“Waste soil siege” is a major obstacle to rapid urbanization in China, posing potential safety hazards to the surrounding environment due to the landslide of landfills. In terms of the complexity of the landslide risk assessment of landfills, a method to evaluate the landslide risk level of landfills was proposed. In this method, the characteristics of waste soil and landslides were considered in each physical process of landslide risk assessment in a qualitative and semi-quantitative way. The method established a corresponding relationship between the slope safety factor and the failure probability grade, which divided the failure probability and damages of the landfill slope into four grades of extremely high, high, medium, and low, meanwhile， a risk level matrix of 4×4 was established. Landslide risk control countermeasures for the entire process of landfill construction were proposed, including site selection, construction and management, monitoring and early warning, as well as emergency response. A landfill in Hangzhou was taken as an example to illustrate the application of this method in an actual site. Through the slope stability analysis, migration distance estimation, and damage result statistics of the study area, the landslide risk level of the landfill after the filling was evaluated.

With the accelerated urbanization process in China, the remediation of existing informal landfills has become an imminent task. In-situ excavation and sorting disposal technology offered a dual advantage of releasing land resources and permanently eliminating potential sources of pollution, making it widely applied in practical engineering projects. Conventional sorting disposal technologies often had limitations such as a single sorting system, frequent clogging during the process, poor sorting quality, and low efficiency and capacity. A landfill was taken as an example, and the characteristics of aged waste at the landfill was considered, a refined sorting process was proposed, which could effectively reduce the impurity content of the sorted product and the frequency of clogging during the sorting process, thereby improving the sorting efficiency and capacity. At the same time, the existing issues of current sorting disposal technologies were analyzed, and prospects were discussed, so as to provide reference for landfill site sorting and disposal models.

The overall technical routes of “landfill rapid stabilization＋cleaning and excavation＋waste screening＋terminal classification and disposal” combined with “outbound transportation resource utilization” were adopt to carry out the waste treatment and disposal work. The rapid stabilization equipment was operated for two months, and the methane gas concentration ranged from 0.01% to 20.44% to below 3%. Reducing the moisture content of screened waste could improve the screening efficiency, and when the moisture content was lower than 13%, the efficiency was fourteen percentage points higher than the moisture content of about 30%. The leachate that was treated with NaClO, PAC and PAM met the discharge standards. In the process of resource conversion of humus soil, the blending ratio of 40% humus soil could meet the requirement of MU10 strength grade of GB/T 5101—2003 Fired Common Brick. The scale of the waste treatment project was about 180 000 square meters and the total investment was about 135 million yuan. Increasing the air-drying area of waste could provide more low moisture content waste, thus improving the efficiency and volume of waste screening. Because of the uneven distribution of the waste, the rapid stabilization time needs to be longer than the theoretical calculation time.

The interaction of co-pyrolysis of plastic, textile, leather and sponge, which were typical combustible components of automotive shredding residues, was investigated using thermogravimetry-mass spectrometry (TG-MS) and distributed activation energy model (DAEM). The characteristics of pyrolysis weight loss, kinetics and gas production were discussed. The results indicated that interactions existed among all four components, as evidenced by a comparison of the single-component linear weighted fit data and the mixed pyrolysis experimental data. Specifically, the average activation energy of textile and leather, sponge and plastic, sponge and textile co-pyrolysis decreased by 22.2, 25.7 and 33.4 kJ/mol, respectively. In contrast, the average activation energy of sponge and leather co-pyrolysis increased by 7.9 kJ/mol. The participation of sponge could promote the generation of small molecule gases in the mixed sample, while leather, textile and sponge co-pyrolysis could prevent the irregular chain-breaking reaction of plastic to generate small molecule hydrocarbons such as C2H4 and C3H8.

In order to study the transfer and transformation of Zn and Pb under different working conditions and solid matrix components during the firing of electroplating sludge ceramsite, the firing experiments of ceramsite with different Si/Al ratios were carried out using electroplating sludge and shale as raw materials. The sintering temperatures was selected as 700, 800, 900, 1 000 and 1 150 ℃. The residence time was 8, 16, 24, 32, 40 minutes. The results showed that the volatilization rates of Zn and Pb increased gradually with the increased of temperature and reaction time. When the sintering temperature was 1 150 ℃ and the residence time was 40 minutes, the volatilization rate of Zn and Pb reached the maximum, and the volatilization rate of Pb was higher than that of Zn. The volatilization rate of heavy metals decreased with the increased of Si/Al ratio in ceramsite. The kinetic analysis results showed that the reaction order and activation energy of Zn decreased and that of Pb increased with the increased of Si/Al ratio. The results of XRD analysis showed that the distribution of Pb in the ceramide at 1 150 ℃ was small, which may be related to the low melting boiling point of Pb oxides. While Zn mainly existed in the ceramsite in the structure of ZnCr2O4 and ZnGa2O4 with relatively stable properties, and the distribution of Zn in the ceramsite was large. The SEM analysis further showed that the increased of Si/Al ratio in ceramsite raw materials leaded to the increase of glass-phase substances produced by ceramic melting at high temperature, and the inhibition of heavy metal volatilization was enhanced.

Regarding to the difficulty of anaerobic biogas residue treatment in the anaerobic fermentation technology of kitchen waste, the pyrolysis kinetics of kitchen waste anaerobic biogas residue was studied on condition that high-purity N2 was used as the carrier gas, the gas flow rate was 50 mL/min, the heating rates of 5, 10, 15, 20, and 30 ℃/min were selected, and the final pyrolysis temperature was 850 ℃. The three methods of Flynn-Wall-Ozawa（FWO），Kissinger-Akahira-Sunose（KAS） and Coats-Redfern（CR）were used to study the effects of ball-milling time and heating rate on the activation energy distribution of biogas slag pyrolysis, and the optimum mechanism function selected by Popescu method was fitted by CR method. The results showed that the pyrolysis process of kitchen waste was divided into three stages; the activation energy calculated by CR method was close to the actual value, ranged from 41.32 to 46.49 kJ/mol. According to the fitting results of CR method, the pyrolysis reaction mechanism of biogas residue was a three-dimensional diffusion model. The research results provided important basic theoretical data for the pyrolysis and resource reuse of kitchen waste anaerobic biogas residue.

During the COVID-19, domestic waste incineration plants played a key role in the process of emergency disposal of domestic waste related to the epidemic. A domestic waste incineration in Beijing was taken as an example, the operational effects of the renovation project for emergency disposal of domestic waste related to the epidemic were expounded.The practical engineering showed that after the technical transformation, the plant’s emergency disposal capacity of domestic waste related to the epidemic was more than 200 t/d, the existing flue gas and leachate treatment systems could ensure that all pollutants met the discharge standards. After emergency disposal of domestic waste related to the epidemic, furnace slag yield of per ton of waste reduced by 20%, lime and activated charcoal consumption quantities of per ton of waste increased by 28% and 32 %, respectively. Meanwhile， fly ash yield of per ton of waste increased by 11%. The project effectively guaranteed the emergency disposal capability of medical waste in Beijing. The reduction, harmlessness and resource disposal of domestic waste related to the epidemic were realized, and good social and economic benefits were produced.

Domestic waste incineration power generation technology has become the mainstream technology of solid waste treatment in our country. The amount of fly ash produced by solid waste incineration had increased explosively in recent years. The pressure of “city besieged by waste”turned into the distress of fly ash landfill, so the disposal of fly ash became an urgent problem to be solved. Under the background of “waste-free city”construction, an attempt was made to recycle incinerated fly ash by cold top electric melting technology. A 10 t/d cold top electric melting equipment was tested to melt fly ash, quartz sand and co-solvent, and the leaching effect of molten mass metal and dioxins were analyzed. It provided basic data support for the industrialization of the cold top electric melting technology of domestic waste fly ash and proved the feasible of the cold top electric melting technology in the process, so as to explore the economic analysis and environmental benefits of the technology.

The unorganized release of bioaerosols from campus food waste posed a potential threat to the health of campus students and staff. In this study, an Anderson six-stage sampler and a medium-flow total suspended particulate sampler were used to collect air samples from the temporary storage process of food waste in the campus. The culturable and non-cultureable bioaerosols were analyzed by culture techniques and high-throughput sequencing. The results showed that food waste was an important source of bioaerosol release, and the concentration of fungi (224.78±27.69) CFU/m3 in bioaerosol was higher than that of bacteria (116.95±23.01) CFU/m3 and environmental background. That is, the bacterial environmental background value was (32.80±3.61) CFU/m3, and the fungal environmental background value was (54.57±17.24) CFU/m3. In terms of particle size distribution, bacterial aerosols were mainly distributed in stage I (≥7.0 μm), and fungal aerosols were in stage IV (2.1~3.3 μm). The dominant phylum of bacterial aerosols mainly included Proteobacteria and Firmicutes. The former had a higher aerosolization level. The dominant phylum of fungal aerosols mainly included Ascomycota and Basidiomycetes, both of which were easily aerosolization. In terms of health risks, the non-carcinogenic health risk of both breathing and skin-contact were within the maximum acceptable level set by the US EPA. However, the annual exposure risk and disease burden of Pseudomonas and Fusarium were higher than the corresponding limits.

Based on the monitoring data of odor generation sources, discharge outfalls and boundaries of an animal innocuous treatment plant in Shanghai, its odor pollution characteristics were explored and its impact on the surrounding environment and human health was further evaluated. The results showed that the main sources of odor were the corruption of animal carcasses (incineration workshop) and the microbial activities of sewage treatment (sewage station). The main odor pollutants were hydrogen sulfide (H2S), ammonia (NH3), dimethyl disulfide (C2H6S2) and methanethiol (CH3SH), with the maximum source contents of 5.710, 2.462, 0.659 and 0.292 mg/m3, respectively. The incineration workshop was the major contributor of NH3, while the sewage station was the major contributor of H2S. The contents at the outfalls and boundaries satisfied the standards of DB 31/1025—2016 Emission Standards of Odor Pollutants. The main odor-causing factors were H2S, CH3SH, C2H6S2 and NH3, with the maximum threshold dilution times of 9 154, 1 496, 57 and 50, respectively. Comparison of the monitoring data revealed that there were low olfactory threshold factors other than NH3, H2S and CH3SH at the outfalls and boundaries, which were not included in the routine monitoring program. Subsequent consideration should be given to increasing the routine monitoring factors and monitoring frequency to better monitor the odor emission and its impact. Although the odor substance contents in the workshop were lower than the occupational exposure limit, non-carcinogenic risks were identified with the risk index ranged from 4.481 to 1 956.440. The limited space in the workshop should be strictly controlled, and incoming operators should be equipped with protective equipment. The normal operation of the waste gas treatment facilities must be ensured, preventing leakage and protecting health risks from staff.

16 typical ex-situ indirect thermal desorption projects in 12 provinces in China were investigated. The application characteristics of ex-situ indirect thermal desorption technology were analyzed. The results showed that the target pollutants of ex-situ indirect thermal desorption remediation mainly include benzene, chlorinated hydrocarbons, polycyclic aromatic hydrocarbons, pesticides and petroleum hydrocarbons, for a total of five types. The maximum exceedance of pollutants multiples was 7.60~4 409.09. The maximum thermal desorption temperature ranged from 350 to 750 ℃, the thermal desorption residence time of less than 30 min accounted for 94% of the projects, the comprehensive cost of thermal desorption repair was 734~1 400 yuan per square meter, the average value was 1 210 yuan per square meter. At the same time, the operation problems of thermal desorption equipment in engineering applications were identified, and it was found that the running stability of thermal desorption equipment was poor, which restricted the processing capacity. And the energy utilization efficiency of thermal desorption system was low, which affected the processing cost. It was necessary to further strengthening the research of thermal desorption process heat and mass transfer mechanism, improving the level of equipment integration and standardization and improving the energy utilization efficiency.

It was of great significance to clarify the high performance of urban community solid waste classification management for recognizing the mechanism of urban community domestic waste classification management and the operation mechanism of grassroots community social governance community. The generation path of domestic waste classification and governance performance of 100 urban communities in Beijing was compared and analyzed by using the configuration method. It was confirmed that the role and synergy and complementarity of the three levels of party committee and government, community and residents were the main reasons for urban communities to obtain the high performance of domestic waste classification and governance. The willingness of residents to participate had a “veto” effect on achieving high performance. Therefore, it was suggested that to improve the urban community domestic waste classification and governance mechanism and the grassroots community social governance community operation mechanism, we should not only pay attention to improving the work of the party committee government and the community, but also pay attention to cultivating residents’ sense of community and willingness to participate, so that the role of the governance subject could form a good synergy and complementarity.

The results of the changes in domestic waste generation after COVID-19 in Shenzhen was forecast and analyzed, which was an important basis for local governments to scientifically make relevant plansand rationally layout the construction of sanitation facilities. To this end, the changes of the predicted domestic waste generationvalue from 2022 to 2035 was analyzed by combining grey model, multiple linear regression and other methods. The results showed that the output of domestic waste kept increasing year by year, and the specific value of the end of the planning level year （2035） had been adjusted to some extent. It was predicted that the generation of domestic waste in 2035 would be 45 547 t/d, among which the recycling amount of regenerated resources would be 14 576 t/d, and the disposal amount of domestic waste would be 30 971 t/d. It was suggested that the construction of sanitation facilities could adjust the scale and construction period of facilities flexibly to improve the efficiency of domestic waste treatment.

In the context of waste sorting, and in the forms of field investigation, sampling analysis and investigation and research, the practical exploration and work experience of the construction of urban waste treatment system in Tengzhou city in recent years were studied. The current problems such as the lagging development of domestic waste sorting, collection and transportation system, the shortcomings of waste terminal disposal facilities, and the overall low utilization rate of construction waste resources were analyzed. At the same time,combined with the practice, the countermeasures and suggestions were put forward, such as building an optimal waste classification, collection and transportation chain in an all-round way, building a new environment-friendly solid waste circular economy venous industrial park and exploring the implementation of construction waste “integration”operation and so on.

With the proposed goal of carbon neutrality, in addition to production costs, energy consumption, and environmental benefits, carbon emissions have become a new focus when the organic solid waste treatment process were compared and selected. Based on accounting guidelines provided by the United Nations Intergovernmental Panel on Climate Change (IPCC), and combined with life cycle assessment (LCA), the carbon emissions of the three-phase organic solid residue of food waste pretreatment were calculated by dry incineration, anaerobic digestion and black tabanus biological culture. The results showed that after considering direct emissions, indirect emissions, and carbon offsets, the sequence of the total carbon emission from low to high was black tabanus biological culture, anaerobic digestion and incineration. The black tabanus biological culture was a high energy consumption process with the highest direct emission (54.92 kgCO2/t) and indirect emission (163.48 kgCO2/t). However, it could produce approximately 233 kg of organic fertilizer and 67 kg of biological feed by treating one ton of organic solid residue, resulted in significant carbon offsets benefits (274.09 kgCO2/t) and an overall carbon emission reduction effect of 55.69 kgCO2/t could be achieved. From the perspective of carbon emission, this treatment and disposal method was worth advocating.

A co-aerobic composting treatment facility for food waste and agricultural waste and garden waste in a town in North China was taken as an example, the emission factor method was used to calculate the carbon emissions from collection, transportation, treatment and resource utilization. The carbon emissions were 143.71 kgCO2/t. The results showed that the carbon emissions in the collection and transportation stage were 1.04 kgCO2/t, which was lower than transporting to a centralized treatment facility. The direct carbon emissions in the treatment stage were 193.50 kgCO2/t. The unorganized escape of CH4 and N2O produced in the aerobic composting process was the key factor affected its carbon emissions level. The indirect carbon emissions in the treatment stage were 4.16 kgCO2/t, and the carbon emissions from equipment energy consumption were lower than the process of using heating and oxygen-supply equipment. The carbon reduction of compost products was 55 kgCO2/t, with obvious carbon reduction effects. Therefore, measures should be taken to reduce direct carbon emissions by maintaining the oxygen content of the heap at no less than 8%, the moisture content of 50% to 65%, the reaction temperature was above 55 ℃, and increasing closed auxiliary facilities, regularly turning operations, and ensuring sufficient composting time.