Water pollution by heavy metal contaminants was emerging as a grave problem for the aquatic systems in the environment. Microalgae being photoautotrophic and heterotrophic are promising traits that provoke researchers to use them in treating industrial wastewater. Owing to the advantageous feature of biochar, microalgal biochar with chemical and biological modification was used in the production of value-added products, and their spent sorbent was used for bioremediation. The incorporation of microalgal biomass with magnetic nanoparticles will remove hazardous metals from the aquatic environment. Integration of microalgae with nanoparticles used in the removal of chromium and selenium metal ions was discussed in the present review with the removal mechanism. The economic perspectives, advantages and challenges of using the integral magnetic microalgal system in the treatment process were also evaluated in the present study providing insight for the researchers to use it in the large-scale applications of multi-pollutant removal.
Residual biomass from the agro-forestry industry has become an attractive bioenergy resource for developing countries in tropical regions due to its ease and adaptability in the short and medium term. However, these projects must be comprehensively analyzed to select the best alternative that adapts to each location with minimal risk to investors, the government, and the benefited communities. Therefore, this work used a multi-criterial analysis (MCA) to compare and select the best alternative energy source power plant capacity to produce energy in northern Costa Rica. The study compared eight alternatives based on residual biomass (proceeding of four agro-forestry crops) and diesel (current option) sources in four power plant capacities (5, 15, 30, and 50 MW). The MCA considered spatial–technological, economic, and environmental criteria; then, the top three were used in the uncertainty analysis (Monte Carlo simulation and sensitivity test) to recommend the best alternative. The results suggested that bioenergy from residual biomass would be sustainable compared to diesel due to lower supply logistics, affecting a value of energy generation between 10 and 26% lower and a reduction in greenhouse gas emissions between 11 and 21%. The power plant capacity at 15 MW was the most attractive alternative because it had better MCA and uncertainty analysis results. Finally, our results support the possibility of bioenergy based on residual biomass as an alternative to non-renewable energy for tropical regions that allow greater energy security and efficient use of local resources.
The consortium between microalga and fungus can be used in wastewater treatment due the combination of their metabolisms, but this application in petroleum-produced water has not been verified in the literature. This study investigated the microalga-fungus consortium for the treatment of oil-produced water by varying the initial TPH (total petroleum hydrocarbons) concentrations in the effluent between 312 and 2500 mg L−1, the salinity between 5 and 50 g L−1, and at different concentrations of nitrogen (25, 50, and 100 mg L−1) and phosphorus (approximately 30 mg L−1). A synthetic effluent (modified BG-11 medium) with crude oil as a carbon source was used. The microalga Tetradesmus obliquus LCE-01 and the filamentous fungi Aspergillus niger, Penicillium oxalicum, and Cunninghamella echinulata were the species chosen. The experiments were performed in an aerated bubble column reactor at a rate of 1.5 vvm, using illumination of 100 µmol m−2 s−1 (for microalgal experiments) and room temperature between 30 and 35 °C. By cultivating all fungi and microalga separately and in co-culture, it was found that the highest contribution to TPH removal was made by the filamentous fungi, with C. echinulata achieving removal efficiencies between 90 and 95%. With respect to salinity, it was observed that T. obliquus was able to survive up to concentrations of 25 g L−1, and C. echinulata not only grew in all saline concentrations tested but also significantly removed TPH at rates between 80 and 95%. The co-cultivation of the fungus with the microalga removed higher percentages of nitrogen (as nitrate), of 63.4, 44.4, and 31.7%, considering initial concentrations of 25, 50, and 100 mg L–1, respectively. A similar average of 36.58 ± 4.82% of phosphorus removal percentage was found for all experiments (initial phosphorus concentration of 30 mg L–1). When the real effluent was tested, TPH, nitrogen, and phosphorus were removed efficiently by the microalga–fungus consortium presenting higher efficiency than the monocultures.
Given the variable nature of wind speed and the importance of accurately determining the energy that can be generated at a given site, understanding the wind speed at different time scales is crucial. In addition to differences within a very short period (i.e., hourly and daily), these changes are also pronounced throughout the seasons. They are affected by the atmospheric conditions and the terrain's complexity. Therefore, this study investigates the seasonal wind speed variability and its impact on the potential energy generation in a representative study case of Koznica, the mountainous region in Kosovo. The wind speed measurements campaign started in May 2019 and ended in April 2020; the measurements were made at a 10 min time scale. Ground measurements show that the wind direction is mainly northwest and southeast. Then, the wind speed and potential energy generation variability analysis were conducted for three different measurement heights. The results show that winter and spring have the highest potential wind energy capacity with an average speed of 6.7 m/s. In comparison, the average wind speed is 6.12 m/s. Potential energy generation for each season (i.e., spring, summer, autumn, and winter is as follows: 64,396.7, 22,040.3, 42,539.3, and 46,417.2 MWh/year, respectively, while the average capacity factor is 25%. Solution-oriented findings from this study might provide valuable insights to policymakers and investors regarding wind power energy exploration in Kosovo and other places with similar geo-climatic conditions.
Climber species tend to provide various important ecosystem services within the habitat condition. Very little study was conducted on climber diversity, biomass, carbon (C) stock, and CO2 mitigation under urban setup. To address this research gap, the present study was conducted to evaluate the phytosociological attributes, diversity, climbing mode, host specificity, and their potential role in combating climate change. The study was carried out across the four directions of Ambikapur in various seasons using a random sampling method. Results revealed 11 species of climbers representing 9 families across the various study sites in different seasons. Most of the climber species were found to be herbaceous vine and woody wine in nature followed by the higher representation of stem twiner as climbing mode. Variation in species diversity across the study sites revealed higher value toward the west direction as reflected by the beta diversity value. Further, species richness and diversity were mostly reported from the east and north direction. The higher biomass, C stock, and mitigation value were recorded for the south direction in various seasons. Species such as Ampelocissus latifolia, Cuscuta reflexa, Cryptolepis buchanani, Ipomoea quamoclit, Mucuna pruriens, and Thladiantha cordifolia reflected higher biomass accumulation followed by C stock and greater CO2 mitigation potential among the observed climber species across various sites in various seasons. The present study highlights the importance of climber species under the urban ecosystem as a potential alternative for regulating the urban ambient environment followed by mitigation of changing climate.
The global population is continually generating vast amounts of waste materials across various sectors, leading to environmental challenges associated with landfill disposal. This study aims to examine the leachate and the antimicrobial properties of several waste materials to explore their potential applicability in the construction industry. Here, ICP-OES analysis and Kirby Bauer test were conducted on ready-mix concrete plant (powder residues), precast industries, recycled alkali-activated materials, municipal solid waste incinerated (MSWI) bottom ash, MSWI fly ash, High alumina tailing, and High magnesia tailing, to explore their potential applicability in the construction industry. Aluminium, calcium, silicon, potassium, and magnesium were the major ions leached from the waste materials, with MSWI fly ash and bottom ash showing higher levels of heavy metal leaching. The levels of leached aluminium, barium, chromium, lead, and zinc from MSWI fly ash and bottom ash were quantified, with values reaching up to 28.7 ppm, 4 ppm, 3.9 ppm, 11 ppm, and 25 ppm, respectively. Additionally, all samples demonstrated some level of antimicrobial activity against Escherichia coli and Staphylococcus aureus, which could be related to their alkaline pH and the release of certain ions. Improper disposal of waste materials in an open environment can potentially lead to contamination by heavy metals and harmful bacteria, which can pose a significant health risk during handling. This study results provided valuable information regarding the safety of using these wastes in the construction industry.