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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]

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]

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]

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]

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]

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]

Kitchen waste is composed of complex and diverse ingredients with a variety of organic matter and inorganic salts, which is perishable and foul-smelling under high temperature conditions in summer. To reduce the deterioration rate of kitchen waste in the collection and storage process and cool down the kitchen waste in community residences for short time before treatment, the intelligent temperature- controlled dustbin was designed based on the fan-pad cooling device. Several temperature sensors were distributed inside the dustbin and controlled by Siemens PLC. The execution conditions of the fan-pad cooling device were programmed, and the PID algorithm was used for software optimization, while the data was visualized by touch screen. The intelligent control of the fan-pad cooling system was realized to maintain the internal temperature of the dustbin in the set range, and the system debugging and test verification were conducted. The results show that the detection error of the intelligent temperature control system is less than 0.5 °C, which meets the accuracy requirements. When the outdoor temperature is as high as 35 °C, the average temperature in the dustbin can be maintained at about 25 °C, which meets the constant temperature storage requirements of kitchen waste. [ABSTRACT FROM AUTHOR]

Simple Summary: The disposal of slaughterhouse blood poses significant environmental challenges due to its biological instability and high nutrient content. This study investigates the potential of using black soldier fly larvae (BSFL) to process slaughtered cattle blood mixed with kitchen waste. We examined the growth performance and nutrient composition of BSFL when fed different proportions of slaughtered blood. The results revealed that feeding BSFL with high levels of slaughtered blood is not suitable, as it leads to high mortality rates and poor growth. However, when fed with up to 20% slaughtered blood combined with kitchen waste, BSFL showed excellent performance in terms of weight gain and crude protein, lipid, and amino acid contents. This demonstrates that slaughtered blood can be effectively used as a feed component for BSFL, enabling the recovery of essential nutrients and reducing their loss within the production system. Our findings highlight the potential of this approach for sustainable waste management and animal feed production, offering an environmentally friendly solution to the disposal of slaughterhouse blood. The disposal of slaughterhouse blood poses significant environmental challenges due to its biological instability and high nutrient content. We used a gradient of 10% blood increments (0–100%) to feed BSFL, and the correlation between the proportion of bovine blood and the BSFL weight gain, mortality rate, fatty acid content, and amino acid content was researched. Results indicate a positive correlation between the bovine blood content and BSFL mortality, with survival rates above 95% for blood proportions below 60%. Larval weight exhibited a negative correlation as the bovine blood content increased. Nutritional analysis revealed that the crude protein content in BSFL increased proportionally with bovine blood (14.75–25.45 g/100 g), while the crude fat content decreased correspondingly (10.70–4.66 g/100 g). The sugar content remained relatively constant across groups. Fatty acid analysis showed increased levels of C16:0, C14:0, and C16:1 and decreased levels of C18:1, C18:2, and C18:3 with higher bovine blood contents. The amino acid content generally increased with higher blood proportions. This study highlights the bioconversion potential of BSFL for bovine blood and underscores the impact of protein, lipid, and sugar concentrations in feed on BSFL growth. These findings provide valuable insights for utilizing slaughterhouse waste in BSFL rearing, contributing to the development of more sustainable waste management and animal feed production methods. [ABSTRACT FROM AUTHOR]

Lipid-rich kitchen waste and ingredients of a model kitchen waste were characterized. Waste composition assumptions were veried, and closed mass balances showed that the analytical methods used could quantify waste composition. Anaerobic digestion in batch experiments with low (5 gVSl−1) and high (25 gVS l−1) loadings showed rapid process dynamics. The dynamics of carbohydrates, key intermediates such as volatile acids, and key products such as methane were observed. High loadings resulted in a transient accumulation of volatile acids, and gaps in mass balance over time were observed. Mass balances in the form of chemical oxygen demand were used to validate results and highlight indirect lipid deposition. [ABSTRACT FROM AUTHOR]

The composting performance and nitrogen transformation during membrane-covered aerobic composting of kitchen waste were investigated. The aerobic composting products of the kitchen waste had a high seed germination index of ∼180%. The application of the membrane increased the mean temperature in the early cooling stage of composting by 4.5℃, resulted in a lower moisture content, and reduced the emissions of NH3 and N2O by 48.5% and 44.1%, respectively, thereby retaining 7.9% more nitrogen in the compost. The adsorption of the condensed water layer under inner-membrane was the reason for reducing NH3 emissions, and finite element modeling revealed that the condensed water layer was present throughout the composting process with a maximum thickness of ∼2 mm in the thermophilic stage. The reduction of N2O emissions was related to the micro-positive pressure in the reactor, which promoted the distribution of oxygen, thus weakening denitrification. In addition, the membrane cover decreased the diversity of the bacterial community and increased the diversity of ammonia-oxidizing strains. This study confirmed that membrane-covered composting was suitable for kitchen waste management and could be used as a strategy to mitigate NH3 and N2O emissions. [ABSTRACT FROM AUTHOR]

In the present study, kitchen waste is chosen as a solid feed for producing high‐caloric valuable syngas using CO2 as a gasifying agent. Dried kitchen waste is gasified in a spouted fluidized bed reactor for syngas production. In the process, along with syngas, a significant quantity of oil (48 wt.%) and solid char residue is obtained during pyrolysis. Further, the spouted bed process is simulated in ASPEN PLUS using various reactor modules and the calculated results is validated with the experimental data. A model using the combination of continuous stirred tank reactor (CSTR) and plug flow reactor (PFR) with recycling of gas and char fits the behaviour of spouted bed. Further, the experimental investigation of fixed and spouted bed gasification of kitchen showed that the calorific value of syngas obtained during gasification is 10.45 MJ/nm3 with 30.00 vol.% CO and 24.00 vol.% H2. Further, the effect of process parameters such as pressure, temperature, spouting gas flow rate, and feed rate of kitchen waste on overall syngas composition is evaluated using ASPEN PLUS software. [ABSTRACT FROM AUTHOR]

Lignocellulose is a major biopolymer in plant biomass with a complex structure and composition. It consists of a significant amount of high molecular aromatic compounds, particularly vanillin, syringeal, ferulic acid, and muconic acid, that could be converted into intracellular metabolites such as polyhydroxyalkanoates (PHA) and hydroxybutyrate (PHB), a key component of bioplastic production. Several pre-treatment methods were utilized to release monosaccharides, which are the precursors of the relevant pathway. The consolidated bioprocessing of lignocellulose-capable microbes for biomass depolymerization was discussed in this study. Carbon can be stored in a variety of forms, including PHAs, PHBs, wax esters, and triacylglycerides. From a biotechnology standpoint, these compounds are quite adaptable due to their precursors' utilization of hydrogen energy. This study lays the groundwork for the idea of lignocellulose valorization into value-added products through several significant dominant pathways. [ABSTRACT FROM AUTHOR]

The reuse of solid wastes has awakened much attention and triggered extensive research, especially given the fact that kitchen waste (KW) and waste bentonite as typical solid wastes are increasing rapidly worldwide. In this work, the KW and waste bentonite were co-valorized to produce KW-bentonite (KWB) adsorbent at the mass ratio of 7:3 at 1000 °C. The effects of adsorbent dose, solution pH, and coexisting substances on the phosphate removal by KWB adsorbent were explored in a batch system, achieving the maximum adsorption capacity of 23.04 mg/g. Besides, it could be seen that the adsorption process of phosphate by KWB adsorbent depends on chemisorption through the analysis of thermodynamic and kinetic results. The properties of KWB adsorbent were analyzed to explore the adsorption process while an economic analysis was conducted to identify the practical application potential of KWB adsorbent for P-contaminated wastewater. In conclusion, the present study not only offers new insights into the synergistic effect of kitchen waste and waste bentonite for environmental pollution control, but also provides a feasible waste-to-wealth strategy for converting kitchen waste and waste bentonite into KWB adsorbent that can be used as an effective phosphate adsorbent. [ABSTRACT FROM AUTHOR]

Food waste is generated in large amounts locally and globally, and requires expenditure for disposal. However, it has high nutritional value and almost no toxic components. Therefore, it can be returned to mushroom mediums for further use, leading to food waste circulation. Though disposing of spent mushroom substrate (SMS) after harvesting is an additional problem, there have been increased efforts to compost it and apply it to the soil for growing vegetables. This study, therefore, aimed to optimize (1) mushroom spawn production with rice hull, (2) mushroom substrates using food waste to accelerate food waste recycling, and (3) the utilization of SMS as an organic fertilizer. An optimal substrate composition and high yield were obtained at 120–140 g of food waste per bag among substrates from Pleorutus ostreatus and Pleorutus citrinopileatus; therefore, using a high ratio of food waste in the mushroom mediums was achieved. On the other hand, the SMS of P. citrinopileatus demonstrated higher plant biomass growth, at 36 g, than that of P. ostreatus, at 21.2 g, in a treatment using SMS + okara. The present discovery is that people may be encouraged to be mindful of food loss by the delivery of mushrooms and plants grown from agro/food waste to the dining table, and this circular system may therefore be used as a key resource in mushroom and plant cultivation and to achieve a zero-emission cycle. [ABSTRACT FROM AUTHOR]

Quantitative dynamics of the key intermediates, gases and carbohydrates during anaerobic digestion of different lipid rich kitchen waste and lipid rich model kitchen waste were modeled. Six batch reactors loaded with 25 g VS l - 1 (∼ 39 g O 2 l - 1 ) kitchen waste and model kitchen waste during a batch experiment were considered in simulation. Observed dynamics of carbohydrates, volatile organic acids and gases were described by an extended benchmark simulation model no. 2 (BSM2). In this study the extended BSM2 included a more detailed β -oxidation for prediction of caproic acid. Furthermore, the extensions included carbohydrate digestion with an additional intermediate before propionic acid was released. In addition, a novel simplification approach for initial pH estimation was successfully applied. For parameter estimation a Markov Chain Monte Carlo method was used to obtain parameter distributions. With the presented model it was possible even with no calibrated data to predict point of times of intermediates maxima and propionic acid with relative stable concentration over several days for kitchen waste. [ABSTRACT FROM AUTHOR]

Anaerobic co‐digestion using an anaerobic dynamic membrane bioreactor (AnDMBR) can separate the sludge retention time and hydraulic retention time, retaining the biomass for efficient degradation and the use of less expensive large pore‐size membrane materials and more sustainable dynamic membranes (DMs). Therefore, anaerobic co‐digestion of toilet blackwater (BW) and kitchen waste (KW) using an AnDMBR was hypothesized to increase the potential for co‐digestion. Here, the efficiency and stability of AnDMBR in anaerobic co‐digestion of toilet BW and KW were investigated. DM morphology and structural characteristics, filtration properties, and composition, as well as membrane contamination and membrane regeneration mechanisms, were investigated. Average daily biogas yields of the reactor in two membrane cycles before and after cleaning were 788.67 and 746.09 ml/g volatile solids, with average methane content of 66.64% and 67.27% and average COD removal efficiencies of 82.03% and 80.96%, respectively. The results showed that the bioreactor obtained good performance and stability. During the stabilization phase of the DM operation, the flux was maintained between 43.65 and 65.15 L/m2/h. DM was mainly composed of organic and inorganic elements. Off‐line cleaning facilitated DM regulation and regeneration, restoring new Anaerobic morphology and structure. Practitioner Points: High efficiency co‐digestion of BW and KW was realized in the DMBR system.Average daily biogas yields before and after membrane cleaning were 788.67 and 746.09 ml/g volatile solids.Off‐line cleaning facilitated DM regulation and regeneration as well as system stability.The flux was maintained between 43.65 and 65.15 L/m2/h during operation. [ABSTRACT FROM AUTHOR]

Amino acid fermentation liquid was prepared from waste feathers by microbial fermentation, and the influence of composting of kitchen waste was investigated. The results showed that the addition of amino acid fermentation liquid could improve the decomposition process and weight reduction effect of kitchen waste compost, and could effectively increase the content of alkali-hydrolytic nitrogen and available phosphorus in compost, and improved the activity of microorganisms, among which the activities of protease, amylase, cellulase and lipase increased by 21.29%, 36.42%, 43.83% and 11.16%, respectively. The addition of amino acid fermentation broth increased the complexity of bacterial community interaction and changed the structure of bacterial community, and the relative abundance of Bacillus and Klebsiella increased. GI, mass digestion rate, HA and amylase were positively correlated with colony structure, while HS, cellulase and available phosphorus were negatively correlated with colony structure. The study provides a new idea for using waste protein resources to cooperate with aerobic composting of kitchen waste in the future. [ABSTRACT FROM AUTHOR]

The study compared nutrient intake and growth performance of local chickens to that of local x broiler crossbreds under scavenging and indoor conventional systems. A total of 48 male and 48 female chickens for each of the two chicken types were allocated to four outdoor free-range pens. The chickens were allowed to scavenge whilst being supplemented with sorghum plus kitchen waste and broiler growers from week 5 to week 13 of age. The same design was repeated using the indoor conventional system. Local chickens and their crosses with broilers had higher growth rates under the scavenging system than the indoor production system (P < 0.05). Local chickens and their crosses with broilers had the same growth rates when fed the same diet (P > 0.05). Crop and gizzard contents from local chickens had the same crude protein as their crosses with broilers under both systems (P > 0.05). The crude protein values of crop and gizzard contents ranged from 25.4 to 30.4%. Crop and gizzard contents from scavenging chickens had energy content ranging from 16.2 to 17.1 MJ/Kg which was lower (P < 0.05) than that from chickens under the indoor conventional system (20.3 to 25.8 kJ/Kg). Iron content ranged from 655.7 to 1619.4 mg/Kg in scavenging chickens and 156.1 to 621.4 mg/Kg in enclosed chickens. Chickens of the same type had higher iron content in their crop and gizzard contents under the scavenging system than the conventional system (P < 0.05). Crossbreds between local chickens and broilers matches the scavenging abilities of the local chickens but have lower growth rates under the scavenging system. [ABSTRACT FROM AUTHOR]

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The burgeoning food waste problem is driving environmental pollution and climate change due to landfilling of waste. It is imperative to reduce greenhouse gas emissions and lower carbon footprint through food waste management. In the culinary setting, a vast amount of food waste is generated from food preparation. However, there is no module to educate staff on this. In this study, a culinary waste management (CWM) module was introduced to train culinary arts students to reduce culinary waste in the food preparation process, from cleaning to assembling. It is essential to assess the user-friendliness of the module during practical implementation. This study aimed to explore participants’ awareness and understanding of CWM before and after implementing of a CWM module in teaching kitchens and identify the motivators and barriers to its implementation. A total of 35 participants, consisting of students, teaching chefs and cleaning staff’s were recruited at Sunway University, Malaysia. Themes derived in the pre-module interview revealed a varying degree of engagement among participants, with low literacy, alongside barriers like labor-intensiveness and concern over hygiene. The post-module interview highlighted positive psychological and cognitive impacts on participants with motivators that drive them to practice CWM. Nevertheless, barriers such as resistance to novelty impeded the implementation. Therefore, CWM is the way forward to reduce the significant amount of waste generated in culinary settings. Integrating this CWM module into the education-industrial system will equip future culinary professionals with the knowledge and skills needed for.g a sustainable culinary career.

Kitchen waste is a complex biomass waste, whose composition and properties vary with factors such as source, season and region. It is challenging to classify and characterize it. A thermogravimetric and kinetic study was performed to estimate pyrolysis characteristics and gas emissions of starch, peel, nut shell, and vegetables. Samples underwent pyrolysis in the Simultaneous Thermal Analysis from room temperature to 1200 K at different heating rates of 10, 20, 30 and 50 K/min. The starch had the narrowest pyrolysis temperature range, while nut shell exhibited the highest residual rate. The average activation energy for pyrolysis process calculated using Coats–Redfern method was in order of starch > vegetable ≈ nut shell > peel. The gaseous products and typical functional groups of the released volatiles were identified using specific information from Fourier Transform Infrared Spectroscopy (FTIR) and Mass Spectrometry (MS). These primarily included small inorganic molecules, aldehydes, aromatics, ethers, furans, ketones, organic acids, and phenols. Aliphatic hydrocarbons significantly contributed to the total gas yield and were the most abundant for all samples. The characteristic ion fragment with m/z = 60 was only observed in peel and nut shell, while m/z = 58 ion fragments were exclusive to starch and vegetables. The practical research can provide theoretical basis for the resource utilization and environmental management of kitchen waste.

Copyright of Journal of Agricultural Science & Technology (1008-0864) is the property of Journal of Agricultural Science & Technology 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.)

In this study, the effects of organic and chemical fertilizer sources on some essential nutrient elements content, nitrate (NO3−-N) accumulation, and the growth of spinach plant (Spinacia oleracea L.) were investigated. The experiment was carried out in a randomized plot design under greenhouse conditions, with two levels. 1st level; applications with chemical fertilizer. 2nd level; applications without chemical fertilizer. One compost material (kitchen waste compost = KWC), five different doses (0, 0.4, 0.8, 1.2, and 1.6%), and three replications. For chemical fertilization, nitrogen (N) dose of 150 kg ha−1 was applied by using 15-15-15 NPK (N:P2O5:K2O) fertilizer. Overall, KWC applications increased plant growth and nutrient content. However, the most significant increases occurred in the trial subjects where chemical fertilizer and KWC were applied together. The use of KWC together with chemical fertilization increased the leaf width, leaf and stem length, fresh weight, and dry weight, as well as nitrate accumulation, N, potassium (K), and iron (Fe) content of the plant. The highest values of these parameters were obtained at 0.8% dose of KWC + NPK medium. As a result, compost applications were effectively uptake of nutrients and nitrate accumulation remained at acceptable values. [ABSTRACT FROM AUTHOR]

The medium temperature amylase, glucose oxidase and p-gluconase, which were added to the pile at a ratio of 60 mg/kg・ To investigate their effects and potential mechanisms on the composting cycle, nitrogen fixation effect, and organic matter degradation during the aerobic composting process・ The results showed that although the addition of three exogenous enzymes did not enhance the peak performance during the high temperature period during the composting process, medium temperature amylase and glucose oxidase could significantly promote an increase in the organic matter degradation rate of compost by 3.8% 〜4. 1%, which may be attributed to acid accumulation caused by enzymatic hydrolysis pretreatment. In addition, medium temperature amylase and p-gluconase effectively accelerated the ammonification process of compost, while glucose oxidase was beneficial for the accumulation of n让rate nitrogen, significantly increasing the nitrate nitrogen content by 6・ 0% ・ The results indicated that exogenous enzymes can produce a chain reaction of enzymes, stimulating each other separately p-gluconase and dehydrogenase. [ABSTRACT FROM AUTHOR]

Kitchen waste is listed among the top global sustainability issue as it contributes to global warming and climate change. Composting is one of the solutions to tackle the issue of kitchen waste increment. However, a manual composting system has led to several problems for the waste management authorities to invest more in human labor, cost, and time to segregate and dispose of the kitchen waste and its composting soil. Therefore, this project proposes an intelligent kitchen waste composting system via deep learning and Internet-of-Things (IoT) that is fully automated to cater for that issue. Firstly, the proposed system utilized Convolutional Neural Network (CNN) to detect and segregate kitchen waste into compostable and non-compostable categories. Then, the classified compostable waste went through composting stage inside an automated compost bin with the feature of IoT. The IoT compost bin requires less human labor as it used sensors, actuators, and Wi-Fi connection to monitor and control the composting process. Finally, the compost soil is transferred to the designated gardening area via smart compost soil transportation system. The system consists of a robot equipped with infrared sensors. The sensors control the robot's movement by tracking the predefined black tape path. A prototype is built to investigate the performance of the proposed system. Results show that each sub-system managed to interact with one another, thus creating a large intelligent system that succeeded in completing the kitchen waste segregation, composting and ready compost delivering tasks automatically. In the future, it is expected that the proposed intelligent system has the potential to be commercialized to tackle the kitchen waste increment issue as it offers an economical yet high-efficiency solution. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board 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.)

The cost of producing xanthan gum by Xanthomonas campestris is heavily impacted by the use of sugar or dextrose as a carbon source from an industrial standpoint. To address this, the researchers in this study opted to use kitchen waste, a substantial solid waste from the food industry, as a valuable source of fermentable sugars. Inedible parts of broccoli and cauliflower used as kitchen waste in this study show promising potential as an economically and ecologically sustainable material for fermenting biomolecules. This study aims to evaluate the viability of utilizing kitchen waste as a cost-effective, ecologically sustainable carbon source to produce xanthan, making use of Xanthomonas campestris NCIM 2961 in the process. Aqueous extracts of inedible parts of cauliflower and broccoli were fermented with Xanthomonas campestris NCIM 2961 at standard conditions. The fermentation parameters, including, pH, temperature, agitation, and incubation period were varied at different levels to study the effects of varying conditions on the xanthan yield and to determine the optimum levels of the fermentation parameters. After the fermentation process, the xanthan gum was separated from the broth through alcoholic precipitation and subsequent drying. The weight of the dried gum was recorded. To analyze the properties of the xanthan obtained from the alternative medium under standard conditions, it was compared with commercial food-grade xanthan using Fourier-transform infrared (FTIR) spectroscopy. The FTIR spectra of xanthan produced from the alternate medium showed a close resemblance to that of the commercial food-grade xanthan. The results obtained validate the potential of kitchen waste as a cost-effective, and eco-friendly alternative carbon source for xanthan production, thereby decreasing the cost of production and solid waste generated. [ABSTRACT FROM AUTHOR]

Ionizing irradiation, as a new pretreatment method for the anaerobic fermentation of organic pollutants, is featured with fast reaction speed, good treatment effect, no need to add any chemical reagents, and no secondary pollution. This study explores the mechanism of improving anaerobic fermentation performance of rice samples pretreated by cobalt-60 gamma irradiation through the influence on fermentation substrate, acidogenic phase and methanogenic phase. The results reveal that the soluble chemical oxygen demand of the irradiated rice sample at an absorbed dose of 9.6 kGy increases by 12.4 times due to the dissolution of small molecules of fat-soluble organic matter. The yield of biogas in the acidogenic phase increases by 22.2% with a slight increase in hydrogen gas content. The yield of biogas and methane gas content in the methanogenic phase increases by 27.3% and 15%, respectively. Microbial genome analysis, performed with MiSeq high-throughput sequencing and metagenomic methods, suggests the microbial abundance and metabolic functions in the anaerobic fermentation process change significantly as a result of the pretreatment by gamma irradiation. [ABSTRACT FROM AUTHOR]

To realize the energy and resource utilization from organic solid waste, a two-phase microbial desalination cell (TPMDC) was constructed using dewatered sludge and kitchen waste as the anode substrate. The performance of electricity generation and composting efficacy was investigated, along with a comprehensive assessment of the potential health risks associated with the land use of the resulting mixed compost products. Experimental outcomes revealed a maximum open-circuit voltage of 0.893 ± 0.005 V and a maximum volumetric power density of 0.797 ± 0.009 W/m³. After 90 days of composting enhanced by microbial electrochemistry, a significant organic matter removal rate of 31.13 ± 0.44 % was obtained, and the anode substrate electric conductivity was reduced by 30.02 ± 0.04 % based on the anode desalination. Simultaneously, there was an increase in the content of available nitrogen, phosphorus, and potassium, as well as an improvement in the seed germination index. The forms of heavy metals shifted from bioavailable to stable residual states. The non-carcinogenic hazard index (HI) values for heavy metals and polycyclic aromatic hydrocarbons (PAHs) during the land use of compost products were less than 1, and the total carcinogenic risk (TCR) values for heavy metals and PAHs were below the acceptable threshold of 10−4. The occupational population risk of infection from five pathogens was higher than that of the general public, with all risk values ranging from 8.67 × 10−8 to 1, where the highest risk was attributed to occupational exposure to Legionella. These outcomes demonstrated that the mixture of dewatered sludge and kitchen waste was an appropriate anode substrate to enhance TPMDC stability for electricity generation, and its compost products have promising land use suitability and acceptable land use risk, which will provide important guidance for the safe treatment and disposal of organic solid waste.

ABSTRACT The selection of an appropriate production system plays a crucial role in ensuring the health, welfare, and productivity of American Pekin ducks. The aim of this study was to investigate the influence of various rearing production systems on the performance of American Pekin Ducks. A total of 180 straight run ducklings (10 days old) were randomly allocated into three experimental groups: intensive production system (IPS), free-range production system (FRPS), and pool with yard production system (PYPS). The distribution was carried out following a completely randomized design. We investigated the morphological parameters, growth performance, serum chemistry, meat cholesterol and triacylglycerol, cellular immunity, intestinal morphology, and carcass traits of Pekin ducks. The results indicate that PYPS birds exhibited significantly better morphometric parameters compared to IPS and FRPS ones. Ducks raised in PYPS had the highest growth rate till the 75th day as compared to those reared in IPS and FRPS. Triacylglycerol, total lipids, blood and meat fat and triacylglycerol were higher in IPS; whereas albumin, AG ratio, total proteins, glucose, and globulin were higher in PYPS. Similarly, cellular immunity (phagocytic activity, eosinophils, basophils, and monocytes) was increased in PYPS. Intestinal morphology and overall carcass traits were better in birds reared under PYPS than in those of IPS and FRPS. American Pekin ducks raised in PYPS showed improved growth, serum chemistry, cellular immunity, and carcass traits. These results suggest that the PYPS could be a promising production system for raising ducks in sub-tropical regions.

Anaerobic digestion (AD) has been widely used as a promising technology for the treatment of kitchen waste (KW). The effects of several acidification-resisting methods were compared, which included the supplementation of trace elements (TEs) and zero-valent iron (ZVI) / powdered activated carbon (PAC), and the application of the sludge domesticated by acetic acid (HAc) and KW as inoculum. The results showed that the supplementation of TEs and ZVI/PAC at total solid (TS) content of 6% and optimal addition doses resulted in an increase in methane yield to 346 and 366 mL/g VS, respectively. In addition, the methane yields of 327 and 241 mL/g VS were obtained by applying the sludge domesticated with KW and HAc as inoculum, while the methane yield of the control was only 89.2 mL/g VS, representing a relative increase of 288%, 311%, 267%, and 170%. The acidification could be alleviated by applying these methods, and also the methanogenic profile was improved. Furthermore, microbial community analysis revealed that the enrichment of Methanosarcina, which enhanced the substrate utilization capacity and subsequently increased methane production, was achieved through the addition of TEs and ZVI/PAC, along with the application of sludge domesticated by KW.

【Objective】The study was carried out to evaluate the feasibility and efficacy of feeds produced by fermented kitchen waste to spotted-brown chickens as a partial replacement of basal diets, with a view to providing basic data for the resource utilization and promotion of kitchen waste feed.【Method】One-day-old spotted-brown chickens were selected, and 0% (CK), 10% and 20% fermented kitchen waste feeds (FKWF) were added to the basal diet, and the amount of basal diet was reduced accordingly. At the 63rd day of the test period, the growth performance, slaughter performance and nutritional performance indexes such as crude protein, crude fat, calcium, phosphorus, zinc, selenium, inosinic acid and amino acids in chicken meat were measured.【Result】The results of broiler growth performance showed that the differences in feed-to-weight ratios between broilers in the 10% and 20% FKWF groups and CK were not significant, however, broilers in the 10% FKWF group had the highest weight. The results of slaughter performance showed that there were no abnormality in the skin color, muscle tissue elasticity, pH and odor of broilers of 10% and 20% FKWF groups, and the differences in organ coefficients were not significant compared with that of CK; the results of muscle nutritional performance showed that the crude protein contents of chicken meat in 10% and 20% FKWF groups increased by 7.50% and 3.42%, phosphorus contents increased significantly by 11.44% and 4.37%, and inosinic acid contents increased significantly by 7.10% and 6.00%; the fresh-flavored amino acid (FAA), sweet amino acid (SAA), essential amino acid (EAA), and total amino acid (TAA) were significantly higher in 10% and 20% FKWF groups than those in CK; aspartic acid, glycine, alanine, valine, isoleucine, leucine, tyrosine, phenylalanine, histidine and cysteine were significantly increased by 4.49%to 12.79% compared with CK; aspartic acid, valine, isoleucine, and leucine in the 20% FKWF group were significantly increased by 3.37% and 5.74%, compared with CK.【Conclusion】It is feasible and effective to replace the basal diet by a certain proportion of biofeed produced by fermented kitchen waste to feed broilers, which can save feed costs and improve economic benefits.

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.

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.

Water accounts for 70 % - 90 % of the total mass of food waste, and the contents of organic matter, oil, and salt in the waste are high. These conditions are highly suitable for the growth and reproduction of bacteria and other microorganisms. Therefore, anaerobic digestion is a common approach to treat food waste. Despite its long history, the research on anaerobic digestion has gradually developed with the progress in science and technology. This study aimed to explore the influence of temperature fluctuation on the anaerobic digestion characteristics of food waste by performing batch experiments; also, the characteristics were analysed from a microscopic perspective. The anaerobic digestion process was subjected to the interactions between various microorganisms and enzymes. The experimental results indicated that the activity of bacteria belonging to the phyla such as Proteobacteria and Chloroflexi was relatively high at a constant temperature. In contrast, the activity of the bacteria belonging to the phyla such as Bacteroidota and Acidobacteriota was relatively high at regulated temperatures. The activity of cellulase and lipase increased whereas that of protease decreased at a constant temperature. Regardless of the fluctuation mode of temperature, the activity of amylase did not obviously alter. These microorganisms with different responses to temperature fluctuation had unique functions in the anaerobic digestion process, and they participated in different anaerobic digestion stages. Therefore, based on the attribute of kitchen waste, an appropriate temperature mode can be selected to make anaerobic digestion more efficient. [ABSTRACT FROM AUTHOR]

Dark fermentation (DF) of kitchen waste (KW) is a promising technology for the production of renewable biohydrogen. It can be both a method of obtaining clean energy and a sustainable waste management. Despite its potential, this process requires further research to improve efficiency. The aim of the research was to test the effect of thermal pretreatment of the inoculum on H2 and volatile fatty acids (VFAs) production in the DF process. The process was carried out at 37 °C, in batch mode. The digested sludge from the Group Wastewater Treatment Plant in Lodz was used as inoculum. KW from households was used as substrate. The inoculum was pre-treated at 70 °C for 15 and 30 min. Two control reference experiments were also used. The first without the inoculum, and the second without heating the inoculum. The thermal pretreatment inhibited methane production and increased hydrogen production. After the thermal pretreatment, the amount of CO2 produced during the process decreased compared to the bioreactor without inoculum pretreatment. Additionally, the main VFAs in the samples with pretreated inoculum were acetic and butyric acids, which are associated with hydrogen production in the biochemical pathways of the DF process. However, the time of thermal pretreatment had no significant effect on H2 production. [ABSTRACT FROM AUTHOR]