Waste Recycling Research Articles

Phosphorus Fractionation of Dairy Processing Waste Recycled Fertilizers Reveals Inadequacy of the Standards, Measurement and Testing (SMT) Protocol

ABSTRACT The Standards, Measurements and Testing (SMT) protocol is widely used to fractionate phosphorus (P); however, it lacks the focus on defining the solubility of P-fractions, which is usually performed independently. In this paper, the addition of a separate pre-wash step with H2O as a first step prior to the SMT protocol was tested to account for the solubility of P. Results were compared to a control unmodified SMT experiment. The differences in P-fractions were analyzed to determine the origin of the readily available P (soluble P). Six different dairy processing waste treatment products were investigated in the form of sludge, hydrochar, and ash. Water-soluble P (WSP) was correlated with weakly bound calcium (Ca), aluminum (Al) and iron (Fe). However, the SMT protocol failed to correctly identify the different pools of P as unexpected correlations were found between P and Ca, Al and Fe. Moreover, large concentrations of organic P were present in ashes (>10 mg P g−1). The organic P fraction included substantial amounts of Fe that correlated highly with P (R2 = 0.84). No association between WSP and any of the pools of P defined by SMT was detected, with the exception of total P and inorganic P. The paper concludes that SMT erroneously classifies P into different discrete fractions across various recycled P-products with fertilizer potential. A critical reevaluation of the SMT protocol is recommended, by abandoning the categorization of P into discrete pools and switching to solvent-based categories referring to the chemicals used in each extraction.

Carbon footprint of private dental clinics in Egypt: a cross-sectional study

BackgroundClimate change is a global challenge, caused by increasing greenhouse gas (GHG) emissions. Dental clinical practice contributes to these emissions through patient and staff travel, waste, energy and water consumption and procurement. Carbon footprinting quantifies GHG emissions. This study assessed the Carbon Footprint (CFP) of private dental clinics in Egypt.Materials and methodsData were collected from private dental clinics in Alexandria and Elbeheira, in Northwestern Egypt from July to August 2024 through interview questionnaires. A CFP calculator was used to estimate carbon emissions from patient and staff travel, waste, energy and water consumption, and procurement. To determine the average CFP per clinic and per patient visit, the CFP of all clinics was averaged, both with and without considering the depreciation of dental equipment.ResultsData from 27 dental clinics were collected. The average CFP of an Egyptian private dental clinic, which, per year, received 3,322 patient visits, and where 5 personnel worked 279 days was 14,426.8 kg CO2e, or 4.3 kg CO2e per patient visit. The largest contributor to the CFP was patient travel (45.6%), followed by staff travel (19.6%), energy consumption (18%), procurement (12.4%), waste (4.2%), and water consumption (0.3%). After considering the yearly depreciation of dental equipment, the CFP per clinic in a year increased by 12.2%.ConclusionPrivate dental clinics in Egypt produce substantial carbon emissions. Patient travel was the major contributor to the CFP. While there was a high CFP of electricity consumption, the CFP of gas was zero. The high CFP of waste was likely due to improper segregation and the lack of recycling. Country-specific CFP calculators are needed to accurately measure the carbon emissions of dental clinics in various settings. Preventing oral diseases, raising public awareness to sustainable practices, promoting walking and cycling, improving public transportation, implementing waste recycling, shifting to renewable sources of energy, and local manufacturing of dental products are important to reduce carbon emissions in dental clinics.

Recycling of Building Interior Decoration and Renovation Waste: A Case Study in China

Recycling of Building Interior Decoration and Renovation Waste: A Case Study in China

The Role of Ionic Liquids in Textile Processes: A Comprehensive Review

Thanks to their unique physicochemical properties, ionic liquids (ILs) have moved from niche academic interest to critical components in various industrial applications. The textile industry, facing significant environmental and economic pressures, has begun to explore ILs as sustainable alternatives to traditional solvents and chemicals. This review summarizes research on the use of ILs in various textile processes, including dyeing, finishing, and fiber recycling, where their high thermal stability, tunable solubility, and low volatility are exploited to reduce resource consumption and environmental impact. The discussion also extends to the integration of ILs in textile waste recycling, highlighting innovative approaches to fiber dissolution and regeneration aimed at circular economy goals. Despite these advances, challenges such as high production costs and scalability remain barriers to the widespread adoption of ILs in the textile sector. Addressing these barriers through continued research and development is essential to fully realize the potential of ILs for sustainable transformation in textiles.

Assessing the Environmental Impact of the Mining Industry

Mining is very vital to the production of goods, services and infrastructure; it advances the quality of lives in the society. However, the possible hazard of waste and radioactivity generated by mining, dumping and tailing, has called on the society to find ways of seeking remedy that will adequately treat mining waste from mine dump, tailing and abandoned mine. Mine waste reuse and recycling in mining industries could offer cost-effective benefits through offsetting raw material requirements and decreasing the volumes of waste to be managed. Impact and mechanism of mine damage to the environment was discussed together with the remediation principles. Practical ways in which country’s state authority and civil society can keep a close watch and enhance the enforcement of laws and regulations were highlighted. The prediction for the control of mineral exploration and environmental assessment was also discussed for executing a specific control to take preventive measures.

Leaves to Lifestyle: Raising Awareness of Responsible Production Through Eco-Print Training in Yosowilangun, Gresik

The dimension of Responsible Consumption and Production encompasses the conscientious manufacturing process of a product, with a focus on minimizing waste and residues that may pose environmental risks. Strategically situated within an industrial region, Gresik plays a pivotal role in advancing Sustainable Development Goal 12: Responsible Consumption and Production. This research endeavors to achieve a dual objective. Firstly, it aims to raise awareness about the significance of responsible production in Yosowilangun, Gresik, one of the busiest villages in the area. Additionally, the research seeks to economically empower women residing in this village. The Eco-Print fabrication employed in this study goes beyond utilizing random waste materials; instead, it leverages the recycling of dried leaves waste, a readily available resource in Gresik. Acknowledging certain limitations, such as the scale of prototype production and the ongoing nature of the study due to the gradual nature of awareness-raising efforts, this research introduces a novel aspect by uniquely applying recycled leaf waste in textile production. This approach, not extensively explored in the industry, opens a new avenue for sustainable manufacturing and women's empowerment in developing regions. The product resulting from this research is not only environmentally friendly but also holds the potential to improve the socio-economic well-being of women in Yosowilangun Village.

Experimental Investigation of Marine Soil Stabilization with Recycled Aggregates and MgO: Implications for CO<sub>2</sub> Sequestration

Dredged marine soils are increasingly recognized as a valuable resource amidst growing environmental concerns and the need for sustainable waste recycling. This study presents an innovative soil stabilization technique combining recycled aggregate (RA) and magnesium oxide (MgO), with a dual focus on enhancing soil properties and promoting carbon dioxide (CO2) sequestration. The stabilizing effects of RA and MgO were evaluated independently and synergistically under varied curing conditions and durations, with microstructural and mechanical properties analysed using scanning electron microscopy (SEM), X-ray diffraction (XRD), and uniaxial tests. Carbonation experiments quantified CO2 fixation potential, demonstrating that the formation of hydration and carbonation products, in conjunction with the dynamic moisture content and pH conditions, played a significant role in enhancing the structural reinforcement of the soil. The combined RA-MgO treatment achieved superior mechanical stability (1.28-3.02 MPa) and a CO2 sequestration capacity of up to 11 g/kg without compromising performance. This study highlights the dual environmental and structural benefits of utilising RA and low-content MgO for marine soil stabilization, offering a sustainable pathway to reduce carbon emissions, promote waste recycling, and support resilient infrastructure development.

Sustainability Assessment of Employing Chemical Recycling Technologies on Multilayer Packaging Waste

While multilayer plastic is difficult for recycling, innovative technologies and tactics are being developed to improve the process. New technologies in chemical recycling show promising results; however, the net improvement brought to the environment, economy, and society should be assessed for their wider adoption and diffusion. This study focuses on a Life Cycle Sustainability Assessment (LCSA) of an innovative process for the sorting and chemical recycling of multilayer plastic packaging waste from post-consumer sources to obtain new packaging for the food industry. The analysis indicated that the packaging made of rPET obtained through depolymerization is environmentally and economically competitive compared to the virgin PET. Packaging made of rPET and rLDPE obtained through delamination usually performed worse (or comparable) than the virgin counterparts. The social impact assessment indicated some areas of concern (e.g., workers’ health and safety risks due to exposure to hazardous substances), as well as potential opportunities (e.g., improved local employment). This paper is the first to present a synergetic approach to the sustainability assessment of chemical recycling technologies to obtain new high-performance packaging solutions. It provides useful insights to academics, managers, and decision makers in the plastic recycling sector whether (and under what conditions) the chemical recycling of multilayer plastic waste is feasible from the environmental, economic, and social perspectives. Despite associated uncertainties, the results are promising as an attractive option for further research, optimization, and upscaling.

Potential Use of Silk Waste in Sustainable Thermoplastic Composite Material Applications: A Review

Global warming and climate change demand rapid and swift action in terms of reducing resource consumption, gas emissions, and waste generation. The textile industry is responsible for a large share of global pollution; therefore, to define a route to tackle part of the issue, a literature review on the current state of research in the field of recycling silk waste was conducted. The methods used to recover, process, and characterize silk waste fibers were summarized. The aim of this work was to investigate the possible applications of recycled silk waste in the field of composite materials for load bearing applications. In this sense, some prominent studies in the field of silk-based composites were reported, favoring thermoplastic materials for sustainability reasons. Studies on nonwoven silk waste fabrics were covered as well, finding an abundance of results but no applications as a reinforcement for composite materials. In a circular economy approach, we believe that the combination of nonwoven silk waste fabrics, thermoplastic polymers, and possibly hybridization with other fibers from sustainable sources could be beneficial and could lead to green and high-performance products. The aim of this work was to summarize the information available so far and help define a route in that direction.

Possible usage of five percent chloride ion by cement weight (2.56 M NaCl) in mixing water with pozzolanic materials emerging as sustainable construction materials

Abstract Using recycled waste brine or recycled seawater as mixing water in concrete manufacturing and the cement production have led to an increase in CO2 emission, and thus, another alternative needs to be sought. This work was the first in incorporating 5% $$\:{\text{C}\text{l}}^{-}$$ by cement weight (2.56 M NaCl) into mixing water blended with four different pozzolanic materials, examining its effect on fresh, 28-day hardened properties and the embedded reinforcing-steel (RS) corrosion. Results indicated that, with 5% $$\:{\text{C}\text{l}}^{-}$$ , the slump flows of Portland cement type I (CemI), 8% CemI replaced by fly ash (CemI + FA), 8% CemI by silica fume (CemI + SF), and Portland cement type III (CemIII(slag)) at water/binder 0.55 were 193–223 mm, the bending and the compressive strengths were 4.43–7.12 MPa and 33.47–42.66 MPa, respectively, the porosities were 11.44–17.86%, the pore diameters were 0.024–0.026 μm and the bulk densities were 2087–2151 kg/m3. The chloride binding capacity was higher in CemI + SF (0.75%) and CemIII(slag) (0.74%) than in CemI (0.62%) and CemI + FA (0.63%). 5% $$\:{\text{C}\text{l}}^{-}$$ encouraged the presence of an expansive gel sodium oxide (Na2O) in CemI (0.51%), CemI + FA (0.59%), CemI + SF (1.02%) and CemIII(slag) (1.27%) after 28-day curing. Due to better chloride binding in CemIII(slag), the RS mass loss was sequenced as CemIII(slag) (14.30 mg) < CemI + SF (51.30 mg) < CemI + FA (66.10 mg) < CemI (78.33 mg) at 430 days and the RS corrosion rate was CemIII(slag) (5.92 μm/year) < CemI + SF (6.54 μm/year) < CemI + FA (14.89 μm/year) < CemI (21.05 μm/year).

Occupational Exposure to Mercury at an Electronics Waste and Lamp Recycling Facility - Ohio, 2023.

Workers in electronics waste and lamp recycling facilities are at risk of exposure to elemental mercury through inhalation of mercury vapor and mercury-containing dust. Employers at an electronics waste and lamp recycling facility in Ohio that crushes mercury-containing lamps expressed concerns about mercury exposure from work processes and requested a health hazard evaluation by CDC's National Institute for Occupational Safety and Health (NIOSH). In April 2023, NIOSH conducted a multidisciplinary investigation to assess elemental and inorganic mercury exposures, including epidemiologic, environmental, and ventilation assessments. Results indicated that mercury vapor was detected throughout the facility, with six of 14 workers having elevated urine mercury levels. These workers had a median job tenure of 8 months; four did not speak English, and five reported symptoms consistent with mercury toxicity, such as metallic or bitter taste, difficulty thinking, and changes in personality. Recommendations included improving the ventilation system, changing work practices to reduce mercury exposure, and providing training and communication tailored to the worker. As the electronic waste recycling industry continues to grow, it is important for employers to evaluate mercury exposure and safeguard employees using a hierarchy of controls. Health departments should consider monitoring occupational mercury exposure in recycling facilities, and clinicians should be aware of the potential for mercury toxicity among workers in these settings.

Front Cover: One‐Step Esterification of Phosphoric, Phosphonic and Phosphinic Acids with Organosilicates: Phosphorus Chemical Recycling of Sewage Waste

Front Cover: One‐Step Esterification of Phosphoric, Phosphonic and Phosphinic Acids with Organosilicates: Phosphorus Chemical Recycling of Sewage Waste

Front Cover: One‐Step Esterification of Phosphoric, Phosphonic and Phosphinic Acids with Organosilicates: Phosphorus Chemical Recycling of Sewage Waste

Front Cover: One‐Step Esterification of Phosphoric, Phosphonic and Phosphinic Acids with Organosilicates: Phosphorus Chemical Recycling of Sewage Waste

The Role of Universities in Building Strong Institutions as a Sustainable Development Goal

The aim of the research is to assess the impact of implementing sustainable development programmes in universities on their effectiveness in achieving sustainable development goals (SDGs). The research employed the following methods: SWOT analysis, case study, and impact assessment. The standard methods of descriptive statistics were used. Triangulation and internal consistency models were used to check the validity and reliability of research methods. Universities from Group 1 are significantly inferior to universities from Group 2 for all indicators. They have a smaller share of educational sustainable development programmes — 17.5% vs. 52.5%. The level of energy consumption per unit area is higher — 165 kWh/m² vs. 85 kWh/m², and the waste recycling rate is lower — 27.5% vs. 82.5%. Students’ average environmental awareness score is also lower — 3.35 vs. 4.5, with significantly fewer student eco-initiatives — 4 vs. 16.67. Universities are critical to sustainable development, influencing through the integration of strategy, investment, and student engagement. Different universities have their own advantages and challenges, which require adapting strategies to the specific conditions of each of them. Further research may focus on partnerships between universities and businesses and on implementing innovative approaches in project-based learning to achieve the SDGs in Ukraine.

Insights on the social and economic factors of the circular economy: A study of the Italian industrial and urban waste recycling sector.

In order to achieve the ambitious goals of the European Union (EU) Green Deal, Member States must implement an efficient and modern recycling industry that can combine high environmental standards with high economic performance. According to Eurostat, the amount of waste recovered, both industrial and urban, increased by 33.9% from 2004 to 2020, and the share of recovery in total waste treatment rose, respectively, from 45.9% to 59.1%. Among the EU countries, Italy exhibits the highest waste recycling rate (83.2% in 2020). This paper empirically investigates the economic, institutional, and social aspects that may be correlated to the performance of firms involved in industrial and urban waste recycling. Better performing firms would definitely provide larger benefits to the recycling industry, since turning waste into resources is crucial for the transition to a cleaner, climate neutral and circular economy. Working on a panel dataset of 3715 Italian companies, it emerges that firms performance is positively influenced by several firm-specific factors, such as age of experience, size, degree of specialization and digitalization, and by territorial factors, such as separate collection rate, regional GDP, and regional political ideology.

Addressing barriers and unveiling opportunities for plastic waste recycling in the New Zealand construction industry

Addressing barriers and unveiling opportunities for plastic waste recycling in the New Zealand construction industry

Chemical substances in plastics of electrical and electronic equipment and waste recycling problems

Chemical substances in plastics of electrical and electronic equipment and waste recycling problems

Properties characterization and microstructural analysis of alkali-activated solid waste-based materials with sawdust and wastewater integration

Construction materials are significantly exposed to ecological hazards due to the presence of hazardous chemical constituents found in industrial and agricultural solid wastes. This study aims to investigate the use of sawdust particles (SDPs) and sawdust wastewater (SDW) in alkali-activated composites (AACs) made from a mixture of different silicon-aluminum-based solid wastes (slag powder-SP, red mud-RM, fly ash-FA, and carbide slag-CS). The study examines the impact of SDP content, treated duration of SDPs, and SDW content on both fresh and hardened properties of the AACs, including electrical conductivity, fluidity, density, flexural and compressive strengths, and drying shrinkage. The study also analyzes the microstructures and product compositions of the AACs influenced by SDW through a comprehensive analysis of microstructures and product compositions by using XRD, SEM-EDS, and FTIR. The results show that treating SDPs with a 2.5 mol/L NaOH solution for 12 hours decreases the fluidity and electrical conductivity of the AACs but improves their flexural and compressive strengths. Additionally, in the synthesis of a composite material incorporating binder materials SP, RM, and FA in a mass ratio of 10:3:18, a 2.0 mol/L NaOH solution is employed. The liquid-to-solid ratio is maintained at 20:31, and the sand-to-binder ratio is set at 3:1. The substitution of 12.28% SDW to NaOH solution improves the resistance to drying shrinkage and long-term mechanical strength development of the AACs. Interestingly, the addition of SDW does not affect the product compositions due to the generation and decomposition of organic acid salts from organic impurities in the acidic SDW during long-term curing at room temperature. These findings provide valuable insights for the sustainable recycling of bioresources and solid wastes containing silicon-aluminum in construction materials.

Design and Development of Green Trash Compactor for Recyclable Waste Management

A trash compactor is a mechanical device invented to reduce the volume of trash, making it suitable for use in various scenes such as domestic, public, and industries. Utilizing this kind of machine provides significant benefits in the waste accumulation system, as it allows for more efficient waste management by compacting the trash, enabling larger quantities to be collected at once. In this study, a Green Trash Compactor is designed and developed as an innovative semi-automated machine to efficiently reduce the size and volume of recyclable materials such as plastics, paper cups, and PET bottles. The project focuses on optimizing the sensor layout to minimize the impact during the compaction process, thereby reducing the requirement for heavy load cells or weight sensors. The working output is achieved by recording different input commands through buttons, where the system employs load cells to identify the detected force, and the microcontroller makes corresponding decisions. The results indicated that the Green Trash Compactor successfully operated with its mechanical and programmed codes, demonstrating impressive volume reduction during the compaction process. This substantial reduction in volume contributes to lowering transportation costs for the trash, making the compactor a highly efficient waste management solution.

Catalytic Deconstruction of Commercial and End-Of-Life Polyurethane with Heterogeneous Hydrogenation Catalyst.

Polyurethane (PU), as a thermoset polymer, is extensively utilized in various applications, such as refrigerator foams, sponges, elastomers, shoes, etc. However, the recycling of post-consumed PU poses significant challenges due to its intricate and extensive crosslinking structures. Catalytic hydrogenation is one of the most effective methods for recycling PU waste, nevertheless, there is currently a lack for a hydrogenation catalyst that is both high-performing, recyclable, and cost-effective for breaking down post-consumed PU materials. In this work, model PU and commercial PU were efficiently hydrodegraded into aromatic amines and polyol fractions by using a commercial NiMo/Al2O3 catalyst. Notably, the results indicated that PU waste can be efficiently degraded at a pressure of 5 MPa and at a temperature of 185 °C and yielding a significant amount of a valuable chemical monomers. With the assistance of hydrogenation catalyst, the C-N and C-O bonds with low energy barriers inside the polymer are cracked and the polymer hydrogenation process becomes feasible. This study demonstrates the capability of fluidized bed hydrogenation process, employing recyclable heterogeneous catalysts for the recycling of PU waste.