Method for producing planting soil by using titanium gypsum and wet organic garbage

Abstract

The invention belongs to the field of solid waste resource utilization, and particularly relates to a method for producing planting soil by utilizing titanium gypsum and wet organic garbage. The method specifically comprises the following steps: taking titanium gypsum and organic garbage as main materials, uniformly mixing the main materials with auxiliary materials and a functional bacterial agent, and then performing composting treatment; the functional bacterial agent is characterized in that a bacterial strain in the functional bacterial agent comprises a fungus of the genus Plectosphaerellaceae, and the fungus of the genus Plectosphaerellaceae is used as a culture medium. According to the invention, the titanium gypsum is directly introduced into the composting process and is combined with the wet organic garbage for treatment, so that not only is a large amount of waste resources effectively utilized, but also nutrient elements such as calcium, sulfur and iron can be added to the compost product, and the growth of crops is facilitated; besides, the complementary characteristics of the raw materials are utilized, and the dosage ratio of the raw materials is limited, so that the compost body has proper physicochemical properties such as moisture, organic matters and carbon nitrogen ratio, and the quality of a compost product is improved. Meanwhile, the proportion can consume the titanium gypsum on a large scale, so that the problem of on-site stacking of the titanium gypsum is relieved to a great extent, and the land pressure is relieved.

Description

Technical Field

[0001] This invention belongs to the field of solid waste resource utilization, specifically relating to a method for producing planting soil using titanium gypsum and wet organic waste. Background Technology

[0002] Food waste and municipal sludge are wet organic wastes, which are organic solid wastes generated by human activities. Titanium gypsum, as a common industrial byproduct, is piled up in large quantities because it cannot be fully utilized. With urban development and the significant increase in the living standards and industrial levels of Chinese residents, the safe disposal of the ever-growing volume of wet organic waste and titanium gypsum has become an unavoidable challenge for the environmental protection industry.

[0003] Food waste is easily perishable and difficult to transport; sludge has limited disposal technologies and a low resource utilization rate, and improper treatment can cause serious environmental problems. Although both have similar characteristics of high water content and high organic matter content, there is a lack of effective combined treatment technologies. Titanium gypsum is characterized by high water content, high viscosity, and high impurity content, making it difficult to use directly; currently, its comprehensive utilization rate is only 10%. The disposal difficulties of titanium gypsum affect the economic benefits of the titanium dioxide industry, occupy land resources, and pollute water and air.

[0004] Composting technology transforms organic resources into stable humus through the physiological activities of relevant microorganisms, which can then be used to produce bio-fertilizers for soil improvement and crop cultivation. This technology can safely and effectively recover organic matter from wet organic waste, creating significant economic and environmental benefits.

[0005] While wet organic waste possesses abundant organic resources, its low porosity makes it unsuitable for composting alone. Current research has confirmed the potential of titanium gypsum as a soil conditioner. Combining wet organic waste with titanium gypsum for composting not only recycles the organic matter from the former but also solves the problems of low economic efficiency and long-term idleness of the latter when disposed of alone.

[0006] Existing technology CN117356393A discloses a method for producing plant growth nutrient soil from industrial waste residue. This method involves neutralizing phosphogypsum and titanium gypsum, calcining the mixture at high temperature, and then mixing it with red mud biochar and peat moss for composting to produce the nutrient soil. However, this method has at least the following drawbacks:

[0007] 1. High-temperature calcination consumes a large amount of energy, which is not conducive to energy conservation and environmental protection;

[0008] 2. Wet organic waste is not being utilized;

[0009] 3. The utilization rate of titanium plaster is not high.

[0010] Therefore, it is still necessary to develop a resource utilization method that consumes less energy and can consume large quantities of wet organic waste and titanium gypsum. Summary of the Invention

[0011] The purpose of this invention is to overcome the above shortcomings and provide a method for producing planting soil using titanium gypsum and wet organic waste, which solves the problem of long-term idle titanium gypsum while recycling wet organic waste.

[0012] The objective of this invention is achieved through the following technical solution:

[0013] A method for producing planting soil using titanium gypsum and organic waste, wherein titanium gypsum and organic waste are used as the main materials, and the main materials are mixed with auxiliary materials and functional microbial agents and then composted.

[0014] The microbial species in the functional microbial agent include fungi of the genus Plectosphaerellaceae.

[0015] The hyphae of fungi in the genus *Arbuscular mycorrhizosum* can interact with plant root cells in a mutually beneficial way. The plant provides carbon and energy to the fungi in the form of carbohydrates, while the fungi provide essential minerals to the root cells. *Arbuscular mycorrhizosum* and *Arbuscular mycorrhizosum* play a bidirectional regulatory role in nutrient transfer within plant roots, such as nitrogen-phosphorus interactions. They form symbiotic relationships (AMS) with *Arbuscular mycorrhizosum*, where the fungi transfer phosphorus (P) and other elements (such as nitrogen) to the host plant, exchanging organic carbon in the form of fatty acids and hexoses.

[0016] In some implementations, the organic waste includes municipal sludge and kitchen waste in a mass ratio of 1-3:1.

[0017] In some implementations, the mass ratio of titanium gypsum to organic waste in the main material is 15-30:8.

[0018] In some implementations, the auxiliary material includes corn stalks.

[0019] In some implementations, the mass ratio of the main ingredient, the auxiliary ingredient, and the functional microbial agent is 23-30:4:3-4.

[0020] In some embodiments, the method for preparing the functional microbial agent includes:

[0021] Fresh chicken manure, municipal sludge, sawdust and biochar were mixed evenly at a fresh weight ratio of 4-6:1-2:1-2:1-2 to obtain a mixed compost.

[0022] The mixed material was transferred to a compost bin and covered with a nanofilm.

[0023] The mixed stockpile is maintained at a temperature of 60-70°C and a moisture content of 75-85% for 13-18 days to obtain cultured material. During the culture period, the mixed stockpile is intermittently ventilated.

[0024] Take 4-5 parts by weight of the culture material and add it to a container containing 2-3 parts glucose, 4-5 parts peptone and 8-10 parts titanium gypsum. Culture at 60-70℃ for 5-7 days to obtain the functional bacterial agent.

[0025] In some embodiments, when the intermittent ventilation is performed on the mixed stockpile, the interval between two ventilations is 10-15 minutes, the duration of a single ventilation is 10-20 minutes, and the ventilation volume is 0.2-0.6 L·kg DM. -1 min -1 .

[0026] In some embodiments, the microbial species in the functional microbial agent also include: thermophilic schistosomes, rhizobia, Bacillus aquaticus, Bacillusaceae, Thermo-actinomycetes, and Debarlosaceae.

[0027] In some embodiments, the viable count of the functional microbial agent is 1500-2500 CFU / g.

[0028] In some implementations, the composting process includes the following steps:

[0029] The main material, the auxiliary material and the functional microbial agent are mixed evenly to obtain a pile;

[0030] The pile was transferred to a compost bin and covered with a nanofilm.

[0031] Fermentation lasts 25-35 days, during which the pile is intermittently ventilated.

[0032] In some embodiments, when the intermittent ventilation is performed on the stack, the interval between two ventilations is 10-20 minutes, the duration of a single ventilation is 10-20 minutes, and the ventilation volume is 0.2-0.5 L·kg DM. -1 min -1 .

[0033] The present invention also provides planting soil obtained by the above method.

[0034] The beneficial effects of this invention are:

[0035] 1. Titanium gypsum, as an industrial waste with no leaching toxicity, contains rich plant nutrients. This invention introduces titanium gypsum directly into the composting process and treats it together with wet organic waste. This not only makes effective use of a large amount of waste resources, but also adds nutrients such as calcium, sulfur, and iron to the compost products, which is beneficial to crop growth.

[0036] 2. This invention utilizes the complementary properties of the raw materials and, by limiting their respective proportions, achieves suitable physicochemical properties in the compost pile, such as moisture, organic matter, and carbon-nitrogen ratio, which is beneficial for improving the quality of compost products. Simultaneously, this proportion allows for large-scale consumption of titanium gypsum, significantly alleviating the problem of on-site titanium gypsum disposal and reducing land pressure.

[0037] 3. The functional microbial agent used in the composting process of this invention contains Plectosphaerellaceae fungi, which is a microbial community not found in existing bulk industrial solid waste composts. The presence and quantity of this fungus determine the quality of the compost. Compared with commercial microbial agents on the market, the microbial community of this invention has the following advantages: (1) it increases the maximum fermentation temperature to a maximum of 69.5℃; (2) it maintains the high-temperature stage (50-65℃) in the compost for a longer period of time; (3) it can produce more dissolved organic matter (DOM); (4) it can produce more humic acid-like substances.

[0038] 4. The composting method of the present invention combines the advantages of open aerobic fermentation and closed aerobic fermentation. It has low investment and maintenance costs, is easy to operate, and is flexible in use, making it cost-effective. It can effectively solve the problems of long fermentation cycle and odorous gas emission in traditional composting treatment. Attached Figure Description

[0039] Figure 1 This is a schematic diagram and physical image of the composting device used in the composting process of this invention.

[0040] Figure 2 This is a diagram showing the state of the material before and after composting in Embodiment 1 of the present invention;

[0041] Figure 3 The graph shows the temperature change of the pile body over time in each experimental example of the present invention.

[0042] Figure 4 This is a graph showing the change in carbon-nitrogen ratio of the stack in each experimental example of the present invention over time;

[0043] Figure 5 The changes in the germination index of the materials in each experimental example of the present invention before and after composting;

[0044] Figure 6 This is a three-dimensional fluorescence spectrum of the DOM (Dissolved Oxygen Deposition) of the compost pile at different composting stages, as shown in Embodiment 1 of the present invention.

[0045] Figure 7 This is a three-dimensional fluorescence spectrum of the DOM (Dissolved Oxygen Deposition) of the compost pile at different composting stages, as shown in Comparative Example 1 of this invention.

[0046] Figure 8 This is a comparative example 2 of the present invention, showing the DOM three-dimensional fluorescence spectrum of the compost pile at different composting stages;

[0047] Figure 9 This is a comparative example 3 of the present invention, showing the DOM three-dimensional fluorescence spectrum of the compost pile at different composting stages;

[0048] Figure 10 The standard region integral P of the fluorescence region at different composting stages in each experimental example of this invention is given by [the relevant data point]. i,n Change diagram;

[0049] Figure 11 The bacterial community composition of each experimental example of the present invention under different composting periods;

[0050] Figure 12 This is an analysis of bacterial alpha diversity in each experimental example of the present invention;

[0051] Figure 13 The fungal community composition of each experimental example of the present invention under different composting periods;

[0052] Figure 14 This is an analysis of fungal alpha diversity in each experimental example of the present invention. Detailed Implementation

[0053] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0054] Composting equipment:

[0055] As attached Figure 1 As shown, the composting device constructed by this invention mainly consists of three parts:

[0056] The main body consists of a PVC composting bin (680mm long, 470mm wide, and 385mm high). The second part is a rectangular ventilation duct system consisting of three 550mm long and six 150mm long stainless steel pipes (inner diameter: 10mm) arranged at the bottom of the PVC bin. Each pipe has 3mm diameter ventilation holes spaced 50mm apart on both sides to ensure uniform airflow. The third part is an air pump connected to the outside of the bin via ventilation ducts, which forces airflow into the bin. During operation, a nanofilm covers the top of the bin, creating a semi-sealed environment. The device includes a built-in stainless steel probe digital thermometer for real-time monitoring of the composting temperature.

[0057] Raw material source:

[0058] Urban sludge: collected from a wastewater treatment company in Chongqing;

[0059] Food waste: collected from the canteen of Chongqing Academy of Chinese Academy of Sciences;

[0060] Titanium gypsum: It was collected from a titanium dioxide company. Because titanium gypsum is stored in the open air all year round, it exists in two forms: air-dried and fresh.

[0061] Corn stalks: purchased locally in Chongqing;

[0062] Commercial microbial agent: Beihai Qiangxing Biotechnology Co., Ltd. (Beihai City, Guangxi Province), mainly composed of soil functional bacteria, filamentous fungi, yeast and other effective substances.

[0063] Functional microbial agents:

[0064] Autonomous domestication, specifically the domestication process is as follows:

[0065] Fresh chicken manure (source: Chongqing Fengdu Deqingyuan Chicken Farm), urban sludge, sawdust and biochar were mixed evenly at a fresh weight ratio of 5:1:2:1 to obtain 30 kg of mixed compost.

[0066] The mixed material was transferred to a compost bin, covered with a nanofilm, and the area around the compost was buried with fine sand.

[0067] The mixed stockpile was maintained at a temperature of 60-70℃ and a moisture content of 80% for 15 days to obtain the cultured material. During the culture period, the mixed stockpile was intermittently ventilated, with an interval of 15 minutes between two ventilations and a single ventilation time of 10 minutes. The ventilation volume was 0.4 L·kg DM. -1 min -1 ;

[0068] Take 500g of the culture material and add it to a fermenter containing 200g of glucose, 500g of peptone and 1000g of titanium gypsum. Culture the mixture at 60-70℃ for 7 days to obtain the functional microbial agent.

[0069] The physicochemical properties of each raw material are shown in Table 1 below.

[0070] Table 1

[0071]

[0072]

[0073] Example 1: Group A

[0074] A method for producing planting soil using titanium gypsum and organic waste involves taking 15 parts by weight of fresh titanium gypsum and 8 parts by weight of organic waste as the main materials, mixing the main materials with 4 parts of corn stalks and 3 parts of the above-mentioned functional microbial agent, and then performing composting treatment.

[0075] The organic waste is urban sludge and kitchen waste in a 1:1 mass ratio.

[0076] The composting process includes the following steps:

[0077] The main material, the auxiliary material and the functional microbial agent are mixed evenly to obtain a 30kg pile.

[0078] The pile is transferred to the PVC compost bin, and a nanofilm is used to cover the top of the compost bin.

[0079] Composting is carried out for 30 days. During the composting period, the compost pile is intermittently ventilated using an air pump. The interval between two ventilations is 10 minutes, and the duration of each ventilation is 10 minutes. The ventilation volume during ventilation is 0.2 L·kg DM. -1 min -1 .

[0080] After composting, the planting soil is obtained.

[0081] Figure 2 This is a diagram showing the state of the material before and after composting in this embodiment.

[0082] Comparative Example 1: Group B

[0083] A method for producing planting soil using titanium gypsum and organic waste differs from Example 1 in that the functional microbial agent is replaced with the aforementioned commercial microbial agent, while the remaining steps remain unchanged.

[0084] Comparative Example 2: Group C

[0085] A method for producing planting soil using titanium gypsum and organic waste differs from Example 2 in that fresh titanium gypsum is replaced with air-dried titanium gypsum, while the other steps remain unchanged.

[0086] Comparative Example 3: CA Group

[0087] A method for producing planting soil using titanium gypsum and organic waste involves taking 15 parts of fresh titanium gypsum and 8 parts of organic waste as the main materials, mixing the main materials with 4 parts of corn stalks, and then composting them.

[0088] The organic waste is urban sludge and kitchen waste in a 1:1 mass ratio.

[0089] The difference between Comparative Example 3 and Example 1 is that no external microbial agent is added, while the rest, such as the composting treatment steps, are the same.

[0090] Appendix Figure 3 The figure shows the temperature changes of the compost piles in each group of experimental examples during the composting process. In the figure, a represents group A, b represents group B, c represents group C, d represents group CA, and e represents the average temperature of each group. It can be seen that the temperature changes in the four groups are consistent, all experiencing stages of heating, high temperature, cooling, and maturation. The high temperature period (≥50℃) lasted for more than three days, meeting the general requirements for sustained high temperature in composting treatment, effectively killing pathogens in the compost. In comparison, group A maintained the high temperature stage (50-65℃) for a longer time; group C experienced a sudden drop and then rise in temperature, possibly because the air-dried titanium gypsum has poor water retention, and the rapid decrease in moisture content led to microbial inactivation, resulting in a temperature drop. Subsequently, because the nanofilm slowed down water evaporation, once the moisture content stabilized, the microorganisms became active again, using organic matter to reproduce, causing the temperature to rise again.

[0091] The basic physicochemical properties of the planting soil obtained from the above examples were measured, and the results are shown in Table 2 below.

[0092] Table 2

[0093]

[0094] As shown in Table 2, the conductivity of the planting soil in each group was below the standard limit of 4 mS / cm, indicating that it was non-toxic to plants. Regarding ammonia nitrogen levels, group A showed increases of 137%, 51%, and 79% compared to groups B, C, and CK, respectively. Ammonia nitrogen levels can be used to evaluate the degree of organic matter mineralization and ammonification in compost; therefore, the organic matter mineralization and ammonification effects of Example 1 were superior to the comparative example. Furthermore, after 30 days of composting, the germination rate of the planting soil in all four examples exceeded 80%, indicating that the compost product had reached the maturity standard and was non-toxic to seeds.

[0095] Figure 4 The data shows the decreasing trend of the carbon-nitrogen ratio in the compost piles of the four groups of examples. It can be seen that the decreasing rate is the most obvious in group A, and the final carbon-nitrogen ratio of the planting soil is the lowest. A lower carbon-nitrogen ratio means a better degree of composting maturity. It is evident that the degree of maturity of Example 1 is higher than that of the other comparative examples.

[0096] Figure 5 The changes in the germination index of materials before and after composting are shown for four sets of examples.

[0097] Dissolved organic matter (DOM) plays a crucial role in material migration and transformation, and is an important component of energy supply and material cycling in ecosystems. Some studies suggest that composting is essentially a process of organic matter stabilization and humification occurring in the aqueous phase; therefore, DOM is considered the most actively transformed part of the composting system. DOM mainly consists of two parts: bioactive substances such as amino acids and carbohydrates, which are easily decomposed by microorganisms; and humic substances, including humic acid and fulvic acid, which are more difficult for microorganisms to decompose. Studying the evolutionary characteristics of DOM using three-dimensional fluorescence spectroscopy provides valuable insights into the transformation process of compost organic matter and the assessment of compost maturity.

[0098] This invention collects samples from each compost pile on days 0, 1, 9, and 30, and uses a fluorescence spectrometer to measure the DOM extract from the samples. Three-dimensional fluorescence spectroscopy and related data processing tools are used to quantitatively and qualitatively characterize the DOM.

[0099] Appendix Figure 6-9 The three-dimensional fluorescence spectra of the DOM (Dissolved Oxygen Spectroscopy) of the samples at different composting stages are shown. The spectra reveal five types of fluorescence peaks, totaling six peaks, in the three-dimensional fluorescence spectra of the DOM at different composting stages for the four groups of samples. Based on the regional division of the three-dimensional fluorescence spectra, peak A (E...) is identified as... x / E m =200 / 320), B(E) x / E m =220 / 340), C(E) x / E m =215 / 410) belong to tyrosine-like, tryptophan-like, and fulvic acid-like substances, respectively. Peak D1 (E x / E m =275 / 430), D2(E x / E m =330 / 420) belongs to humic acid-like substances. Peak E (E x / E m=275 / 330) belongs to soluble microbial metabolites. In the four treatment groups, the changes in DOM (Dissolved Oxygen Species) showed similar patterns with increasing composting time. In the early stages of composting, peaks A and B had the highest fluorescence intensity, while peaks C and E had weaker fluorescence, and peak D was very weak or absent. As composting entered the high-temperature phase, the fluorescence intensity of peak C significantly increased, and peak D began to form. In the middle and late stages of composting, the fluorescence intensity of peaks C and D continued to increase, indicating that the content of fulvic acid-like and humic acid-like substances gradually increased with the progress of composting. Simultaneously, the fluorescence intensity of peaks A and B decreased, reflecting the decomposition of protein-like substances by microorganisms and the increased accumulation of humic substances. Throughout the composting process, the fluorescence intensity of peak E generally decreased, indicating that soluble microbial metabolites were also gradually degraded by microorganisms. These changes are consistent with the general pattern of DOM evolution during composting.

[0100] The integral standard volume (Pi) of each fluorescence region i in the three-dimensional fluorescence spectrum was analyzed and calculated using the fluorescence region integration (FRI) method. i,n This method quantifies three-dimensional fluorescence spectral data, allowing for a more intuitive observation of the changes in various fluorescence regions at different composting stages through numerical analysis (see appendix). Figure 10 In the diagram, 'a' represents group A, 'b' represents group B, 'c' represents group C, and 'd' represents group CA. Figure 10 It is evident that the overall variation patterns of the integrated volume in each fluorescence region are consistent across the four compost groups. Regions I and II (representing tyrosine-like and tryptophan-like proteins, respectively) show a decreasing trend, consistent with the weakening fluorescence intensity of peaks A and B within the corresponding regions, indicating that these two substances are oxidized and decomposed by microorganisms during composting. Regions III and V (representing fulvic acid-like and humic acid-like substances, respectively) gradually increase, also consistent with the increasing fluorescence intensity of peaks C and D, suggesting that fulvic acid-like and humic acid-like substances accumulate and are generated during composting, gradually increasing the degree of aromatization and humification, and the compost tends to stabilize. For groups A, B, C, and CK, from the start to the end of composting, the integrated volume of region I, P... Ⅰ,n The reductions were 31.13%, 22.21%, 34.66%, and 26.96% respectively (C > A > CK > B), and the integral region P of region II... Ⅱ,n The reductions were 34.68%, 30.42%, 24.43%, and 20.12% respectively (A>B>C>CK), and the integral region P of region III. Ⅲ,n The percentages increased by 98.00%, 93.85%, 85.54%, and 54.40% respectively (A>B>C>CK), and the integration region P of region V... Ⅴ,nThe increases were 186.11%, 118.96%, 136.18%, and 72.05%, respectively (A > C > B > CK). Overall, groups A, B, and C showed better performance than the control group CK in terms of humus formation and organic matter degradation, especially treatment group A, which showed the highest humus increase rate and the most effective organic matter degradation capacity.

[0101] Regarding the bacterial community, the bacterial community composition of each example at different composting stages is as follows: Figure 11 As shown in the figure, a represents the phylum-level community structure, and b represents the genus-level community structure. Figure 11 The analysis of relative abundance at the phylum level showed that the dominant phyla were Firmicutes, Proteobacteria, Actinobacteriota, Bacteroidetes, Chloroflexi, and Acidobacteriota. The first four phyla accounted for over 80% of the total relative abundance in all samples, meaning that Firmicutes, Proteobacteria, Actinobacteria, and Bacteroidetes were the dominant phyla in each group's representative period. This result indicates that the addition of exogenous bacterial agents has little impact on the relative abundance of the bacterial community at the phylum level. The relative abundance trends of Firmicutes in the four groups were quite similar: increasing during the high-temperature period and gradually decreasing during the cooling and decomposition periods. According to related reports, this phylum is tolerant of high temperatures; therefore, it was the dominant phylum with a relative abundance of over 76% during the high-temperature period in all four groups.

[0102] At the bacterial genus level, the dominant genera in both commercial and functional bacterial agents included *Bacillus*, *Weissella*, *Ureibacillus*, *Saccharomonospora*, *Geobacillus*, *Pseudomonas*, *Thermobifida*, and *Lactococcus*. Among the top 15 most abundant genera, there were 11 Firmicutes, 2 Actinobacteria, and 1 each of Bacteroidetes and Proteobacteria. In the control group (CK), *Weissella* had a high relative abundance of 73.12%, but its community structure diversity was lower compared to the other three groups at the same time point. This was also reflected in the Shannon index, verifying that the addition of bacterial agents can increase bacterial species diversity. During the high-temperature period, *Lactococcus lactis* was the dominant bacterial group, with its relative abundance in the order A>CK>B>C. The changes in *Bacillus* showed a similar overall trend across the four treatment groups: initially increasing and then decreasing in relative abundance as the temperature decreased. Therefore, peak relative abundance was reached in groups A1, B1, and C1, at 33.86%, 13.99%, and 28.68%, respectively. The overall relative abundance of *Bacillus* in group A was higher than that in group B.

[0103] Figure 12 The figure shows the bacterial alpha diversity analysis for each group of examples. In the figure, a is the Shannon index and b is the Chao index.

[0104] Studies have shown that thermophilic bacteria such as Bacillus and Ureaplasma can produce a variety of thermostable enzymes, enabling them to degrade lignocellulose and other recalcitrant organic matter even at high temperatures. Due to their thermophilic or heat-resistant characteristics, these bacteria are stimulated by rising temperatures, thus promoting organic matter degradation and prolonging the duration of the thermophilic phase. Perhaps because Bacillus is more heat-resistant than Ureaplasma, the high-temperature phase in group A, where Bacillus was the dominant genus, lasted longer than in group B, where Ureaplasma was the dominant genus. Bacillus and Pseudomonas are the main ammonifying and denitrifying bacteria, and as important drivers of ammonification and denitrification, they are crucial for nitrogen conversion in compost. Reports indicate that changes in ammonia nitrogen are related to the quantity and activity of Bacillus. Among the four treatments, the highest relative abundance peak of Bacillus in group A is consistent with the highest pH peak in group A. As the composting process neared its end, the temperature gradually decreased, and community diversity gradually recovered. *Saccharomyces* gradually became the new dominant species, while *Weissella*, which was dominant in the early stages, almost completely disappeared by days 9 and 30 of all composting. *Weissella*, a common functional bacterium during composting, was the dominant genus in the high-temperature phases of groups CK, A, and B. It can ferment sugars into lactic acid, which may explain the low pH at the beginning of composting. During the high-temperature phase, *Bacillus* and *Weissella* were both dominant bacteria, but the pH of the compost pile increased significantly, possibly indicating that ammonification products outweighed acidification products at this point. In the natural environment, lactic acid bacteria can stabilize plant and animal waste and degrade complex organic matter such as lignin and cellulose. Some researchers have found that biofertilizers containing a mixture of *Bacillus* and lactic acid bacteria enhance the degradation of organic matter, and some *Bacillus* species in the soil can increase the relative abundance of lactic acid bacteria, showing a certain synergistic effect between the two.

[0105] Regarding the fungal community, the fungal community composition in each example at different composting stages is as follows: Figure 13 As shown in the figure, a represents the phylum-level community structure, and b represents the genus-level community structure. Analyzing the relative abundance of the fungal community at the phylum level, the dominant phyla are relatively singular. Ascomycota, Basidiomycota, SAR supergroup, and Mucoromycota account for more than 99% of the relative abundance of the fungal community. Among them, Ascomycota are aerobic fungi and are the largest group of fungi, with a relative abundance of more than 91.63% in compost at various stages in different experimental groups.

[0106] Observing the fungal community structure at the genus level, the top ten abundant genera all belonged to Ascomycota. The abundance of dominant genera varied significantly across groups and time periods, indicating that both functional and commercial inoculants significantly altered the fungal community structure in the composting environment. *Debaryomycetaceae* was the dominant genus in groups CK and A on days 0 and 1, with its relative abundance peaking on day 1 (the high-temperature period) at 70.28% and 38.18%, respectively, before rapidly decreasing to almost disappearing. The relative abundance of thermophilic fungi (*Thermomyces*) showed a consistent pattern across groups A, B, C, and CK, initially increasing and then decreasing, peaking on day 9 at 35.14%, 9.45%, 64.47%, and 40.85%, respectively. In groups B and C, the dominant genera were similar in the early and middle stages of composting, with *Saccharomycetaceae* being the most dominant genus. Microascales were the dominant genus in all four groups on day 30, with relative abundances of 57.72%, 92.48%, 42.99%, and 67.86% in groups A, B, C, and CK, respectively.

[0107] In addition to the bacteria and fungi shared with commercial microbial agents, Group A also includes a unique genus of fungi derived from the functional microbial agent, *Plectosphaerellaceae*. Although the abundance of this fungal species varies throughout the fermentation cycle, it persists throughout the entire process, participating from the beginning of composting to the high-temperature stage and the later stages of fermentation. This fungus is alkali-resistant and heat-resistant, overcoming the inherent alkaline pH of titanium gypsum. Furthermore, when working in synergy with filamentous ascomycetes, it can metabolize complex organic matter such as plant and animal residues. Therefore, the presence of this fungus plays a crucial role in the successful composting of titanium gypsum in conjunction with wet organic waste. Compared to commercial microbial agents, the microbial community of this invention has the following advantages: (1) it achieves a higher maximum fermentation temperature, reaching up to 69.5°C; (2) it maintains the high-temperature stage (50-65°C) in the compost for a longer period; (3) it produces more dissolved organic matter (DOM); and (4) it produces more humic acid-like substances.

[0108] Figure 14 The figure shows the fungal alpha diversity analysis for each group of examples. In the figure, a is the Shannon index and b is the Chao index.

[0109] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A method for producing planting soil using titanium gypsum and organic waste, characterized in that, Titanium gypsum and organic waste are used as the main materials. The main materials are mixed with auxiliary materials and functional microbial agents and then composted. The microbial species in the functional microbial agent include fungi of the genus Plectosphaerellaceae.

2. The method for producing planting soil using titanium gypsum and organic waste according to claim 1, characterized in that, The organic waste includes municipal sludge and kitchen waste in a mass ratio of 1-3:

1.

3. The method for producing planting soil using titanium gypsum and organic waste according to claim 1, characterized in that, In the main material, the mass ratio of titanium gypsum to the organic waste is 15-30:

8.

4. A method for producing planting soil using titanium gypsum and organic waste according to claim 1, characterized in that, The auxiliary material includes: corn stalks.

5. A method for producing planting soil using titanium gypsum and organic waste according to claim 1, characterized in that, The mass ratio of the main ingredient, the auxiliary ingredient, and the functional microbial agent is 23-30:4:3-4.

6. A method for producing planting soil using titanium gypsum and organic waste according to claim 1, characterized in that, The preparation method of the functional microbial agent includes: Fresh chicken manure, municipal sludge, sawdust and biochar were mixed evenly at a fresh weight ratio of 4-6:1-2:1-2:1-2 to obtain a mixed compost. The mixed material was transferred to a compost bin and covered with a nanofilm. The mixed stockpile is maintained at a temperature of 60-70°C and a moisture content of 75-85% for 13-18 days to obtain cultured material. During the culture period, the mixed stockpile is intermittently ventilated. Take 4-5 parts by weight of the culture material and add it to a container containing 2-3 parts glucose, 4-5 parts peptone and 8-10 parts titanium gypsum. Culture at 60-70℃ for 5-7 days to obtain the functional bacterial agent.

7. A method for producing planting soil using titanium gypsum and organic waste according to claim 6, characterized in that, When intermittently ventilating the mixed stockpile, the interval between two ventilations is 10-15 minutes, the duration of a single ventilation is 10-20 minutes, and the ventilation volume is 0.2-0.6 L·kg DM. -1 min -1 .

8. A method for producing planting soil using titanium gypsum and organic waste according to any one of claims 1-7, characterized in that, The composting process includes the following steps: The main material, the auxiliary material and the functional microbial agent are mixed evenly to obtain a pile; The pile was transferred to a compost bin and covered with a nanofilm. Fermentation lasts 25-35 days, during which the pile is intermittently ventilated.

9. A method for producing planting soil using titanium gypsum and organic waste according to claim 8, characterized in that, When intermittent ventilation is performed on the pile, the interval between two ventilations is 10-20 minutes, the duration of a single ventilation is 10-20 minutes, and the ventilation volume is 0.2-0.5 L·kg DM. -1 min -1 .

10. The planting soil obtained by the method according to any one of claims 1-9.

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