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Household kitchen waste (HKW) is produced in large quantity and its management is difficult due to high moisture content and complex organic matter. Aerobic composting of HKW is an easy, efficient, cost-effective and eco-friendly method. This study is designed to achieve a zero-waste concept and to convert HKW. We optimized the type and size of three different bulking agents to speed up the composting process. The tested bulking agents were fallen leaves, sawdust and fly ash. The results showed a higher and longer thermophilic phase (55oC) for 11 days in C2. Higher moisture content (69%) and higher organic matter degradation (38.4%) were also observed in C2. The pH range in all compost treatments was 7-8.5, Electrical conductivity range was 1.8-3.55 mS/cm, C/N ratio range was 15.4-18.1, water holding capacity range was 3.25-4.3 g water/g dry sample, total potassium range was 1.52-1.61%, total phosphorous range was 0.83-1.14%. The highest germination index (119.1%) was also obtained in C2. The highest chili height (16.7 cm), greater number of leaves (20), greater shoot fresh weight (4.75 g) and root fresh weight (1.2 g) was obtained in the presence of C2. Similarly, greater water WHC (2.8 g water/g DW), higher porosity (55.49%) and higher aggregate stability (54.14%) of soil was also obtained by C2. This research effectively reduced the maturation time to 32 days and converted kitchen waste into compost (resource). This is a very practical idea for home composting and kitchen gardening to combat food security issues in developing countries.

Due to its environmental friendliness, composting is widely used for the treatment of chicken manure and kitchen waste. However, the composting effect still needs to be improved due to the low pH of kitchen waste and low C/N of chicken manure. This paper analyzed the composting effects of chicken manure, kitchen waste, and combined chicken manure and kitchen waste. The maximum composting temperature, relative abundance of thermophilic bacteria, organic matter degradation, and water content decrease for the combined treatment were 77.00 °C, 67.04%, 15.00%, and 28.74%, respectively, which were significantly greater than those for the separate treatment of chicken manure and kitchen waste. Moreover, the results revealed that the composting products of the combined treatment had a higher degree of harmlessness and humification based on seed germination, Escherichia coli, and humification indicator, which is advantageous for the resource application of the products. In conclusion, combined treatment can enhance the composting effect due to the pH and C/N of the material being improved by mixing chicken manure and kitchen waste. This study provides a powerful assistance for understanding the composting mechanism of combined treatment of chicken manure and kitchen waste, laying the theoretical foundation for engineering application. Highlights: Combined treatment enhances composting effect by improving pH and C/N of material. Combined treatment increases temperature and thermophilic bacterial reproduction. Combined treatment promotes organic matter degradation and water evaporation. Combined treatment raises harmlessness and humification of composting products. Statement of Novelty: Chicken manure is characterized by low C/N and high pH, while kitchen waste is characterized by high C/N and low pH. They are poorly composted separately, and need to add conditioners in the process. Therefore, combined treatment of chicken manure and kitchen waste was considered to achieve suitable C/N and pH, which enhances the composting effect and also reduces the use of conditioners. This study provides a novel approach to the composting of chicken manure and kitchen waste. [ABSTRACT FROM AUTHOR]

Growing volumes of solid wastes such as wastes from industries, commercial sites, agricultural lands, and households are mostly diverted to improper land fillings in developing countries, thus causing major public health and environmental issues. Sustainable approaches are necessary for the safe management of solid wastes. Kitchen waste (KW) like leftover organic matter from household kitchens, restaurants, etc. and food waste (FW), also termed as plate waste, that is the food which has been served but has not been eaten completely, stale food, etc. are ubiquitous in all communities. They contain a high amount of organic matter and hence should be considered a major source for producing value-added products. Biogas generation for harnessing energy and bioconversion for producing fertilizers are specific examples of value-added products. They are faced with issues including the heterogeneous nature of waste and an increased level of moisture, which are essential to be addressed. There is a dire urge to convert KW into products of significant importance intending to reduce the adverse effects of waste on land with less contagion in the atmosphere, water, and soil, respectively. In this review paper, we precisely deal with the conversion of KW into useful value-added products such as biofuels, biocomposites, nutraceuticals, antioxidants, bioenergy, and industrial enzymes, and thus sustainable management of waste. Importantly, the paper also explains numerous instances to provide better knowledge and idea about the bioconversion of KW into useful products with a notion of food security, costs associated with the waste, environmental hazards, etc. following economic policies and opportunities. [ABSTRACT FROM AUTHOR]

An internal two-stage bioreactor constructed with a hydrogen chamber and a methane chamber with a working volume of 300 mL and 4700 mL, respectively, was operated using various kitchen waste (KW) concentrations from 10 to 80 g COD/L with a hydraulic retention time of 2 days to characterize the biomethane production performance. The results showed that daily biohythane production exhibited a similar increasing trend at KW concentrations of 10 to 40 g COD/L. The peak biomethane production was 2481 mL/day at a KW concentration of 40 g COD/L. The KW concentration could also affect the COD, carbohydrate, lipid, and protein removal efficiencies. These removal efficiencies were somehow dependent on the KW concentration, with two notable KW concentration groups of 10–20 g COD/L and 40–80 g COD/L. After 80 days of cultivation, Firmicutes dominated the hydrogen chamber, and Methanobacteriaceae and Methanomicrobiaceae dominated the methane chamber. This study presents the optimal KW concentration for high biohythane production efficiency in a novel internal two-stage bioreactor and reveals the dominant microorganisms in its microbial community. [ABSTRACT FROM AUTHOR]

The anaerobic acid production experiments were conducted with the pretreated kitchen waste under pH adjustment. The results showed that pH 8 was considered to be the most suitable condition for acid production, especially for the formation of acetic acid and propionic acid. The average value of total volatile fatty acid at pH 8 was 8814 mg COD/L, 1.5 times of that under blank condition. The average yield of acetic acid and propionic acid was 3302 mg COD/L and 2891 mg COD/L, respectively. The activities of key functional enzymes such as phosphotransacetylase, acetokinase, oxaloacetate transcarboxylase and succinyl-coA transferase were all enhanced. To further explore the regulatory mechanisms within the system, the distribution of microorganisms at different levels in the fermentation system was obtained by microbial sequencing, results indicating that the relative abundances of Clostridiales, Bacteroidales, Chloroflexi, Clostridium, Bacteroidetes and Propionibacteriales , which were great contributors for the hydrolysis and acidification, increased rapidly at pH 8 compared with the blank group. Besides, the proportion of genes encoding key enzymes was generally increased, which further verified the mechanism of hydrolytic acidification and acetic acid production of organic matter under pH regulation. The anaerobic acid production of the pretreated kitchen waste was enhanced with pH regulation and pH 8 was considered to be the most suitable condition, especially for the formation of acetic acid and propionic acid. The regulatory mechanisms were adequately demonstrated by microbial sequencing and the genes encoding key enzymes. [Display omitted] [ABSTRACT FROM AUTHOR]

Copyright of Low-Carbon Chemistry & Chemical Engineering is the property of Low-Carbon Chemistry & Chemical Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Eco-Industry Science & Phosphorus Fluorine Engineering is the property of Zhengzhou University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Proper disposal of accumulated leaf litter and kitchen waste has become a challenging problem. The aim of the present study was to use garden waste, Jamun leaf litter (JLL), and kitchen waste (KW) for preparation of vermicompost which was used for the conservation of Rare, Endangered and Threatened plant species, Withania somnifera. For this, JLL and KW were mixed with cattle dung (CD) in different proportions to produce three different feed mixtures (VCA1, VCA2, and VCA3) for vermicomposting using earthworm species Eisenia fetida. Composition of feed mixtures is as follows: VCA1-JLL (50%) + CD (50%), VCA2-JLL (25%) + KW (25%) + CD (50%), VCA3-KW (50%) + CD (50%). CD (100%) was used as control. Scanning electron microscopy and Fourier transmission infrared spectroscopy of initial feed mixtures and their final products (vermicompost) showed good maturity of vermicompost. Minimum mortality and maximum population size of worms were observed with VCA2 followed by VCA1. Nutrients like N, P, K, and Na increased while organic content and C:N ratio decreased in all the end products of vermicomposting. Heavy metal contents in vermicompost decreased significantly (P < 0.05) when compared with initial feed mixture. The effect of different concentrations (5, 10, and 15%) of vermicompost extracts on the seedling growth parameters of W. somnifera revealed that the seeds treated with VCA2 (10%) showed the best response with maximum seed germination response (95.55%), minimum germination time (3 days), and maximum shoot (3.3 cm) and root (3.8 cm) lengths. [ABSTRACT FROM AUTHOR]

Kitchen waste images encompass a wide range of garbage categories, posing a typical multi-label classification challenge. However, due to the complex background and significant variations in garbage morphology, there is currently limited research on kitchen waste classification. In this paper, we propose a multi-head attention-driven dynamic graph convolution lightweight network for multi-label classification of kitchen waste images. Firstly, we address the issue of large model parameterization in traditional GCN methods by optimizing the backbone network for lightweight model design. Secondly, to overcome performance losses resulting from reduced model parameters, we introduce a multi-head attention mechanism to mitigate feature information loss, enhancing the feature extraction capability of the backbone network in complex scenarios and improving the correlation between graph nodes. Finally, the dynamic graph convolution module is employed to adaptively capture semantic-aware regions, further boosting recognition capabilities. Experiments conducted on our self-constructed multi-label kitchen waste classification dataset MLKW demonstrate that our proposed algorithm achieves a 8.6% and 4.8% improvement in mAP compared to the benchmark GCN-based methods ML-GCN and ADD-GCN, respectively, establishing state-of-the-art performance. Additionally, extensive experiments on two public datasets, MS-COCO and VOC2007, showcase excellent classification results, highlighting the strong generalization ability of our algorithm. [ABSTRACT FROM AUTHOR]

[Objective] To study the nutrient laws of Hermetia illucens transformation treatment of kitchen waste. [Method]Using Hermetia illucens and kitchen waste as research objects, Hermetia illucens were used to convert kitchen waste at normal temperature (S1, S2, S3) and high temperature constant temperature (S1, S2, S3), and the reduction rate, conversion rate, insect protein, fat and other parameters of kitchen waste were measured. [Result] Hermetia illucens significantly increases the conversion rate of kitchen waste at temperatures ranging from 30 to 33℃ compared to normal temperature. S1, S2 and S3 increased the conversion rate by 9. 26%, 10. 73% and 19. 63% compared to C1, C2 and C3, respectively. The S3 group with 7. 2 kg added had the highest conversion rate, and a feed to insect ratio of 2. 68 to 3. 20 ∶ 1 showed its observable economic benefits. Hermetia illucens could convert 24. 46% of low protein and 21. 24% of low fat kitchen waste into high-quality feed and biodiesel raw materials with high protein and fat content of up to 43. 12% and 28. 58% in 21 days. 58. 32% - 62. 74% of protein and 60. 14%-63. 47% of fat in kitchen waste were ultimately converted into the protein and fat of the insect itself. [Conclusion]This utilization method of converting kitchen waste through Hermetia illucens will have great potential in the future. [ABSTRACT FROM AUTHOR]

To investigate the effects of kitchen waste on the chemical properties of acidic red soil and the community structure of ammonia–oxidizing archaea (AOA) and ammonia–oxidizing bacteria (AOB), a study was conducted in the flue–cured tobacco farmland ecosystem of the Erlongtan small watershed in central Yunnan. Eight fertilization methods were applied: no fertilization control CK, single application of chemical fertilizer T1 (1 t·hm−2), kitchen waste combined with a chemical fertilizer (T2:12 t·hm−2 + 1 t·hm−2, T3:15 t·hm−2 + 1 t·hm−2, T4:18 t·hm−2 + 1 t·hm−2), and single application of kitchen waste (T5:12 t·hm−2, T6:15 t·hm−2, T7:18 t·hm−2). The numbers twelve, fifteen, and eighteen in brackets represent the amount of food waste applied, and one represents the amount of chemical fertilizer applied. The study evaluated the effects of kitchen waste on soil chemical properties, the community structure and composition of AOA and AOB, and the relationship between soil chemical properties and these microbial communities in acidic red soil. The results showed that: (1) single application of kitchen waste (T5, T6, T7) effectively improved soil nutrient status (SOC increased by 15.79–217.24%; TN increased by 1.53–92.99%; NH4+–N increased by 18.19–520.74%; NO3−–N) increased by 15.54–750.61%), and alleviated acidification. (2) Temporal variations had a more significant effect on the community structure of AOA and AOB than different treatments. The dominant phyla of AOA were Thaumarchaeota, Crenarchaeot. The dominant phylum of AOB was Proteobacteria, and the dominant genera were Nitrosospira and norank_Bacteri. (3) The number of AOA co–occurrence network nodes were equivalent to that of AOB, but AOB had more connection edges, indicating a more complex interaction network. In contrast, AOA exhibited higher modularity, reflecting tighter internal connections and greater stability. The AOA co–occurrence network showed stronger performance during the maturity and fallow stages, while AOB interactions were most active during the topping stage. (4) AOA demonstrated a strong correlation with soil chemical properties during the topping and maturity stages, whereas AOB showed a stronger correlation at the rosette and fallow stages. Among soil chemical factors, pH and SOC were identified as the primary drivers influencing AOA and AOB community abundance and structural differentiation. In conclusion, kitchen waste application enhances the nutrient content of acidic red soil and influences the niche differentiation of AOA and AOB, thereby affecting nitrogen recycling. This approach represents an environmentally friendly and sustainable fertilization method. [ABSTRACT FROM AUTHOR]

This study proposes an integrated and sustainable approach for the effective conversion of kitchen waste into valuable products through a two-step process. The primary step involves the implementation of greenhouse solar drying to reduce the moisture content of kitchen waste. The secondary step implies microwave pyrolysis for effective degradation of kitchen waste to biooil, biogas and biochar. Biooil and biogas can be used as renewable fuel source. Biochar can be used as soil amendment. Selection of atmospheric conditions for biochar preparation is discussed, highlighting its crucial role in biochar characteristics. This article highlights, technology readiness level of biochar production from kitchen waste to assess the economic viability for the scalability of the process. In this entirety, the conversion of kitchen waste to valuable products through microwave pyrolysis has significant potential to address the challenges posed by high moisture content and heterogenous nature. With continued research and innovation, it is possible to develop a wide array of value-added products from kitchen waste, ultimately leading to a more eco-friendly and economic approach to waste management. [ABSTRACT FROM AUTHOR]

Since the implementation of China's mandatory waste sorting policy, the recycling of kitchen waste has become one of the core tasks of waste classification. The problem of designing the locations and the optimization configuration strategy for kitchen waste transfer stations faces great challenges in reconstructing the municipal solid waste collection and transportation system. This paper establishes an integer programming model for the bi-objectives of the location and optimal configuration for a kitchen waste transfer station, with the goal of minimizing the total cost and overall negative environmental impact. An improved non-dominated sorting genetic algorithm with an elite strategy (NSGA-II) is used to solve the problem, resulting in a Pareto-optimal solution set that includes several non-dominated solutions, thereby providing diversified choices for decision-makers. Finally, a pilot case involving cooperative enterprises is used as an example in this study, and the results demonstrate the effectiveness of the model and algorithm, as well as their feasibility in practice. [ABSTRACT FROM AUTHOR]

Copyright of Industrial Water Treatment is the property of CNOOC Tianjin Chemical Research & Design Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Polyurethane sponge particles were employed as bio-immobilized cell carriers for dark fermentation hydrogen production with heating-treated cow dung inoculum from epipremnum aureum waste and kitchen waste. This study explored the performance changes of batch dark fermentation hydrogen production systems under different influent substrates. Different influent total solids concentration and substrate types both had a large effect on the efficiency of the biological hydrogen production process. Based on the combined analysis of hydrogen production efficacy, VFA, and energy conversion efficiency, the optimal influent total solids concentration was 2 g/L and 10 g/L for epipremnum aureum waste and kitchen waste, respectively. For the epipremnum aureum waste, the energy conversion efficiency was 13.6% and the metabolic type was mixed fermentation at a total solids concentration of 2 g/L. For kitchen waste, the energy conversion efficiency was 14.4% and the metabolic type was ethanol/acetic fermentation at a total solids concentration of 10 g/L. The results indicate that epipremnum aureum waste and kitchen waste can be used as substrates for dark fermentation hydrogen production, and kitchen waste performed better than epipremnum aureum waste at the same influent total solids concentration. Compared to other nutrients, both epipremnum aureum waste and kitchen waste also showed better hydrogen production efficacy and energy conversion efficiency. The study can provide a more economical and efficient method for residential household waste recycling. [ABSTRACT FROM AUTHOR]

Abstract Household kitchen waste (HKW) is produced in large quantity and its management is difficult due to high moisture content and complex organic matter. Aerobic composting of HKW is an easy, efficient, cost-effective and eco-friendly method. This study is designed to achieve a zero-waste concept and to convert HKW. We optimized the type and size of three different bulking agents to speed up the composting process. The tested bulking agents were fallen leaves, sawdust and fly ash. The results showed a higher and longer thermophilic phase (55oC) for 11 days in C2. Higher moisture content (69%) and higher organic matter degradation (38.4%) were also observed in C2. The pH range in all compost treatments was 7-8.5, Electrical conductivity range was 1.8–3.55 mS/cm, C/N ratio range was 15.4–18.1, water holding capacity range was 3.25–4.3 g water/g dry sample, total potassium range was 1.52–1.61%, total phosphorous range was 0.83–1.14%. The highest germination index (119.1%) was also obtained in C2. The highest chili height (16.7 cm), greater number of leaves (20), greater shoot fresh weight (4.75 g) and root fresh weight (1.2 g) was obtained in the presence of C2. Similarly, greater water WHC (2.8 g water/g DW), higher porosity (55.49%) and higher aggregate stability (54.14%) of soil was also obtained by C2. This research effectively reduced the maturation time to 32 days and converted kitchen waste into compost (resource). This is a very practical idea for home composting and kitchen gardening to combat food security issues in developing countries.

This work took the kitchen wastes from Liuta Mining Area of Shendong Coal as example, to investigate the effects of hydrogen peroxide(H2O2) pretreatment on the performance of kitchen waste and the production efficiency of volatile fatty acid(VFAs) from anaerobic fermentation. Then the nitrogen and phosphorus removal effect of wastewater treatment with anaerobic fermentation slurry from kitchen waste as carbon source were investigated. Results indicated that the H2O2 pretreatment could promote the release of dissolved organic matters in kitchen wastes and enhance the fluidity of kitchen waste slurry. As a result, the VFAs production after H2O2 pretreatment increased from 10 810-18 131 mg/L to 21 000-28 000 mg/L, while the dominant fermentation products were converted from butyric acid to acetic acid. These suggested that the H2O2 pretreatment achieved a significant improvement in the production efficiency of VFAs. Furthermore, when the anaerobic fermentation slurry from pre-treated kitchen waste as carbon source of wastewater treatment plants, the concentration of NH4+-N and TP in the effluent was less than 1 mg/L and 0.5 mg/L, which was equivalent to the treatment effect when glucose was used as the carbon source. All these demonstrated that the kitchen waste in the mining area had good usability.

There is a growing recognition that food waste (FW) comprises a significant amount of unused energy. Indeed, FW shows great potential to produce methane (CH4)-rich biogas via an anaerobic digestion (AD) process. Nevertheless, to ensure high AD process performance, deepening the knowledge of FW characteristics is required. Furthermore, the biogas yield is strongly influenced by several operational parameters. Taking into account the above, in the current study, based on the data in the literature, the physicochemical parameters of FW generated throughout the world are presented and discussed. In addition, the performance profile of the single-stage anaerobic mono-digestion process with the use of FW as a feedstock was investigated. The performed analysis clearly demonstrated that FW is characterized by significant variations in several parameters, such as pH, the total solid (TS) and volatile solid (VS) contents, the volatile solids to total solids ratio (VS/TS), soluble chemical oxygen demand (sCOD), the concentrations of VFAs and ammonium nitrogen (NH4+-N), and the carbon-to-nitrogen ratio (C/N). Moreover, it was shown that the selected operational parameters, such as temperature, pH, the ratio of food waste to inoculum (I) (FW/I), and the organic loading rate (OLR), may have the most significant impact on the performance of the single-stage anaerobic mono-digestion process. In addition, it was found that most of the experimental investigations presented in the literature were conducted on a laboratory scale. Hence, in future research, more effort should be made to determine the biogas yield with the use of full-scale systems. To summarize, it should be clearly highlighted that the analysis presented in this study may have important implications for the management and application of FW as feedstock for an anaerobic mono-digestion process on an industrial scale. [ABSTRACT FROM AUTHOR]

Current research on microplastics (MPs) in kitchen waste primarily focuses on their end-of-life disposal processes, neglecting the rapid decomposition phase prior to disposal. This study investigated MPs' instantaneous release during a 20 h kitchen waste stacking process. The results revealed significant temperature-dependent release, with up to 96.1% entering the liquid phase and 5768 items/kg released and with an average of 85.7% of the MPs transferring into the entrapped water released from the tiny tissue structures and membranes. These MPs were primarily in small sizes (4–400 μm) as particles and fragments. Hydrolysis acidification primarily influences MPs' release, with temperature and stacking time as intermediate factors. Acetic acid drives MPs' release, contributing up to 38.5%. High temperatures accelerate organic matter dissolution and MP migration, while low temperatures slow down the release of MPs. The findings confirmed MPs' release risks during kitchen waste stacking and contributed to optimize kitchen waste management to control MP pollution at its source. [ABSTRACT FROM AUTHOR]

Kitchen waste is a misplaced resource that is characterized by a high organic matter content, high water content, and a tendency to rot easily. Biochar is a black solid substance produced under high-temperature, anaerobic conditions using agricultural organic wastes as the raw material. It possesses a large specific surface area, a loose and porous structure, and functional groups, which confer high thermal stability and strong adsorption capabilities. However, little is known about how humic products made from biochar affect the composition and structure of soil humus. To solve the above problems, this study carried out a two-year outdoor field experiment by means of element analysis, infrared spectroscopy, and differential thermal analysis (0.4 kg/m2 (W4), 0.8 kg/m2 (W8), 1.2 kg/m2 (W12), 1.6 kg/m2 (W16), and 2.0 kg/m2 (W20)); CK was the blank control (no application). The samples were collected one year and two years after they returned to the field. The results showed that the application of organic materials facilitated the accumulation of soil organic carbon (SOC) and increased the total nitrogen (TN) content. The highest SOC content in the W20 treatment was 12.39 g/kg and 14.67 g/kg in one and two years, respectively. The maximum relative HA content in the W20 treatment was 22.99% one year after returning to the field. The PQ value (the ratio of HA/(fulvic acid (FA) + HA)) for the W20 treatment was 88.21%. The W20 treatment greatly increased the SOC and humus carbon contents. Compared with the CK treatment, all the organic materials applied for one year improved the structure of the humic acid to varying degrees, increased the degree of oxidation, reduced the degree of condensation and thermal stability of the HA in the soil, and gradually simplified the structure of the humic acid; among all the treatments, the W20 treatment had the greatest effect. [ABSTRACT FROM AUTHOR]

Nowadays, the enormously growing amount of kitchen waste and wasted sludge has greatly received global attention. Vermicomposting has been represented as an eco-friendly and sustainable alternative for organic waste management. This study utilized kitchen waste generated by the university canteen and excess sludge from municipal wastewater treatment to collaboratively realize waste to resource through vermicomposting with a composting control. The results indicated that the treatment utilizing an equal mass ratio of wasted sludge and kitchen waste (T3) exhibited the greatest reduction in total organic carbon and the highest increase in total nitrogen. Furthermore, the predominant phyla observed were Proteobacteria, Actinobacteriota, Bacteroidetes, and Firmicutes. Functional prediction analysis demonstrated higher relative abundances of β-glucosidase (ascF) and 6-phospho-β-glucosidase (bglA, celF) in the vermicomposting, suggesting that the earthworms essentially enhanced the cellulose degradation. More importantly, the co-occurrence network analysis demonstrated that the vermicomposting showed a stronger interaction between Gordonia and other bacteria, thereby enhancing its ability to degrade macromolecular compounds. In general, the vermicomposting can smoothly and remarkably stabilize the kitchen waste, assisted by excess sludge and sawdust. [ABSTRACT FROM AUTHOR]

Fermentative kitchen waste to produce high-value chemicals (e.g., acetic acid) has been investigated actively in the past decades. Creating an alkaline condition is widely used to improve the hydrolysis of polysaccharide and inhibit the methanogenesis, but this method significantly increases the overall cost. Herein, the present study investigated the bioaugmentation with rumen fluid to improve acetic acid production from kitchen waste at neutral condition via strengthening hydrolytic and acid-forming bacteria. Results showed that the highest acetic acid yield reached 1.52 g/L at rumen fluid and granular sludge ratio of 1:1. The proportion of acetic acid in volatile fatty acids (VFAs) has increased by 10% compared to control. Microbial community analysis revealed that bioaugmentation with rumen fluid increased the relative abundance of Prevotella and Rikenellaceae_RC9_gut_group which has the ability to degrade polysaccharides and produce acetic acid. Moreover, the proliferation of butyric acid producers (Clostridium_sensu_stricto_1 and Clostridium_sensu_stricto_7) were inhibited significantly, which was in agreement with high acetic acid proportion in VFAs. The bioaugmentation strategy and process optimization provided an energy and cost-saving method for acetic acid production from kitchen waste. [ABSTRACT FROM AUTHOR]

To evaluate the dietary value of different sources of black soldier fly larvae（BSFL）for red tilapia (O. mossambicus×O. niloticus), the meal of BSFL reared on pineapple residue (PR), wheat bran (WB), and kitchen waste (KW) was used to replace fish meal in the basal diet at a ratio of 4%, and the commercial xanthophyll was supplemented into the basal diet formulate five iso-nitrogenous and iso-energetic diets. They were fed to red tilapia fry [initial weight (0.35±0.01) g] for 9 weeks, then the skin color changes of fish were recorded, the growth performance, physical indicators, and tissue carotenoid concentration were measured. A cold stress trial was conducted with the water temperature reducing from 26 ℃ to 10 ℃ within 8 hours, and the mortality rate of the fish was calculated. The results showed that, the value of the weight gain rate of the fry from high to low was:the WB-BSFL group, PR-BSFL group, the control group, the Xanthophyll group, and the KW-BSFL group. Among them, the weight gain rate of theWB-BSFL group was significantly higher than that of the KW-BSFL group, while the hepatosomatic index and the viscerosomatic index were significantly lower than those of the WB-BSFL groupand PR-BSFL group (P<0.05). The highest yellowness (b*) of the fish head and dorsum was observed in the PR-BSFL group, while that of the abdomen was found in the Xanthophyll group. The total concentration of carotenoid in the scales, skin, and dorsal fin reached the highest levels in the PR-BSFL group, WB-BSFL group, and Xanthophyll group, respectively, which were all significantly higher than that of the control and KW-BSFL groups (P<0.05). After the cold stress, the survival rates of the WB-BSFL and the PR-BSFL groups were 92.5% and 85.0%, higher than that of the control group (76.7%), and significantly higher than those of the KW- BSFL group (69.2%) and the Xanthophyll group (72.5%) (P<0.05). In conclusion, this study indicates that the meal of BSFL reared on pineapple residue and wheat bran can improve the growth performance and physical indicators of red tilapia fry, and promote its cold resistance ability by partially substituting dietary fish meal. Furthermore, the meal of BSFL reared on pineapple residue improves the skin color of fish effectively by increasing the accumulation of carotenoid in tissues, with close effects to the supplementation of commercial xanthophyll. [ABSTRACT FROM AUTHOR]

Anaerobic fermentation (AF) can effectively dispose of kitchen waste (KW) without the shortcomings of traditional methods such as incineration and sanitary landfill. However, KW has a high organic content, which easily leads to acidification and ammonia inhibition during digestion. To mitigate this issue, anaerobic co-digestion (AnCoD) with other substrates helps to adjust the carbon to nitrogen ratio (C/N) and enhance the stability of the reaction system. The hydrolysis of substrate is the rate-determining step in AF, prompting the adoption of necessary pretreatment methods to accelerate substrate hydrolysis. Among physical, chemical, and enzymatic pretreatments, the latter is more efficient. And the enzymatic pretreatment does not need additional equipment or reagents. Therefore, coupling enzyme treatment before AnCoD received more attention. In this review, we conduct a comparative analysis of the biogas production efficiency of enzymatic pretreatment against other pretreatment methods. The challenges and strategies concerning enzymatic pretreatment coupled with AnCoD system were discussed. Finally, the pilot-scale study and industrial application for KW co-digestion are also analyzed. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Aerobic composting is one of the primary steps for the resource utilization and harmless treatment of rural kitchen waste. The treatment device of food waste is ever increasingly needed for single or multiple households, as the development of separate waste collection and promotion of on-the-spot organic waste disposal and utilization. In this study, an aerobic composting device was designed to consider segmented fermentation for composting material, precise aeration and turning control, and multi-function integration. According to the four-stage aerobic composting, four chambers of sequential fermentation were utilized to achieve the separate fermentation of materials in different stages for the harmless treatment of the product. This integrated system also incorporated the agitation apparatus, aeration equipment, control devices, leachate collection mechanisms, and odor control systems. Continuous feeding was employed to introduce the kitchen waste and sawdust daily at a wet-to-weight 10:3. The aeration strategy was set at one minute of aeration every 10 min, and an aeration rate of 10L/min. The stirring frequency was positive for 4 min, reverse for 6 min, and stop for 240 min. The mixing performance simulation and composting experiment were conducted using kitchen waste and pine sawdust as the feedstock. In the simulation test: a fermentation tank and material particle model were constructed and calibrated the simulation parameters of kitchen waste and pine sawdust. The mixing state was simulated to explore the effect of kitchen waste and pine sawdust in four fermentation tanks using the discrete element simulation software EDEM. The mixing degree was calculated for the two kinds of materials in the fermentation tank using the coefficient of variation. The working performance of the equipment was verified in the test. In the composting experiment, solid samples were collected on days 21, 23, and 25 of the composting process, termed as the feeding port (P1), discharge port (P6), and the mid-sections of the first to fourth fermentation tanks (P2 to P5). Physical and chemical properties were determined for the maturity indices of the fermented products. The gas samples were analyzed using portable gas detectors to measure the concentrations of ammonia (NH3) and hydrogen sulfide (H2S) within the first, second, third, and fourth fermentation chambers, as well as at the outlet of the deodorization unit (P7). The results show that the mixing uniformity of materials in the fermentation bin was about 94%, which fully met the requirement that the mixing degree of fermentation materials reached 90%. Furthermore, the color of the fermented material was gradually darkened, the unpleasant odor gradually dissipated, and the fermented material was loose and granular after aerobic fermentation. The compost experienced a high-temperature phase exceeding 55°C for over 5 d, and following 20 d of continuous fermentation. The number of fecal coliforms reached the hygienic safety standard. And egg mortality rate reached 100% for Ascaris lumbricoides. The seed germination index was 73%, fully meeting the requirements of the National Standard for Organic Fertilizer (NY/T 525-2021). In summary, continuous composting and independent fermentation control can be expected to effectively enhance the quality of the fermentation product in different stages. This research can also provide technical references for local resource utilization, fertilizer application, and harmless disposal of kitchen waste in rural regions. [ABSTRACT FROM AUTHOR]

Bioconversion using insect larvae has proven to be a feasible option for food waste disposal and has generated products with high economic value. Technological optimization can further improve costs and applicability. In this study, the effects of different substrate intensities and feeding methods on housefly larvae bioconversion were investigated using the solid-phase fraction of kitchen waste obtained after a three-phase separation as the raw material. The results showed that a substrate intensity of 30 kg/m2 combined with one-time feeding was the most appropriate. Under these conditions, an appropriate substrate temperature prevented the escape and early pupation of larvae, and the bioconversion and reduction rates of kitchen waste reached 16.75% and 50.51%, respectively. In addition, the physical and chemical properties of frass were found to be conducive to subsequent aerobic composting. [ABSTRACT FROM AUTHOR]