This study explores the potential environmental impacts of replacing natural coarse aggregates with agricultural by-products and construction waste in concrete production. The research focuses on three types of concrete: oil palm shell aggregate concrete (OPSC), natural aggregate concrete (NAC), and recycled aggregate concrete (RAC). The potential environmental impact of the concrete was assessed based on its life cycle, including abiotic depletion (fuel), global warming potential, acidification, eutrophication, photochemical oxidation. In assessing these impacts, we considered the functional unit of 1 m3 and the compressive strength, CO2 uptake over a 25-year service life of the concrete, and the allocation between natural and recycled aggregate concrete production. Preliminary findings indicate that recycled aggregate concrete is the lowest potential environmental impacts among the other concretes. The results show that RAC demonstrated the lowest environmental impact, with 8.6 % lower GWP, 10.2 % lower acidification, and 11.4 % lower abiotic depletion compared to NAC. While OPSC offered reductions in cement-related impacts but had higher transport-related emissions due to long distance transportation of raw materials.
{"title":"A comparative study of the life cycle assessment of natural, recycled, and oil palm shell aggregate concretes","authors":"Sotya Astutiningsih , Dasi Agung Ospaman , Nuraziz Handika , Dwica Wulandari","doi":"10.1016/j.clwas.2025.100397","DOIUrl":"10.1016/j.clwas.2025.100397","url":null,"abstract":"<div><div>This study explores the potential environmental impacts of replacing natural coarse aggregates with agricultural by-products and construction waste in concrete production. The research focuses on three types of concrete: oil palm shell aggregate concrete (OPSC), natural aggregate concrete (NAC), and recycled aggregate concrete (RAC). The potential environmental impact of the concrete was assessed based on its life cycle, including abiotic depletion (fuel), global warming potential, acidification, eutrophication, photochemical oxidation. In assessing these impacts, we considered the functional unit of 1 m<sup>3</sup> and the compressive strength, CO<sub>2</sub> uptake over a 25-year service life of the concrete, and the allocation between natural and recycled aggregate concrete production. Preliminary findings indicate that recycled aggregate concrete is the lowest potential environmental impacts among the other concretes. The results show that RAC demonstrated the lowest environmental impact, with 8.6 % lower GWP, 10.2 % lower acidification, and 11.4 % lower abiotic depletion compared to NAC. While OPSC offered reductions in cement-related impacts but had higher transport-related emissions due to long distance transportation of raw materials.</div></div>","PeriodicalId":100256,"journal":{"name":"Cleaner Waste Systems","volume":"12 ","pages":"Article 100397"},"PeriodicalIF":3.9,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144913565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-18DOI: 10.1016/j.clwas.2025.100393
Milady Ruiz-Nieves , Erika Leonor Zambrano-Moreno , Jhon Edinson Nieto Calvache , Juan Camilo Solarte-Toro , Leonardo A. Alonso-Gómez
The cocoa pod husk (CPH) is a by-product that represents around 76 % of the fruit. The cellulose, lignin, and hemicellulose content of the CPH was analyzed, and then the response surface methodology was used to carry out a CPH delignification process with H2O2 at different concentrations, temperatures, and treatment times. The results showed that CPH was composed of 20.95 %, 7.9 %, and 20.4 % (dry basis) cellulose, hemicellulose, and lignin, respectively. The delignification treatment achieved a removal rate of 73 % for lignin, 30.3 % for hemicellulose, and 17.6 % for cellulose (values very close to the statistically estimated values). Analysis in the mid- and near-infrared region showed the characteristic signals of lignin, hemicellulose, and cellulose, allowing the reduction of their signals in the characteristic bands to be visualized. It is concluded that the H2O2 delignification method allows for high lignin removal comparable to that of traditional methods. Finally, the environmental impact analysis performed with the waste reduction algorithm found that increasing hydrogen peroxide concentration in CPH delignification significantly elevates atmospheric and toxicological environmental impacts; it is therefore suggested to optimize the use of this reagent.
{"title":"An alternative for cocoa pod husk delignification using hydrogen peroxide","authors":"Milady Ruiz-Nieves , Erika Leonor Zambrano-Moreno , Jhon Edinson Nieto Calvache , Juan Camilo Solarte-Toro , Leonardo A. Alonso-Gómez","doi":"10.1016/j.clwas.2025.100393","DOIUrl":"10.1016/j.clwas.2025.100393","url":null,"abstract":"<div><div>The cocoa pod husk (CPH) is a by-product that represents around 76 % of the fruit. The cellulose, lignin, and hemicellulose content of the CPH was analyzed, and then the response surface methodology was used to carry out a CPH delignification process with H<sub>2</sub>O<sub>2</sub> at different concentrations, temperatures, and treatment times. The results showed that CPH was composed of 20.95 %, 7.9 %, and 20.4 % (dry basis) cellulose, hemicellulose, and lignin, respectively. The delignification treatment achieved a removal rate of 73 % for lignin, 30.3 % for hemicellulose, and 17.6 % for cellulose (values very close to the statistically estimated values). Analysis in the mid- and near-infrared region showed the characteristic signals of lignin, hemicellulose, and cellulose, allowing the reduction of their signals in the characteristic bands to be visualized. It is concluded that the H<sub>2</sub>O<sub>2</sub> delignification method allows for high lignin removal comparable to that of traditional methods. Finally, the environmental impact analysis performed with the waste reduction algorithm found that increasing hydrogen peroxide concentration in CPH delignification significantly elevates atmospheric and toxicological environmental impacts; it is therefore suggested to optimize the use of this reagent.</div></div>","PeriodicalId":100256,"journal":{"name":"Cleaner Waste Systems","volume":"12 ","pages":"Article 100393"},"PeriodicalIF":3.9,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144864653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-15DOI: 10.1016/j.clwas.2025.100395
Subham Mishra , Eng Abdirizak Abdi Elmi , Swetapadma Panda , Pradip Sarkar
The construction sector is grappling with an immense lack of natural sand that meets the requisite specifications for use in concrete. At the same time, the disposal of used rubber tires poses ecological, health, and aesthetic challenges due to the difficulty of recycling them. Utilizing industrial waste materials as alternative aggregates and binder components offers a promising solution that enhances environmental awareness, reduces adverse impacts, and promotes sustainable development in the construction industry. This study investigates the performance of M-40 grade concrete incorporating crumb rubber (CR) and binary blends of silica fume (SF) and rice husk ash (RHA). Crumb rubber, sourced from end-of-life tires, was used to replace 10 % and 20 % of natural sand by volume. Simultaneously, cement was partially replaced by binary combinations of SF and RHA in the range of 10–20 % and the fresh properties, mechanical strength, durability, and microstructural characteristics of the resulting crumb rubber concrete (CRC) are evaluated. Natural sand was replaced by CR alone (10–20 %), a reduction in compressive strength of up to 25.4 % was observed but however, this strength loss was significantly mitigated by incorporating binary blends of SF and RHA. Notably, the CRC mix containing 20 % CR, 20 % SF, and 10 % RHA demonstrated improved performance: a 37.5 % increase in compressive strength, a 25 % increase in split tensile strength, and a 42.5 % increase in flexural strength compared to the control mix. These enhancements are attributed to improved particle packing and the formation of additional hydration products from the blended pozzolanic materials, as confirmed by FESEM microstructural analysis. Moreover, this optimized CRC mix exhibited significantly higher static and dynamic moduli of elasticity—16.2 % and 65 % greater than the control mix, respectively—indicating increased stiffness. Non-destructive tests such as Ultrasonic Pulse Velocity (UPV), microhardness, and rebound hammer also showed markedly superior performance in the hardened CRC specimens.
{"title":"Experimentation of concrete properties of crumb rubber with SCMs: Mechanical, stiffness, NDT and micro-structural","authors":"Subham Mishra , Eng Abdirizak Abdi Elmi , Swetapadma Panda , Pradip Sarkar","doi":"10.1016/j.clwas.2025.100395","DOIUrl":"10.1016/j.clwas.2025.100395","url":null,"abstract":"<div><div>The construction sector is grappling with an immense lack of natural sand that meets the requisite specifications for use in concrete. At the same time, the disposal of used rubber tires poses ecological, health, and aesthetic challenges due to the difficulty of recycling them. Utilizing industrial waste materials as alternative aggregates and binder components offers a promising solution that enhances environmental awareness, reduces adverse impacts, and promotes sustainable development in the construction industry. This study investigates the performance of M-40 grade concrete incorporating crumb rubber (CR) and binary blends of silica fume (SF) and rice husk ash (RHA). Crumb rubber, sourced from end-of-life tires, was used to replace 10 % and 20 % of natural sand by volume. Simultaneously, cement was partially replaced by binary combinations of SF and RHA in the range of 10–20 % and the fresh properties, mechanical strength, durability, and microstructural characteristics of the resulting crumb rubber concrete (CRC) are evaluated. Natural sand was replaced by CR alone (10–20 %), a reduction in compressive strength of up to 25.4 % was observed but however, this strength loss was significantly mitigated by incorporating binary blends of SF and RHA. Notably, the CRC mix containing 20 % CR, 20 % SF, and 10 % RHA demonstrated improved performance: a 37.5 % increase in compressive strength, a 25 % increase in split tensile strength, and a 42.5 % increase in flexural strength compared to the control mix. These enhancements are attributed to improved particle packing and the formation of additional hydration products from the blended pozzolanic materials, as confirmed by FESEM microstructural analysis. Moreover, this optimized CRC mix exhibited significantly higher static and dynamic moduli of elasticity—16.2 % and 65 % greater than the control mix, respectively—indicating increased stiffness. Non-destructive tests such as Ultrasonic Pulse Velocity (UPV), microhardness, and rebound hammer also showed markedly superior performance in the hardened CRC specimens.</div></div>","PeriodicalId":100256,"journal":{"name":"Cleaner Waste Systems","volume":"12 ","pages":"Article 100395"},"PeriodicalIF":3.9,"publicationDate":"2025-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144860906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, a reduced modulus high-calcium fly ash geopolymer concrete was developed as a sustainable and environmentally efficient construction material for road pavement. The recycled concrete aggregate (RCA) was used to replace natural coarse aggregate (NA) in making geopolymer concrete. The waste glass fiber reinforced plastic (GFRP) of 2.36–4.75 mm was then added at dosages of 0–2.0 % of fly ash by weight. In the final step, ordinary Portland cement (OPC) was used to replace 0–15 %fly ash to produce a low elastic modulus RCA geopolymer concrete containing GPRF and OPC. Test results showed that the RCA high calcium fly ash geopolymer concrete with 1.5 %GFRP and 15 % OPC gave low elastic modulus of 16.96 GPa with high compressive strength of 41.2 MPa and flexural strength of 3.17 MPa. The RCA was incorporated for its low rigidity, GFPR for its low rigidity and contribution to strength particularly in flexure, and OPC for setting and strength development with curing at ambient temperature. The developed low elastic modulus was 56 % of that of normal OPC concrete of the same compressive strength calculated from ACI318 of 30.18 GPa.
{"title":"Enhanced strength reduced modulus high calcium FA geopolymer concrete containing recycled aggregate concrete and Portland cement","authors":"Athika Wongkvanklom , Patcharapol Posi , Ampol Wongsa , Yuwadee Zaetang , Wanchai Yodsudjai","doi":"10.1016/j.clwas.2025.100384","DOIUrl":"10.1016/j.clwas.2025.100384","url":null,"abstract":"<div><div>In this paper, a reduced modulus high-calcium fly ash geopolymer concrete was developed as a sustainable and environmentally efficient construction material for road pavement. The recycled concrete aggregate (RCA) was used to replace natural coarse aggregate (NA) in making geopolymer concrete. The waste glass fiber reinforced plastic (GFRP) of 2.36–4.75 mm was then added at dosages of 0–2.0 % of fly ash by weight. In the final step, ordinary Portland cement (OPC) was used to replace 0–15 %fly ash to produce a low elastic modulus RCA geopolymer concrete containing GPRF and OPC. Test results showed that the RCA high calcium fly ash geopolymer concrete with 1.5 %GFRP and 15 % OPC gave low elastic modulus of 16.96 GPa with high compressive strength of 41.2 MPa and flexural strength of 3.17 MPa. The RCA was incorporated for its low rigidity, GFPR for its low rigidity and contribution to strength particularly in flexure, and OPC for setting and strength development with curing at ambient temperature. The developed low elastic modulus was 56 % of that of normal OPC concrete of the same compressive strength calculated from ACI318 of 30.18 GPa.</div></div>","PeriodicalId":100256,"journal":{"name":"Cleaner Waste Systems","volume":"12 ","pages":"Article 100384"},"PeriodicalIF":3.9,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144853005","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-14DOI: 10.1016/j.clwas.2025.100392
Md. Mohibul Islam, Md. Limonur Rahman Lingkon
The supply chain management (SCM) network is struggling to enhance profitability while managing shorter-lived products, particularly electronic items like cell phones. This challenge arises because customers continuously upgrade to new models within a very short timeframe. As a result, maintaining an optimal inventory level in retail outlets becomes difficult to prevent stock-outs and overstock situations in a dynamic market. Furthermore, electronic waste (e-waste) increases significantly, raising additional environmental concerns. This study develops a new closed-loop supply chain (CLSC) logistics model to tackle these issues. This CLSC model is designed by integrating a new production approach known as rolling planning production schedules (RPPS). The main feature of the RPPS is that real market demands dictate the manufacturing quantity at the factory. Additionally, RPPS lead time is included in developing the proposed CLSC model, replacing simultaneous flow systems with periodic flow systems of goods from one stakeholder to its successive stages. Also, K-means algorithm was applied to cluster stores for efficient shipment. Afterward, a second alternative model was also developed to compare the performance of the suggested model, where a fixed production volume manufacturing approach was utilized instead of the RPPS. The findings indicate that the proposed model yields better results than the second alternative. Moreover, by adjusting the model's parameters, a sensitivity analysis is conducted to confirm the model's robustness and the reliability of the results. The sensitivity study demonstrated that the suggested model can produce consistent outcomes when a large-scale problem size and a recurrent simulation environment are employed.
{"title":"Rolling planning-based closed-loop supply chain logistics model under an unstable demand scenario","authors":"Md. Mohibul Islam, Md. Limonur Rahman Lingkon","doi":"10.1016/j.clwas.2025.100392","DOIUrl":"10.1016/j.clwas.2025.100392","url":null,"abstract":"<div><div>The supply chain management (SCM) network is struggling to enhance profitability while managing shorter-lived products, particularly electronic items like cell phones. This challenge arises because customers continuously upgrade to new models within a very short timeframe. As a result, maintaining an optimal inventory level in retail outlets becomes difficult to prevent stock-outs and overstock situations in a dynamic market. Furthermore, electronic waste (e-waste) increases significantly, raising additional environmental concerns. This study develops a new closed-loop supply chain (CLSC) logistics model to tackle these issues. This CLSC model is designed by integrating a new production approach known as rolling planning production schedules (RPPS). The main feature of the RPPS is that real market demands dictate the manufacturing quantity at the factory. Additionally, RPPS lead time is included in developing the proposed CLSC model, replacing simultaneous flow systems with periodic flow systems of goods from one stakeholder to its successive stages. Also, <em>K</em>-means algorithm was applied to cluster stores for efficient shipment. Afterward, a second alternative model was also developed to compare the performance of the suggested model, where a fixed production volume manufacturing approach was utilized instead of the RPPS. The findings indicate that the proposed model yields better results than the second alternative. Moreover, by adjusting the model's parameters, a sensitivity analysis is conducted to confirm the model's robustness and the reliability of the results. The sensitivity study demonstrated that the suggested model can produce consistent outcomes when a large-scale problem size and a recurrent simulation environment are employed.</div></div>","PeriodicalId":100256,"journal":{"name":"Cleaner Waste Systems","volume":"12 ","pages":"Article 100392"},"PeriodicalIF":3.9,"publicationDate":"2025-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144860905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-12DOI: 10.1016/j.clwas.2025.100383
F.S. Hassan , W.U. Eze , R. Umunakwe , T. Oyegoke , M.I. Uzochukwu
The accumulation of plastic waste, particularly low-density polyethylene (LDPE) and expanded polystyrene (EPS or Styrofoam), presents a growing environmental challenge due to their widespread use and limited biodegradability. In resource-constrained regions like Nigeria, uncompatibilized recycling of LDPE/EPS waste offers a low-cost path to valorize plastic pollution. Addressing this issue requires innovative recycling strategies that can transform waste into valuable materials. This study developed an uncompatibilized sustainable polymer blend from post-consumer waste and investigated the physical and mechanical properties of recycled LDPE blended with EPS under resource-constrained conditions as a sustainable rigid alternative to polypropylene (PP) for static applications, though trade-offs in impact resistance were observed. In achieving this, triplicate samples were statistically validated (ANOVA, p < 0.05), LDPE/EPS blends were prepared in varying weight ratios (80/20, 75/25, 70/30, 65/35, and 60/40) using a two-roll mill and compression molding. A series of tests; density, tensile strength, elongation at break, tensile modulus, flexural strength, hardness, and impact resistance; were conducted on triplicate samples, with results expressed as mean ± standard deviation. In the study, the 60/40 blend achieved a tensile modulus of 202 MPa (surpassing PP's 179 MPa) but exhibited 39 % lower impact strength than PP (0.20 vs. 0.33 J/mm²). However, increasing EPS content reduced elongation at break, indicating increased brittleness due to EPS's rigidity, though flexural strength (23.77 MPa) remains 56 % lower than PP (53.59 MPa), restricting load-bearing use. Findings validated suitability for rigid, static applications. Beyond performance, the blend contributes to plastic waste reduction and supports circular economy initiatives by transforming problematic waste materials into functional products.
{"title":"Physico-mechanical characterization of recycled LDPE blended with EPS as a sustainable rigid alternative to polypropylene","authors":"F.S. Hassan , W.U. Eze , R. Umunakwe , T. Oyegoke , M.I. Uzochukwu","doi":"10.1016/j.clwas.2025.100383","DOIUrl":"10.1016/j.clwas.2025.100383","url":null,"abstract":"<div><div>The accumulation of plastic waste, particularly low-density polyethylene (LDPE) and expanded polystyrene (EPS or Styrofoam), presents a growing environmental challenge due to their widespread use and limited biodegradability. In resource-constrained regions like Nigeria, uncompatibilized recycling of LDPE/EPS waste offers a low-cost path to valorize plastic pollution. Addressing this issue requires innovative recycling strategies that can transform waste into valuable materials. This study developed an uncompatibilized sustainable polymer blend from post-consumer waste and investigated the physical and mechanical properties of recycled LDPE blended with EPS under resource-constrained conditions as a sustainable rigid alternative to polypropylene (PP) for static applications, though trade-offs in impact resistance were observed. In achieving this, triplicate samples were statistically validated (ANOVA, p < 0.05), LDPE/EPS blends were prepared in varying weight ratios (80/20, 75/25, 70/30, 65/35, and 60/40) using a two-roll mill and compression molding. A series of tests; density, tensile strength, elongation at break, tensile modulus, flexural strength, hardness, and impact resistance; were conducted on triplicate samples, with results expressed as mean ± standard deviation. In the study, the 60/40 blend achieved a tensile modulus of 202 MPa (surpassing PP's 179 MPa) but exhibited 39 % lower impact strength than PP (0.20 vs. 0.33 J/mm²). However, increasing EPS content reduced elongation at break, indicating increased brittleness due to EPS's rigidity, though flexural strength (23.77 MPa) remains 56 % lower than PP (53.59 MPa), restricting load-bearing use. Findings validated suitability for rigid, static applications. Beyond performance, the blend contributes to plastic waste reduction and supports circular economy initiatives by transforming problematic waste materials into functional products.</div></div>","PeriodicalId":100256,"journal":{"name":"Cleaner Waste Systems","volume":"12 ","pages":"Article 100383"},"PeriodicalIF":3.9,"publicationDate":"2025-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144843006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-12DOI: 10.1016/j.clwas.2025.100391
Md. Abul Hashem, Tasnim Zaman Afrin, Sumaiya Tasnim, Sasbir Rahman Sium, Md. Mukimujjaman Miem, Md. Enamul Hasan Zahin
The basic chromium sulfate is used in leather tanning to stabilize the collagen protein. In tanning, a large amount of trivalent chromium is released into wastewater, which harms the environment, especially aquatic bodies. This research focuses on the adsorption capacity of trivalent chromium on activated pineapple crown biowaste adsorbent (APCBA). The equipped adsorbent was characterized using an Energy Dispersive X-ray Spectrometer (EDS), Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy, and pHpzc (point of zero charge). A batch assessment was performed for chromium adsorption on APCBA. The trivalent chromium removal efficacy was 98.50 % at an APCBA dose of 0.5 g/50 mL wastewater for a short stirring time (15 min), with a 2 h settling at 30℃ temperature. The reductions in environmental pollutants BOD, COD, and Cl- were 62.4 %, 55.3 %, and 49.2 %, respectively. The morphological changes of pure and Cr-loaded APCBA were well documented through SEM micrographs and EDS spectra. The presence of functional groups on Cr-loaded APCBA ensures the adsorption of pollutants. The Freundlich isotherm and PSO kinetics of linear fit revealed a good fit for Cr adsorption with correlation coefficient (R2) values of 0.9896 and 0.9999, respectively. Thermodynamic studies indicate the reaction was exothermic and spontaneous. pHpzc assessment of APCBA represents the Cr adsorption mechanism. Therefore, the application of APCBA in wastewater treatment, especially chrome tanning wastewater, is recommended before discharging it into the environment.
{"title":"Trivalent chromium adsorption on activated carbon derived from biowaste: Kinetic, isotherm, and thermodynamic studies","authors":"Md. Abul Hashem, Tasnim Zaman Afrin, Sumaiya Tasnim, Sasbir Rahman Sium, Md. Mukimujjaman Miem, Md. Enamul Hasan Zahin","doi":"10.1016/j.clwas.2025.100391","DOIUrl":"10.1016/j.clwas.2025.100391","url":null,"abstract":"<div><div>The basic chromium sulfate is used in leather tanning to stabilize the collagen protein. In tanning, a large amount of trivalent chromium is released into wastewater, which harms the environment, especially aquatic bodies. This research focuses on the adsorption capacity of trivalent chromium on activated pineapple crown biowaste adsorbent (APCBA). The equipped adsorbent was characterized using an Energy Dispersive X-ray Spectrometer (EDS), Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy, and pHpzc (point of zero charge). A batch assessment was performed for chromium adsorption on APCBA. The trivalent chromium removal efficacy was 98.50 % at an APCBA dose of 0.5 g/50 mL wastewater for a short stirring time (15 min), with a 2 h settling at 30℃ temperature. The reductions in environmental pollutants BOD, COD, and Cl<sup>-</sup> were 62.4 %, 55.3 %, and 49.2 %, respectively. The morphological changes of pure and Cr-loaded APCBA were well documented through SEM micrographs and EDS spectra. The presence of functional groups on Cr-loaded APCBA ensures the adsorption of pollutants. The Freundlich isotherm and PSO kinetics of linear fit revealed a good fit for Cr adsorption with correlation coefficient (R<sup>2</sup>) values of 0.9896 and 0.9999, respectively. Thermodynamic studies indicate the reaction was exothermic and spontaneous. pHpzc assessment of APCBA represents the Cr adsorption mechanism. Therefore, the application of APCBA in wastewater treatment, especially chrome tanning wastewater, is recommended before discharging it into the environment.</div></div>","PeriodicalId":100256,"journal":{"name":"Cleaner Waste Systems","volume":"12 ","pages":"Article 100391"},"PeriodicalIF":3.9,"publicationDate":"2025-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144830154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study uses a mixed-methods design to examine university waste management practices, particularly waste sorting on campus. It combines quantitative surveys to assess the baseline perception of knowledge, attitude, and practice and evaluate behavioral changes and patterns among the participants, with experimental studies to examine the impact and effectiveness of the intervention materials. The data for the quantitative approach were collected in two steps: survey 1 (n = 154) and survey 2 (n = 69) participants. The 69 participants in Survey 2 also participated in the experimental study, which employed a within-subjects design. The convenience sampling technique was used to collect the data due to its practicality and efficiency. The survey found that the respondents have a high Knowledge, attitude, and practice toward waste sorting, while a gap was observed between knowledge, perception, and waste-sorting practices. Moreover, visual prompts can bridge these gaps; there was a significant improvement when visual prompts were used to assist waste sorting. Missorted waste dropped from 40.9 % at baseline (Task 1) to 10.2 % after visual prompts (Task 2), with the green bin improving most. Task 3 further reduced errors to 8.3 %, a 32.6-point decrease from baseline. Correspondingly, the observation also emphasised the effectiveness of combining visual prompts and intervention campaign materials to promote waste sorting knowledge and practices. The results of this research contribute to the current state of knowledge and guide policymakers and waste management managers in designing effective waste management strategies.
{"title":"Examining the impact of visual prompt and intervention campaign materials on waste sorting: Knowledge, attitudes, and practices (KAP) and a mixed-methods approach","authors":"Rakotoarisoa Maminirina Fenitra, Emenda Sembiring, Aisya Rahmania Dangkua, Zayinatun Biladiyah Al Khoeriyah","doi":"10.1016/j.clwas.2025.100390","DOIUrl":"10.1016/j.clwas.2025.100390","url":null,"abstract":"<div><div>This study uses a mixed-methods design to examine university waste management practices, particularly waste sorting on campus. It combines quantitative surveys to assess the baseline perception of knowledge, attitude, and practice and evaluate behavioral changes and patterns among the participants, with experimental studies to examine the impact and effectiveness of the intervention materials. The data for the quantitative approach were collected in two steps: survey 1 (n = 154) and survey 2 (n = 69) participants. The 69 participants in Survey 2 also participated in the experimental study, which employed a within-subjects design. The convenience sampling technique was used to collect the data due to its practicality and efficiency. The survey found that the respondents have a high Knowledge, attitude, and practice toward waste sorting, while a gap was observed between knowledge, perception, and waste-sorting practices. Moreover, visual prompts can bridge these gaps; there was a significant improvement when visual prompts were used to assist waste sorting. Missorted waste dropped from 40.9 % at baseline (Task 1) to 10.2 % after visual prompts (Task 2), with the green bin improving most. Task 3 further reduced errors to 8.3 %, a 32.6-point decrease from baseline. Correspondingly, the observation also emphasised the effectiveness of combining visual prompts and intervention campaign materials to promote waste sorting knowledge and practices. The results of this research contribute to the current state of knowledge and guide policymakers and waste management managers in designing effective waste management strategies.</div></div>","PeriodicalId":100256,"journal":{"name":"Cleaner Waste Systems","volume":"12 ","pages":"Article 100390"},"PeriodicalIF":3.9,"publicationDate":"2025-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144830152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-10DOI: 10.1016/j.clwas.2025.100388
P. Sivakumar , R. Saravanane , S. Mohan , B. Sankar
There is a growing interest in meeting the rising energy demand from a more sustainable source. Biomass energy has the potential to act as a sustainable and environmentally friendly alternative to fossil fuels and help achieve net-zero emissions in the near future. This study proposes an economically feasible method to enhance biogas efficiency by co-digesting cow dung (CD), food waste (FW), rice straw (RS), with the addition of Coconut husk Bio-Char (BC). The present research aims to study the variation in the biogas yield from biochar addition by monitoring the alteration in the influential parameters such as pH, temperature, total solids (TS), volatile solids (VS), volatile fatty acids (VFA), and carbon to nitrogen ratio (C/N). The biochar addition stabilized both pH and temperature due to its intrinsic properties by transforming intermediates like H2S and CO2. It also significantly increased the VFA accumulation and degradation attributed to the buffering ability of the biochar. The methane yield of blends with biochar was significantly higher than that of the blends without biochar. The mixture CD 30: FW 50:RS 20 containing biochar showed a peak methane yield of 165.08 mL. The statistical model developed using response surface methodology (RSM) predicted the methane yield with an accuracy of 99.07 % and a statistical significance level of 0.05. The accuracy of the RSM model was validated by comparing it with the existing Gompertz kinetic model. The performance evaluation error metrics, Coefficient of Correlation (R), and Root Mean Square Error (RMSE) results were observed to be 0.966, 0.925, and 62.89 mL/gVS, 87.24 mL/gVS for RSM model and Gompertz model, indicating the superior performance of the RSM model developed in this study.
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Pub Date : 2025-08-10DOI: 10.1016/j.clwas.2025.100389
Yi Huan Tan , Hwai Chyuan Ong , Raja Affendi Raja Ali , Lai Ti Gew
Research labs rely on disposable plastics for sterility, safety, and affordability, but their environmental and economic impact has been largely overlooked. While the impact of single-use plastics is well-known, laboratory waste poses an additional challenge due to necessary treatment processes. Hence, this study investigated both the environmental and economic impact associated with single-use plastic waste management in a university laboratory, serving as a case study for Southeast Asia. A retrospective analysis was conducted on laboratory plastic waste management between 2014 and 2023 at a Malaysian university. Three waste management methods, i.e. incineration, landfilling with microwave pre-treatment, and landfilling with ozone pre-treatment, were implemented at consecutive intervals. Environmental impact was assessed by quantifying the GHG emissions in terms of carbon dioxide equivalent (CO₂eq) emissions, while economic assessment was evaluated based on invoiced costs. A total of 29,180.11 kg of single-use plastic waste resulted in 46,420.08 kg CO₂eq emissions and a cumulative disposal cost of RM 84,890.49. Among the three methods, landfilling with ozone pre-treatment demonstrated the lowest environmental impact (1.55 kg CO₂eq/kg) and cost (RM 2.79/kg). Direct emission from the end-of-life stage was the main source of GHG emissions, while disposal fees represented the largest portion of total costs. In light of these findings, it is crucial for universities and research institutions to recognise the environmental and economic impact of laboratory single-use plastics. This case study will serve as a foundation for advancing pre-treatment technologies and future end-of-life solutions.
研究实验室依赖于一次性塑料的无菌性、安全性和可负担性，但它们对环境和经济的影响在很大程度上被忽视了。虽然一次性塑料的影响是众所周知的，但由于必要的处理过程，实验室废物构成了额外的挑战。因此，本研究在一所大学实验室调查了与一次性塑料废物管理相关的环境和经济影响，作为东南亚的案例研究。对马来西亚一所大学2014年至2023年的实验室塑料废物管理进行了回顾性分析。垃圾焚烧、微波预处理堆填和臭氧预处理堆填三种废物处理方法相继实施。对环境影响的评估是根据二氧化碳当量（CO₂eq）排放量对温室气体排放量进行量化，而经济评估是根据发票成本进行评估的。总共29,180.11 公斤一次性塑料废物导致46,420.08 公斤二氧化碳当量排放，累计处理成本为84,890.49令吉。三种方法中，臭氧预处理填埋对环境的影响最低（1.55 kg CO₂eq/kg），成本最低（RM 2.79/kg）。使用寿命结束阶段的直接排放是温室气体排放的主要来源，而处理费占总成本的最大部分。鉴于这些发现，大学和研究机构认识到实验室一次性塑料对环境和经济的影响至关重要。本案例研究将为推进预处理技术和未来的生命终结解决方案奠定基础。
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