Search Results (2,277)

Calcium propionate (Ca(CH₃CH₂COO)₂) was successfully synthesized from cockle shell biowaste through a reaction with propionic acid at concentrations of 80%, 90%, and 99%, valorizing seafood processing biowaste as a renewable calcium source in support of circular economy principles. The synthesis was conducted at ambient temperature with a fixed CaCO₃: propionic acid molar ratio of 1:2, enabling rapid reaction completion without external heating or complex purification steps. The prepared samples were characterized by FTIR, XRD, TGA, and SEM techniques, which confirmed the formation of calcium propionate monohydrate (Ca(CH₃CH₂COO)₂^.H₂O), while XRF confirmed more than 97 wt% CaO across all samples with non-toxic impurities corresponding to compositional requirements for food additive calcium propionate (E282). The sample prepared using 80% propionic acid exhibited the highest yield (90.24%) and soluble percentage (98.23%). The proposed approach demonstrates an effective valorization of cockle shell waste into a food additive, calcium propionate, offering advantages in terms of sustainability, cost efficiency, and scalability, and highlighting its strong potential for industrial food additive production within a circular economy framework. Full article

This paper explores the internal rock plugging rules induced by oily sludge profile control systems in oilfields. Three typical sludges including wastewater tank bottom sludge (WTBS), crude oil tank bottom sludge (CTBS) and floating scum sludge (FSS) are adopted. Combined with micro-CT scanning and digital core technology, this paper systematically investigates the pore–throat structure evolution and damage mechanism before and after sludge injection into rock cores. Key parameters such as plugging rate, average pore radius, throat radius, coordination number, shape factor, pore–throat ratio and pore–throat volume are quantitatively characterized macroscopically and microscopically, which reveal diverse damage modes and plugging mechanisms of the three sludges. The results indicate that pores of 10–50 μm are preferentially blocked by all sludges. CTBS causes the severest core damage with an average plugging rate of 79.67%, and the average coordination number decreases from 4 to 1, governed by the mechanism of adsorption diameter reduction and structural destruction. WTBS leads to uniform jamming of fine particles. Its average parameters change slightly, yet permeability declines due to broken critical throats. It follows the mechanism of uniform filling and weak adsorption with an average plugging rate of 56.75%, showing mild reservoir modification capacity. FSS causes moderate damage. Retained emulsion droplets trigger uniform slight shrinkage of pore throats under partial and overall selective filling mechanism, with an average plugging rate of 63.36% and favorable selective plugging performance. This study clarifies the inherent correlation between macroscopic damage and microscopic behaviors of oily sludge, offering microscopic theoretical references for differentiated management of sludge reinjection and oil displacement with composite sludge profile control agents. Full article

The Peruvian anchoveta fishmeal industry generates wastewater (pumping water) during the transport of fish from boats to production plants. This study represents the first evaluation in Peru of Moringa oleifera (MOD) and chitosan as bio-coagulants specifically applied to the coagulation–flocculation treatment of pumping water, providing a direct comparative analysis against traditional ferric sulfate under identical experimental conditions. The effluent is characterized by an extreme turbidity of 5,683 NTU, total suspended solids (TSS) at 3359.3 mg/L, and oils and fats at 451.3 mg/L, and it was treated using optimized doses: 4.0 g/L for MOD and 0.2 g/L for chitosan. The results demonstrate that natural alternatives achieve turbidity removal exceeding 97.5%, matching the efficiency of inorganic salts. Notably, chitosan achieved 88.59% TSS removal with no significant statistical difference (p > 0.05 according to the Kruskal–Wallis test) from ferric sulfate, while MOD excelled in oil reduction (37.84%) compared with chitosan. Beyond treatment efficiency, this research fills a gap in circular economy data by identifying that the resulting sludge, containing >4% non-toxic nitrogen, is suitable for composting. These findings establish a new renewable benchmark for the Peruvian fishing industry’s transition toward sustainable, zero-waste water management. Full article

Microplastics (MPs) are persistent contaminants widely distributed across aquatic, terrestrial, and atmospheric environments. Previous reviews have shown that MPs can carry pollutants and change their environmental behavior, but the field is now broad enough that a simple repetition of sources, adsorption mechanisms, and toxicity would add limited value. This review therefore organizes MPs–pollutant–interactions as a connected chain from sources and environmental pathways to interaction mechanisms, biological effects, and management actions. It summarizes the major MPs input pathways and representative polymer types across water, soil, and air, and then explains how partitioning, surface adsorption, desorption, and pore filling control the binding and release of pollutants. The review further discusses how MPs properties, pollutant characteristics, pollutant mixtures, biofilms/plastisphere, and environmental factors jointly regulate these processes. In addition, it evaluates the consequences of MPs-pollutant coupling for pollutant mobility, bioavailability, biodegradation, bioaccumulation, trophic transfer, ecological toxicity, and human exposure. Finally, the review links these processes with practical management needs, including wastewater treatment, sludge reuse, agricultural plastic control, atmospheric monitoring, environmental education, and long-term risk assessment. By bringing these topics into one framework, this review provides a clearer basis for understanding and managing MPs-associated mixed pollution in environmental systems. Full article

Oily sludge is one of the most challenging solid wastes generated during petroleum production and wastewater treatment, posing long-term environmental risks and demanding effective resource-recovery strategies. This study systematically investigated the physicochemical characteristics, compositional differences, and oil–solid interaction mechanisms of oily sludge (OS) from three representative Chinese oilfields, Panjin, Daqing and Xinjiang, through integrated analyses of elemental composition, oil composition, X-ray diffractometer (XRD), Fourier-transform infrared (FT-IR), Gas chromatograph (GC), and Confocal laser scanning microscope (CLSM). The results revealed pronounced regional variations in oxidation degree, hydrocarbon composition, and mineralogy that critically influenced oil occurrence and removal behavior. The Panjin OS sample (PJ-OS) exhibited a high oxidation degree, enriched resins and asphaltenes, and compact film-like oil–solid structures, resulting in the lowest oil mobility and recovery potential. The Daqing OS (DQ-OS) was dominated by light saturates and showed the weakest oil–solid bonding, while the Xinjiang OS (XJ-OS) displayed moderate oxidation and intermediate properties. A novel room-temperature high-speed stirring cleaning method was applied to evaluate oil removal performance under ambient conditions. The residual oil contents after treatment were 4.43% (PJ-OS), 1.65% (DQ-OS), and 1.22% (XJ-OS), corresponding to removal efficiencies of 80.86%, 86.74%, and 90.33%, respectively. The cleaning efficiency was strongly governed by the sludge composition and oxidation state: higher O/C ratios and enrichment of polar heavy fractions enhanced oil–solid adhesion and hindered oil detachment, whereas higher saturate contents and lower oxidation degrees facilitated rapid oil separation. Overall, the findings demonstrate that the treatability of oily sludge is controlled by its intrinsic physicochemical properties. The proposed high-speed stirring technique provides a promising, energy-efficient, and environmentally sustainable approach for oily sludge remediation and resource recovery, offering valuable insights for optimizing treatment parameters and scaling up green petroleum waste management technologies. Full article

The foreseen implementation of the recast European Union Urban Wastewater Treatment Directive (EU) 2024/3019 will extend the previous regulation’s purpose to cover agglomerations from 1000 population equivalent upwards, and impose more stringent requirements on larger plants. Member States’ local authorities will be responsible for carrying out a range of organizational and infrastructural tasks, including the expansion of sewerage networks and the construction/modernization of wastewater treatment plants. This study presents an analysis aimed at assessing the readiness of small and medium-sized wastewater treatment plants in Poland to meet the new forthcoming requirements. The study examines the extent to which the present performance of small and medium-sized treatment plants in Poland complies with current regulations, and their readiness to comply with future environmental standards set by the new Directive. The structure of the national sewerage system is taken into account with the case study analysis of the present situation in the Opolskie Voivodeship. The novelty and methodological contribution of the study lies in bridging the regulatory analysis with local-scale operational data from selected facilities, as well as statistical data on the national wastewater treatment system published by Statistics Poland (GUS), linking local-scale WWTP performance with broader systemic conditions at the national level. Full article

This article presents a systematic review of land-based marine pollution in the Southern African Development Community (SADC), focusing on the river–sea interface. Using the PRISMA protocol, 30 articles published between 2015 and 2025 were selected. Key pollutants identified include microplastics, nutrients, heavy metals, and urban effluents, which travel through river basins and impact coastal ecosystems and communities. The region faces serious challenges due to limited wastewater treatment coverage, with many urban areas lacking adequate infrastructure or using outdated technologies. This leads to widespread discharge of untreated effluents into rivers. Fragmented governance, weak institutional capacity, and insufficient implementation of regional treaties further hinder pollution control. Climate change exacerbates these pressures by increasing hydrological extremes and the vulnerability of sanitation systems. Despite existing legal instruments, cooperation on monitoring and wastewater management remains limited. The integration of basin and coastal planning, improved governance, and transboundary collaboration are essential to reduce pollution and promote ecological and social resilience in the region. Full article

Hurricanes cause severe impacts on lives, livelihoods, and essential systems. Hurricane Melissa impacted Jamaica as a Category 5 cyclone, resulting in estimated losses of approximately 41% of national GDP (US$8.8 billion) and eliciting widespread damage to housing, healthcare, agriculture, and urban infrastructure. Agriculture sustained heavy losses, with 41,000 hectares of damaged farmland and the loss of more than 1 million livestock animals. These impacts resulted in exposed animal closures with biological hazards. Using systems thinking, the PESTHEEL framework, and a One Health lens, we argue for viewing Hurricane Melissa as series of cascading inter-related One Health threats of waterborne and vector-borne diseases, zoonoses, antimicrobial resistance, degraded indoor and outdoor air quality, chemical pollution, and shifting migration and border dynamics. These each unfold at different timings. A structured synthesis for Jamaica and other Caribbean Small Island Developing States is provided by integrating systems thinking, One Health, and the PESTHEEL framework. Immediate and lagged risk pathways are identified, and practical risk reduction actions are proposed to support anticipatory, multisectoral recovery: enhanced syndromic, laboratory, wastewater, vector, and rodent surveillance; resilient WASH and shelter systems; non-insecticidal and integrated vector management; biosecure aid and border protocols; environmental toxicology monitoring; and climate–health intelligence. Full article

The increasing presence of pharmaceutical compounds in aquatic environments poses a significant challenge for wastewater treatment systems worldwide. Among these emerging contaminants, bicyclic non-steroidal anti-inflammatory drugs (NSAIDs) are particularly concerning due to their high consumption, partial metabolism, and long-lasting persistence in wastewater. This review was prepared critically based on popular databases such as PubMed and the Google Scholar website, and using the modern Nested Knowledge platform. The bibliometric analysis was performed using the VosViewer program with the keywords co-occurrence method. The review aims to systematically compile and synthesize current knowledge on the impact of bicyclic non-steroidal anti-inflammatory drugs (NSAIDs) on biological wastewater treatment systems, with particular emphasis on activated sludge. It discusses how these compounds influence microbial community composition, metabolic activity, sludge structure, and overall treatment performance. Furthermore, the distribution of these contaminants in the environment and their degradation efficiency were analyzed. By integrating evidence from both laboratory and industrial studies, this article provides a comprehensive perspective on the environmental risks posed by bicyclic NSAIDs. Our findings also underscore the urgent need for systematic monitoring and adaptive management to mitigate the ecological impact of these widely used pharmaceuticals in the future. Full article

To mitigate the effects of climate change, the world must significantly reduce its reliance on fossil fuels to lower greenhouse gas emissions. The nuclear power and renewable energy sources, such as solar, wind, water, waste, and geothermal energy, emit minimal to no greenhouse gases or pollutants during operation. These sources are considered crucial for combating climate change and supporting sustainable development. However, the production of electricity, like most industries, generates waste. Comparisons show clear differences: fossil fuel plants produce the largest total waste mass (primarily combustion ash, flue gas desulfurization residues, and wastewater sludge), while nuclear facilities generate a minimal volume but high-activity spent fuel and long-lived radioactive materials. Solar PV systems generate significant end-of-life electronic waste and glass encapsulant, and wind turbines yield moderate composite blade residues. Hydropower sediment management and geothermal scaling contribute unique waste streams of local concern. Regardless of the energy source, responsible waste management is critical to minimize environmental impacts. This article explores the sustainability of low-carbon energy sources, specifically focusing on waste management with the aim of highlighting the need of implementing targeted strategies such as advanced recycling and material substitution in order to minimize environmental impacts and enhance the circularity of low-carbon energy systems. Full article

Metformin (MET) is a widely prescribed pharmaceutical compound used for the management of glucose levels and body weight. However, it is only partially metabolized in the human body, and a significant fraction is excreted unchanged, leading to its frequent detection in aquatic environments. Consequently, the removal of MET from wastewater has become a matter of increasing concern due to its potential impact on aquatic ecosystems. Furthermore, as a nitrogen-containing compound, MET has been extensively employed as a model pollutant to evaluate the performance of physical and chemical treatment technologies for pharmaceutical contaminants. This review aims to critically assess and summarize the efficiency and key limitations of various processes applied for MET removal. The reviewed approaches include physical–chemical treatments such as adsorption; biological treatments (activated sludge, biofiltration and phytoremediation), which rely on microbial metabolic activities or plant uptake to degrade or sequester metformin; and advanced oxidation processes (AOPs), such as ozonation, photolysis, photocatalysis, Fenton, and photo-Fenton systems. The efficiency of MET removal and mineralization is strongly dependent on the treatment method employed. Among the evaluated processes, the photo-Fenton reaction emerges as one of the most promising technologies, achieving high removal efficiencies under both ultraviolet (UV) and visible (Vis) irradiation. Full article

Wastewater treatment plants (WWTPs) are significant contributors to anthropogenic greenhouse gas (GHG) emissions through both direct biological processes generating methane (CH₄), nitrous oxide (N₂O), and biogenic carbon dioxide (CO₂) and indirect energy consumption. This comprehensive research paper synthesizes findings from 30 peer-reviewed studies to present a holistic analysis of carbon footprints in wastewater treatment, with a specific quantitative assessment of a sequencing batch reactor (SBR) facility processing 5000 m³/day. The SBR operates with anoxic–aerobic cycles (fill–anoxic react–aerobic react–settle–decant–idle). The analysis reveals that N₂O emissions can constitute up to 75% of a plant’s carbon footprint, while aeration accounts for 40–75% of total energy consumption. For the SBR facility, the baseline carbon footprint is 1648 tCO₂e/year [95% CI: 1420–1910] (0.90 kg CO₂e/m³) under conservative assumptions, with CH₄ yield of 0.03 kg CH₄/kg COD removed and N₂O yield of 0.008 kg N₂O-N/kg TN removed. A realistic baseline using median literature values gives 0.52 kg CO₂e/m³. The carbon footprint of WWTPs varies by treatment technology, scale, and operational conditions, ranging from 61 to 161 kg CO₂e per population equivalent (PE) annually. Through anaerobic digestion with biogas recovery and anoxic phase optimization, emissions can be reduced by 38% to 1018 tCO₂e/year [95% CI: 860–1190]. The findings underscore that achieving carbon neutrality requires extending accounting beyond plant boundaries to include effluent exports, sludge management, and urban infrastructure integration. This paper provides a transparent, practitioner-ready framework for understanding, quantifying, and mitigating carbon emissions from wastewater treatment, with particular emphasis on SBR technology. Full article

Accurate prediction of wastewater influent quality is critical for optimizing treatment plant operations, minimizing environmental impact, and enabling proactive management under dynamic conditions. However, the complex, nonlinear, and temporally dependent nature of influent processes poses significant challenges to traditional modeling approaches. This study introduces a robust stacked ensemble learning framework that integrates Long Short-Term Memory (LSTM), Support Vector Regression (SVR), and Extreme Gradient Boosting (XGBoost) to forecast three key influent quality parameters: biochemical oxygen demand (BOD₅), total phosphorus (TP), and total solids (TS) at a municipal wastewater treatment plant (WWTP) in Canada. Through sequential backward feature selection and SHapley Additive exPlanations (SHAP), the model achieves both high predictive accuracy and interpretability, providing insights into temporal, environmental, and process-based drivers of influent variability. The ensemble consistently outperforms individual models, delivering high generalization performance across all three influent quality targets. This work demonstrates that stacked ensemble models, when coupled with explainable AI techniques, can bridge the gap between black-box performance and operational transparency in wastewater forecasting. The proposed framework lays the groundwork for more resilient, data-driven decision-making in municipal WWTPs. Full article

Hydrolyzed polyacrylamide stabilized oil-in-water emulsions are highly persistent because the polymer strengthens both continuous-phase rheology and the oil–water interfacial film, making demulsification difficult in polymer-flooding produced liquids. Here, an hydrolyzed polyacrylamide degrading bacterium, Delftia lacustris EPDB-8, was isolated, and its ability to destabilize hydrolyzed polyacrylamide-containing emulsions was investigated from molecular, bulk rheological, and interfacial perspectives. EPDB-8 effectively degraded HPAM, causing marked reductions in total organic carbon, total nitrogen, absolute zeta potential, and polymer molecular weight, with an approximately 63-fold decrease after 7 days. SEM, FT-IR, and GPC analyses showed that biodegradation proceeded through deamidation and random chain scission, collapsing the polymer network and generating low-molecular-weight fragments. Driven by bacterial hydrolyzed polyacrylamide degradation, these structural alterations disrupted the viscoelastic composite interfacial film formed by hydrolyzed polyacrylamide and indigenous surface-active species, directly causing emulsion stabilization to shift from polymer-assisted viscous and steric protection to a less effective asphaltene-dominated interfacial structure and thereby accelerating droplet aggregation, coalescence, and phase separation. Although bacterial cells exerted a transient particle-assisted interfacial effect, long-term emulsion stability remained governed by polymer integrity. This study establishes a mechanistic link between hydrolyzed polyacrylamide biodegradation and the rheological and interfacial evolution governing emulsion breakdown, providing a cost-effective and environmentally benign biological strategy for demulsification and treatment of polymer-flooding produced water. These findings offer practical guidance for the design of microbial-based produced-water treatment systems and contribute to the sustainable management of oilfield wastewater generated during enhanced oil recovery operations. Full article

Water is fundamental to urban sustainability, structuring the urban water cycle from supply to wastewater treatment and discharge. Basic sanitation services are a core component of this system, directly influencing sustainable water use and environmental quality. Sanitation 4.0 applies Industry 4.0 technologies to enable real-time monitoring, data-driven management, and process optimization. This study investigates how the implementation of Industry 4.0 technologies transforms the management of basic sanitation services. A systematic literature review (SLR) was conducted to provide a theoretical foundation and identify research gaps. Articles were selected using a structured and reproducible method, and qualitative data were coded and analyzed with NVivo software. The results indicate that Sanitation 4.0 encompasses diverse applications, with artificial intelligence (AI), big data and data analytics, and internet of things (IoT) emerging as the most frequently implemented technologies in water distribution, wastewater treatment, and service management. IoT demonstrated broad versatility, while robots and augmented reality remain underexplored. Data security emerged as the area most in need of attention. This research concludes that Industry 4.0 technologies are reshaping the management and delivery of sanitation services, supporting innovation and progress toward universal access. Full article