Search Results (455)

Coffee grounds can be used in agriculture as a bio-input to enhance soil fertility and biodiversity in the long term. Furthermore, the use of coffee grounds in agriculture is a sustainable practice because it reuses an organic waste product as natural fertilizer and minimizes the environmental impact resulting from the improper disposal of waste. This study aimed to identify the effects of coffee grounds on the growth and yield of iceberg lettuce plants. The experiment was conducted in a greenhouse using 4 kg of substrate in containers with a 5.356 dm³ capacity, following a completely randomized design in a 2 × 2 factorial arrangement. The primary treatment consisted of plants grown in two types of substrate: soil and sand (01) and soil, sand, and 10% coffee grounds (02). The secondary treatment corresponded to irrigation with water (01) and a 10% coffee ground extract solution (02). Coffee grounds incorporated into the soil increase soil fertility; however, they reduce lettuce growth due to the toxicity of the compounds present and should not be used without prior treatment. Processing coffee grounds into irrigation solutions shows promise due to its high potential for use as an agricultural bio-input in lettuce production. This solution enhances the growth and development of the species, resulting in vigorous plants with market value. Full article

Optimizing coagulant dosages in Drinking Water Treatment Plants (DWTPs) is critical for reducing operational costs, minimizing chemical waste, mitigating environmental impacts, and ensuring consistent water quality, particularly in resource-constrained settings where conventional jar tests are labor-intensive and poorly suited to real-time demands. This study develops and validates a Random Forest (RF) machine learning model to predict optimal dosages of aluminum sulfate, polyaluminum chloride, and a polymer flocculant at the Miguel de la Cuba Ibarra DWTP in Peru, addressing the need for an efficient, real-time decision support system. Using a historical dataset of 2556 jar tests, a univariate RF model was developed to predict settled water turbidity, tailored to the plant’s typical operational range. The model demonstrated robust predictive performance, achieving a coefficient of determination (R²) of 0.92 during training and 0.76 during validation with unseen data, alongside a Root Mean Square Error (RMSE) of 0.11 NTU and a Mean Absolute Percentage Error (MAPE) of 0.11 in the training phase. Integrated into a digital platform, the model generates real-time NTU ppm dosing curves, providing a practical and responsive tool to enhance operational efficiency for DWTP operators. This work offers a scalable, data-driven solution to improve water treatment processes in resource-limited contexts. Full article

Wastewater treatment plants (WWTPs) have been identified as the major sources of contaminants of emerging concern (CECs) in water bodies, as they are not designed to remove organic micropollutants efficiently. Consequently, many technologies have been explored for WWTP upgrading, including activated carbon adsorption. However, the high production cost and environmental challenges associated with activated carbon production limit its application in industrial settings. Therefore, a wide range of alternative materials has been investigated as potential replacements. In this study, biochar produced from waste raspberry biomass was evaluated as an adsorbent for the removal of pharmaceuticals and pesticides quantified in the secondary effluent of municipal WWTP. The results showed that the biochar efficiently removed almost all detected compounds, except for three compounds (clarithromycin, propranolol, and linuron). The wastewater pH (6–8) did not significantly affect removal efficiency significantly, and kinetic tests demonstrated rapid adsorption. The potential for biochar reuse was confirmed through three consecutive batch adsorption cycles. A comparative study between biochar and powdered activated carbon (PAC) revealed some differences in efficiency, primarily attributed to the larger surface area of PAC. π-π interactions, hydrogen bonding, and pore-filling were proposed as possible adsorption mechanisms based on the adsorption efficiency and biochar characterization. Full article

The aim of this paper is to investigate the measures adopted by higher education institutions (HEIs) for sustainable water management in university campuses. Rain and storm water harvesting and treatment, rain and storm water reuse, wastewater treatment and reuse and technologies for runoff reduction were found to be frequently undertaken. Sustainable approaches to water supply such as water-efficient appliances, irrigation algorithms and the use of drought-resistant plants have been adopted as well. In support, monitoring of consumed water and of rain and storm waters has been a widespread practice. Important considerations were given to the impact of the identified measures on campuses’ energy consumption and greenhouse gas emissions. Nature-based solutions, employment of renewable energies and sustainable disinfection methods are measures to prioritize. Some wastewater technologies may deserve priority in virtue of their positive contribution to circular economy. Drawbacks such as groundwater and soil contamination due to wastewater reuse and the release of pollutants from fertilized nature-based technologies were identified. Despite their variety, it must be noted that many of these measures have generally involved rather limited portions of campuses, taken more for demonstration or pilot/full-scale research purposes. Additional measures not identified in the current review—for instance the prevention of pollution from micropollutants and waste mismanagement—should be implemented to boost HEIs’ environmental sustainability. The findings of this review pave the way for a more structured implementation of water sustainability measures in university campuses. Full article

The growing demand for sustainable and circular construction materials has increased interest in reusing by-products from municipal solid waste incineration. Due to the variability in the chemical composition of bottom ash (BA) between different plants, sampling seasons, and particle sizes, an individualized approach depending on its origin is essential. This study examines the potential of BA as a binding material in composite structures. Composites were prepared from BA fractions of different granulometries, including ground and thermally treated material. Compressive strength tests and structural analyses of density, porosity, and water permeability were performed to evaluate the influence of particle size and heat treatment on binding activity. The results show that smaller particle sizes significantly improved compressive strength, while the highest strength was obtained for samples calcined at 1000 °C, with an average increase of 84% compared to untreated material. Thermal treatment enhanced binding activity through the mobilization of hydration-active compounds bound in non-reactive mineral phases formed during water cooling and also increased water permeability due to the breakdown of porous structures. These findings confirm the potential of BA as a secondary binder in construction materials; however, further research is needed to improve its reactivity and mechanical performance. Full article

The imperative for sustainable water management strategies is driven by challenges, such as limited water availability, economic development, population growth, and escalating environmental concerns. A viable strategy involves water collection and reuse. This study assessed the quality of wastewater produced by paint manufacturing companies, which is characterised by high chemical oxygen demand and turbidity, as well as the presence of organic materials, suspended particles, and heavy metals. Such wastewater requires treatment prior to environmental discharge. After analysing the current methods of wastewater treatment in the paint industry, this study seeks to establish a conceptual framework for developing a methodology for the collection of wastewater from rinsing machines and containers within the paint manufacturing sector while identifying optimal practices in raw wastewater management. It examines various strategies for minimising the waste generated in the paint manufacturing industry, drawing upon the waste management practices of a specific plant. Utilising data from 190 samples, the quality of the generated wastewater was estimated using probabilistic methods, including the Monte Carlo simulations, distribution fitting, and Student’s t-test. Based on the results, a wastewater management strategy was formulated for the company. By implementing water treatment and recycling systems, paint manufacturers can reduce their reliance on freshwater resources, lower the costs associated with wastewater disposal, and mitigate their environmental impact. Effective management in this domain can significantly enhance the treatment of industrial wastewater and facilitate the development of strategies for the reuse of rinse wastewater, thereby supporting the principles of a circular economy. Full article

Radioactive organic anion exchange resins present a significant challenge in nuclear power plant waste disposal due to their volatility, instability, and biotoxicity. Based on experimental degradation data from the supercritical water oxidation (SCWO) of organic anion exchange resin waste liquids from the nuclear industry, this study conducted correlation analysis, cluster analysis, and Sobol sensitivity analysis of key process parameters. The results indicate that temperature is the primary factor influencing chemical oxygen demand (COD) and total nitrogen (TN) removal, while oxidant dosage exhibits a notable synergistic effect on nitrogen transformation. A Gaussian Process Regression–Non-Dominated Sorting Genetic Algorithm II (GPR–NSGA-II) multi-objective optimization model was developed to balance COD/TN removal rate and treatment cost. The optimal operating conditions were identified as a temperature of 472.2 °C, an oxidant stoichiometric ratio (OR) of 136%, an initial COD concentration of 73,124 mg·L⁻¹, and a residence time of 3.8 min. Under these conditions, COD and TN removal efficiencies reached 99.63% and 32.92%, respectively, with a treatment cost of 128.16 USD·t⁻¹. The proposed GPR–NSGA-II optimization strategy provides a methodological foundation for process design and economic assessment of SCWO in treating radioactive organic resin waste liquids and can be extended to other studies involving high-concentration, refractory organic wastewater treatment. Full article

Water scarcity is a major constraint to agricultural productivity, particularly in arid and semi-arid regions. This study evaluated the effects of gardening waste-based compost and compost tea (CT) on tomato (Solanum lycopersicum L.) plants subjected to osmotic and water deficit stress. The first experiment assessed seed germination and early growth under polyethylene glycol (PEG)-induced osmotic stress. An inverse correlation between PEG concentration and seed and plant development was found. CT improved the germination rate and early seedling development under moderate stress (2% PEG). The second experiment examined the effect of compost and CT on tomato growth in a 45-day pot trial under three irrigation levels: 100%, 60%, and 40% field capacity (FC). Compost-treated plants consistently showed significantly greater growth and biomass accumulation across all FC levels, especially under moderate water stress. In contrast, CT-treated plants showed a general reduction in growth parameters. In addition, there was a positive association between compost treatment and multiple growth traits, particularly under reduced irrigation conditions. These findings underscore the beneficial effects of compost on plant performance under drought conditions. Full article

The sustainability of rural areas depends on effective wastewater management to reduce human impact on the environment, including the risk of pollution to surface water, groundwater, and soil from human waste. However, organized sanitation systems, which include pipeline networks and wastewater treatment plants in rural communities with low population densities, often have very low profitability and cost-efficiency, which greatly reduces their acceptance and residents’ willingness to pay. This study examines the economic profitability and cost-efficiency of selected on-site household sewage collection and treatment systems operating under real economic conditions in Poland. An evaluation was conducted on seven contemporary models of individual bioreactors, as well as a standard anaerobic septic tank equipped with drainage filters. Additionally, all options were tested on permeable and poorly permeable soils. For each variant, investment costs, as well as operation and maintenance expenses, were calculated. Financial evaluation utilized indicators of economic profitability and cost-efficiency, including the Payback Period, Net Present Value, Benefits–Cost Ratio, and Dynamic Generation Costs. The potential financial benefits included savings from avoiding the use of holding septic tanks and sewage transport by slurry wagons. All the studied designs of on-site sanitary sewage management showed significant economic feasibility and cost-efficiency. Full article

Recycling water treatment sludge (WTS) offers a sustainable solution to reduce environmental waste and enhance soil stabilisation in geotechnical applications. This study investigates the mechanical performance of soil-sludge-cement-lime mixtures through an extensive experimental program and focuses on compaction characteristics and California Bearing Ratio (CBR) values. Mixtures containing 40% soil, 50% sludge, and 10% lime achieved a CBR value of 58.7% and represented a 550% increase compared to untreated soil. Additionally, advanced predictive modelling using symbolic metaheuristic-based genetic programming (GP) techniques, including the Dingo Optimisation Algorithm (DOA), Osprey Optimisation Algorithm (OOA), and Rime-Ice Optimisation Algorithm (RIME), demonstrated exceptional accuracy in predicting CBR values. The GP-RIME model achieved an R² of 0.991 and a mean absolute error (MAE) of 1.02 in predicting CBR values, significantly outperforming traditional regression methods. Four formulas are proposed to predict CBR values. This research highlights the dual benefits of sustainable WTS recycling and advanced modelling techniques, providing scalable solutions for environmentally friendly infrastructure development. This research aligns with global sustainability goals by valorising waste streams from water treatment plants. The reuse of sludge not only reduces landfill disposal but also lowers demand for energy-intensive binders, contributing to circular economy practice and sustainable infrastructure development. Full article

Fly ash from coal-fired power plants is a promising precursor for zeolite synthesis due to its aluminosilicate-rich composition. However, its direct utilization is often limited by impurities and a low silicon-to-aluminum ratio (SAR). This study demonstrates the conversion of Class C fly ash from the Soma thermal power plant (Turkey) into FAU- and CHA-type zeolites through optimized acid leaching and hydrothermal synthesis. Acid treatment increased the SAR from 1.33 to 2.85 and effectively reduced calcium-, sulfur-, and iron-bearing impurities. The SAR enhancement by acid leaching was found to be reproducible among Class C fly ashes, whereas Class F materials exhibited a limited response due to their acid-resistant framework. Subsequent optimization of alkaline fusion-assisted synthesis enabled selective crystallization of FAU and CHA, while GIS and MER appeared under prolonged crystallization or higher alkalinity. SEM revealed distinct morphologies, with MER forming rod-shaped clusters, and CHA exhibiting disc-like aggregates. Water sorption analysis showed superior uptake for metastable FAU (~23 wt%) and CHA (~18 wt%) compared to stable GIS and MER (~12–13 wt%). Overall, this study establishes a scalable and sustainable route for producing high-performance zeolites from industrial fly ash waste, offering significant potential for adsorption-based applications in dehumidification, heat pumps, and gas separation. Full article

A low-scale Food Waste Compost (FWC1), characterized by optimal physic-chemical parameters and high organic matter percentages, was used as a fertilizer and a bio-stimulant for vegetable plants. Groups of treated plants were inoculated with active juveniles of root-knot nematodes to detect the effect on plant defense. Optimal amounts of compost mixed with soil increased plant biomass 30% compared to untreated plants. Moreover, when plants were inoculated, treated roots contained about 50% less sedentary forms (SFs) of nematodes and a lower reproduction rate of the parasites than untreated plants. Although the performance of FWC1 as defense activator was similar to other microbiome-generating commercial formulations, the compost was found to be the best fertilizer in both un- and inoculated plants. Diffuse root colonization by arbuscular mycorrhizal fungi (AMF) was observed after treatments with FWC1. FWC1 water extracts did not show any toxic effect on living nematode juveniles. Expression of the marker gene of immune response PR4b was found to be 3–5-fold higher in the roots of inoculated plants treated with FWC1 with respect to untreated plants, thus indicating that FWC1 primes plants against RKNs (root-knot nematodes, Meloidogyne incognita (Kofoid White) Chitw). Data are reported to associate immunization of plants with mycorrhization occurring in FWC1-treated plants. The proposed compost is indicated as having optimal performance both as a bio-fertilizer and a bio-stimulant. Full article

As the global imperative to decarbonize infrastructure intensifies, wastewater treatment plants (WWTPs) are emerging as critical nodes for implementing circular and energy-positive solutions. Among these, thermal energy recovery from sewage sludge presents a transformative opportunity to reduce greenhouse gas (GHG) emissions, enhance energy self-sufficiency, and valorize waste streams. While anaerobic digestion remains the dominant stabilization method in large-scale WWTPs, it often underutilizes the full energy potential of sludge. Recent advancements in thermal processing, including pyrolysis, gasification, hydrothermal carbonization, and incineration with energy recovery, offer innovative pathways for extracting energy in the form of biogas, bio-oil, syngas, and thermal heat, with minimal carbon footprint. This review explores the physicochemical variability of sewage sludge in relation to treatment processes, highlighting how these characteristics influence thermal conversion efficiency and emissions. It also compares conventional and emerging thermal technologies, emphasizing energy yield, scalability, environmental trade-offs, and integration with combined heat and power (CHP) systems. Furthermore, the paper identifies current research gaps and outlines future directions for optimizing sludge-to-energy systems as part of net-zero strategies in the water–energy nexus. This paper contributes to a paradigm shift toward sustainable, decarbonized wastewater management systems by reframing sewage sludge from a disposal challenge to a strategic energy resource. Full article

Aquafaba, a legume cooking water typically discarded as waste, represents a sustainable and plant-based protein source with promising functional applications. In this study, aquafaba hydrolysates were produced by enzymatic treatment with flavourzyme and savinase, yielding two products with distinct degrees of hydrolysis (DH: ~10% and ~29%). Aquafaba hydrolysates obtained using flavourzyme (AFHs) and savinase (ASHs), together with aquafaba isolate (AI), were incorporated into muffin cakes as partial flour substitutes (5%). The addition of hydrolysates significantly influenced cake quality parameters, particularly antioxidant capacity and textural attributes. Enzymatic hydrolysis, particularly with savinase, produced the most pronounced functional improvements. Technologically, ASHs supplementation significantly enhanced cake expansion, with specific volume values (2.23 mL/g) nearly doubling compared to the control (1.04 mL/g). Crust color was markedly altered, with L* decreasing and a* and b* rising, reflecting darker, more browned surfaces due to intensified Maillard reactions. Both ABTS and DPPH assays demonstrated increased radical scavenging activity with higher DH, while SDS-PAGE confirmed the release of smaller peptide fractions. The ABTS radical scavenging activity of the control muffin (CM, 262.53 mg TE/100 g) significantly increased in AIM (muffin cake substituted with aquafaba protein isolate, 481.87 mg TE/100 g) and reached its highest values in muffins containing AFHs (489.74 mg TE/100 g) and ASHs (530.56 mg TE/100 g), respectively. Hardness, a critical quality parameter particularly relevant to storage stability, decreased in hydrolysate-enriched samples compared with both control and isolate formulations. Oxitest results showed that extended induction periods for hydrolysate-containing cakes (18:47 h) were longer relative to control muffins (15:08 h). Thermal analysis also indicated improved thermal stability in the presence of aquafaba. Overall, the findings demonstrate that aquafaba hydrolysates can be effectively utilized in bakery systems to enhance antioxidant activity, oxidative stability, and technological properties, while simultaneously contributing to sustainable food valorization. Full article

The water sector faces a dual challenge: reducing energy consumption and carbon footprint while improving wastewater treatment efficiency. Anaerobic digestion (AD) remains the primary method for energy recovery in wastewater treatment plants (WWTPs). To enhance methane production and move toward carbon neutrality, co-digestion of sewage sludge with external substrates is gaining attention. This study evaluated nine organic substrates for their methane potential using the standardized Automatic Methane Potential Test System (AMPTS). The highest methane yield was obtained from sediment from a wine tank, reaching 1387 NmL CH₄/g VS, followed by yeast slurry, with 524 NmL CH₄/g VS. These values were over 6 and 2.5 times higher, respectively, compared to the methane potential of conventional mixed municipal sludge. Apple pomace, whey, food biowaste, and herbal maceration waste showed moderate improvements (301–388 NmL CH₄/gVS). When considering methane yield per gram of wet substrate, herbal maceration waste was the most efficient. A techno-economic analysis revealed that this substrate consistently achieved a net-positive energy balance (up to 170%) in large WWTPs, even at transport distances of 50 km. Other substrates also showed high potential, covering nearly 100% of energy demand under optimal conditions. In contrast, whey showed limited applicability due to transport constraints. These findings highlight the importance of substrate selection, particularly in practical efforts aimed at achieving energy self-sufficiency in wastewater treatment plants. It also provides WWTP operators with clear and practical insights into enhancing methane yields from anaerobic digesters while minimizing the risk of process inhibition. Full article