Based on the generation mode and characteristics of municipal solid waste incineration fly ash, the inorganic chloride salts recovery and treatment technologies, calcium element separation and recovery technologies, heavy metal elements separation and extraction technologies of incineration fly ash were explored. The advantages and disadvantages of each technology were analyzed, and the latest resource utilization industrialization progress of incineration fly ash were summarized. According to the study, two widely accepted systems were low-temperature dioxin detoxification + washing + evaporation recovery of heavy metal-containing salt water + calcium component forming cement, and high-temperature sintering/melting for dioxin detoxification + salt and heavy metal volatilization recovery + calcium component forming pottery/glass. In both systems, dioxins could be decomposed effectively. Calcium could be recycled, but the added value was not high, and in the process of calcium recycling, attention should be paid to the long-term environmental risks caused by the total amount of heavy metals entering the environment. There was currently a lack of cost-effective resourcing of chloride components. In the future, more investigations should be focused on developing effective recycling of calcium and chloride in fly ash, and need more detailed technical guidance documents as theoretical support and design basis.

The harmless disposal of waste incineration fly ash is the key link in the pollution control of waste incineration. Fly ash and its solidification/stabilization products from typical waste incineration plants were selected to compare and analyze the changes of heavy metal content, morphology, leaching characteristics and micro-morphology of fly ash before and after solidification/stabilization. Meanwhile, the potential risk evaluation method and environmental risk index method were used to evaluate the pollution risk differences of heavy metals before and after solidification/stabilization treatment. The results showed that the content of Zn， Pb and Cu in fly ash from waste incineration in Chongqing was high, especially the leaching toxicity of Pb reached 80.8 times of the standard limit value, and the migration of Pb, Cu, Zn, As and Hg was strong. Solidification/stabilization treatment significantly reduced the leaching toxicity and mobility of heavy metals, but the leaching toxicity of Pb still exceeded the standard. The results of the environmental pollution risk suggested that the environmental pollution risk of fly ash after solidification/stabilization treatment was significantly reduced, but the treatment effect of Pb and Cd still needs to be improved. The research results could provided crucial data support for the optimization of fly ash disposal technology.

The stockpile of iron tailings in China exceeds 10 billion tons, with about half consisting of refractory hematite/limonite ores. The efficiency of conventional sorting methods for these ores was low and costly. Magnetization roasting is the most effective technology for utilizing refractory iron ore, with the primary challenges being the efficient magnetization of iron minerals and the separation of impurities. In this study, municipal sludge (35% moisture content) and iron tailings were used to recover iron resources from typical sulfur-bearing and polymetallic refractory iron tailings by synergistic magnetization roasting technology. Under optimal roasting conditions (roasting temperature of 800 ℃, roasting time of 30 min, and municipal sludge doping of 15%), the resulted iron concentrate achieved an iron grade of 63.11%, an iron recovery rate of 96.23%, and impurity contents of sulfur, phosphorus, and aluminum all met the index requirements of C60 in GB/T 36704—2018 Iron Ore Concentrate. The study provided a new approach for the efficient resource utilization of iron tailings.

The sedimentation effect, changes of viscosity and extracellular polymeric substance （EPS） concentration of kitchen biogas slurry under different irradiation doses were investigated using electron beam （EB） irradiation technology, and kitchen biogas slurry was taken as the research object. SS concentration in kitchen biogas slurry was significantly reduced through the EB coupled coagulation and low-speed centrifugation (EBCC) process. Results showed that when the irradiation absorbed dose of EB exceeded 10 kGy, the sedimentation rate could reach over 60% in 10 minutes. The viscosity and the EPS concentration could be reduced from 52.18 mPa·s to 6.57 mPa·s and 410.00 mg/L to 215.63 mg/L, respectively. Moreover, the SS concentration of the slurry rapidly decreased from 15 100 mg/L to 2 650 mg/L, resulted in an SS removal efficiency reaching up to 82.45% by using the EBCC process with the optimal dosage of coagulants (4‰ PAFC and 4‰ PAM). Additionally, from a technical and economic perspective, the operating cost of EBCC process was 7.71 yuan/m3. These findings demonstrated that the potential of EB technology has significant advantages in high-viscosity solid-liquid separation for kitchen biogas slurry.

There is a huge amount of organic solid waste resources such as kitchen waste anaerobic fermentation biogas residue and garden waste in China. Pyrolysis carbonization is an effective way to recycle organic solid waste. The yield, physical and chemical properties and structural characterization of pyrolysis biomass char from different biomass raw materials still need to be systematically studied. The kitchen waste anaerobic fermentation biogas residue and garden waste were used as raw materials, the physical and chemical properties such as nutrient content, microstructure, functional groups, and structural characteristics of two kinds of solid waste pyrolysis biochar were analyzed. The biogas residue biochar yield and garden waste biochar yield were 62.7% and 70.1%, respectively. The pH values were 9.61 and 10.01, and the electrical conductivity were 1.25, 0.55 mS/cm, respectively. The total nutrient content were 6.26% and 4.63%, and the fixed carbon content were 54.80% and 67.90%, respectively. The specific surface area of biogas residue biochar was basically the same as that of garden waste biochar（with values of 7.73, 8.03 m2/g, respectively）, and pore volumes of 0.025, 0.011 cm3/g, with pore sizes of 10.14, 4.70 nm, respectively. There were significant differences in the types of functional groups between the two types of biochar, with biogas residue biochar had more functional groups than garden waste biochar, but the crystal structures of the two were basically the same. Both biogas residue and garden waste could be used to produce biochar-based fertilizers, but the nutrient content and pore structure of biogas residue biochar were better than those of garden waste biochar, which could be used to improve soil comprehensive fertility. The organic carbon content of garden waste biochar was higher, which was beneficial for increasing soil carbon sink.

With the implementation of waste classification, the generation amount of wet waste has been increasing. The wet waste mainly consists of household kitchen waste and food waste, both often treated by anaerobic digestion. During the waste sorting process, some paper towels may be mixed with wet waste and enter the anaerobic digestion system. The impact of low-dosage paper (5%, measured in TS) on subsequent individual and co-anaerobic digestion of kitchen waste and food waste was investigated. The results showed that the addition of paper increased the cumulative biogas production by 5.8% and 4.5% for kitchen waste and co-digestion groups, respectively. It also promoted an increase in NH4+-N concentration and pH recovery. In addition, it caused an increase in the relative abundance of cellulose-degrading bacteria, promoting the degradation of cellulose in the paper. Therefore, the mixture of some paper towels could promote the anaerobic biogas production performance of wet waste, so it may not be necessary to completely remove paper during waste classification process.

The soil-red skin radish system was taken as the research subject. A pot experiment was conducted to study the effects of different proportions (0, 5%, 10%, 15%, 20%) of rural organic waste compost on soil physicochemical properties, heavy metal content of soil and plant, plant biomass, and to evaluate the ecological security of soil. The results showed that the application of rural organic waste composts significantly increased the soil available nitrogen, available phosphorus content, organic matter content and red radish biomass (P<0.05), and increased the pH of soil. When the application ratio was 5% and 10%, the pH of soil increased significantly (P<0.05). After applying rural organic waste composts, except for no significant changes of Cu (P<0.05), the total amount of Cd, Pb, Zn, and Cr in soil all increased, and the potential ecological risk of the soil increased. Among them, the total amount of soil Pb increased significantly (P<0.05) by 20.49%-92.04% compared to the control. When the fertilization ratio were 15% and 20%, the total amount of Cd and Zn in soil increased significantly (P<0.05) by 19.72%-34.75% and 8.55%-21.79%, respectively. When the fertilization ratio was higher than 5%, the total amount of Cr increased significantly (P<0.05) by 19.51%-63.04% compared to the control. After the application of rural organic waste composts, the Cd content in various parts and Pb content in the root of red radish were reduced to a certain extent. While the Zn, Cr, and Cu content in the root were all increased, all of which met the GB 2762—2017 National Food Safety Standard for Contaminants Limits in Food. In general, among the five heavy metals, Cd was the most important element affected the soil ecological risk, and its contribution rate was as high as 76%. Redundancy analysis revealed that pH was the main factor that influenced the content of heavy metals in the soil, and the content of Cd and Pb were found to be significantly affected by soil physical and chemical indexes(P<0.05).

The integrated flue gas purification process is a new flue gas treatment method with catalyst ceramic fiber filter tube as the core, which could achieve efficient collaborative removal of dust, acid gas,NOx,dioxins and other pollutants. A pilot test was conducted in a domestic waste incineration plant in Zhejiang province to verify the effect of denitrification, dust removal and dioxins removal process and explore the key technical parameters. The fingerprint characteristics and regeneration of dioxins in domestic waste incineration smoke was emphatically analyzed. The results showed that when the reaction temperature was from 210 ℃ to 220 ℃, the filter wind speed was 0.60 m/min, the highest efficiency of dust removal, denitrification and dioxin removal were 99.87%, 94.28% and 95.68%, respectively, which could meet the EU 2010 emission targets. The economic calculation showed that when the flue gas reached the ultra-net emission standard, compared with the conventional six-step process of flue gas purification, the investment and operating cost of 750 t/d waste incineration line using the integrated process could save at least 2.405 1 million yuan per year.

More than 300 incinerators in operation from 2016 to 2022 in China were taken as the research object, statistical analysis was made on the variation rules of design and operation parameters such as single-furnace treatment scale, main steam design parameters and incineration load rate. The results indicated that the number of grate furnaces with a single furnace treatment scale of less than 600 t/d accounted for the highest proportion of 63.54%, and the number of large grate furnaces with a single furnace treatment scale of 750 t/d and above had increased significantly in recent years. The proportion of medium temperature and medium pressure (4.0 MPa, 400 ℃) in the steam parameters of waste heat boiler was 59.37%, and the number of incinerators with higher parameters such as 13.5 MPa, 450 ℃ and 13.7 MPa, 485 ℃ had an increasing trend. From 2016 to 2022, the total scale of waste incineration treatment in China had increased from 2.558×105 t/d to 8.047×105 t/d, while the incineration load rate had decreased from 86.60% to 72.78%. The collaborative disposal of industrial organic solid waste by domestic waste incineration power generation facilities was helpful to improve the incineration load rate of incineration plants and could enhance technical and economic benefits.

Coconut shell active carbon has gradually become the major catalyst carrier for the degradation of volatile organic compounds due to its large specific surface area and good activation performance. The impregnation method was used to prepare the metal oxide catalysts with porous coconut shell active carbon particles as carriers in this study. It was loaded with single metal oxide and composite metal oxide catalysts with metal elements of Mn, Co and Fe. The catalysts with different compositions were characterized and analyzed by XRD, SEM and EDS. The results showed that catalysts with different activities could be prepared by changing the doping metal ratio and calcination temperature. When the loading ratio of metal components was Mn∶Co∶Fe = 3∶2∶1，and the calcination temperature was 550 ℃, the catalyst showed that the optimal catalytic performance. The research could not only help to realize the resource utilization of solid waste coconut shells, achieve the purpose of economic and environmental protection, but also provide technical support and theoretical basis for practical environmental protection work.

The disposal of membrane filtration concentrate generated during the leachate treatment process is a difficult problem in the leachate treatment industry, and it is the most ideal solution to achieve full quantification treatment of concentrated leachate. However, the organic matter, hardness and inorganic salt in the concentrated liquid would cause corrosion and scaling of the equipment, so the corresponding treatment process should be set up. The concentrated leachate treatment project in a northern city adopted a treatment process of “pre-treatment+steam mechanical recompression technology (MVR) evaporation+drying reduction+incineration synergy”. The effluent quality could meet the design standards, and the operating cost was 295.32 yuan/m3. The stable operation of the project had achieved the full quantitative disposal of concentrated leachate in the park, and has the value of promotion and application.

Based on the leachate quality index, leachate treatment and derivative depth treatment system operation practice of a municipal solid waste incineration plant in the southern city from 2019 to 2023， the key parameters and control requirements for the stable operation of leachate and concentrate treatment system were analyzed and summarized. The leachate treatment adopted the process of “anaerobic（UASB）+ denitrification + nitrification + ultrafiltration (UF) + first-stage pipe network reverse osmosis (STRO) + second-stage reverse osmosis (RO)”, the concentrate treatment process was “two-stage oxidation + two-stage flocculation and sedimentation + three-stage evaporation + mother liquid reinjection”. The practice indicated that the volumetric load（calculated by COD）of UASB process was 5-10 kg/(m3·d), the sludge concentration was about 8 000 mg/L, COD∶N∶P was （350-500）∶5∶1, and the hydraulic retention time was 7-15 d. The hydraulic retention time ratio of nitrification and denitrification in primary A/O was controlled at 3∶2, the reflux ratio of nitrification solution was about 300%-1 000%, the sludge concentration was 20 g/L, and the sludge age was about 30 d. After further advanced treatment by UF, STRO and RO, the effluent could be recycled after reaching the standard.

Based on the management and distribution status of urban public toilets in Beijing, the selection criteria of various parameters were defined in accordance with the Beijing Environmental Sanitation Work Budget Quota. The urban public toilets operating cost calculation model was established systematically, and the cost was compared and analyzed with the actual cost tracking data in recent years. The results showed that the calculation operating costs of the first class, second class and third class public toilets were 0.436 8, 0.408 1 and 0.215 4 million yuan per seat per year, respectively. The proportion of labor costs in the operating costs ranged from 55.1% to 60.5%. After comparison, the actual costs of the operation of the three types of public toilets were lower than the estimated costs, which were 0.320 9, 0.293 1 and 0.144 6 million yuan per seat per year, respectively. The revised model estimated cost was 0.342 2, 0.313 6 and 0.158 6 million yuan per seat per year, respectively. Using SPSSAU to conduct stepwise regression analysis on actual cost tracking data, the operating cost model was established (Operating cost =19.649-4.130× types of public toilets + 6.238×number of workers) . The main factors affecting operating cost were found to be number of workers and types of public toilets. Suggestions were put forward that to carry out standardized budget and expense management, protect the legitimate rights of sanitation workers, strengthen personnel management, and further strengthen the application of quotas. In order to provide expense reference for the market-oriented reform and operation of sanitation, promote the rational allocation of human, financial, material and other resources in the classification management of public toilets, and improve the level of fine sanitation management.

The management of public toilets is an important component of urban environmental management. It is of great significance and necessary to learn from other countries to improve public toilet management and create a beautiful toilet environment. Based on this, the relevant standards, laws and regulations of public toilets in Germany was introduced. The successful experiences and practices of Germany’s strong promotion of “public toilet for all”, intelligent public toilets and unisex-toiletten were analyzed which adopt market-oriented operation mode, actively utilized social resources, attached importance to friendly evaluation, and carried out harmless treatment of public toilet sewage. At the same time, combined with the public toilet management problems in China, four innovative suggestions were put forward, namely, improving the service quality of barrier-free public toilets, increasing investment in the construction of smart public toilets, introducing market players to participate in the renovation of public toilets and promoting toilet civilization education and publicity.

The establishment of China’s waste incineration standards could be divided into “the beginning stage before 2000”, “important development stage from 2001 to 2010”, and “refined optimization stage from 2011 to present” in terms of the development stage of waste incineration engineering technology in China. The three stages of waste incineration standards were systematically reviewed and analyzed, showed that before 2000, there were only a few national and industry standards in the field of waste incineration. From 2001 to 2010, more than ten important national and industry standards related to waste incineration were released. Since 2011, in addition to the optimization and revision of the original standards, more emphasis has been focused on the refinement of the standards. At the same time, the differences before and after the revision of important standards and the limits of local domestic waste incineration pollution control standards were compared according to the development process of the industry. After a comprehensive analysis of the problems existed in the current standard, the corresponding suggestions were put forward, that was, strengthening the standardization of drafting rules in the process of standard formulation, accelerating the formulation of recommended national and industry standards and improving the coordination between the standards, formulating local environmental standards in line with economic and technical factors, raising the entry threshold for group standards, and improving the construction of implementation mechanisms.

With the general implementation of the municipal solid waste(MSW)classification system and the continuous improvement of the classification system, it was very important to explore the establishment of a metered and categorized charging system that was connected with the MSW classification system. On the basis of a comprehensive analysis of the three types of MSW disposal fee charging system, namely tax, direct charge and indirect charge, the corresponding methods and application cases of calculating fees, as well as the advantages and disadvantages of different methods of calculating fees, the specific implementation conditions of various methods of calculating fees for MSW were studied, and countermeasures and suggestions were put forward to provided references for the establishment, improvement and implementation of the MSW disposal fee charging system.

The process of grade evaluation of incineration plant involves reliability evaluation and analysis, the reliability evaluation of waste incineration project could further improve the operation and management level of the project. The reliability evaluation scope, reliability evaluation indicators, and system equipment discrimination of domestic waste incineration project were analyzed, and the reliability evaluation method of waste incineration project was expounded. It was found that most domestic waste incineration projects still have room to further improve the level of refined operation and management. Suggestions were put forward to continuously pay attention to the relationship between the waste amount and waste incineration calorific value, strengthen the sampling analysis of domestic waste, and strengthen the energy-saving management, so as to provide references for the construction and operation management of domestic waste incineration projects.