Food Waste Compost Research Articles

Enhancing Oxygen-Dissolving Capacity of Rotary Drum Food Waste Composting: Tumbling Process Optimization and Experimental Validation with Discrete and Finite Element Methods

An optimized tumbling process can significantly improve the oxygen dissolving capacity of composting and fertilizer quality: by increasing the fluffiness of the lower layer of the pile, localized anaerobic fermentation can be avoided, thereby enhancing compost quality. This paper presents a method for improving the oxygen dissolving capacity of rotary drum food waste composting through a combination of simulation optimization and experimental validation. First, the discrete element method was used to optimize the key parameters of the tumbling process. The response surface method was then employed to analyze the composting test results and determine the optimal conditions. To ensure the reliability of the equipment under this method, failure risk analysis was conducted using the finite element method. The simulation optimization results showed that with a rotary drum reactor speed of 3.5 r/min, a horizontal angle of inclination of 2.5°, a mixing blade angle of inclination of 43°, and a blade pitch of 580 mm, the fluffiness of the lower layer of the pile increased by 8.515%, achieving the best tumbling and indirectly enhancing oxygen dissolving capacity. The maximum deformation of the load-bearing components was only 0.0548 mm, and the minimum safety factor was 4.408 (≥1 is considered safe). A 14-day composting experiment was conducted to validate the optimized parameters. The results showed that the maximum temperature of the compost pile reached 68.34 °C (lasting 7 days), with the pH, moisture content, C/N ratio, humus substances, humic acid, and fulvic acid contents of the fertilizer all meeting or exceeding the levels recommended by Chinese national standards. These findings indicate that the optimized tumbling device effectively improved the stability and dissolved oxygen efficiency of food waste composting, providing valuable practical insights and a research foundation for enhancing oxygen efficiency in the composting of other organic wastes.

Enhanced removal of Fe, Cu, Ni, Pb, and Zn from acid mine drainage using food waste compost and its mechanisms

Heavy metals (HMs) in acid mine drainage (AMD) pose serious threats to aquatic life and soil. Biosorbents are promising materials to remove HMs from wastewater. Herein, food waste compost was used as a low-cost and sustainable biosorbent to remove Fe3+, Cu2+, Ni2+, Pb2+, and Zn2+ from an AMD and other model solutions with an initial pH of 2.24. Batch adsorption tests were conducted to systematically investigate the influences of initial pH, compost dose, the presence of Fe3+ and SO42− ions, and the pH-induced Fe precipitates on the removal performance. The involved removal mechanisms were explored by conducting stepwise precipitation tests, sequential extraction tests, and Fourier transform infrared spectroscopy (FTIR) characterization. It was found that the addition of the compost removed over 90% of Zn, Ni, Cu, and Pb at pH 5.80, 5.50, 4.50, and 3.00, respectively. At low compost doses, the presence of Fe3+ and SO42− ions hindered the removal since the competition effect of Fe3+ ion and lower absorbability of metal-sulfate complexes, respectively. Sequential extraction tests revealed that higher fractions of Fe, Cu, and Pb were strongly immobilized through complexation and precipitation relative to Ni and Zn. Additionally, the pH-induced Fe precipitates did not favor the removal of the HMs, probably due to the adsorption of organic components released from the compost. This study suggests that compost have the potential to remove HMs from acidic wastewater without pre-neutralization.

Short‐term effects of food waste composts on physicochemical soil quality and horticultural crop production

AbstractAimComposts made from food waste will soon become more widespread on the market thanks to the upcoming enforcement of the legal obligation to sort biowaste. Our experiment aims at improving knowledge on the short‐term effects of these composts on soils’ physicochemical properties and vegetable crops.MethodsThree composts with contrasting characteristics were tested: a 100% v/v green waste compost (C1), and two composts composed of 50% v/v food waste and 50% v/v green waste, one prepared directly on the soil (C2) and the other from a competing producer who have the French NFU 44‐051 (AFNOR NF U 44‐051, 2006) certification for an organic amendment (C3). They were applied at a rate of 100 t ha−1 (dry matter) on two cropped soils with contrasting textures. Soil‐and‐compost mixes and compost‐free soil were planted with lettuce, radish, and potato.ResultsSeventy‐four days after planting, composts improved some soil physicochemical properties. The compost‐amended soils had better saturated hydraulic conductivity (Ks, 1 10−3–2.5 10−3 cm s−1) than the compost‐free soil (0.5 10−3 cm s−1), and water‐stable aggregates were higher than the initial value in C3 soil, equal to it in C2 soil, and lower in C1 soil. pH, total nitrogen, and organic carbon increased in all compost‐amended soils. Food waste compost stimulated crop production. The yields (dry matter) of all three crops were two to three times higher in the two soils amended with food waste compost compared to unamended soil, whereas they decreased almost two times in the soil amended with green waste compost due to nitrogen immobilization. Trace metals (particularly Pb and Cd) added by the composts, although present in edible parts of the plants, did not exceed the European rules for trace metals.ConclusionThus, food waste composts have positive effects on soils and vegetable crops, and the higher their organic matter content, the higher these positive effects.

Assimilatory sulphate reduction by acidogenesis: The key to prevent H2S formation during food and green waste composting for sustainable urbanization

Food and green waste composting is a nature-based process for sustainable management of municipal organic waste. Although widely used for these organic wastes, composting is hindered by rapid organic acidification and malodor emission, particularly hydrogen sulphide (H2S). Using genome-resolved metagenomics, this study aimed to decipher the underlying mechanisms of sulphate reduction to H2S by acidogenesis during food and green waste composting. Results showed that both volatile fatty acids (VFAs) and H2S were significantly produced within the first week of composting. Further analysis identified that bacteria (e.g. Lactobacillus) with acid-producing genes (ackA and LDH) were key accomplices to assimilatory sulphate reduction for producing H2S by providing VFAs, especially acetic and lactic acids, as a carbon source. Such sulphate reduction could be directly induced by bacteria (e.g. Bacillus, and Ureibacillus) with intact assimilatory sulphate-reducing genes (cysNC, cysH, and cysJ/I). Nevertheless, individual bacteria (e.g. Paenibacillus and Acetobacter) without any sulphate-reducing genes could collaborate with their partners carrying complemented genes to complete sulphate reduction toward H2S. Furthermore, VFAs production could acidify composting substrates to abiotically aggravate the conversion of sulphur ions (e.g. S2- and HS-) to H2S. Nevertheless, alkaline additives suppressed these mechanisms to prevent both acidogenesis and H2S production, thereby, reducing the global acidification and human toxicity potentials of food and green waste composting.

Effects of composite microbial agent with straw or sawdust on organic matter degradation, enzyme activity and functional genes during aerobic composting of food waste

Bulking agent and microbial agent are widely used to improving the aerobic composting condition. This study aimed to evaluate the effects of composite microbial agent which is consisted of Azotobacter salinestris, Aspergillus oryzae, Bacillus licheniformis, Bacillus cereus and Trichoderma viride with different bulking agents (straw or sawdust) on organic matter degradation, enzyme activities, and functional genes associated with carbon and nitrogen cycling during aerobic composting of food waste. The results demonstrated that the inoculation of composite microbial agent significantly improved the degradation of starch, protein, cellulose, and grease, along with boosting microbial enzyme activity and the abundance of carbon degradation genes. Furthermore, the degradation of organic matter (OM), protein, cellulose, and grease were higher in the straw bulked composting with composite microbial agent treatment (B). Meanwhile, B also exhibited a higher abundance of cdh and rbcL genes compared to the other treatments. Pearson regression analysis identified temperature as the primary factor controlling organic matter degradation, while cdh and cex genes exhibited strong associations with cellulose degradation during food waste composting. These findings suggest that incorporating straw as bulking agent with composite microbial agent during food waste composting can effectively enhance organic matter degradation.

Preparation of efficient adsorbent for methylene blue and Congo red by co-hydrothermal of red mud with food waste compost

Herein, a novel red mud-carbon composite (RFBC) was prepared through co-hydrothermal treatment of red mud with food waste compost, and its adsorption property was evaluated on Methylene blue (MB) and Congo red (CR), selected model dyes in aqueous solution. The adsorption process conformed to pseudo-second-order kinetic, intraparticle diffusion, and the Redlich-Peterson isotherm models. RFBC exhibited a maximum sorption of 124.06 mg·g-1 for MB and 2959.35 mg·g-1 for CR at 298 K. Isothermal and thermodynamic studies demonstrated that adsorption of MB and CR by RFBC were spontaneous and exothermic, governed by physisorption and chemisorption. Furthermore, the possible adsorption mechanisms are pore filling, electrostatic attraction, hydrogen bonding, and π-π interactions. After five consecutive adsorption-desorption cycles were completed, the RFBC demonstrated an adsorption efficiency exceeding 70 % in relation to dyes, affirming its exceptional reusability. This study suggested this red mud-carbon composite had high potential as a novel and promising adsorbent for dye removal from wastewater.

Academia's Role in Climate Action: Enhancing Awareness and Reducing Environmental Impact of Academic Events

A clean environment is vital for both population health and the well-being of our planet (Brusseau et al., 2019). In-person gatherings, like academic conferences, significantly contribute to carbon emissions that harm the environment, highlighting the importance of finding opportunities to reduce these emissions (Tao et al., 2021). Cognizant of the environmental cost of our annual national in-person research team gathering, our team sought to minimize the environmental impact of our 2023 gathering while raising awareness among team members. Our actions included using reusable tableware, composting food waste, and hosting an education session by the local environment office. Not only did our efforts increase awareness among gathering attendees about the importance of considering environmental impact reduction opportunities in their work, but they also catalyzed similar efforts at two national conferences. Our team took the lead in developing an evaluation of the environmental impact of each national conference and surveyed over 150 conference attendees. We collected demographic information, travel mode to the conference, and attitudes about environmental harms via a digital conference application. We also observed environmental actions implemented by event organizers and venue hosts. A carbon emission score and frequency distributions of attitudes surrounding the environment were calculated. Where possible, a food waste assessment was conducted. Findings showed that event organizers made efforts to minimize the environmental impact of their event by selecting a venue whose management was interested in collaborating; by encouraging attendees to carpool and use reusable water bottles; by serving plant-based meals, and by minimizing single-use products. Findings also revealed that most conference attendees consider it important to reduce the environmental impact of their professional lives. Given the value of face-to-face interaction in facilitating knowledge exchange (Chan et al., 2023), it is important that organizers continue to make efforts to reduce carbon emissions when planning events.

Themes and sentiments in conversations about food waste on Twitter: Proposal of a framework using neural topic modeling

There is growing research interest in the role of social media in the food industry, and its potential has yet to be fully exploited. This study extracted and analyzed data from Twitter, now X, (2018–2023) using relevant keywords related to food waste (FW), identified frequently discussed topics, and determined the sentiments involved in tweets. With the aid of neural topic modeling techniques, this study found that the main topics discussed in this social network include “Food and Garden Waste Composting and Recycling,” “Global Food Waste and Management,” “Reducing Food Waste & Saving Money,” “Single-Use Plastic and Waste Management,” and “Creative Uses of Leftovers in Meals”. Some of the subject categories often discussed are FW Environmental concerns, FW events, Leftovers management, and FW household management. Most subject categories are associated with positive sentiments, which are associated with topics like tips and recommendations for reducing FW. Negative sentiments are related to discussions around the environmental and social impacts of FW. Our study found a gap in knowledge and awareness of food recycling practices. Our study extends previous research because the analyzed messages are not restricted to specific geographical regions. Moreover, our study also used a more varied dataset in terms of user profiles and employed a search string that comprised a more varied set of terms, making our search more thorough. A comprehensive framework of discussed topics and associated sentiments is proposed. Our study has crucial implications for the design of FW reduction campaigns and interventions in social media.

Optimizing native vegetation establishment in urban soils: Assessing the impacts of organic amendments on specific growth parameters

Following soil disturbances, establishing healthy roadside vegetation can reduce surface water runoff, improve soil quality, decrease erosion, and enhance landscape aesthetics. This study explores the use of organic soil amendments (OAs) as alternatives to conventional vegetation growth approaches, aiming to provide optimal compost mixing ratios for poor soils, and clarify guidelines for OAs’ use in roadside projects. Three sandy loam soils and one loam soil were chosen for the study. Organic amendments included yard waste (Y), food waste (F), turkey litter and green waste-based (T) composts, and wood-derived biochar (B). Treatment applications targeted specific increases in the organic matter (OM) percentage of the soils. A selection of seven native species (grasses and forbs) in a total of 156 pots (4 control soils + 4 soils x 4 OAs x 3 application rates, all prepared in triplicates) was used for the pot study experiment. A significant correlation between electrical conductivity (soluble salts) in soil-OA blends and corresponding percent green coverage (%GC) was found. High salts from the T compost either delayed or curtailed growth. Notably, 3 out of the 4 soils amended with biochar exhibited rapid vegetation coverage during initial growth stages compared to other soil-OA blends but reduced the nitrogen (N) uptake and leaf area in black-eyed Susan (BES) plants. In contrast, N uptake was higher in the BES plants emerging from composts T, F, and Y compared to biochar. It is recommended to minimize concentrated manure-based (e.g., turkey litter) composts for roadside projects as an OM source, and alternatively, enriching wood-based biochar with nutrients when used as a soil amendment. Within the current study, composts such as F and Y were well-suited to establish healthy and long-lasting vegetation.

Effects of food waste compost on the growth and plant metabolites production in Amaranthus tricolor L. (Chinese spinach)

Effects of food waste compost on the growth and plant metabolites production in Amaranthus tricolor L. (Chinese spinach)

Impacts of Compost Amendment Type and Application Frequency on a Fire-Impacted Grassland Ecosystem

Composting organic matter can lower the global warming potential of food and agricultural waste and provide a nutrient-rich soil amendment. Compost applications generally increase net primary production (NPP) and soil water-holding capacity and may stimulate soil carbon (C) sequestration. Questions remain regarding the effects of compost nitrogen (N) concentrations and application rates on soil C and greenhouse gas dynamics. In this study, we explored the effects of compost with different initial N quality (food waste versus green waste compost) on soil greenhouse gas fluxes, aboveground biomass, and soil C and N pools in a fire-impacted annual grassland ecosystem. Composts were applied annually once, twice, or three times prior to the onset of the winter rainy season. A low-intensity fire event after the first growing season also allowed us to explore how compost-amended grasslands respond to burning events, which are expected to increase with climate change. After four growing seasons, all compost treatments significantly increased soil C pools from 9.5 ± 0.9 to 30.2 ± 0.7 Mg C ha−1 (0–40 cm) and 19.5 ± 0.9 to 40.1 ± 0.7 Mg C ha−1 (0–40 cm) relative to burned and unburned controls, respectively. Gains exceeded the compost-C applied, representing newly fixed C. The higher N food waste compost treatments yielded more cumulative soil C (5.2–10.9 Mg C ha−1) and aboveground biomass (0.19–0.66 Mg C ha−1) than the lower N green waste compost treatments, suggesting greater N inputs further increased soil stocks. The three-time green waste application increased soil C and N stocks relative to a single application of either compost. There was minimal impact on net ecosystem greenhouse gas emissions. Aboveground biomass accumulation was higher in all compost treatments relative to controls, likely due to increased water-holding capacity and N availability. Results show that higher N compost resulted in larger C gains with little offset from greenhouse gas emissions and that compost amendments may help mediate effects of low-intensity fire by increasing fertility and water-holding capacity.

Techno-economic assessment of industrial food waste composting facility: Evaluating bulking agents, processing strategies, and market dynamics

Techno-economic assessment (TEA) of a valorization of bulking agent (BA) ratios on the food waste compost value chain is made to assess economic feasibility. TEA was performed with two plans (Plan A: existing composting facilities; Plan B: new composting facilities) and each plan was under four scenarios. The BA (i.e. corn stalks, garden waste, and watermelon seedlings) ratio of 5 % (S1), 10 % (S2), 20 % (S3), and garden waste with a ratio of 20 % (S4). Results indicate that S2, with a net present value (NPV) of 128.9 million, represents Plan A’s most economically viable scenario. Although the total operating costs of S4 were 18.9 %–23.5 % higher, 25.6 %–42.2 % higher total revenue made S4 have an NPV of 92.9 million, making it the most viable scenario in Plan B. All scenarios show positive NPV within a ± 20 % fluctuation range. Organic fertilizer price, government subsidies, and processing capacity were the key factors influencing NPV.

Performance of Effective Microorganism (EM) in Food Waste Composting and Their Association with Seed Germination on Kale Seed

Food waste has an influence throughout the whole food supply chain, from production to consumption. Composting effectively and affordably reduces the need for synthetic fertilizers, water, soil erosion, pesticides, and soil carbon storage. Composting may also improve crop yields and soil fertility, leading to more sustainable farming practices. The potential of efficient microorganisms (EM) for dehydrated food waste decomposition was investigated in this study. The research assessed the temperature and pH profiles during composting, whereas nitrogen, phosphorus, potassium, organic content, and E. coli were measured in mature composts. Therefore, the study revealed that EM greatly hastened the composting process by boosting critical factors such as temperature, pH, nitrogen content (TN : 1.17±0.6%, TP: 0.059±1.92%, K: 0.12±5.3%) organic enrichment (85%), and E-coli (<1 MPN/g). The germination index (GI) of kale seed was then analysed with the study’s findings indicating an 80% soil-compost ratio was the best. This research investigates the use of effective microorganisms (EM) to transform food waste into beneficial agricultural resources, with favourable results for soil health and kale seed germination. Researchers and circular economy officials may use the results to promote sustainable agriculture. The research helps to minimize landfill food waste, methane emissions, and synthetic fertilizer consumption, all of which benefit the environment. Farmers and gardeners may use the findings to boost soil fertility and crop yields on a budget. This research indicates that food waste may be transformed into useful resources, encouraging sustainable and eco-friendly agricultural.

Mechanism investigation of food waste compost as a source of passivation agents for inhibiting pyrite oxidation

Pyrite oxidation causes the generation of acid mine drainage (AMD), posing significant challenges in the management of sulfide tailings. Passivation agents such as humic acid have been tested to prevent pyrite oxidation. The potential of using humate rich food waste compost as a source of passivation agents to suppress pyrite oxidation was explored in this study. Batch leaching tests were conducted at room temperature, involved oxidatively leaching a pure pyrite and a pyrite-containing coal refuse sample, respectively, with and without adding the compost at acidic pH. The involved passivation mechanisms were investigated by solution leaching tests and spectroscopic (XPS) and microscopic (SEM) analysis of the pure pyrite sample and its leaching residues. Compared to the control, adding the compost led to the increases in solution pH, removal of the Fe2+/Fe3+ ions from the solutions by adsorption, and remarkable decreases (≥58 %) in sulfur concentration in both samples. Both SEM and XPS analysis indicated that a coating layer was successfully established on pyrite surface after being leached in the presence of the compost. The coating layer comprised a mixture of organic species (e.g., O-CO and N-H/C groups) and phosphate, potentially improving the likelihood of providing antioxidant protection over acidic pH. As a low-cost material, food waste compost can benefit the source control of AMD not only in terms of its surface passivation, but also its intrinsic alkalinity, metal immobilization, and low environmental risk.

The Impact of Food Waste Compost, Vermicompost, and Chemical Fertilizers on the Growth Measurement of Red Radish (Raphanus sativus): A Sustainability Perspective in the United Arab Emirates.

The pressing need for sustainable agricultural practices, especially with the increasing population, has directed attention towards alternative fertilizers that enhance crop yield while preserving soil integrity and reducing food loss. The current study investigated the comparative efficacy of food waste compost (FOWC), vermicompost, and chemical fertilizers on the growth of red radish. The present work used a systematic experimental design to evaluate plant growth parameters, including radish weight and height. The soil quality was determined by measuring the pH and electrical conductivity for all soil samples. The results indicated a significant variation in red radish fresh weight among different treatments. For example, the 25% vegetable and fruit waste compost (VFWC) treatment demonstrated a relatively high mean fresh weight, while the 50% mixed compost (MC) treatment yielded a much lower mean fresh weight. These numbers underscore the potential efficacy of specific food waste treatments in enhancing plant growth, with vermicompost at 50% and VFWC at 25% showing considerable promise in increasing crop yield. The current study concluded that FOWC and vermicompost significantly improved plant growth, advocating for their use as sustainable and environmentally friendly alternatives to chemical fertilizers. The current findings emphasized the importance of selecting appropriate fertilizer types and concentrations to optimize agricultural productivity and environmental sustainability, supporting the incorporation of food waste into agricultural systems as a beneficial resource.

Effect on Growth and Yield of Red Pepper (<i>Capsicum annuum</i> L.) by the Application Ratio of Food Waste Compost with Manure under Upland

Effect on Growth and Yield of Red Pepper (<i>Capsicum annuum</i> L.) by the Application Ratio of Food Waste Compost with Manure under Upland

Investigating the sources and fate of per- and polyfluoroalkyl substances (PFAS) in food waste compost

Composting municipal food waste is a key strategy for beneficially reusing methane-producing waste that would otherwise occupy landfill space. However, land-applied compost can cycle per- and polyfluoroalkyl substances (PFAS) back into the food supply and the environment. We partnered with a pilot-scale windrow composting facility to investigate the sources and fate of 40 PFAS in food waste compost. A comparison of feedstock materials yielded concentrations of ∑PFAS under 1 ng g−1 in mulch and food waste and at 1380 ng g−1 in leachate from used compostable food contact materials. Concentrations of targeted ∑PFAS increased with compost maturity along the windrow (1.85–23.1 ng g−1) and in mature stockpiles of increasing curing age (12.6–84.3 ng g−1). Among 15 PFAS quantified in compost, short-chain perfluorocarboxylic acids (PFCAs) – C5 and C6 PFCAs in particular – led the increasing trend, suggesting biotransformation of precursor PFAS into these terminal PFAS through aerobic decomposition. Several precursor PFAS were also measured, including fluorotelomer carboxylic acids (FTCAs) and polyfluorinated phosphate diesters (PAPs). However, since most targeted analytical methods and proposed regulations prioritize terminal PFAS, testing fully matured compost would provide the most relevant snapshot of PFAS that could be land applied. In addition, removing co-disposed food contact materials from the FW feedstock onsite yielded only a 37 % reduction of PFAS loads in subsequent compost, likely due to PFAS leaching during co-disposal. Source-separation of food contact materials is currently the best management practice for meaningful reduction of PFAS in food waste composts intended for land application.

Effect of Food Waste on The Growth Performance, Waste Reduction Efficiency and Nutritional Composition of Black Soldier Fly (Hermetia illucens (L.), Diptera: Stratiomyidae) Larvae

The rate of solid waste generation, especially in Malaysia, has become one of the major concerns for environmental and public health issues. Food waste accounts for the highest percentage of solid waste that ends up in landfills. Due to the living nature of humans and their involvement in agricultural, industrial, and municipal activities, the disposal of food waste happens on a regular basis. Due to the absence of an incineration plant, these wastes are commonly sent into landfills which are considered to be the most cost-effective method for disposal. Nevertheless, consideration for an alternative disposal method such as composting shall not be ruled out entirely. One of the established methods for composting food waste is the utilization of the larvae of the Black Soldier Fly. A study was conducted to assess the growth and nutritional composition, waste reduction capacity and nutritional composition of Black Soldier Fly Larvae (BSFL) reared on food waste. We found that the larvae reared with the food waste and effective microorganism (EM), LFWEM (BSFL reared with a mixture of food waste and effective microorganisms), have a slightly better relative growth rate (2.66 ± 0.35 day-1) compared to larvae reared with only food waste (2.44 ± 0.17 day-1). The waste reduction index was higher in the LFWEM group (5.36 ± 0.18 g/day) compared to the control group, LFC (BSFL reared with chicken feed) (4.85 ± 0.03 g/day) and the LFW (BSFL reared with food waste) group (5.13 ± 0.17 g/day). The nutritional composition of the BSFL reared using food waste shows some potential as it surpasses some of the amount of essential amino acids including Arginine, Histidine, Threonine and Valine, found in the commercially available animal feeds. This finding serves as a baseline to propose potential replacements for animal protein by using BSFL reared with food waste.

The Influence of Compost Bin Volume and Effective Microorganisms (EM) Quantity for Efficient Food Waste Composting

The utilization of effective microorganisms (EM) in composting has gained substantial prominence since this additional microorganism is believed to overcome natural composting issues, such as slow decomposition and odour generation. However, a lack of awareness and education about proper composting practices involving EM can result in errors that diminish the decomposition process's effectiveness. Thus, this study aims to enhance the decomposition process's efficiency with emphasis on the balance between EM and food waste, as well as the void space within the compost bin. The investigation employed a varying EM quantity ranging from 20 to 100 ml and compost bin volumes of 6, 9, and 21 L. The food waste is mixed with 60% of the volume of each compost bin. The parameters assessed during the composting process include temperature and pH profile. Additionally, the mature sample after 20 days was then examined through the organic matter (OM), total organic carbon (TOC), and nutrient content, including nitrogen (N), phosphorus (P) and potassium (K). A series of controlled experiments found that the 21L compost bin possessing over 65 % free space reached a thermophilic temperature of 51.5oC within a remarkably brief one-day period and attained maturity within seven days, accompanied by a pH level of 7.4. Conversely, the 6L and 9L compost bins did not progress into the thermophilic phase or reach maturity during the seven-day observation period. The findings also indicate that the optimal quantity of EM required to decompose 600 grams of food waste exceeds 80 mL. They reached thermophilic temperature within eight days. These conditions fostered an environment conducive to accelerated decomposition and nutrient preservation. Notably, the final compost produced from these settings met established criteria for high-quality organic compost. This paper provides practical insights into achieving optimal conditions for EM application, thereby maximizing its effectiveness in food waste composting at source. Beyond the technical aspects, the research gives the broader social and environmental effects of home food waste composting, including its contribution to reducing landfill waste, greenhouse gas emissions, and community engagement.

Phosphate additives promote humic acid carbon and nitrogen skeleton formation by regulating precursors and composting bacterial communities

This study aimed to compare the effect of different phosphate additives including superphosphate (CP) and MP [Mg(OH)2 + H3PO4] on nitrogen conversion, humus fractions formation and bacterial community in food waste compost. The results showed the ratio of humic acid nitrogen in total nitrogen (HA-N/TN) in CP increased by 49 %. Ammonium nitrogen accumulation was increased by 75 % (CP) and 44 % (MP). Spectroscopic techniques proved that phosphate addition facilitated the formation of complex structures in HA. CP enhanced the dominance of Saccharomonospora, while Thermobifida and Bacillus were improved in MP. Structural equation modeling and network analysis demonstrated that ammonium nitrogen can be converted to HA-N and has positive effects on bacterial composition, reducing sugars and amino acids, especially in CP with more clustered network and synergic bacterial interactions. Therefore, the addition of phosphate provides a new idea to regulate the retained nitrogen toward humification in composting.