In order to improve the inspection efficiency of large domestic waste sanitary landfill for diseases such as puncturing and tearing of the covering film, the Xingfeng landfill in Guangzhou was taken as an example. The selection and cruise parameters of unmanned aerial vehicles (UAV) were investigated based on UAV aerial photography and depth learning model, the disease samples collected by UAV were trained by oversampling strategy in the disease image recognition model. A subtle target recognition layer was added to the YOLOv5 model, which achieved high recognition accuracy and recall rate. The test results showed that the oversampling strategy improved the representativeness and balance of the samples and significantly improved the accuracy of disease identification of the model under the condition that the number of samples in the disease map database was relatively limited. UAV combined with high-precision RTK positioning technology could accurately locate the coordinates of aerial photos, solved the problem of difficult positioning of film coating diseases without obvious reference objects. By querying the geographic information of disease defect photos, the location of the disease could be quickly found and repair operations could be carried out in a timely manner.

The amount of construction waste(CW) is huge and the composition is complex. If not properly treated, the asphalt, gypsum, heavy metals and paint in CW would react with the surrounding air, soil and water to produce harmful products, which would seriously endanger the human living environment. The construction requirement of “waste-free city” in China clearly put forward the strategy of comprehensive management of solid waste to improve the resource utilization rate of waste. As the largest municipal solid waste in China, CW has become the focus of attention, and it was urgent to realize the resource utilization of CW. The traditional CW disposal methods adopt manual and mechanical means to sort CW, and then make resource utilization of CW. There were some problems in the process, such as difficult management, low efficiency and high cost. As the core of artificial intelligence, machine learning has been gradually applied to CW treatment, which could effectively improve the resource utilization rate of CW. The basic situation of CW and machine learning were described, the process of CW treatment was introduced, and the research progress of machine learning in the field of CW treatment was summarized. Finally, combined with the national condition of China, some suggestions for CW treatment were given, in order to provide reference for realizing automation and intelligence of CW treatment.

The humus of domestic waste was of great practical significance to the sustainable development of landfill. The effects of landfill age, initial dry density and the maximum particle size on soil-water and microscopic properties of humus were studied by centrifuge test and nuclear magnetic resonance. The unsaturated hydraulic parameters of humus were obtained by combining experimental data with VG model. The initial dry density mainly affects the saturated water content and air intake value of the compacted sample, and the soil-water characteristic curves with different dry densities tended to coincide within the range of more than 100 kPa. With the increase of landfill age and initial dry density, the pore diameter decreased. With the increase of the maximum particle size, the pore size distribution showed the opposite trend.

Due to the shortage of land resources in China, the mainstream treatment process of domestic waste has changed from landfill to incineration, and the proportion of incineration disposal had reached more than 50%. The accurate analysis of calorific value of waste, as the key factor of whether waste could be incinerated, is of great significance. The dry-base high caloric value determination and C, H, O, N, S, Cl content analysis of thirteen kinds of rubber and plastic, eight kinds of fabrics, eighteen kinds of paper, thirty kinds of kitchen waste and eight kinds of wood and bamboo single components were realized by using bomb calorimetric method and analytical methods of elemental analyzer. The calorific value test results showed that the dry-base high calorific value data scale of rubber and plastic, fabric, paper, kitchen waste and wood and bamboo were 20 790~48 228、16 903~37 854、10 046~16 923、15 704~26 434、16 082~26 932 kJ/kg, respectively. It was also found that the dry-base high caloric value was mainly positively correlated with the content of carbon and hydrogen, and negatively correlated with the content of oxygen.

Currently, how to handle domestic waste with high quality in the context of waste classification has become an important research topic. Sampling experiment and rule analysis of important physical and chemical characteristics of municipal solid waste in Qingdao were carried out through experimental analysis and data statistics methods. The results showed that in the next few years, the volume of domestic waste removal and per capita waste generation in Qingdao would continue to grow, the kitchen waste generated by residents would still have a certain space to decline, other waste and low-value recyclables would increase, harmful waste would remain at the current level, the water content of waste would continue to be at a high level in the next few years, and the wet-based low calorific value would continue to grow.

In view of the problems existed in the process of resource utilization and energy utilization of kitchen waste, continuous anaerobic fermentation experiments were conducted at medium temperatures (38 ℃) and intermediate temperatures (44 ℃) to analyze the gas production characteristics, process parameters, microbial colony structure and composition of different temperature fermentation systems. The results showed that under the same organic load, compared to medium temperatures experimental group, the intermediate temperatures experimental group had biogas production characteristics such as higher volumetric biogas production rate and methane production rate. And it had a high degradation rate of VS. The intermediate temperatures fermentation system was more stable in the analysis of process parameters such as VFAs, ammonia nitrogen, total alkalinity, pH, etc, and it had a certain resistance to load impact. In the exploration of high-throughput microbial community diversity, intermediate temperatures fermentation was characterized by a relatively abundance diversity of bacterial species, and archaea had obvious superiority in producing methane, which indicated that during the anaerobic fermentation process, the mutual promotion and coordination between microbial colonies in the intermediate temperatures anaerobic fermentation system promoted the stable and orderly transformation of various material parameters, and guaranteed the stable and efficient operation of the anaerobic system.

Fruit and vegetable wastes can be used as substrates for ethanol production by anaerobic fermentation, and the fermentation effect is affected by various factors. The pattern of ethanol production by anaerobic fermentation of mixed fruit and vegetable wastes under different conditions was analyzed, including hydrothermal pretreatment and sterilization, addition of cellulase, and inoculation of yeast. The results showed that the addition of cellulase and yeast were both beneficial to improve the hydrolysis effect of the system. The addition of yeast could effectively improve the ethanol production rate, while the addition of cellulase had a limited effect on the promotion of ethanol production in the system. The ethanol production rate of adding yeast and yeast with cellulase reached (0.164±0.040) g/g and (0.161±0.039) g/g per unit of fruit and vegetable waste organic matter, respectively, which was 34.23 times and 33.45 times higher than the control group. The fermentation pattern of fruit and vegetable wastes before and after hydrothermal pretreatment was similar, but hydrothermal pretreatment promoted the hydrolysis of the substrate and increased the yield of each product. The highest ethanol yield was obtained under the conditions of combined hydrothermal pretreatment and inoculation of yeast. Under this condition, the final concentration of ethanol could reach (16 672.09±2 304.85) mg/L with a yield of (0.233±0.032) g/g. Therefore, the addition of 0.5% mass of yeast could change the type of fermentation of the system, which made ethanol become the main product. The combined application of hydrothermal pretreatment and addition of yeast resulted in the highest ethanol yield.

Relied on the newly built domestic waste incineration plant, a long-term feasibility test for screening stale waste in landfill and co-incineration with municipal solid waste was carried out. Through the composition characteristics analysis of the screened materials obtained by the excavation of stale waste in domestic waste landfills and the pre-processing with “drum screening + air sorting”, it was found that the proportion of light substances such as plastics in the screened materials (dry basis) accounted for about 53%, and had a negative linear relationship with the moisture content of the screened materials. The screened material was transported to the incineration plant and mixed with raw waste at certain designed ratios. Based on data such as the amount of waste entering the furnace, tonnage of evaporation, etc, the calorific value of the screened material was about 6 258 kJ/kg by using the law of conservation of energy. Blended combustion could lead to a significant increase in the average daily unit consumption of slaked lime in the waste gas treatment system, but could not affect the average daily unit consumption of urea, and it could also significantly increase the average daily production of slag and fly ash. Based on the highly automated waste gas treatment system, blended combustion would neither significantly increase the hourly average concentration of flue gas pollutants, nor significantly increase the instability of tail gas emissions. And all maximum concentrations of pollutants met the relevant emission standards requirements.

Based on the introduction of collaborative disposal technology of solid waste and polluted soil preparation ceramic particles at home and abroad, and the research progress of ceramic particle technology in China and the collaborative disposal technology of solid waste and polluted soil preparation ceramic particles were summarized. Through a comparison of domestic and foreign scholars in the preparation of ceramic particles from solid waste and polluted soil, it was found that using polluted soil and solid waste as raw materials to produce ceramic particles is an upgrade and improvement on the basis of the original process. According to the existing research, the maximum amount of contaminated soil or solid waste added could reach to 40%, and the ceramic particles prepared by this method basically meet the national standards in terms of compressive strength, water absorption, bulk density, apparent density, and other ceramic particle quality. In terms of pollutant treatment, the solidification effect of heavy metals was relatively excellent, up to 99.80%. Due to the high temperature conditions required for the preparation of ceramic particles, secondary pollution may occur during the treatment process. Therefore, in practical applications, it is necessary to add exhaust gas treatment devices to meet the national emission standards. The collaborative disposal technology of solid waste and polluted soil preparation with ceramic particles could not only effectively treat pollutants, but also could achieve resource reuse and generate considerable economic benefits.

The effects of the number of mesh belt layers and the thickness of the mesh belt sludge spreading on the return air temperature, humidity, aqueous output capacity, and pressure drop were investigated. The optimum working conditions applicable to the mesh belt of a sludge low-temperature dryer for sludge particles were evaluated. The result indicated that in four-layer mesh（a condition of four-layer a）, the sludge particles in the 0.60 m/s mesh belt air velocity had the lowest water yield of 20.7 kg/h after drying. Compared with the maximum water yield (19.7 kg/h) of the sludge particles in the two-layer mesh belt after drying , it was still 5.1% higher. It could be shown that the water yield after drying of the four-layer mesh belt sludge particles was more, and the drying effect was superior. Under the influence of the number of layers of mesh belt, the water yield of the four-layer mesh belt could be improved by 60.1% when compared to the two-layer mesh belt. Under the impact of the thickness of the mesh belt sludge spreading, the maximum output capacity of the four-layer mesh belt could be increased by 11.3%. And the maximum output capacity of the two-layer mesh belt could be increased by 44.0% when compared to the minimum output capacity. The maximum increase of the water yield under 0.90 m/s mesh belt air velocity could be raised by 36.0% when compared to 0.60 m/s. The study founded that the number of mesh belt layers had the greatest influence on the dehumidification efficiency of sludge low-temperature dryer.

Greenhouse gases CO2, CH4 and N2O were monitored for up to one year in the tail gas of five municipal solid waste incinerators, the areas covered with films of two domestic waste landfills and open processing pools of two wastewater disposals, respectively. The average annual CO2 emission capacity of tons of waste in the flue gas of incinerator tail was in the range of 0.653 to 0.797 t. The relative error between the calculated value and the monitored value was as low as 1.86% under stable operating conditions. The greenhouse gas emission flux in the covered area of landfill fluctuated greatly with the seasons. The maximum emission levels of CO2 could reach 11.13 g/(m2·h), CH4 could reach 0.98 g/(m2·h), and N2O could reach 3.519 mg/(m2·h) in the southern region in summer. The CO2 and N2O emissions from the wastewater treatment process tank were mainly in the aeration tank, in which CO2 was not affected by the seasonal change, and N2O fluctuated greatly throughout the year. As to CH4, the discharge fluxes in the north sewage plant had obvious seasonal differences, and the values of anoxic pool, selective pool and anaerobic pool were the highest in summer. The highest data was 1.60 g/(m2·h). The CH4 discharge capacity of the sewage treatment process tank in southern China was still dominated by three aeration tanks, which fluctuated greatly throughout the year and had no obvious seasonal difference, and could reach about 0.40 g/(m2·h).

Urban management, as one of the sources of urban greenhouse gas emissions, involves environmental sanitation management, solid waste collection, transportation and disposal and urban lighting management, etc. The 2021 greenhouse gas emissions study in the field of urban management in Chengdu indicated that solid waste collection, transportation and disposal was the most important source of greenhouse gas emissions, accounted for more than 95.81%. Followed by urban lighting management and environmental sanitation management, with emission contributions of 1.87% and 1.82%, respectively. Future scenario analysis demonstrated that the greenhouse gas emissions would decline rapidly with the increase of domestic waste incineration disposal rate, reached the lowest level in 2025. Then showed a slow increase trend with the growth of domestic waste collection and transportation scale. The emission contribution of solid waste collection, transportation and disposal was 94.66% when the peak was reached in 2030. At the same time, the emission contribution ratio of urban lighting management and municipal road, bridge and utility tunnel maintenance would rise to 2.80% and 1.20%, respectively. The contribution of environmental sanitation management emissions would fall to 1.07%. Finally, the countermeasures and suggestions for carbon emission reduction by urban management departments were proposed under the background of carbon peaking and carbon neutrality.

To investigate the current status, hotspots, and frontier trends in the research on campus waste classification and recycling, based on the literature collected in the core collection of the Web of Science (WoS) database from 1990 to 2023 and their references, bibliometric analysis and knowledge mapping were conducted, which included the state of publications, the distribution of research power, keywords co-occurrence and time-zone distribution, literature co-citation and cluster analysis, and burst analysis of keywords. The results showed that the number of articles in this field keep increasing annually, with a significant growth from 2010 to 2017, and the disciplines mainly focused on environmental science and education. The overall number of publications issued by developing countries and developed countries was comparable, but the research level of developed countries was relatively higher. Most research institutions had a small number of publications and a weak cooperative relationship. The main research hotspots had gradually enriched from early stages of solid waste, environmental education, attitude, behavior, and circular economy to multiple themes, including electronic waste, plastic waste, food waste, zero waste, planned behavior and extended theory, willingness, sustainability, environmental knowledge, and environmental performance. Environmental knowledge, environmental sustainability and reduction, and circular economy could be the research frontiers in the future, with a focus on the study of the characteristic components of campus waste, behavior, willingness, and influencing factors of waste sorting, as well as the establishment of green campus and sustainable campus.

In order to effectively prevent and control the environmental risks of hazardous waste, enterprises shall implement standardized environmental management of hazardous waste and evaluate it, and how to evaluate, analyze and take measures is the key to improve the level of hazardous waste management. Based on the evaluation index of standardized environmental management of hazardous waste, the current status of standardized environmental management of hazardous waste in enterprises of a certain province was evaluated, and the results showed that qualification rate of enterprises was as high as 95.1%. The number and proportion of enterprises with problems were counted, it was found that many enterprises had problems such as incomplete content of hazardous waste management plan, incorrect reporting and missing reporting of ledger records and declaration and registration, inadequate environmental management of storage facilities, non-standard identification marks of hazardous waste, imperfect pollution prevention and control responsibility system, missing content of operation and management ledger records and operation reports, and inadequate implementation of pollutant discharge permit system. At the same time, countermeasures and suggestions were put forward, such as improving the quality of hazardous waste declaration materials, strengthening the environmental management of hazardous waste and encouraging third-party technical services, so as to solve the problem of standardized management of hazardous waste.

Urban environmental sanitation is a comprehensive reflection of city image and overall quality. With the development of urban economy and society and the promotion of civilization, environmental sanitation quality management has become a key part of urban management. Based on the study of urban environmental sanitation quality evaluation methods and in accordance with the characteristics of the diversification of urban components,an urban environmental sanitation evaluation model with high urban fitness and good evaluation effect was established. The construction principle, basic composition,acquisition and calculation methods of each component of the comprehensive evaluation model of environmental sanitation quality based on multi-site combination were expounded, and Wuhan city was taken as an example to carry out the evaluation. The evaluation results were close to the actual situation, the evaluation model is reasonable and feasible, which could provide a certain reference for the evaluation of environmental sanitation quality.