Waste Management through Composting: Challenges and Potentials

Crosstalk between gut metabolomics, bioaccumulation, and microbial enrichment in earthworms for effective remediation of toxic metals: Insights from green waste-based vermicomposting systems

The knowledge on earthworm gut metabolomic variations in metal-enriched green waste (GW)-based vermicomposting systems is scarce. Earthworm's gut metabolite-metal accumulation interactions have also not been studied earlier. Therefore, GW-based Eisenia fetida-mediated vermicomposting and aerobic composting systems were spiked with Pb-Cr-Cu (1:1:1)-mixed solutions. While earthworm reproduction, body weight, and gut microbial growth were slightly lower in metal-spiked GW-vermibeds compared to unspiked vermibeds, the temporal increase in N-P-K enrichment, feedstock microbial counts, and microbial biomass-C&N were significantly more in metal-spiked vermicomposts than in metal-spiked composts. Interestingly, the metal removal efficiency was ∼1.2-3.0 times higher in metal-spiked vermibeds than in unspiked vermibeds and composting beds. Furthermore, the degree of bioaccumulation for Pb (spiked - 1.64 mg kg-1 versus unspiked - 0.22 mg kg-1), Cr (spiked - 0.92 mg kg-1 versus unspiked - 0.40 mg kg-1), and Cu (spiked - 1.54 mg kg-1 versus unspiked - 0.79 mg kg-1) was significantly higher in earthworms grown in spiked than in unspiked GW feedstocks. The LC-QTOF-MS-mediated earthworm-gut metabolomic profiling revealed that 655 biomolecules were significantly up or down-regulated due to metal spiking. Interestingly, compounds known for stress-ameliorating roles (e.g., methylcitisine and trans-anethole) have increased most dramatically in metal-spiked vermibed-borne earthworms. A KEGG-database analysis revealed that the phenylpropanoid pathway metabolites augment in metal-rich feedstock-borne earthworms. Finally, the correlation statistics clarified that earthworm gut metabolite distribution meaningfully alters to enhance the detoxification of non-essential toxic metals (Pb and Cr) more than essential micronutrient metals (Cu) in waste-based vermicomposting systems.

Ecological packaging and creating sustainable solutions for biodegradable cellulose derivatives: A review

Packaging made from conventional petroleum-based plastics has been in widespread use for many years by different industries, but demand has soared with the development of the food industry. Whereas plastics have benefited the food industry, their non-biodegradability has resulted in immense environmental damage, including the destruction of our aquatic ecosystems and air pollution. Hence, the development and use of biodegradable and sustainable food packaging to counter the menace of plastic pollution and the degrading environment is now a global necessity. In this review, we highlight recent advancements in sustainable food packaging materials, with special emphasis on cellulose-based biopolymers. Cellulose, derived from a renewable source, and its derivatives, namely cellulose acetate, carboxymethyl cellulose, nanocellulose, and methylcellulose, are being studied as environmentally friendly alternatives to conventional plastics for food packaging purposes. Limitations associated with the use of cellulose derivatives in this regard are also presented. In the end, the research documents cellulose derivatives as having great potentials in replacing conventional plastic in food packaging, thereby reducing plastic pollution and further reducing the environmental footprint of packaging materials.

Life-Cycle Assessment in Agri-Food Systems and the Wine Industry-A Circular Economy Perspective

Rapid population growth, climate change, and resource depletion pose significant challenges to global food production, demanding sustainable solutions. A Life-Cycle Assessment (LCA) provides a structured framework for evaluating the environmental impact of food systems throughout their entire life cycle. This review examines how an LCA can be integrated with circular economy principles to address sustainability challenges, optimize resource use, and minimize waste in food and alcoholic beverage production. A systematic review of LCA applications in the agri-food sector was conducted, analyzing studies published across different regions. The selection criteria included relevance to circular economy strategies, waste valorization approaches, and assessing environmental impacts using LCA methodologies. The analysis explores explicitly the synergy between food and wine production within the broader agri-food system, considering shared sustainability challenges and opportunities for resource optimization. Key methodologies include cradle-to-grave assessments and the evaluation of waste-to-resource technologies. The findings demonstrate that LCA effectively identifies critical environmental hotspots, enabling the implementation of eco-design and resource recovery practices. Circular strategies, such as the use of renewable energy, precision agriculture, and nutrient recovery, significantly enhance sustainability. However, gaps remain in accounting for social and regional variability, as well as in integrating advanced technologies. When combined with circular economy principles, LCA provides actionable insights for policy development and sustainable practices. Advancing LCA methodologies and fostering multi-stakeholder collaboration are essential for creating resilient and environmentally responsible agri-food systems.

Socio-demographic drivers of household food waste management practices in Thailand

OBJECTIVE

The escalating food waste crisis, with millions of tons of food being discarded annually, highlights the pressing necessity to improve household food waste management practices. This complex and multifaceted challenge is a crucial element of a comprehensive national strategy for reducing food waste. This article seeks to examine the diverse demographic and social factors that shape household food waste management practices in Thailand.

METHODS

A substantial national dataset (n =  2,500) was meticulously gathered through questionnaires, using multi-stage sampling and multiple regression analysis to reveal critical insights.

RESULTS

This study reveals that educational attainment (β =  0.299), household size (β =  0.201), and monthly income (β =  0.058) are positively associated with effective household food waste management practices. Notably, the type of housing, such as single houses over 200 square meters (β = .058**) and condominiums/apartments (β = .063**), significantly influence food waste management behaviors. However, townhouses (β =  -.074***) are negatively associated with improved food waste management practices. The research also identifies key barriers to effective food waste prevention, including the lack of organizational guidance (29.4%), the perception that waste reduction does not save costs (26.1%), and uncertainty about where to donate surplus food (25.2%). Additional challenges of managing food scraps include the uncertainty about options for donation or sale of food scraps (43.3%) and the limited knowledge of composting or bio-fermentation methods (30.2%).

CONCLUSIONS

In conclusion, this study provides essential insights for policymakers, practitioners, and researchers by identifying key demographic, knowledge-based, and behavioral factors that shape household food waste management. The study's findings underscore the need for targeted educational initiatives and infrastructure enhancements. Policymakers can leverage these insights to develop policies that support public-private partnerships and improve waste management infrastructure. Practitioners can apply this knowledge to implement more effective waste segregation strategies, while researchers are encouraged to explore socio-economic factors influencing food waste at a national scale, thereby addressing critical research gaps. This comprehensive approach is vital for reducing household food waste and promoting sustainable waste management practices across diverse communities.

A review on textile solid waste management: Disposal and recycling

Due to global population growth and living standards improvements, textile production and consumption are increased. Textile solid waste has become challenging issue for waste management authority. It is reported that textile materials are discarded daily, representing approximately 1.5% of the generated waste around the world. Over the past few decades, special attention has been given to the used clothes in all regions globally, which can reduce energy costs by 80% and also represent a source of raw materials economically profitable and environmentally responsible. This review article attempted to address different topics including: source of solid textile waste, environmental impact of textile waste as a result of massive consumption of clothing, textile waste management processes such as recycling, reuse of textile waste, landfill and incineration and energy recovery from textile waste. Narrative review with collection of recent quantitative information was carried to reflect the status of textile solid waste. In this article, the possibilities of bio-ethanol production from textile waste as valuable cellulosic raw material are investigated and presented. Results show that developing countries lack of systematic waste management. On another side of the globe, some countries are trying to recover energy these days by incineration. The heat and power that recovered from this process can be used instead of other energy sources. Throughout the incineration process, flue gases (CO2, H2O, O2, N2) are generated so it should be properly designed to avoid pollution. During energy recovery, different pre-treatment methods and different enzymatic hydrolysis parameters are recommended to be implied for better results.

Influence of microbial agents-loaded biochar on bacterial community assembly and heavy metals morphology in sewage sludge compost: Insights from community stability and complexity

Enhancing the passivation of heavy metals and increasing organic matter content during the composting of sewage sludge poses significant challenges for maximizing its utilization value. Results indicated that in the control, biochar, microbial agents and microbial agents-loaded biochar (BCLMA) groups, BCLMA addition led to a higher composting temperature, with increases of 17-62% in humic acid, 25-73% in germination index, and 30-35% in organic matter consumption. And the residual fraction of Cu, Zn, Cr and Cd were increased by 30%, 12%, 22% and 17%, respectively. Furthermore, BCLMA promotes community cohesion, robustness, and microbial nutrient cycling, and increases the relative abundance of heavy metals-degrading bacteria (Acinetobacter and Corynebacterium) and resistance genes. Structural equation model analysis revealed that heavy metal passivation is attributed to improved community cohesion and robustness, which facilitates the proliferation of heavy metal-resistant microorganisms. These results indicate that community robustness and cohesion are critical for mitigating the heavy metals bioavailability.

Agronomic Efficiency of Compost Extracts and Nitrogen-Fixing Bacteria in Soybean Crops

Regenerative agriculture and the use of bioinputs have been gaining prominence in the global agribusiness sector, driven by the growing demand for healthier foods produced with minimal impact on ecosystems. In this context, compost and its derivatives (compost extracts and teas) are used to provide effective microorganisms to crops, although production processes affect the efficiency of compost extracts, as well as the soil microbiota. Thus, the hypothesis raised was that the organic matter source used for compost formation affects the agronomic efficiency of compost extracts. The objective of this study was to evaluate the effect of compost extracts based on litterfall of angiosperm (AC) and gymnosperm (GC) species, and the use of inoculation with the nitrogen-fixing bacteria Bradyrhizobium japonicum and Azospirillum brasilense (Bra+Azo), on soil quality, crop growth, grain yield, and disease control in soybean (Glycine max L.) crops. Using AC and GC resulted in varying effects on soybean growth and soil microbial biomass carbon (SMBC), confirming the hypothesis that the organic matter source affects the agronomic efficiency of compost extracts. Plants inoculated with Bra+Azo exhibited higher chlorophyll contents, resulting in a higher photochemical yield than for those treated with compost extracts (AC and GC). However, plants inoculated with AC and GC exhibited high plasticity in mitigating photochemical stress, reaching similar photosynthetic and transpiration rates to those observed in plants inoculated with Bra+Azo. Additionally, inoculation with Bra+Azo, overall, improved the photosynthetic efficiency of soybean plants, and the compost extracts (AC and GC) were more effective than the inoculation with Bra+Azo in increasing soybean 1000-grain weight, probably due to improvements in root development. The growth promotion observed with AC and GC is likely attributed to increases in SMBC by these compounds, denoting improvements in soil quality and biocontrol of damage caused by insect attacks.

Exploring strategies for kitchen waste treatment and remediation from the perspectives of microbial ecology and genomics

Nowadays, the rapid growth of population has led to a substantial increase in kitchen waste and wasted sludge. Kitchen waste is rich in organic matter, including lignocellulose. Synergistic treatment involving kitchen waste and wasted sludge can enhance treatment process. Vermicomposting can facilitate microbial activities on organic matter. Nevertheless, the underlying mechanisms remain unclear. In this study, metagenomics was used to analyze microbial functional genes in vermicomposting. Redundancy analysis found that TOC, TN and DTN adversely affect earthworm growth and reproduction. The relative abundance of Bacteroidetes and Firmicutes increased with earthworms, thereby potentially augmenting lignocellulose degradation. The predominant functional genes included amino acid, carbohydrate, and inorganic ion conversion and metabolism. Metagenomics analysis demonstrated that GH1, GH3, GH5, GH6, GH9, GH12, GH44, GH48 and GH74, GT41, GT4, GT2, and GT51 were dominant. Furthermore, there was higher abundance of carbohydrate-active enzymes in the vermicomposting, particularly during the later phases (30-45 days). Co-occurrence network revealed that Cellvibrio in the vermicomposting exhibited a relatively dense positive correlation with other microbial groups. The findings elucidated the mechanism of vermicomposting as a promising approach for managing kitchen waste and wasted sludge.

Optimizing Bioaugmentation for Pharmaceutical Stabilization of Sewage Sludge: A Study on Short-Term Composting Under Real Conditions

A significant concentration of pharmaceuticals has been detected within composted sewage sludge. Their uncomplete removal and lack of monitoring during composting neglects their potentially toxic effects when used as a soil organic amendment. Previously, we successfully implemented a bioaugmentation-composting system focused on toxicity and pharmaceuticals' concentration reduction. This method, however, comprised a long inoculant-acclimatization period, making it an unprofitable technology. Hence, this work aimed to explore a shorter and yet effective composting process by simultaneously implementing the inoculation of a native microbial consortium and the fungus Penicillium oxalicum XD 3.1 in composting piles of sewage sludge and olive prunings. All the piles were subjected to frequent inoculation, windrow turning, and monitoring of the physicochemical and biological parameters. Additionally, both the bioaugmentation stability and pharmaceuticals degradation were evaluated through different analysis and removal rates calculations. One hundred days earlier than previous attempts, both bioaugmentation treatments achieved adequate composting conditions, maintained core native populations while improving the degrading microbial diversity, and achieved around 70-72% of pharmaceutical remotion. Nevertheless, only Penicillium inoculation produced favorable toxicity results ideal for organic amendments (acute microtoxicity and phytotoxicity). Thus, a shorter but equally stable and effective degrading bioaugmentation-composting with P. oxalicum was achieved here.

Unraveling the mechanisms of post-treatment to enhance humification and Cd remediation in compost through EDTA-Fenton-Like systems

This study aimed to enhance humification and cadmium (Cd) remediation in compost by investigating the effects of three post-treatments: ultrapure water, citric acid, and ethylenediaminetetraacetic acid disodium (EDTA). The results revealed that the EDTA post-treatment significantly enhanced humification by facilitating an EDTA-Fenton-like system within compost comprising rice straw and river sediment to remediate Cd-contaminated sediment. EDTA post-treatment not only promoted humic substances and humic acid concentrations of up to 66.30 g/kg and 30.40 g/kg, respectively, but also led to a reduction in the Cd content and bioavailability factor by 75.02 % and 9.76 %, respectively. In addition, parallel factor analysis revealed two distinct components, while two-dimensional correlation spectroscopy showed that the polysaccharides and carboxyl groups in humic acid were preferentially bound to Cd. Overall, this study proposes a promising approach for enhancing humification and Cd remediation in compost by the EDTA post-treatment.

Unraveling the impact of intervention strategies and oxygen disparity in humification during domestic waste composting

This study constructs three different photovoltaic assisted composting systems to treat rural domestic waste, and explores the interaction pathways between biomacromolecules and other factors under oxygen disparity at gradient heights of the compost. The optimized mode of regular turning and ventilation-dehydration significantly reduced the moisture content by 53.6% and increased the seed germination index by 35.6%. The oxygen content at different heights under the optimized mode significantly affects the physicochemical properties of the compost, and the degradation of cellulose, hemicellulose, and protein in the middle is higher than other parts. The structural equation model shows that the physicochemical properties at the bottom are affected by biomacromolecules, which may be related to volatile fatty acids(VFAs) produced under low oxygen conditions.The research results show that using manual turning and ventilation-dehydration as the optimized process can promote compost maturity, and oxygen concentration has an important impact on the humification process of the compost.

The simultaneous addition of chitosan and peat enhanced the removals of antibiotics resistance genes during biogas residues composting

Direct reuse of biogas residue (BR) has the potential to contribute to the dissemination of antibiotic resistance genes (ARGs). Although high-temperature composting has been demonstrated as an effective method for the harmless treatment of organic waste, there is few researches on the fate of ARGs in high-temperature composting of BR. This research examined the impact of adding 5% chitosan and 15% peat on physicochemical characteristics, microbial communities, and removal of ARGs during BR-straw composting in 12 Biolan 220L composters for 48 days. Our results showed that the simultaneous addition of chitosan and peat extended the high-temperature period, and increased the highest temperature to 74 °C and germination index. These effects could be attributed to the presence of thermophilic cellulose-decomposing genera (Thermomyces and Thermobifida). Although the microbial communities differed compositionally among temperature stages, their dissimilarity drastically reduced at final stage, indicating that the impact of different treatments on microbial community composition decreases at the end of composting. Peat had a greater impact on aerobic genera capable of cellulose degradation at thermophilic stage than chitosan. Surprisingly, despite the total copy number of ARGs significantly decreased during composting, especially in the treatment with both chitosan and peat, intl1 gene abundance significantly increased 2 logs at thermophilic stage and maintained high level in the final compost, suggesting there is still a potential risk of transmission and proliferation of ARGs. Our work shed some lights on the development of waste resource utilization and emerging contaminants removal technology.

Exploring compost production potential and its economic benefits and greenhouse gas mitigation in Addis Ababa, Ethiopia

The increasing amount of municipal organic waste (MOW) and human excreta (HE) has led to socio-economic and environmental challenges in the cities of developing countries. This study estimated MOW and HE, compost production potential from MOW and HE, and compost application potential for urban agriculture fertilization, economic benefits, soil carbon sequestration, and greenhouse gas (GHG) mitigation in Addis Ababa, Ethiopia, for the period 2025-2050. MOW was forecasted using the Holt-Winters forecasting model. HE was estimated using the daily average rate of HE generation. The compost production potential was estimated using the forecasted MOW and HE. Compost fertilization was determined by considering compost nitrogen (N), phosphorus (P), and potassium (K) and the fertilizer requirements of cereals and vegetables. The economic benefits of compost were determined by considering the price of compost-equivalent urea, NPS, and potassium chloride fertilizers. The mitigation of GHG emissions from compost application was estimated using the IPCC Tier 1 method. The forecasted quantities of MOW, HE, and compost for 2050 are 301, 462, and 343 Gg, respectively. The compost could supply 5 Gg of N and 2.2 Gg of P in 2050, sufficient to fertilize 14,129 ha of vegetable fields. The economic benefits of using compost as a substitute for synthetic fertilizers could reach 10 million USD in 2050. Compost production and application could offset the total GHG emissions of Addis Ababa by 13.1 % (10,241Gg CO2-eq year-1) in 2050. The application of compost generated from MOW and HE in Addis Ababa can substitute synthetic fertilizers, provide economic benefits, and mitigate GHG emissions.

Characterization and analysis of municipal solid waste generated in the semi-urban region of Thanamandi, Jammu and Kashmir (J&K), India: a basis for developing a suitable waste management approach

Population growth, urbanization, lifestyle changes, and consumption patterns increase waste management problems in Thanamandi town. The waste generation rate in Thanamandi town is expanding, and there is a need for adequate waste segregation, recycling programs, and sorting facilities. Therefore, this study aims to estimate the municipal solid waste (MSW) generation rate in Thanamandi town, including an analysis of its composition. Additionally, statistical methods are used to assess the potential MSW management approaches. A comprehensive methodology has been adopted, including house-to-house waste collection from 25 pre-selected locations, to ensure representation across different income groups. The collected waste was segregated into food, plastic, paper, and textile waste categories, and the moisture content was analyzed using the oven-drying method. Further, it has been observed from the obtained result that 0.44 kg per/capita/day of MSW has been generated from the study area. The result shows that vegetable waste contributes the most followed by food waste and plastic. Additionally, the moisture content of the waste ranged between 12% and 76.25%, with high moisture content primarily found in organic wastes. Moreover, interpolation maps created using QGIS highlighted the spatial distribution of waste generation across the town. They showed a strong correlation between vegetable and food waste and paper and plastic waste. Thus, to manage MSW in the study area, a holistic approach to MSW management is necessary to deal with a mixture of Vegetable and Food waste, i.e., organic matter.

Factors influencing management of dry cell battery waste: a case of Greater Accra Region in Ghana

Indiscriminate disposal of dry cell battery (DCB) waste contributes to environmental and public health issues in developing countries such as Ghana, due to the toxic nature of this specific waste. Accordingly, a study was conducted in Accra, Ghana, to determine the socio-economic and demographic factors influencing handling DCB waste, aiming a sustainable environment. Using a random sampling technique, a descriptive cross-sectional survey was conducted, encompassing 367 respondents from the Accra-Tema Metropolitan areas and Tema West Municipal Assembly in Greater Accra, Ghana. Using descriptive and multivariate statistical methods, the survey data were analysed with the Statistical Package for Social Sciences (SPSS) version 27. The results of this study show that female gender and residential area are likely to positively influence the use of DCB at home. Education significantly affects the use of DCB and its proper disposal. The results also suggest that 78% of the respondents disposed of DCB waste in waste bins. The mean monthly income of the respondents stands at USD 270, which is average and likely partially to positively influence the disposal of the DCB. The data collected revealed that female gender, age group, family size, and education level influence the indiscriminate disposal of DCB waste and DCB waste recycling. The results highlight that educated females above the age of 55, with a monthly income, are likely to properly segregate DCB waste. This study contributes to the knowledge gap in relation to dry cell battery waste management (DCBWM) in developing countries, aiming to advance global sustainability. This study is expected to contribute to educate and create awareness in managing DCB waste to reduce its indiscriminate disposal which leads to environmental pollution and negatively affects human health and environmental sustainability in Ghana.

Biostabilization of fecal sludge and tannery liming sludge: A novel approach

Fecal sludge and tannery liming sludge management is essential for humans and the environment. The emitted amount of waste from two industries is reduced in composting leading to value-added products. This research focused on the effectiveness and feasibility of co-composting fecal sludge and hair-burning liming sludge from tannery. Fecal sludge was intermittently mixed with hair-burning liming sludge which also consisted of chicken manure and sawdust. Five piles (Pile 1, Pile 2, Pil3, Pile 4, and Pile 5) indicated respectively as P#1, P#2, P#3, P#4, and P#5, contained various ratios of composting materials were mixed, piled onto a horizontal bamboo frame, and observed for 120 days. To ensure a suitable oxygen supply, the composting piles were turned on in the thermophilic stage so that pathogens could not survive. The highest temperatures in the thermophilic stage were 39.0°C, 49.2°C, 55.7°C, 41.7°C, and 51.3°C. These referred to the respective piles P#1, P#2, P#3, P#4, and P#5. The Dewar stability index confirmed the stability of each composting pile, and the maximum degradation was found for P#3. The metals chromium (Cr), zinc (Zn), lead (Pb), iron (Fe), and nickel (Ni) in the final compost were found to be 38.1, 144.7, 15.1, 450.5, and 22.7 mg/kg, respectively. TCLP results reveal only an insignificant amount of metal leaching. Fecal coliform of the compost was below the standard level; Helminth eggs and Salmonella spp. were absent. SEM micrographs reflect the decomposition of composting materials. The maximum germination index and germination capacity of compost pile P#3 for compost-soil ratio 1:0 and 1:1 were 90%-92.8% and 100%, respectively. The present approach produced nutrient-enriched compost from fecal sludge and hair-burning liming sludge from a tannery emerges as a suitable solution for reducing solid wastes.

Recycling of domestic sludge cake as the inoculum of anaerobic digestion for kitchen waste and its benefits to carbon negativity

Organic waste recovery has been a concerning issue in line with resource conservation. In the present study, the kitchen waste of vegetables, fish, and beef was digested anaerobically using domestic sludge as the inoculum, the methane and carbon dioxide were monitored, and the environmental benefits of the anaerobic digestion (AD) process were evaluated. AD using sludge cake as the inoculum was shown to treat kitchen waste effectively. Raw beef was found to produce more gas than raw fish or vegetables. Investigations also indicated that celluloses within vegetables were not as readily biodegradable as the proteins in beef and fish. Moreover, cooking altered the protein structures in beef and fish, thus increasing methane production. Meanwhile, oil inhibited methane generation as carbon dioxide generation remained, implying that the hydrolysis and acedogenesis still proceeded in the digestion process containing oil. Anaerolineaceae and Synergistaceae are the two most abundant microbial species observed in an anaerobic digestion system. However, the carbon conversions to liquid (i.e., leachate), solid (i.e., digestate), and gaseous (i.e., methane and carbon dioxide) occurred in the AD process, showing a diverse transforming process from waste to reusable valuables. Moreover, the kitchen waste treatment by domestic sludge cake was shown to have positive effects on reducing carbon dioxide emissions compared to the conventional treatment of kitchen waste and domestic sludge. More environmental benefits could be expected if the resulting products (i.e., methane gas, leachate, digestate) were applied as an energy source, liquid fertilizers, and soil conditioners.

The prospect of fruit wastes in bioethanol production: A review

Utilising agricultural byproducts specifically fruit wastes for bioethanol production offers a promising approach to sustainable energy production and waste mitigation. This approach focuses on assessing the biochemical composition of fruit wastes, particularly their sugar content, as a key aspect of bioethanol production. This study evaluates the potential of pineapple, mango, pawpaw and watermelon fruit wastes for bioethanol production, highlighting the substantial organic waste generated during fruit processing stages such as peeling and pulping. Various techniques, including enzymatic hydrolysis, fermentation, and distillation, are reviewed to optimise bioethanol yields while addressing challenges such as seasonal availability, substrate variability and process optimisation. Besides, the environmental benefits of bioethanol derived from fruit wastes, such as reduced environmental pollution, decreased reliance on fossil fuels, and promotion of sustainable agricultural practices, are emphasised. The study deployed a comprehensive literature review using keywords, specific research questions, and a search strategy that included academic databases, library catalogues, and Google Scholar. Search results were systematically screened and selected based on their relevance to the topic.

Feasibility study of plasma pyrolysis on dairy waste

Considering the ever-increasing necessity of the disposal of industrial and household waste and using mechanisms through which the utmost potential of the waste is directed to the efficient recycling of materials or forms of energy, the current study aims to investigate plasma pyrolysis as an eco-friendly and appropriate approach that leads to the production of value-added products. The novelty of this study lies in its development of a method for spoiled milk disposal since no efficient solution has been provided yet in this respect. The other benefit of implementing the proposed disposal method is the production of high-quality syngas. The maximum produced hydrogen percentage and syngas rate during the process under study in this research were obtained as 60.396 % and 2.166, respectively. A plasma method is a rare approach to yielding products with such values. The obtained results revealed that the transferred thermal plasma could efficiently dispose of the spoiled milk waste and be used as a novel approach to the green synthesis of hydrogen through plasma pyrolysis.

Green hybrid coagulants for water treatment: An innovative approach using alum and bentonite clay combined with eco-friendly plant materials for batch and column adsorption

Textile industries contribute to water pollution through synthetic dye discharge. This study explores the use of natural bio-coagulants to remove acid dyes from wastewater, investigating factors like pH, coagulant dose, dye concentration, contact time, and temperature for optimal results. The optimum pH and coagulants capabilities of (CAAPP, CAAPH, CBAGL, CBAPP and CBAPH) were 3 (49.6 mg/g), 3 (42.5 mg/g), 3 (38.9 mg/g), 4 (35.7 mg/g), 4 (34.1 mg/g), and 4 (29.4 mg/g) respectively, while treating of selected BRF-221 dyes from water solution. The acidic range (3-4) was found to have the best pH for the maximal coagulation, and the optimal dose were found to be 0.05 g/50 mL. The equilibrium was attained within 45-60 min for all coagulants. After 60 min of shaking, the maximum coagulation capacities (21.9, 21.02, 16.5, 27.9, 25.3, and 23.4 mg/g) of several coagulant composites (CAAGL, CAAPP, CAAPH, CBAGL, CBAPP, CBAPH) were determined. The initial BRF-221 dye concentration in the range of 10-200 mg/L was considered as optimum for gaiting maximum elimination of dye using different coagulants. At a dye value of 100 mg/L of BRF-221, maximal coagulation capacities CAAGL (179.19 mg/g), CAAPP (166.06 mg/g), CAAPH (141.60 mg/g), and CBAGL (126.49 mg/g), CBAPP (113.9 mg/g), CBAPH (93.08 mg/g) were attained. The study found 35 °C to be the optimal temperature for maximum acid dye removal using bio-coagulants. Increasing temperature reduced coagulation capacity, indicating an exothermic process. Freundlich and Langmuir isotherms showed suitability for pseudo-first-order and pseudo-second-order kinetics in biosorption. Thermodynamic parameters were assessed for process feasibility. Effective coagulants demonstrated sensitivity to electrolyte variations. In column studies, adjusting parameters achieved maximum coagulation efficiency for removing BRF-221 dyes. The study successfully applied optimal parameters to remove real textile effluents at a practical scale. SEM, FT-IR, BET and XRD characterized coagulants, providing insights into stability and morphology.

Biochar addition influences C and N dynamics during biochar co-composting and the nutrient content of the biochar co-compost

This study investigated the effects of corn cob biochar (CCB) and rice husk biochar (RHB) additions (at 0%, 5%, and 10% w/w) on nitrogen and carbon dynamics during co-composting with poultry litter, rice straw, and domestic bio-waste. The study further assessed the temperature, moisture, pH, and nutrient contents of the mature biochar co-composts, and their potential phytotoxicity effects on amaranth, cucumber, cowpea, and tomato. Biochar additions decreased NH4+-N and NO3- contents, but bacteria and fungi populations increased during the composting process. The mature biochar co-composts showed higher pH (9.0-9.7), and increased total carbon (24.7-37.6%), nitrogen (1.8-2.4%), phosphorus (6.5-8.1 g kg-1), potassium (26.8-42.5 g kg-1), calcium (25.1-49.5 g kg-1), and magnesium (4.8-7.2 g kg-1) contents compared to the compost without biochar. Germination indices (GI) recorded in all the plants tested with the different composts were greater than 60%. Regardless of the biochar additions, all composts treatments showed no or very minimal phytotoxic effects on cucumber, amaranth and cowpea seeds. We conclude that rice husk and corn cob biochar co-composts are nutrient-rich and safe soil amendment for crop production.

A novel micro-CT approach for in situ visualization of the spatial dynamics of mesovoids in aerobic composting piles

The spatial configuration of mesovoids profoundly affects the aerobic composting microenvironment, which governs vital processes such as greenhouse gas production and emission, thermal conduction, and overall composting efficiency. Nondestructive in-situ characterization of the composting spatial structure is crucial to better understand its interaction mechanism with the microenvironment. In this study, a valuable contribution to the field of composting research was made by introducing micro-computed tomography (micro-CT) tool for in situ three-dimensional (3D) visual characterizing the void structure dynamics of straw and manure compost pile units at the mesoscale. Representative samples at different composting stages derived from wheat straw and cow manure were procured by pre-embedding samplers in laboratory-based aerobic composting reactor systems. Based on an advanced Skyscan 1275 micro-CT system, scanning conditions and image processing algorithms were determined, and the void structure and their dynamic changes in the pile unit during composting were in-situ 3D visualized for the first time. The micro-CT images effectively reveal well-developed void structures exhibiting spatiotemporal dynamics during composting, and they exhibit excellent consistency with conventional macrophysical effects and wet chemical analyses. Micro-CT quantification results of the void structure parameters changes in pile unit during composting were as follows: percentage of the total voidage and the connected voidage in pile unit were in the range of 52.34%-58.56%, indicating a very suitable composting spatial structural microenvironment. This new micro-CT method provides a valuable perspective for analyzing and understanding the complex aerobic composting process.

Effect of Biochar on Composting of Cow Manure and Kitchen Waste

Composting is a common method for managing organic waste and creating nutrient-rich soil amendments. Recently, biochar, a carbon-rich material from biomass pyrolysis, has been noted for potentially improving composting. This study examines the impact of adding biochar to compost made from cow manure and kitchen waste through a controlled lab experiment. The treatments were labeled as CMX (cow manure), KWX (kitchen waste), and CMKWX (both) with X being the percentage of CM, KW, and CMKW minus that of biochar in the mixture. Key parameters such as temperature (T), pH, and electric conductivity (EC) were tracked during the composting processes, and the final composts were analyzed for total nitrogen (N), available nitrogen (AN), total phosphorus (TP), available phosphorus (AP), total potassium (TK), organic carbon (OC), calcium (Ca2+), magnesium (Mg2+), and organic matter (OM). The results showed that adding less than 10% biochar influenced composting positively. Specifically, 5% biochar amendment led to higher thermophilic temperatures (45–57 °C) and stable pH levels (6.3–8.7) compared to controls. However, biochar did not significantly enhance EC, which peaked at 1.78 dS/m in both the control and 5% biochar treatments. Nutrient analysis revealed that biochar increased Ca2+ (13.62 meq/g) and Mg2+ (5.73 meq/g) retention in CM composts (CM85 and CM100). The highest OM content was 16.84% in CM90, while the lowest was 3.81% in CM95. Higher OM negatively affected TN, with CM treatments having more OM and KW treatments having more TN. TP and TK were higher in control treatments without biochar. This study highlights the benefits of integrating biochar with organic waste for enhancing compost nutrient profiles and soil fertility. It was observed that the more diverse the compost feedstock, i.e., CMKW, the higher the nutrient content for treatments containing less than 10% biochar.

Possibilities and prospects of bioplastics production from agri-waste using bacterial communities: Finding a silver-lining in waste management

To meet the need of the growing global population, the modern agriculture faces tremendous challenges to produce more food as well as fiber, timber, biofuels, etc.; hence generates more waste. This continuous growth of agricultural waste (agri-waste) and its management strategies have drawn the attention worldwide because of its severe environmental impacts including air, soil and water pollution. Similarly, growing concerns about the sustainable future have fuelled the development of biopolymers, substances occurring in and/or produced by living organisms, as substitute for different synthetic and harmful polymers, especially petroleum-based plastics. Now, the components of agri-waste offer encouraging opportunities for the production of bioplastics through mechanical and microbial procedures. Even the microbial, both bacterial and fungal, system results in lower energy consumption and better eco-friendly alternatives. The review mainly concentrates on cataloging and understanding the bacterial 'input' in developing bioplastics from diverse agri-waste. Especially, the bacteria like Cupriavidus necator, Chromatium vinosum, and Pseudomonas aeruginosa produce short- and medium-chain length poly(3-hydroxyalkanote) (P3HB) polymers using starch (from corn and potato waste), and cellulose (from sugarcane bagasse, corn husks waste). Similarly, C. necator, and transformant Wautersia eutropha produce P3HB polymer using lipid-based components (such as palm oil waste). Important to note that, the synthesis of these polymers are interconnected with the bacterial general metabolic activities, for example Krebs cycle, glycolysis cycle, β-oxidation, calvin cycle, de novo fatty acid syntheses, etc. Altogether, the agri-waste is reasonably low-cost feed for the production of bioplastics using bacterial communities; and the whole process certainly provide an opportunity towards sustainable waste management strategy.

Characterization of fungal microbiome structure in leaf litter compost through metagenomic profiling for harnessing the bio-organic fertilizer potential

Sustainable waste management through composting has gain renewed attention since it could upcycle organic waste into valuable bio-organic fertiliser. This study explored the composition of fungal communities in leaf litter and organic waste composts ecosystems by employing advanced internal transcribed spacer (ITS) metagenomic profiling. This approach provides insights into the diversity, composition, and potential functions of these fungi, offering practical implications for optimising composting processes and enhancing sustainable waste management practices. Various organic composts were collected, including leaf litter composts, from different sources in Delhi-National Capital Region, India, and fungal microbiome composition were characterised through ITS profiling. Results revealed that leaf litter composts and cow dung manure had the highest fungal read counts, while kitchen waste compost had the lowest. Alpha diversity indices, including Chao1 and Shannon, exhibited differences in species richness and diversity among composts, though statistical significance was limited. The leaf composts had relatively higher alpha diversity than the other organic waste composts analysed. The study also identified dominant fungal genera specifically, Wallemia, Geotrichum, Pichia, Mycothermus, Mortierella, Aspergillus, Fusarium, and Basidiobolus, across the compost samples. The presence of beneficial fungal genera like Pichia, Geotrichum, Trichoderma, Mortierella, Basidiobolus, Aspergillus, and others were detected in leaf waste compost and the other organic waste composts. There was also presence of some pathogenic genera viz. Alternaria, Fusarium, and Acremonium, in these composts which underscored the need for proper composting practices and source selection to optimise soil fertility and minimise disease risks in agriculture. Remarkably, leaf compost has highest proportion of beneficial genera with least observed abundance of pathogens. On the other hand, the municipal organic waste compost has least proportion of beneficial genera with higher abundance of pathogens. Overall, these findings contributed to characterisation of composting processes, advancing waste management practices, and enhancing the use of leaf compost as a bio-organic fertiliser.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-024-04028-0.

A comprehensive review of current approaches on food waste reduction strategies

Food waste is a serious worldwide issue that has an impact on the environment, society, and economy. This comprehensive review provides a detailed description of methods and approaches for reducing food waste, emphasizing the necessity of comprehensive strategies to tackle its intricate relationship with environmental sustainability, social equity, and economic prosperity. By scrutinizing the extent and impact of food waste, from initial production stages to final disposal, this comprehensive review underlines the urgent need for integrated solutions that include technological advancements, behavioral interventions, regulatory frameworks, and collaborative endeavors. Environmental assessments highlight the significant contribution of food waste to greenhouse gas emissions, land degradation, water scarcity, and energy inefficiency, thereby emphasizing the importance of curtailing its environmental impact. Concurrently, the social and economic consequences of food waste, such as food insecurity, economic losses, and disparities in food access, underscore the imperative for coordinated action across multiple sectors. Food waste can also be effectively reduced by various innovative approaches, such as technological waste reduction solutions, supply chain optimization strategies, consumer behavior-focused initiatives, and waste recovery and recycling techniques. Furthermore, in order to foster an environment that encourages the reduction of food waste and facilitates the transition to a circular economy, legislative changes and regulatory actions are essential. By embracing these multifaceted strategies and approaches, stakeholders can unite to confront the global food waste crisis, thereby fostering resilience, sustainability, and social equity within our food systems.

Sustainable Agricultural Development

Sustainable agricultural practices improve food security, increase farmers' profitability, and preserve the environment. By implementing sustainable farming methods such as crop rotation, integrated pest management, and conservation tillage, farmers can improve soil health, reduce water usage, and minimize agrochemical inputs. Moreover, sustainable agriculture promotes biodiversity and protects natural resources such as water and soil. Responsible farming practices preserve the environment and ensure that future generations access fertile land and clean water sources. Additionally, sustainable agriculture can help farmers achieve higher crop yields and better-quality produce, adapt to changing climate conditions, and mitigate the impact of climate change on food production. Sustainable agricultural practices are essential for ensuring food security, increasing farmers' profitability, and preserving the environment for future generations. We must continue to support and promote sustainable farming methods to create a more resilient and sustainable food system.

Characteristics of three organic fertilizers and their influence on the mobility of cadmium and arsenic in a soil-rice (Oryza sativa L.) system

The properties of different organic fertilizers and their potential for stabilizing toxic metals(loids) in soil have not been fully investigated. This study characterized and evaluated three organic fertilizers from different raw materials. The mushroom residue organic fertilizer (MO) had higher C, H, and O contents and more functional groups (-OH, C-H, and C = O). Its application significantly increased pH (1.00 ~ 1.32 units), organic matter (OM) content (26.58 ~ 69.11%), and cation exchange capacity (CEC) (31.52 ~ 39.91%) of soil. MO treatments can simultaneously reduce the bioavailable TCLP-Cd and TCLP-As in soil, solving the difficulties of remediating the combined Cd and As pollution. MO treatments inhibited the migration of Cd and As from soil to plant, promoting plant growth. Redundancy analysis (RDA) revealed that metal(loid) variations in plants were related to soil properties (40.09%) and TCLP-Cd/As (44.74%). Furthermore, the toxic metals(loids) risk assessment for all organic fertilizers was at safe levels. This study provided a valuable reference for choosing organic fertilizers and presented a novel option for the "producing while remediating" of farmlands with low pollution.

Alginate Beads with Encapsulated Bioactive Substances from Mangifera indica Peels as Promising Peroral Delivery Systems

Since various bioactive substances are unstable and can degrade in the gastrointestinal tract, their stabilization is crucial. This study aimed to encapsulate mango peel extract (MPE) into edible alginate beads using the ionotropic gelation method for the potential oral delivery of bioactive substances. Mango peels, generally discarded and environmentally harmful, are rich in health-promoting bioactive substances. The alginate beads were examined for entrapment efficiency, particle size, morphology, thermal stability, physiochemical interactions, release profile under gastrointestinal conditions, and antibacterial efficacy. The study demonstrated the successful encapsulation of MPE with an efficiency of 63.1%. The in vitro release study showed the stability of the alginate beads in simulated gastric fluid with a maximum release of 45.0%, and sustained, almost complete release (99.4%) in simulated intestinal fluid, indicating successful absorption into the human body. In both fluids, the MPE release followed first-order kinetics. Encapsulation successfully maintained the antibacterial properties of MPE, with significant inhibitory activity against pathogenic intestinal bacteria. This is the first study on MPE encapsulation in alginate beads, presenting a promising oral delivery system for high-added-value applications in the food industry for dietary supplements, functional foods, or food additives. Their production is sustainable and economical, utilizing waste material and reducing environmental pollution.

Improving Aerobic Digestion of Food Waste by Adding a Personalized Microbial Inoculum

In the context of China's garbage classification policy, on-site aerobic food waste (FW) digestion is crucial for reducing transportation and disposal costs. The efficiency of this process is largely determined by the microbial community structure and its functions. Therefore, this study aimed to analyze the impact of a personalized microbial consortium (MCM) on the efficiency of aerobic FW digestion and to reveal the underlying mechanisms. An MCM, sourced from naturally degrading FW, was selected to enrich degrading bacteria with relatively high hydrolyzing ability. The functionality of the MCM was evaluated by tracing the successions of microbial communities, and comparing the differences in the forms of organic compounds, metabolic functions, and hydrolase activities. X-ray photoelectron spectroscopy demonstrated that the MCM metabolized faster, and produced more acidic metabolites. Metagenomic analysis indicated that FW inoculated with the personalized MCM increased abundance of Bacillaceae producing hydrolysis enzymes and promoted glycolysis metabolic pathways, enhancing energy generation for metabolism, compared to the commercial effective bacterial agent. This paper provides both theoretical and practical evidence for the improvement of biochemical processor of FW with the personalized MCM, which has promising application prospects and economic value.

Vermi-remediation impacts on growth and metals bioaccumulation in tomato irrigated with wastewater

Due to their persistence in the environment, and their highly toxic and bioaccumulative nature, heavy metals are well known to the environment. Vermicompost has gained popularity because it improves soil properties and, most importantly, remediates and immobilizes heavy metals. The present study assessed vermicompost effects on heavy metal bioaccumulation in tomato plants irrigated with wastewater. A plastic bag experiment was carried out with 5 kg of growing media in each bag. Growing media contain garden soil with four levels of vermicompost mixed at 0%, 5%, 15%, and 25%. The pots were irrigated with wastewater from different industries and tap water, which was taken as control. Wastewater was collected from the pharmaceutical industry, plastic industry, and sewage water of Hayatabad Industrial Estate, Peshawar. Vermicompost application significantly affected all tomatoes' growth attributes and heavy metals concentration. Results revealed that minimum Cd (2.48 mg kg-1), Cr (1.27 mg kg-1), Cu (4.10 mg kg-1), and Pb (0.62 mg kg-1) concentrations were recorded in tomatoes cultivated in 25 % vermicompost amended soil, while, maximum Cd (5.23 mg kg-1), Cr (2.29 mg kg-1), Cu (8.84 mg kg-1) and Pb (2.18 mg kg-1) concentrations were reported in sewage water irrigated plants., Overall, vermicompost applied at 25% significantly enhanced plant growth and yield, reducing the bioavailability and bioaccumulation of heavy metals. From the finding of this study, it is observed that wastewater irrigation of plants should be avoided because of the high level of heavy metals; in contrast, the application of vermicompost is highly recommended as compost reduces heavy metals bioaccumulation and enhances productivity.

Optimizing agricultural sustainability: enriched organic formulations for growth, yield, and soil quality in a multi-crop system

Utilizing agricultural and industrial wastes, potent reservoirs of nutrients, for nourishing the soil and crops through composting embodies a sustainable approach to waste management and organic agriculture. To investigate this, a 2-year field experiment was conducted at ICAR-IARI, New Delhi, focusing on a pigeon pea-vegetable mustard-okra cropping system. Seven nutrient sources were tested, including a control (T1), 100% recommended dose of nitrogen (RDN) through farmyard manure (T2), 100% RDN through improved rice residue compost (T3), 100% RDN through a paddy husk ash (PHA)-based formulation (T4), 75% RDN through PHA-based formulation (T5), 100% RDN through a potato peel compost (PPC)-based formulation (T6), and 75% RDN through PPC-based formulation (T7). Employing a randomized block design with three replications, the results revealed that treatment T4 exhibited the significantly highest seed (1.89 ± 0.09 and 1.97 ± 0.12 t ha-1) and stover (7.83 ± 0.41 and 8.03 ± 0.58 t ha-1) yield of pigeon pea, leaf yield (81.57 ± 4.69 and 82.97 ± 4.17 t ha-1) of vegetable mustard, and fruit (13.54 ± 0.82 and 13.78 ± 0.81 t ha-1) and stover (21.64 ± 1.31 and 22.03 ± 1.30 t ha-1) yield of okra during both study years compared to the control (T1). Treatment T4 was on par with T2 and T6 for seed and stover yield in pigeon pea, as well as okra, and leaf yield in vegetable mustard over both years. Moreover, T4 demonstrated notable increase of 124.1% and 158.2% in NH4-N and NO3-N levels in the soil, respectively, over the control. The enhanced status of available nitrogen (N) and phosphorus (P) in the soil, coupled with increased soil organic carbon (0.41%), total bacteria population (21.1%), fungi (37.2%), actinomycetes (44.6%), and microbial biomass carbon (28.5%), further emphasized the positive impact of T4 compared to the control. Treatments T2 and T6 exhibited comparable outcomes to T4 concerning changes in available N, P, soil organic carbon, total bacteria population, fungi, actinomycetes, and microbial biomass carbon. In conclusion, treatments T4 and T6 emerge as viable sources of organic fertilizer, particularly in regions confronting farmyard manure shortages. These formulations offer substantial advantages, including enhanced yield, soil quality improvement, and efficient fertilizer utilization, thus contributing significantly to sustainable agricultural practices.

Vegetable and fruit wastes: Valuable source for organic fertilizer for effective growth of short-term crops: Solanum lycopersicum and Capsicum annum

Agriculture plays a vital role in the food security and economies of Asian countries. Annually, numerous metric tons of vegetable and fruit wastes are disposed of. This research aimed to convert the food wastes encompassing the vegetable and fruit wastes into solid and liquid organic fertilizer and to evaluate their influence on the growth (germination, phytochemicals, and biomolecules) of Solanum lycopersicum and Capsicum annum. Solanum lycopersicum, known as tomato, and Capsicum annum, known as bell pepper or chili pepper, are globally significant crops valued for their medicinal properties and economic importance. The pot experiment was performed with organic fertilizers (solid and liquid organic fertilizer) and compared with the influence of chemical fertilizer and control soil without fertilizers. Interestingly, the liquid organic fertilizer effectively enhanced the biometric profile and chlorophyll content of S. lycopersicum and C. annum Viz., 1.23 mg g-1 and 0.89 mg g-1, respectively. The results of a 30-days pot experiment with various fertilizer treatments showed significant influence of liquid organic fertilizer on the fresh and dry weight biomass of both S. lycopersicum and C. annum. Subsequently, the solid organic fertilizer showed considerable influence on test crops, and the influence of these organic fertilizers was more significant than the chemical fertilizer on crop growth in 30-days experiment. These results suggest that the sustainable approach can effectively convert vegetables and fruit waste into valuable organic fertilizer enriched with plant growth supporting essential nutritional elements.

Hydrogen Production from Enzymatic Pretreated Organic Waste with Thermotoga neapolitana

Biomass from various types of organic waste was tested for possible use in hydrogen production. The composition consisted of lignified samples, green waste, and kitchen scraps such as fruit and vegetable peels and leftover food. For this purpose, the enzymatic pretreatment of organic waste with a combination of five different hydrolytic enzymes (cellulase, amylase, glucoamylase, pectinase and xylase) was investigated to determine its ability to produce hydrogen (H2) with the hydrolyzate produced here. In course, the anaerobic rod-shaped bacterium T. neapolitana was used for H2 production. First, the enzymes were investigated using different substrates in preliminary experiments. Subsequently, hydrolyses were carried out using different types of organic waste. In the hydrolysis carried out here for 48 h, an increase in glucose concentration of 481% was measured for waste loads containing starch, corresponding to a glucose concentration at the end of hydrolysis of 7.5 g·L−1. In the subsequent set fermentation in serum bottles, a H2 yield of 1.26 mmol H2 was obtained in the overhead space when Terrific Broth Medium with glucose and yeast extract (TBGY medium) was used. When hydrolyzed organic waste was used, even a H2 yield of 1.37 mmol could be achieved in the overhead space. In addition, a dedicated reactor system for the anaerobic fermentation of T. neapolitana to produce H2 was developed. The bioreactor developed here can ferment anaerobically with a very low loss of produced gas. Here, after 24 h, a hydrogen concentration of 83% could be measured in the overhead space.

Valorization of Tomato Agricultural Waste for 3D-Printed Polymer Composites Based on Poly(lactic acid)

Agricultural waste is a renewable source of lignocellulosic components, which can be processed in a variety of ways to yield added-value materials for various applications, e.g., polymer composites. However, most lignocellulosic biomass is incinerated for energy. Typically, agricultural waste is left to decompose in the fields, causing problems such as greenhouse gas release, attracting insects and rodents, and impacting soil fertility. This study aims to valorise nonedible tomato waste with no commercial value in Additive Manufacturing (AM) to create sustainable, cost-effective and added-value PLA composites. Fused Filament Fabrication (FFF) filaments with 5 and 10 wt.% tomato stem powder (TSP) were developed, and 3D-printed specimens were tested. Mechanical testing showed consistent tensile properties with 5% TSP addition, while flexural strength decreased, possibly due to void formation. Dynamic mechanical analysis (DMA) indicated changes in storage modulus and damping factor with TSP addition. Notably, the composites exhibited antioxidant activity, increasing with higher TSP content. These findings underscore the potential of agricultural waste utilization in FFF, offering insights into greener waste management practices and addressing challenges in mechanical performance and material compatibility. This research highlights the viability of integrating agricultural waste into filament-based AM, contributing to sustainable agricultural practices and promoting circular economy initiatives.

Integrated nutrient recycling: Ammonia recovery from thermophilic composting of shrimp aquaculture sludge via self-heated bench-scale reactor and mango plant growth enhancement by the compost

Due to the rapid growth of the aquaculture industry, large amounts of organic waste are released into nature and polluted the environment. Traditional organic waste treatment such as composting is a time-consuming process that retains the ammonia (NH3) in the compost, and the compost produced has little economic value as organic fertilizer. Illegal direct discharge into the environment is therefore widespread. This study investigates the recovery of NH3 through thermophilic composting of shrimp aquaculture sludge (SAS) and its application as a soil conditioner for the growth of mango plants. A maximum composting temperature of 57.10 °C was achieved through self-heating in a 200 L bench-scale reactor, resulting in NH3 recovery of 224.04 mol/ton-ds after 14 days. The addition of calcium hydroxide and increased aeration have been shown to increase NH3 volatilization. The recovered NH3 up to 3 kg-N can be used as a source of clean nitrogen for high-value microalgae cultivation, with a theoretical yield of up to 34.85 kg-algae of microalgae biomass from 1 ton-ds of SAS composting. Despite the high salinity, SAS compost improved mango plant growth and disease resistance. These results highlight the potential of SAS compost as a sustainable source of clean nitrogen for microalgae cultivation and soil conditioner, contributing to a waste-free circular economy through nutrient recycling and sustainable agriculture.

A comparative study on compost preparation using lab prepared eco-enzyme and its effect on growth of plant species Phaseolus vulgaris

The augmented rise in population in the last few decades has resulted in gigantic increase in the solid waste production in India and around the globe. The conventional composting methods are slow and sluggish process that has resulted in the advancement techniques for the emergence in new rapid composting processes. Use of eco-enzyme is such a rapid technique that helps to degrade the solid waste in a very accelerative manner. The present study has been carried out by preparing eco-enzyme using the kitchen waste and with the objective to utilize it for degradation of agricultural wastes and preparing compost for its utilization for different plant species as soil conditioner and fertilizer. The prepared eco-enzyme was added during the composting process in each batch with concentration variations of 10%, 15%, and 20% (V/V) once every week. The pH value of the final prepared compost was found to be within the neutral range of 6.51 ± 0.03-7.88 ± 0.50 in all the samples. Overall compost prepared using 10% eco-enzyme has the highest growth promoting effects for Phaseolus vulgaris. The present study will be having twofold advantage as the environment will get rid of such wastes as the same can be utilized as resource and it will also be helpful for the farmers from economical point of view.

Overview of municipal solid waste management in sub-tropical climatic region of North Eastern India

Municipal solid waste management (MSWM) is perceived as a global issue regardless of the place of waste generation. The amount of unmanaged waste is increasing rapidly, along with its impact on the environment and human health. In hilly areas, specifically the North Eastern Region (NER) states of India, due to the unique topography coupled with socio-economic factors, there are inadequate waste management practices marked by insufficient infrastructure, minimal research studies, and limited data availability. This paper comprehensively reviews the existing status of MSWM practices and waste treatment technologies, identifies the challenges, and discusses the prospective approaches for MSWM in NER states of India. NER, is characterized by its hilly terrain and has the most diverse demographic profile in the country. The study highlights the notable increase in waste generation in the urban population in NER. The total amount of waste generated in NER is about 2907 tons per day, with a collection rate of 86.96%, treatment at 31.09%, and landfilling at 33.67%. The biodegradable fraction makes up the majority of waste composition (more than 50%) in NER, followed by recyclables and inert. The existing MSWM consists of waste collection, transportation, and disposal with limited source segregation and treatment. All the states of NER practice open dumping and burning as the primary waste treatment and disposal system. The study discusses the challenges and prospects to ensure effective MSWM in NER. This review is a region-specific study that considers cultural diversity, topography, and socio-economic dynamics. The outcome of this review will be helpful to the researchers and policymakers in making appropriate waste management plans and improve the MSWM system in NER.

From organic fertilizer to the soils: What happens to the microplastics? A critical review

In recent, soil microplastic pollution arising from organic fertilizers has been of a great increasing concern. In response to this concern, this review presents a comprehensive analysis of the occurrence and evolution of microplastics in organic fertilizers, their ingress into the soil, and the subsequent impacts. Organic fertilizers are primarily derived from solid organic waste generated by anthropocentric activities including urban (daily-life, municipal wastes and sludge), agricultural (manure, straw), and industrial (like food industrial waste etc.) processes. In order to produce organic fertilizer, the organic solid wastes are generally treated by aerobic composting or anaerobic digestion. Currently, microplastics have been widely detected in the raw materials and products of organic fertilizer. During the process of converting organic solid waste materials into fertilizer, intense oxidation, hydrolysis, and microbial actions significantly alter the physical, chemical, and surface biofilm properties of the plastics. After the organic fertilizer application, the abundances of microplastics significantly increased in the soil. Additionally, the degradation of these microplastics often promotes the adsorption of organic pollutants and affects their retention time in the soil. These microplastics, covered by biofilms, also significantly alter soil ecology due to the unique properties of the biofilm. Furthermore, the biofilms also play a role in the degradation of microplastics in the soil environment. This review offers a new perspective on the soil environmental processes involving microplastics from organic fertilizer sources and highlights the challenges associated with further research on organic fertilizers and microplastics.

Global perspective of municipal solid waste and landfill leachate: generation, composition, eco-toxicity, and sustainable management strategies

Globally, more than 2 billion tonnes of municipal solid waste (MSW) are generated each year, with that amount anticipated to reach around 3.5 billion tonnes by 2050. On a worldwide scale, food and green waste contribute the major proportion of MSW, which accounts for 44% of global waste, followed by recycling waste (38%), which includes plastic, glass, cardboard, and paper, and 18% of other materials. Population growth, urbanization, and industrial expansion are the principal drivers of the ever-increasing production of MSW across the world. Among the different practices employed for the management of waste, landfill disposal has been the most popular and easiest method across the world. Waste management practices differ significantly depending on the income level. In high-income nations, only 2% of waste is dumped, whereas in low-income nations, approximately 93% of waste is burned or dumped. However, the unscientific disposal of waste in landfills causes the generation of gases, heat, and leachate and results in a variety of ecotoxicological problems, including global warming, water pollution, fire hazards, and health effects that are hazardous to both the environment and public health. Therefore, sustainable management of MSW and landfill leachate is critical, necessitating the use of more advanced techniques to lessen waste production and maximize recycling to assure environmental sustainability. The present review provides an updated overview of the global perspective of municipal waste generation, composition, landfill heat and leachate formation, and ecotoxicological effects, and also discusses integrated-waste management approaches for the sustainable management of municipal waste and landfill leachate.

Pollutant levels in the waters of the industrial area of North Aceh and Lhokseumawe Regency, Indonesia

This research was conducted from June to August 2023. Data and samples were collected using an exploratory survey method in four locations around the industrial area, namely PT. ASEAN Aceh Fertilizer and PT. Kertas Kraft Aceh in North Aceh Regency, while PT. Pupuk Iskandar Muda and PT. Harun NGL in Lhokseumawe Regency, Indonesia. Observations of physico-chemical parameters including measurements of salinity, bicarbonate, calcium, magnesium, nitrate, nitrite, orthophosphate, total alkalinity, and total ammonia were analyzed in the Laboratory of PT Intraco Agroindustri, Langkat Regency, North Sumatra, Indonesia. Microplastic analysis was carried out at the Faculty of Marine and Fisheries, Universitas Syiah Kuala, Banda Aceh, Indonesia. The biological parameters measured in this research include the chlorophyll concentration in the water locations observed. Based on the results of the analysis, it shows that the calcium, magnesium, orthophosphate content at the four research locations has exceeded the quality standards, while the nitrate content is only at PT. ASEAN Aceh Fertilizer and PT. Kertas Kraft Aceh that exceeds the quality standards. The bicarbonate, nitrite, salinity, total alkalinity, and total ammonia content at the four research locations were under normal conditions. The chlorophyll content in the four research locations was categorized as low fertility (oligotrophic). Based on the analysis, it also shows that the four research locations were contaminated with microplastics with a range of 2.78-5.49 particles/l.

The urgency of building soils for Middle Eastern and North African countries: Economic, environmental, and health solutions

Soil degradation is a short or long ongoing process that limits ecosystem services. Intensive land use, water scarcity, land disturbance, and global climate change have reduced the quality of soils worldwide. This degradation directly threatens most of the land in the Middle East and North Africa, while the remaining areas are at high risk of further desertification. Rehabilitation and control of these damaged environments are essential to avoid negative effects on human well-being (e.g., poverty, food insecurity, wars, etc.). Here we review constructed soils involving the use of waste materials as a solution to soil degradation and present approaches to address erosion, organic matter oxidation, water scarcity and salinization. Our analysis showed a high potential for using constructed soil as a complimentary reclamation solution in addition to traditional ones. Constructed soils could have the ability to overcome the limitations of existing solutions to tackle land degradation while contributing to the solution of waste management problems. These soils facilitate the provision of multiple ecosystem services and have the potential to address particularly challenging land degradation problems in semi and dry climates.

Sustainability, performance, and production perspectives of waste-derived functional carbon nanomaterials towards a sustainable environment: A review

The survival of humanity is severely threatened by the massive accumulation of waste in the ecosystem. One plausible solution for the management and upcycling of waste is conversing waste at the molecular level and deriving carbon-based nanomaterial. The field of carbon nanomaterials with distinctive properties, such as exceptionally large surface areas, good thermal and chemical stability, and improved propagation of charge carriers, remains a significant area of research. The study demonstrates recent developments in high-value carbon-based photocatalysts synthesis from various waste precursors, including zoonotic, phytogenic, polyolefinic, electronic, and biomedical, highlighting the progression as photocatalysts and adsorbents for wastewater treatment and water splitting applications. This review highpoints the benefits of using waste as a precursor to support sustainability and circular economy and the risks associated with their use. Finally, we support that a sustainable society will eventually be realized by exploring present obstacles and potential steps for creating superior carbon-based nanomaterials in the future.

Ore improver additions alter livestock manure compost ecosystem C:N:P stoichiometry

Deciphering the pivotal components of nutrient metabolism in compost is of paramount importance. To this end, ecoenzymatic stoichiometry, enzyme vector modeling, and statistical analysis were employed to explore the impact of exogenous ore improver on nutrient changes throughout the livestock composting process. The total phosphorus increased from 12.86 to 18.72 g kg-1, accompanied by a marked neutralized pH with ore improver, resulting in the Carbon-, nitrogen-, and phosphorus-related enzyme activities decreases. However, the potential C:P and N:P acquisition activities represented by ln(βG + CB): ln(ALP) and ln(NAG): ln(ALP), were increased with ore improver addition. Based on the ecoenzymatic stoiometry theory, these changes reflect a decreasing trend in the relative P/N limitation, with pH and total phosphorus as the decisive factors. Our study showed that the practical employment of eco stoichiometry could benefit the manure composting process. Moreover, we should also consider the ecological effects from pH for the waste material utilization in sustainable agriculture.

Morphological diversity of actinobacteria isolated from oil palm compost (Elaeis guineensis)

Composting is a natural process of decomposition of organic matter that occurs by the action of microorganisms such as fungi, bacteria, and actinobacteria. The actinobacteria are present throughout the process due to their resistance to different environmental conditions. They are Gram-positive, filamentous bacteria with a high capacity for producing secondary metabolites of biotechnological importance. Thus, the objective of this work was to isolate and characterize actinobacteria from industrial composting soil of oil palm (Elaeis guineensis) in the municipality of Igarapé-Açu, Pará. Ten samples of the material were collected and seeded on soy tryptone agar, Reasoner's 2A agar, and Columbia agar, using the serial dilution technique. For morphological characterization of the strains, Gram staining and microculture were performed, and for biochemical characterization, the motility, triple sugar iron, Simmons citrate, maltose, phenylalanine, catalase, and DNAse tests were performed. It was observed that compost actinobacteria have a great diversity in morphological and metabolic production, which may be associated with the substrate and cultivation conditions. Therefore, palm oil compost material represents a rich source of bacterial biodiversity, bringing new perspectives for the bioprospecting of actinobacteria of biotechnological importance in little explored environments.

Municipal Compost Public Health, Waste Management, and Urban Agriculture: A Decadal Study of Fugitive Pb in City of Boston, Massachusetts, USA

Compostable materials constitute roughly half of waste generated globally, but only 5% of waste is actually processed through composting, suggesting that expanding compost programs may be an effective way to process waste. Compostable waste, if properly collected and processed, has value-added end use options including: residential and park landscaping, remediation of brownfield sites, and as growing media in urban agriculture (UA). Since 2001, our lab has partnered with The Food Project, a non-profit focused on youth leadership development through urban farming. From 2006 to 2022 we collected compost materials that were delivered to the farm from a variety of local sources and analyzed a suite of biogeochemical properties including lead (Pb) concentrations, organic carbon, and grain size distribution. Pb concentrations of Boston's municipal compost always exceeded the current City of San Francisco soil and compost purchase standard (80 μg/g). In 2012 Boston's composting program was halted when it exceeded the 400 μg/g Environmental Protection Agency's Pb in soil benchmark. Urban Pb is geomobile and must be managed to minimize resuspension and transport of fines whose Pb concentration is often elevated compared to bulk compost. Consequently, urban farmers have to source lower Pb compost from suburban suppliers at significantly greater cost. Over a 15 year period and through several city vendor contracts, Pb concentrations in municipal compost remain at levels that warrant continued surveillance and risk assessment.

Slaughterhouse by-products composting: can microorganisms inoculum addition mitigate final compost odor emission?

Small slaughterhouses generate biowaste, which for economic reasons, is generally destined for composting. Inoculating appropriate microorganisms can improve biodegradation efficiency and mitigate odor generation during the composting process and can give rise to composts with neutral or pleasant odors. Therefore, the aim of this study was to compare the odor intensity reduction of compost generated with and without a formulated inoculum (Saccharomyces cerevisiae, Bacillus subtilis, and Rhodopseudomonas palustris). A set of experimental data was collected and analyzed according to the German "Verein Deutscher Ingenieure" odor protocol. The results showed that adding microorganisms was effective in reducing unpleasant odors in all three composts generated from swine, cattle, and poultry slaughterhouse by-products during both summer and winter seasons. Additionally, soil odor was predominant in composts that were inoculated in the two tested seasons (i.e., summer and winter). On the other hand, composts without inoculation had odors similar to peat for swine compost, ammonia for cattle compost, and manure for poultry compost, regardless of the season tested. Overall, composting process with appropriate inoculum can help in the correct disposal of slaughterhouse wastes by transforming organic matter into composts, which can have economic and environmental value as a soil conditioner and/or fertilizer.

Emerging trends in biomaterials for sustainable food packaging: A comprehensive review

This comprehensive review investigates a variety of creative approaches in the field of sustainable food packaging biomaterials in response to growing environmental concerns and the negative effects of traditional plastic packaging. The study carefully looks at new developments in biomaterials, such as biodegradable polymers, ceramics, composites, and metal alloys, in response to the growing need for environmentally suitable substitutes. It highlights how they might replace conventional plastic packaging and lessen environmental damage. Moreover, the incorporation of nanotechnology into packaging is closely examined due to its crucial function in improving barrier qualities, introducing antimicrobial properties, and introducing smart packaging features. The investigation includes edible coatings and films made of biodegradable polymers that offer new sensory experiences in addition to prolonging the shelf life of products. The review emphasizes the use of biomaterials derived from food processing and agricultural waste, supporting environmentally responsible methods of producing materials while simultaneously using less resources and waste. As a strong defense against plastic pollution, the report highlights the food industry's increasing use of recyclable and biodegradable packaging, which is in line with the concepts of the circular economy. A movement in consumer tastes and regulatory pressures toward sustainable food packaging is evident in global market patterns. Notwithstanding these encouraging trends, there are still issues to be resolved, including cost-effectiveness, technological constraints, and the scalability of biomaterial production. This thorough analysis concludes by highlighting the critical role biomaterials have played in guiding the food industry toward sustainability and emphasizing the need for ongoing research and development to adequately address environmental issues on a worldwide scale and satisfy the growing demand for environmentally friendly packaging options. Biomaterials show great promise as catalysts for the food industry's transition to a sustainable future.

Assessment of municipal solid waste from households in Khulna city of Bangladesh

Waste management is a major concern for both developed and developing countries, with a particular focus on household waste because it makes up a significant proportion of municipal waste. The aim of this study is to assess the state of solid waste management practice in Khulna, as well as to characterize and quantify municipal solid waste as a step toward effective management. To collect information on the existing waste management methods, structured questionnaires were used to conduct surveys of household residents. In this study, whole wards (31 wards) of Khulna City Corporation (KCC) were clustered in 9 groups and selected one ward from each group. To analyze household waste, 75 households from each ward were selected and collected waste for 7 days. The selected household was categorized into five different socioeconomic strata such as low-income, lower-middle-income, middle-income, higher-middle-income and higher-income families. Besides, the assessment was carried out on the production and characterization of household waste that was produced in KCC. The waste samples were quantified, separated and characterized in the laboratory. Results reveal that biodegradable waste is the most prominent type and its percentage is about 81 %. The amount of waste production is positively correlated with income level. The waste generation rate of households for high-income families was 0.652 kg/cap/day while this rate got almost half for a low-income family and its value is o.312 kg/cap/day. Source separation of waste plays a vital role to reduce plastic leakage to the SDP. The result shows the proportion of plastic in mixed waste and source-separated waste after sorting by the waste collector was 4.04 % and 2.99 %, respectively. Survey results show that 42.96 % of respondents think that the source-separated waste should be collected during the period of 12pm to 02pm. A proposed management process was developed for household waste based on the output of this study.