Solid Waste Recycling Research Articles

Исследование влияния комбинированного модификатора из отходов кремниевого производства на свойства серых чугунов

Introduction. During the metallurgical production of silicon, waste is generated that accumulates in dumps, causing harm to the environment. Disposal and recycling of solid waste from silicon production is especially important because They contain important chemical compounds (silicon dioxide, silicon carbide, carbon nanotubes) that can be used in other industries, which will bring greater economic value. Considering the possibilities for extracting these useful components from silicon production waste, it is necessary to bring processing technologies to the stage of widespread practical application. Therefore, the development of a special waste processing technology to obtain a useful product in the form of a composition of silicon dioxide and silicon carbide remains an urgent problem. Purpose of the work: to study the formation of the morphological form of graphite with the introduction of nano-modifiers from silicon production waste. The work examined samples of gray cast iron after modification with a combined modifier obtained from silicon production waste. The research methods are mechanical tests for statistical tension, analysis of the chemical composition and metallographic studies. Results and discussion. It was revealed that the mechanical properties of gray cast iron increased by 30-50% after modification with a combined modifier, compared with witness samples. The morphology of graphite is an important parameter affecting the properties of cast iron. It has been established that during the modification process the morphology of graphite changes from lamellar to vermicular. Specimens of gray cast iron with vermicular form of graphite have high strength values compared to specimens of gray cast iron with lamellar form of graphite. The presented results confirm the promise of the developed approach aimed at obtaining new classes of modifiers and products made of gray cast iron with a high range of mechanical properties.

Mutual Activation Mechanism of Cement–GGBS–Steel Slag Ternary System Excited by Sodium Sulfate

To promote the large-scale recycling of solid waste, the hydration characteristics of blended cement with different amounts of GGBS (ground granulated blast-furnace slag) and SS (steel slag) were investigated. The optimum blending amounts of GGBS and SS in cement were 40% and 10% by mass, and the optimum dosage of Na2SO4 in the C50-S40-SS10 (50 wt.% cement–40 wt.% slag–10 wt.% steel slag) system was 2 wt.%. The flexural and compressive strengths of the C50-S40-SS10 system after adding 2 wt.% Na2SO4 are 57.95% and 9.28% higher than that of pure cement at 28 d. XRD, FT-IR and Ca(OH)2 content analysis were chosen to investigate the hydration products of pure cement and blended cement. The results show that GGBS enhanced the hydration of both cement and SS. And GGBS contributed to the generation of calcium silicoaluminate hydrate (C–A–S–H) in the blended cement system. The addition of Na2SO4 promoted the hydration reaction and contributed to the generation of ettringite (AFt) in the ternary system. The hydration heat evolution results showed that GGBS and SS can reduce the hydration heat of cement. Na2SO4 had similar effects and delayed the time of AFt conversion to monosulfide calcium sulphoaluminate (AFm). A mutual activation mechanism of cement–GGBS–SS ternary system mixed with Na2SO4 was proposed in this study.

Influence of limestone powder mixing method on properties of manufactured sand concrete

For the purpose of enhancing the utilization rate of limestone powder (LP) in concrete and maximizing its activity effect. In this paper, the replacement methods for replacing fly ash (FA) with fine particles and manufactured sand (MS) with coarse particles were proposed. The content of LP replacing FA increased from 10% to 50%, and the content of LP replacing MS increased from 5% to 20%. The effects of LP replacing FA alone, replacing MS alone and particle-screened LP replacing both FA and MS on the workability, mechanical properties, durability of concrete were compared. Analysis of variance (Anova) was used to determine the importance level of the test parameters on the performance characteristics of concrete. The results suggested that LP replacing MS improved the workability and strength of concrete, and ameliorated the carbonation and chloride ion permeability resistance. However, the amount of LP substitution was very low, only 10%. Compared with LP replacing FA alone, the screened substitution improved the cohesion and water retention of concrete. The improvement in strength at 7 and 28 days was better, which was 1.6 MPa and 1.3 MPa higher than replacing FA alone. And there was no significantly adverse effect on the durability of concrete. Moreover, it was conducive to enhancing the utilization rate of LP. According to the research results, the effect of the interaction between LP content and the mixing method on the performance of concrete cannot be ignored. In addition, the screened substitution method was more environmentally friendly and economical, because it was conducive to the recycling of solid waste and landfill waste treatment.

Research on the brightening effect of miscible wetting additives on fly ash coatings

Abstract The resource utilization of fly ash has always been a popular topic in the field of solid waste recycling. This paper is based on the three-phase reaction system of “fly ash (s)-[Ca(OH)2–H2O/ethanol] (l)-CO2 (g)”, using the bubble carbonization method to carry out heterogeneous phase reaction with fly ash as the core crystallized to form a fly ash-based calcium carbonate composite with higher brightness. The composite material is used in the filling of paper instead of calcium carbonate filler. Based on the previous research of our team, we focused on exploring the addition of miscible wettability additives (ethanol and acetone) to improve the wettability of the reaction system, thereby improving the whitening and modification effect of fly ash. The results showed that the addition of ethanol and acetone can significantly improve the coating effect of fly ash, however, acetone is slightly toxic, more volatile, and expensive than ethanol, so ethanol is more suitable as a wetting agent to be added to the reaction system. Under the optimal coating conditions, when the ratio of ethanol and water is 1:1, the brightness of fly ash can reach 71.62 % ISO, which is 17.29 % ISO higher than that without ethanol.

Recycling of MoSi2-based industrial solid wastes for the fabrication and high-temperature oxidation behavior of MoSi2–ZrSi2–SiC composite coating

To protect Nb substrate from oxidation at elevated temperatures and make better use of the industrial solid wastes, spent MoSi2 heating elements, ZrSi2 and SiC were applied as raw materials to prepare MoSi2 and MoSi2–ZrSi2–SiC coatings by Spark Plasma Sintering (SPS). After high-temperature sintering, cracks were found in a single MoSi2 coating while MoSi2–ZrSi2–SiC coating was crack-free without any defects by the CTE mismatch reduction. Diffusion layers formed on the substrate and it strengthened the bonding in the coating system with good metallurgical combination. The oxide scale of the composite coatings possessed compact and crack-free morphologies with fractional consumption after oxidation at 1500 °C. Circular Mo5Si3 phases that possessed pores and cracks generated in the silica layer of MoSi2 coating at 1700 °C while MoSi2–ZrSi2–SiC composite coating still kept crack-free oxide scale, thus showing excellent 1700 °C anti-oxidation properties.

Waste management of household-scale snack industry based on Reduce, Reuse, Recycle (3R) In Watubonang Ponorogo

The household food industry that produces fish-based snacks in Ponorogo needs good waste management. Therefore, the waste is directly disposed of into the irrigation channel and vacant land. The waste produced by the industry contains highly organic compounds, which results in several problems, such as foul odor and eutrophication due to excess nitrogen and phosphorus. The management of water and solid wastes is a must to prevent environmental pollution, reduce waste circulation, and create better production; one of the methods that can be used is Reduce, Reuse, and Recycle (3R). Primary data were collected by sampling, laboratory analysis, and field research. In contrast, the secondary data were collected through literature studies. Based on the analysis results, reduction is done on liquid waste, compostable, and non-recyclable solid waste. Reuse is done on liquid waste and recyclable solid waste. Recycle is done on compostable and recyclable solid waste. Based on waste management, the treatment units begin with a grease, then an equalization basin, an Anaerobic Baffled Reactor (ABR), and constructed wetland. Solid waste storage for all types uses closed High Density Polyethylene (HDPE) tubs. Composting is carried out on compostable solid waste aerobically in a HDPE plastic tub.

Strategy of Finance Service Development in the Field of Collecting and Recycling Solid Municipal Waste in Regions of the Russins Federation

An acute problem facing today’s society is collecting and recycling solid municipal waste (SMW). The author studies this problem on the basis of the growing speculative factor dealing with enormous amount of poorly used SMW and shortage of budget funds for their efficient management and recycling. The goal of the article is to work out effective strategies to raise investment to this field and to raise finance stability of the system of SMW collecting and recycling. To reach this goal the author proposes to analyze the current condition of the industry, study best practices of international and Russian companies and identify hindrances and challenges that bar the development of finance services in the sector. It should be mentioned that successful development of finance services in the field of SMW collecting and recycling requires a complex approach including not only elaboration of new finance mechanisms but instructing people for principles of separate collecting and recycling waste and upgrading technologies of SMW recycling and utilization.

Solid waste recycling and organic particulate hybrid nanocomposite technologies for sustainable infrastructure—A comprehensive review

Solid waste has become a major environmental concern globally in recent years due to the tremendous increase in waste generation. However, these wastes (e.g., plastics and agro-residues) can serve as potential raw materials for the production of value-added products such as composites at low cost. The utilization of these waste materials in the composite industry is a good strategy for maintaining the sustainability of resources with economic and environmental benefits. In this report, the environmental impacts and management strategies of solid waste materials are discussed in detail. The study described the benefits of recycling and reusing solid wastes (i.e., plastic and agro-waste). The report also reviewed the emerging fabrication approaches for natural particulate hybrid nanocomposite materials. The results of this survey reveal that the fabrication techniques employed in manufacturing composite materials could significantly influence the performance of the resulting composite products. Furthermore, some key areas have been identified for further investigation. Therefore, this report is a state-of-the-art review and stands out as a guide for academics and industrialists.

Study on preparation and activation enhancement effect of cold bonded multi-solid waste wrap-shell lightweight aggregates (SWSLAs) with low cement content

Cement production consumes large amounts of depleted resources and energy, and causes environmental pollution. In order to reduce cement consumption and realize the closed-loop recycling of solid waste, cold bonded solid waste wrap-shell lightweight aggregates (SWSLAs) with a sextuplet blended system composed of dredged sediments, mineral powder, steel slag, phosphogypsum, fly ash, and a minimal amount of cement were prepared. Through the single-factor experiment, the influences of the types and dosages of solid wastes in the nuclear phase of SWSLAs (SWSLAs-NP) and shell phase of SWSLAs (SWSLAs-SP) on the strength and water resistance were explored, and the optimum ratio was obtained. On this basis, the influence of the types and amounts of activators incorporated in SWSLAs on the physical properties of aggregates was studied, and the primary microstructure of the aggregate was characterized. Our results showed that the optimal ratio of solid waste in the SWSLAs-NP was: 40 wt% of dredged sediments, 24 wt% of mineral powder, 18 wt% of steel slag, and 18 wt% of phosphogypsum. The optimal weight ratio of cement and solid waste in the SWSLAs-SP was 5:95. The resulting aggregate had a bearing capacity of single grain of 73.83 N and a water-resistance coefficient of 0.67. After the above aggregates were treated with Na2SO4 (activator) at 2%, the bearing capacity and water-resistance coefficient of the aggregates increased by 47.00% and 11.94%, respectively. The performances were even better than that of the aggregate composed of100w cement in the shell phase. Microstructural observations demonstrated that the structure of the raw material was reconstructed under the action of Na2SO4, and the raw materials reacted with each other, and thus the densification of the aggregate and its core-shell interface structure was enhanced, which improved the comprehensive performance of the aggregate. This study represents a step toward efficient utilization of industrial solid wastes.

Recycling of Aluminosilicate-Based Solid Wastes through Alkali-Activation: Preparation, Characterization, and Challenges

Recycling aluminosilicate-based solid wastes is imperative to realize the sustainable development of constructions. By using alkali activation technology, aluminosilicate-based solid wastes, such as furnace slag, fly ash, red mud, and most of the bio-ashes, can be turned into alternative binder materials to Portland cement to reduce the carbon footprint of the construction and maintenance activities of concrete structures. In this paper, the chemistry involved in the formation of alkali-activated materials (AAMs) and the influential factors of their properties are briefly reviewed. The commonly used methods, including X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TG), nuclear magnetic resonance spectroscopy (NMR), and X-ray pair distribution function technology, to characterize the microstructure of AAMs are introduced. Typical characterization results of AAMs are shown and the limitations of each method are discussed. The main challenges, such as shrinkage, creep, efflorescence, carbonation, alkali–silica reaction, and chloride ingress, to conquer for a wider application of AAMs are reviewed. It is shown that several performances of AAMs under certain circumstances seem to be less satisfactory than traditional portland cement systems. Existing strategies to improve these performances are reviewed, and recommendations for future studies are given.

How does green manufacturing promote the recycling of renewable solid waste and carbon reduction?

Solid waste recycling plays a key role in the manufacturer's green transition. By introducing recycled materials into production, manufacturers can enjoy both the benefits of carbon reduction and the addressing of the carbon lock-in problem. However, given the inadequacy of recycling legislation, the supply of recycled material is subject to yield uncertainty. This creates a challenging decision for manufacturers in need of transition: should they build a new carbon-neutral production line or only upgrade the existing production line? We formulate the key tradeoffs including the varying consumer evaluations, the production quality control, and the reform of the supply chain structure. We find that building a new carbon-neutral production line is preferred when the carbon emission level is moderate, the market competition is intensified, and the recycling efficiency is high. We further identify the multi-win opportunities for both environmental and economic sustainability, which shed light on the government's green policy design.

The adsorption properties and mechanisms of magnetic carbon-silicon composites in situ prepared from coal gasification fine slag.

A novel magnetic carbon-silicon composite (Fe-HH-CGFS) was prepared from solid waste coal gasification fine slag (CGFS) by a two-step acid leaching and one-step chemical co-precipitation process, which was optimized using a 3-factor, 3-level Box-Behnken design and then analyzed for correlation. Fe-HH-CGFS was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), thermal gravimetric analysis (TGA), and vibrating sample magnetometer (VSM) measurements. The results demonstrated that Fe-HH-CGFS had a reverse spinel structure with an average particle size of 5.14 nm, exhibiting a microporous/mesoporous structure with a specific surface area (SSA) of 196.84 m2 g-1 and pore volume of 0.346 cm3 g-1. Furthermore, Fe-HH-CGFS could achieve 97.59% removal efficiency of rhodamine B (RhB) under the optimal conditions: an initial concentration of RhB of 100 mg L-1, an adsorption time of 60 min, and a dosage of Fe-HH-CGFS of 1.0 g L-1. The pseudo-second-order model and the Langmuir isotherm satisfactorily described the adsorption behavior. The results indicated that the RhB removal process was a single-molecule layer endothermic adsorption, which is dominated by chemical adsorption reactions. This work is expected to provide an alternative route for the high-value utilization of CGFS and offer a valuable insight for the recycling of other solid wastes, aligning with the green development concept of "treating wastes with wastes".

High-temperature potassium capture by ilmenite ore residue

In-situ alkali metals capture within the furnace is an effective method for mitigating issues such as fouling, slagging, agglomeration, and corrosion associated with the combustion of high-alkali fuels. Oxygen carrier aided combustion (OCAC) technology has been proposed to enhance the combustion efficiency of fluidized bed by replacing inert bed material with active oxygen carrier, demonstrating significant potential in preventing ash-related problems induced by alkali metals. From the perspective of coordinated disposal of solid waste and resource recycling, this study utilized ilmenite ore residue with a relatively low titanium grade as the active bed material in a fluidized bed. The high-temperature in-situ capture characteristics of potassium were investigated under both static and fluidized conditions. Characterization techniques such as ICP-OES, SEM-EDS, and TG-MS, were employed to unveil the behavior of potassium fixation in ilmenite. The results showed that ilmenite ore residue affects the decomposition temperature range and product distribution of K2CO3, thereby reducing the escape of potassium into the gas phase. Over 30 % of the injected potassium was captured in the first 6.5 h, and it remained at about 22.6 % after 19.5 h. Potassium tends to bond with titanium, forming stable KTi8O16 compounds. The high-temperature enrichment and migration mechanism of potassium in two primary mineral phases of ilmenite ore residue are proposed.

Mechanical behavior of silty-clayey lateritic soil stabilized with recycled municipal solid waste ash

Due to the ever growing need to incorporate ecofriendly and sustainable materials in construction projects, this research study was carried out with the purpose of exploring the feasibility of utilizing recycled municipal solid waste ash (RMSWA) as a sustainable material for stabilizing clayey lateritic soils (LS).The research was aimed at investigating the effect of incorporating varying amounts of RMSWA on the engineering properties of weak soils. Laterite specimens were incorporated with the varying ash contents at intervals of 3%, 6%, 9%, 12% and 15% as replacement levels, and tested for Atterberg limits, compaction and unconfined compressive strength (UCS) behavior. The scanning electron microscopic (SEM) test was conducted to determine the morphology changes in the soil when blended with RMSWA contents at curing ages of 1, 7 and 14 days. Based on the results of UCS test, stress - strain behavior, load - deformation relationships curves were also established and analyzed. Results from the Atterberg limit test revealed that the plastic index, plastic limit, liquid limit ranged between 1.6-11.9%, 20.6-24.5% and 26.1-35.0%. The maximum dry density of the samples increased with the ash inclusion, with the maximum dry density value of 2020Kg/m3 achieved at 6% ash inclusion, thus making it suitable in laterite stabilization.

Cordierite glass-ceramics prepared by multi-wastes

Glass-ceramics is prepared by selecting a suitable temperature system to heat the basic glass and controlling the temperature and time of nucleation and crystallization. Cordierite (2MgO·2Al2O3·5SiO2) belongs to the MgO-Al2O3-SiO2 series of glass-ceramics, which has excellent thermal shock resistance, excellent chemical stability, low thermal expansion, low dielectric constant, low dielectric loss, and low thermal conductivity. Because glass-ceramics have a variety of excellent properties, this technology, which has seen extensive development and application across numerous domains, holds significant untapped potential. Converting industrial slag and metallurgical waste into glass ceramics presents a novel strategy for the comprehensive recycling of solid waste. Among various industrial waste slags, coal gangue is the most prevalent of China’s industrial solid waste. Utilizing inexpensive coal gangue slag as a primary ingredient for producing high value-added glass ceramics can diminish pollution, safeguard the environment, and yield considerable economic and social advantages. This study utilizes coal gangue, high carbon chromium iron slag, and iron tailings as the main components, employing the fundamental attributes of sintering testing equipment to create samples of cordierite glass-ceramics. The impact of the basic glass mass, molding pressure, and duration of pressure application on the crystallinity and grain size of the glass-ceramics were evaluated using X-ray diffraction analysis. Findings indicate the optimal combination to be a basic glass powder mass of 6 grams, a molding pressure of 35 MPa, and a holding time of 10 minutes.

Development of Solid Waste Recycling Industry of China in the Context of Carbon Neutrality

Development of Solid Waste Recycling Industry of China in the Context of Carbon Neutrality

Діагностика перспектив розвитку підприємств з переробки ТПВ

The article diagnoses the prospects for the development of enterprises for the processing of solid household waste (SHW). It is specified that improving the quality of services provided by enterprises and the transition to European standards in the field of removal, utilization and processing of solid waste is a top priority, as Ukraine seeks to become a member of the EU in the future. It is noted that recycling is an important component of sustainable development and contributes to the creation of a more efficient and environmentally conscious economy for enterprises and the country. The most common types of solid waste recycling are presented, each of which is aimed at transforming a specific type of waste. The paper analyzes successful business cases that have already been implemented as a result of recycled solid waste and introduced into practice in other countries of the world. It is noted that some Ukrainian enterprises in collaboration with foreign partners have actively begun to implement similar cases. It is noted that a promising direction is the energy sector, which is currently also related to the processing of solid waste. It is noted that, even taking into account the active hostilities taking place on the territory of Ukraine, there are enterprises, organizations and institutions that are already actively working or just starting their business activities in the field of SHW processing. It is concluded that it is an important aspect, in particular, firstly, how the growing awareness of society about the problems of environmental pollution and the need to protect it creates a demand for environmentally friendly technologies and services, including waste recycling. Secondly, legislative and regulatory initiatives aimed at reducing waste and improving waste management create a favorable framework for the development of this sector. Thirdly, technological progress in the field of recycling makes it possible to create new products from waste and reduce the negative impact on the environment. Also, the development of this sector can stimulate investment and contribute to the creation of new jobs in the field of ecological economy. All this testifies to the potentially high investment attractiveness and prospects for the development of solid waste processing enterprises.

Investigating the solid waste recycling management

Abstract 
 Objective: Garbage is waste solid materials that are left over from the use of people and production and service institutions and are unusable. These seemingly inefficient sources are the most important urban pollutant in different amounts and in liquid and solid form and cause harm. and the citizens' interest, but in the case of optimal management and use of these valuable resources as raw materials in addition to protecting the environment, reducing the level of pollution, reducing the amount of diseases and deaths, it can be considered the best driver of production activities, recycling management Household solid waste in Kabul city is handled according to municipal standards and regulations (collection, transfer, burial and reuse), which is the main goal of this research to investigate the effects of household solid waste management and recycling in Kabul city.
 Method and tools: Since the nature of this research is descriptive-applicative, in order to collect information from two sources, the library and a questionnaire with a 7-point Likert scale from 384 citizens of the 15th district of Kabul city were randomly sampled and analyzed using spss software. First, the confidence level of the questionnaire of both variables was determined by Cronbach's alpha method with the output coefficient (waste management 0.86 and recycling rate 0.82) and then its correlation intensity was determined by the Pearson method and also to predict the dependent variable from the linear regression function of the information received and investigated. And the dispute has been placed.
 Finding: Pearson's correlation analysis with 95% confidence level of the number placement (p=0.004, N=384, R=0.86) with a coefficient of determination of 0.73 and a statistical value (t) of 4.76, which is greater than the critical value of table t 2.3, shows the relationship There is a strong positive among the variables and it states that the increase in the amount of recycling and the decrease in the consumption of family solid waste depends on the improvement of waste management, in the same way, the beta coefficient of 0.59 and t=7.31>1.96 and sig<0.05 of linear regression were obtained. It shows that improving family solid waste management will reduce the amount of waste consumption and recycling by 59%, also the extracted information shows that about 97% of household waste is bought and collected by informal garbage collectors.

Research on Mechanical and Shrinkage Characteristics of a Resource-Based Cement Solid-Waste Concrete.

Recycling of multi-source solid waste is of great benefit to energy conservation and environmental governance. In this paper, a new type of environmental protection concrete for railway accessory facilities was prepared from silicon-manganese slag, steel slag, fly ash and recycled macadam. Seven kinds of concrete with different mix proportions were designed. Through unconfined compressive strength, splitting, drying shrinkage and temperature shrinkage tests, the multivariate changing trends of steel slag content, cement dosage and age on the anti-interference ability of concrete were investigated. The main mechanisms of the development of mechanical and dry shrinkage properties were revealed by the hydration process of 3SR-60. The results show that 3SR-60 had better mechanical strength under the same cement dosage. The temperature shrinkage strain decreased and then increased with the rise of the proportion of waste residue, increased with the addition of cement dosage and decreased first and then increased with the descent in the temperature. The temperature shrinkage coefficient reached the lowest value at 0-10 °C. The drying shrinkage coefficient decreases with the increase in the proportion of waste residue and increases with the increase in cement dosage. The dry shrinkage strain increased rapidly during the first 8 days and became almost constant after 30 days. Cementation of calcium silicate hydrate (C-S-H) and ettringite (AFt) developed continuously and filled the internal pores of the structure, interlocking and cementing with each other, which made the microstructure develop from a three-dimensional network to a dense complex, and the macro dimension was reflected in the enhancement of the power to resist external interference. The conclusion of the test summarized that SR-60 had preferable mechanical and shrinkage performance.

Co-pretreatment (calcium peroxide + freeze) to improve anaerobic fermentation of waste activated sludge: Method optimization and mechanism insights

The reduction, harmlessness, and recycling of waste-activated sludge (WAS) can be accomplished by anaerobic fermentation, where sludge disintegration is the key speed-limiting process. Co-pretreatment, as a derivative of pretreatment, has attracted more and more attention. However, obtaining optimal co-pretreatment conditions is difficult. Response surface methodology (RSM) can combine statistical analysis with mathematics to optimize the parameters. Therefore, in the current work, RSM optimization for CaO2-freezing co-pretreatment conditions to improve the production of short-chain fatty acids (SCFAs) from WAS was carried out using the Box-Behnken Design based on Design Expert software. We obtained the optimal values of three pretreatment parameters: −18 °C freezing temperature, 48.6 h freezing time, and 0.19 g CaO2/g VSS addition. After 5 days of fermentation, the maximum cumulative yield of SCFAs was 162.34 mg COD/g VSS. CaO2-freezing co-pretreatment promoted the solubilization and release of organic matter in WAS during anaerobic fermentation, which not only provided more organic matter for the subsequent production of SCFAs but also improved the methane production capacity in the anaerobic digestion stage. 16S rRNA genes sequencing revealed that the abundance of SCFAs-producing bacteria (i.e., Macellibacteroides and Proteiniclasticum) was significantly enriched in the fermentation tank after CaO2-freezing co-pretreatment. All in all, this study successfully optimized the co-pretreatment conditions based on RSM, providing new insights and effective solutions for the environmentally friendly and efficient realization of solid waste recycling.