Livestock slurry, a potential secondary raw material source, boasts macronutrients like nitrogen, phosphorus, and potassium. Valuable fertilizer quality can be achieved through effective separation and concentration of these key compounds. This study evaluated the liquid fraction of pig slurry for nutrient recovery and its use as a fertilizer. The performance of the proposed technology train was evaluated using indicators, all within the scope of a circular economy framework. Due to the high solubility of ammonium and potassium species throughout the full pH range, a study examining phosphate speciation within a pH range of 4 to 8 was performed to improve the recovery of macronutrients from the slurry. This analysis subsequently generated two distinct treatment trains, one for acidic and one for alkaline conditions. A centrifugation, microfiltration, and forward osmosis-based acidic treatment system yielded a nutrient-rich liquid organic fertilizer with 13% N, 13% P2O5, and 15% K2O content. An alkaline valorisation method, involving centrifugation and membrane contactor stripping, created an organic solid fertilizer (77% N, 80% P2O5, 23% K2O), along with an ammonium sulphate solution (14% N) and irrigation water. The circularity assessment revealed that the acidic treatment process recovered 458 percent of the initial water content, while less than 50 percent of the contained nutrients were recovered, including 283 percent nitrogen, 435 percent phosphorus pentoxide, and 466 percent potassium oxide, producing 6868 grams of fertilizer per kilogram of treated slurry. The alkaline treatment process resulted in the recovery of 751% of water usable for irrigation purposes and a marked increase in the content of nitrogen (806%), phosphorus pentoxide (999%), and potassium oxide (834%). This led to the production of 21960 grams of fertilizer per kilogram of processed slurry. Nutrients recovery and valorization show promising results under acidic and alkaline treatment conditions, as the resulting products—a nutrient-rich organic fertilizer, a solid soil amendment, and an ammonium sulfate solution—conform to the European fertilizer regulations for potential agricultural use.
The escalating global trend of urbanization has resulted in the pervasive presence of emerging contaminants (CECs), including pharmaceuticals, personal care items, pesticides, and micro- and nano-plastics, in aquatic environments. The threat to aquatic ecosystems persists even when contaminant levels are low. To gain a deeper comprehension of CECs' impact on aquatic ecosystems, it is crucial to quantify the concentrations of these contaminants within these environments. Current CEC monitoring systems show an imbalance, disproportionately focusing on particular CEC categories, while data on environmental concentrations for other types remains scarce. Citizen science presents a possible means of enhancing CEC monitoring and determining their environmental levels. Incorporating citizen oversight of CECs, while potentially beneficial, also presents some hurdles and queries. The landscape of citizen science and community-based science projects, which study varying CEC groups in freshwater and marine ecosystems, is explored in this literature review. Moreover, we evaluate the benefits and drawbacks of citizen science-based CEC monitoring, offering practical guidance for appropriate sampling and analytical methods. The frequency of monitoring various CEC groups using citizen science reveals a notable disparity, as evidenced by our findings. Volunteer support for programs focusing on microplastic monitoring is more pronounced than support for programs concentrating on pharmaceuticals, pesticides, and personal care products. These distinctions, nevertheless, do not automatically imply that fewer sampling and analytical techniques are present. Our roadmap, finally, provides direction for the application of methods improving the monitoring of all CEC groups with the aid of citizen science.
Bio-sulfate reduction within mine wastewater treatment systems produces sulfur-compounded wastewater which contains sulfides (HS⁻ and S²⁻) and metal ions. Hydrocolloidal particles, typically negatively charged, are the biosulfur generated by sulfur-oxidizing bacteria in wastewater. DHAinhibitor Unfortunately, the recovery of biosulfur and metal resources is problematic using conventional methods. The recovery of valuable resources and control of heavy metal pollution in mine wastewater were investigated in this study by using the sulfide biological oxidation-alkali flocculation (SBO-AF) process, providing a technical reference. A study of SBO's contribution to biosulfur generation and the crucial factors involved in SBO-AF operation led to a pilot-scale wastewater treatment procedure for resource recovery. Results indicate a partial oxidation of sulfide, accomplished using a sulfide loading rate of 508,039 kg/m³d, dissolved oxygen levels of 29-35 mg/L, and a temperature of 27-30°C. Simultaneous precipitation of metal hydroxide and biosulfur colloids occurred at pH 10, driven by the interplay of precipitation capture and adsorption-based charge neutralization. Initial wastewater analyses revealed manganese, magnesium, and aluminum concentrations of 5393 mg/L, 52297 mg/L, and 3420 mg/L, respectively, along with a turbidity of 505 NTU; treatment resulted in a decrease to 049 mg/L, 8065 mg/L, 100 mg/L, and 2333 NTU, respectively. DHAinhibitor Sulfur and metal hydroxides were the principal substances found in the recovered precipitate. On average, the sulfur content was 456%, the manganese content 295%, the magnesium content 151%, and the aluminum content 65%. The economic feasibility analysis, along with the preceding findings, unequivocally highlights the substantial technical and economic benefits of SBO-AF in extracting resources from mine wastewater.
The foremost renewable energy source worldwide, hydropower, offers benefits like water storage and operational versatility; however, environmental impacts are substantial. The pursuit of Green Deal targets requires sustainable hydropower to find a delicate balance among electricity generation, its effects on ecosystems, and its societal advantages. The European Union (EU) is employing digital, information, communication, and control (DICC) technologies as a strategy for effectively supporting both green and digital transitions, acknowledging and addressing the trade-offs inherent in this complex undertaking. This study presents how DICC fosters the ecological integration of hydropower into Earth's various spheres, emphasizing the hydrosphere (water quality/quantity, hydropeaking control, flow regimes), biosphere (riparian health, fish habitats, migration routes), atmosphere (methane emissions and reservoir evaporation), lithosphere (sediment transport, reducing seepages), and anthroposphere (combined sewer overflow pollution, chemical waste, plastic/microplastic contamination). The following discussion comprehensively analyzes the pivotal DICC applications, corresponding case studies, difficulties encountered, Technology Readiness Level (TRL), advantages, limitations, and synergistic effects on energy generation and predictive operation and maintenance (O&M) methodologies, all in relation to the aforementioned Earth spheres. The European Union's important priorities are highlighted for consideration. Despite the paper's main emphasis on hydropower, analogous arguments apply to any artificial obstacle, water retention facility, or civil engineering project that alters freshwater systems.
In recent years, worldwide cyanobacterial blooms have grown more prevalent due to the compounding pressures of global warming and water eutrophication. The resulting suite of water quality problems includes, but is not limited to, the noticeable odor problems affecting lakes. During the latter stages of the bloom, a substantial buildup of algae occurred on the surface sediment, posing a significant risk of odor pollution in the lakes. DHAinhibitor Among the common odorants originating from algae, cyclocitral stands out as a significant contributor to the smell of lakes. To assess the impact of abiotic and biotic factors on -cyclocitral levels in water, this study employed an annual survey of 13 eutrophic lakes in the Taihu Lake basin. The sediment's pore water (pore,cyclocitral) showed a pronounced enrichment of -cyclocitral, exhibiting an average concentration approximately 10,037 times that of the water column. Structural equation modeling showed that algal biomass and pore-water cyclocitral directly impact the concentration of -cyclocitral in the water column. Total phosphorus (TP) and temperature (Temp) supported the growth of algal biomass, which further contributed to increasing -cyclocitral production in both the water column and pore water. It was evident that increasing Chla to 30 g/L substantially increased the influence of algae on pore-cyclocitral, effectively positioning it as a primary regulator of -cyclocitral concentrations in the water column. Our study thoroughly investigated the effects of algae on odorants and the dynamic regulatory processes within complex aquatic ecosystems, unearthing the important contribution of sediments to -cyclocitral in eutrophic lakes. This critical finding advances our understanding of off-flavor evolution and enhances future strategies for odor management in these environments.
The acknowledgment of coastal tidal wetlands' significance, encompassing their contributions to flood protection and biological conservation, is quite justified. Essential for the quantification of mangrove habitat quality is the accurate measurement and estimation of topographic data. This study introduces a novel approach to swiftly generate a digital elevation model (DEM) by integrating instantaneous waterline measurements with recorded tidal levels. Employing unmanned aerial vehicles (UAVs), on-site analysis of waterline characteristics became possible. Image enhancement, per the results, yields an increase in the precision of waterline identification, and object-based image analysis demonstrates the superior accuracy.