm. This study's objective was to design a cyclone with a filter on the vortex detector. These cyclones are utilized in PM_2.5 fine particle filtration systems. Using computational fluid dynamics, cyclone performance is analyzed in terms of removal efficiency and pressure decrease. The research was conducted utilizing the Reynolds tress model with varying inlet velocities of 10, 15, 20, 25 and 30 meters per second. The filter is composed of boiler bottom ash refuse from palm oil mills; 0.310 meters is the height of the filter bed inserted in the vortex finder. The obtained results demonstrated that the PM_2.5 removal efficiency reached 98%, while the pressure decrease was only 93 Pa greater than that of conventional cyclones. Thereby, cyclone designs with bottom ash filters can be used to filter fine particulate matter, particularly particles smaller than 2.5 µm.

Based on the content analysis of the websites of 102 Spanish municipalities related to actions aligned with the 2030 Agenda and the Sustainable Development Goals (SDGs), the X-STATIS technique was applied to analyze the status and dynamic evolution of commitment to the SDGs in regional and local governments over the period of 2016–2021. The results show a low but increasing level of SDG commitment, which also varies significantly across municipalities and regions, as well as by SDGs, which can be attributed to the influence of several sociodemographic factors, such as the number of inhabitants, dependent population and population density. SDG8 and SDG11 stand out as the main priorities of the municipalities, while initiatives related to SDG5, SDG6 and SDG 17 are the least prioritized. The COVID-19 pandemic has marked a turning point in this regard, with greater importance being given to the SDGs more related to people and prosperity. Our findings help citizens and public authorities to understand sustainable regions and municipalities, assess their performance in relation to different dimensions of sustainability and identify key challenges for future improvements. Specifically, the results suggest that public policies should promote actions related to gender equality, drinking water and sanitation and partnerships, as well as favor investment in the regions and municipalities that are lagging behind, in order to improve their level of commitment to the 2030 Agenda and reduce inequalities. From an academic point of view, our results open a door for the analysis of possible trajectories in the implementation of the SDGs at regional and local levels and the study of their determinants.

The province of Zamboanga del Norte is endowed with ample water resources which are the primary sources of domestic water for the people in the area. Nevertheless, these water resources face several man-made and industrial activities that generate unwanted pollution. In this study, the physicochemical characteristics of the major rivers of Zamboanga del Norte, Philippines were investigated to know the present condition and assess the overall water quality. The physicochemical parameters that were investigated includes pH, temperature, nitrate-nitrogen (NO₃-N), total suspended solids (TSS), total phosphates ( PO₄ 2−) and total mercury (Hg). The results of the water analyses revealed that the pH, temperature, nitrate as NO₃-N and the total Hg were within the acceptable range prescribed by Department of Environment and Natural Resources (DENR) and World Health Organization (WHO). However, there was a significant increase of the total suspended solids (TSS) concentrations of 138±58.9,142.3±36.6 and 243±9.5 mg/L, respectively from downstream, midstream and upstream of Sindangan river. The total suspended solids (TSS) concentrations exceeded the permissible limit of 25–65 mg/L recommended by Department of Environment and Natural Resources (DENR). Furthermore, the data showed that all values of the total phosphates for all the river systems exceeded the prescribed limit. Thus, to maintain the water quality of these rivers, proper monitoring and government intervention are very much required.

Although the spatiotemporal characterization of droughts is a key step in the design and implementation of practical measures to mitigate their impacts, it is hampered by the lack of hydro-climatic data with sufficient spatial density and duration. This study aimed to assess the trends and spatial patterns of drought occurrence in the Ouergha catchment in northern Morocco, which has been identified as a hot spot for climate change and variability. The study combined data from various sources, including the North Atlantic Oscillation Index (NAOi); Western Mediterranean Oscillation Index (WeMOi); a meteorological index (SPI), calculated using precipitation data; a hydrological index (SDI), calculated using precipitation data; and satellite images to calculate the Normalized Difference Vegetation Index (NDVI) and Normalized Difference Moisture Index (NDMI) from 1984/85 to 2016/17. The results showed that the adopted statistical analyses were effective in detecting the linearity and trend of drought in the Ouergha catchment scale. The correlations between various indices were moderate to strong between NAOi and SPI, WeMoi and SPI, as well as SPI and SDI, while the Mann-Kendall tests indicate an increasing trend of drought intensity in the catchment. During dry events, vegetation cover and moisture were maintained due to the presence of dam reserves. Overall, the study provides empirical evidence that confirms the severe drought conditions experienced in the Ouergha catchment. The unique set of data adds to the growing body of knowledge about drought in the region and underscores the urgency of preserving dam resources for sustainable use during future droughts.

Juru River is one of the most polluted rivers in Malaysia. A dye-degrading bacterial consortium has been isolated from the river’s sediment. This consortium JR3 consists of Pseudomonas aeruginosa MM01, Enterobacter sp. MM05 and Serratia marcescens MM06, which were able to decolorize up to 700 ppm of the Reactive Red 120 (RR120) dye under optimal conditions with limited substrate available. Substrate inhibition kinetics were investigated, and, based on the best model, Aiba, the maximum growth rate was 0.795 h^–1, while the saturation constant and inhibitory constant were 0.185% and 0.14%, respectively. In addition, the influence of various metal ions on the growth and decolorization rate of this bacterial consortium on RR120 was investigated. Chromium showed the weakest effect on the decolorization of 200 ppm RR120, with 73.5% removal and bacterial growth of 11.461 log CFU mL^–1. Zinc yielded the second weakest effect, followed by silver and lead, with percentages of RR120 decolorization of 63.8%, 54.6% and 50.5%, respectively. Meanwhile, cadmium, arsenic and copper reduced the decolorization of RR120 in consortium JR3 by half. Mercury strongly inhibited decolorization by 32.5%. Based on the least inhibited heavy metal in RR120 decolorization activity of consortium JR3, the best inhibitory kinetic model was Levenspiel, with a maximum growth rate of 0.632 h^–1, while the saturation constant and inhibitory constants were 15.08% and 0.5783%, respectively. The metal-tolerant azo dye-degrading bacterial consortium will be very useful in dye remediation in metal-laden polluted environments.