In order to promote the development of new toilet technology and improve the technology level, International Standardization Organization (ISO) approved to organize a technical committee composed of representatives of 46 countries in 2016. The committee was responsible for compiling international standard ISO 30500 Non-sewered sanitation systems - Prefabricated integrated treatment units - General safety and performance requirements for design and testing. The standard was officially released in October 2018. The background and main content of the standard were introduced, the sanitary standard parameters were compared with the relevant national standards, in order to provide guidance for the development and application of toilet technology in our country and the upgrading of rural toilets.

Physical and chemical properties were the key parameters to determine the technology selection and pollution potential assessment of kitchen waste treatment. The physical and chemical properties of household food waste （HFW）and restaurant food waste （RFW）in China were summarized by sampling test and literature data screening and investigation after source classification. The results indicated that compared with the data reported before the waste classification policy， the contents of impurities （12.60%±2.50%） and heavy metals （below detection limit except for Cr） of the source segregated HFW in Shenzhen were lower， while the organic matter content （90.6%±5.0%） was higher， its resource utilization rate had been effectively improved. The moisture content of HFW by source segregation was higher （76.8%±5.0%， P=0.004 7） than those sampled from mixed collected MSW （65.5%±4.0%）， which could promote the calorific value and recovery potential of other waste components by restricting water diffusion to other waste components. The density， sodium chloride， organic matter and fat content of HFW in China were （0.38±0.16） t/m3， 1.34%±0.51%， 81.8%±5.7%， 12.3%±6.1%， respectively， which were significantly lower than those of RFW of （0.92±0.17） t/m3 （P=0.000 29）， 3.89%±2.00% （P=0.043）， 90.1%±4.8% （P=0.000 1）， 21.6%±7.9% （P=0.022）. And there was no significant difference in other indicators. Accordingly， in waste management system， the collection， transportation， and pretreatment processes of HFW and RFW should be designed independently according to their characteristics. The processing process could achieve a certain degree of coordination after conditioning according to the process characteristics and technical parameters. It was estimated that the salt content of HFW and RFW were both below the limit of inhibition concentration for biological treatment. The heavy metal contents of compost products were also lower than the relevant pollution assessment standards limit.

Since the first batch of food waste treatment projects passed the check, several of food waste treatment projects had put into operation in China. But there were few reports in the industry on whether the food waste treatment projects were profitable. The economic and technical calculation data were compared with the actual operation data in the feasibility study of a typical BOT(Build-Operate-Transfer) project of food waste treatment. And the reasons for their differences were explored. The results showed that the average annual income, annual cost, annual net profit were 26 000 800, 21 239 900 and 3 726 400 RMB in the feasibility study. In the second year of operation, the annual income, cost and the net profit were 16 237 200, 16 194 400 and 42 800 RMB. There for,the project was financially feasible at the project planning stage. The income and cost were basically equal with the high depreciation expense in the second year of operation (2020). Through this analysis, the reference suggestions could be provided for the investment and operation of the new food waste treatment project, and could also provide a reference data for business analysis of food waste treatment projects in operation.

The user experience, community management situation and sewage pipe network of Beijing community were investigated, which the kitchen waste crusher was centralized installed. The results showed that both the household sewer pipes and community pipes clogged in the large-scale and centralized installed investigation communities in Beijing. The effluent of buffer pool (septic tank) in the investigation communities exceeded the standard. Combined with the status quo of sewage pipelines and sewage treatment capacity in Beijing, it was not recommended to popularize the kitchen waste crusher in urban built-up areas and rural areas. The new community should have a surplus of rain and sewage diversion and sewage treatment plant operation, and the establishment of kitchen waste discharge system should meet the relevant engineering and technical standards before large-scale use of kitchen waste shredders. For communities that had installed kitchen waste shredders,oily food waste recommended to be unified recycling.

In order to solve the problem of acidification in restaurant food waste anaerobic fermentation (RFWAF). Different proportions of household food waste (HFW) and biogas residue biochar were added as conditioning agents into the acidogenic reactor. The effects of two conditioners on pH, total volatile fatty acids (TVFAs) and dissolved protein concentrations of restaurant food waste during the process of RFWAF acidification and acidification were studied. The results showed that biogas residue biochar could promote the accumulation of TVFAs and decrease the concentration of dissolved protein，which could not alleviate acidification. Although adding HFW promoted the accumulation of TVFAs, it also improved the content of dissolved protein in fermentation liquid. Under the condition of 15%TS , when the mass of household food waste addition were 1∶3，1∶1，3∶1, the average protein concentration increased by 27.7%, 55.2% and 58.9% compared with control group, respectively. Therefore, the anaerobic fermentation acidification could be alleviated and pH could be maintained stable by improving the alkalinity of the system.

A 500 t/d grate furnace of a domestic waste incineration power plant in Lhasa was taken as the research object， FLIC and ANSYS FLUENT software were respectively used to simulate the bed solid-phase combustion process and furnace gas-phase component combustion process under low pressure conditions. The numerical simulation results were compared with the monitoring data of the power plant， and the simulation results were in good agreement with the test data. After verifying the correctness of the combustion simulation method， the orthogonal test method was adopted to carry out the optimization simulation research on the air distribution of the waste incinerator. Through variance analysis， the operating conditions of the boiler under the optimal working conditions were predicted， and the main and secondary factors affected the boiler operation were determined to be the distribution ratio of primary and secondary air volume， and the distribution of primary air volume and the supply air temperature， respectively. When the furnace temperature did not meet the requirements in low pressure environment， it was provided that the ratio of primary and secondary air volume and the ratio of primary air volume could be preferentially adjusted. On the premise of satisfying the secondary combustion and the disturbance to the flue gas in the combustion chamber， the secondary air volume could be appropriately reduced to improve the flue gas temperature level in the combustion chamber.

As an efficient sludge disposal process, municipal sludge drying and incineration has been increasingly used in Chinese large and medium-sized cities in recent years. An energy-balance model for the systems of a typical drying and incineration process of municipal sludge was established, the energy balance of each system was calculated and analyzed. The results showed that the lower calorific value of dry sludge should reach about 14 200~15 500 kJ/kg to meet the self-sustaining energy balance of the system. Supplementary energy supply was needed when the sludge calorific value was insufficient. Steam was more economical than natural gas as a supplementary energy supply. In the site selection planning of sludge drying incineration project, environmental protection industrial park could be considered for steam coordination.Considering the rationality and economy of the process, it was recommended to control the water content of sludge in sludge incinerator at 60%~70%.

Waste to energy（WtE） plants have significant carbon emission reduction benefits， combined with cogeneration was expected to better help achieve the goal of carbon peak. A WtE plant was taken as an example， focused on the impact of cogeneration on the carbon emission reduction effect of the incinerator. The results showed that the carbon emission reduction per ton of waste without heating was 0.15 tCO2e compared with landfill disposal. If external heating was 20 t/h steam， the carbon emission reduction per ton of waste was 0.17 tCO2e. It showed that the carbon emission reduction benefit of cogeneration in the WtE plant was more obvious.

Two-stage sludge drying process by thin film dryer and linear dryer had features of high dry sludge yield (moisture content 10%~30%), safety (oxygen content<5%), high water evaporation efficiency, low equipment investment, stable operation and so on. The process flow, core equipment, process design and commissioning operation of a large-scale domestic municipal sludge treatment and disposal project with a capacity of 1 442.5 t/d was introduced. The project was equipped with 10 two-stage sludge drying lines, and the moisture content of feeding sludge was 78%~82%, the outgoing sludge moisture content could reach to 20%~33%. All performance assessment index and energy consumption index were up to standard.

Taking Nanjing as an example, the economic feasibility of recycled brick was studied by comparing the brick made from coal gangue, fly ash and construction and demolition debris. Only the revenue of the three brick-making methods during the operation period was considered, and the 3.0×105 t coal gangue, fly ash and construction and demolition debris were taken as an example. The operating costs were 48.00, 38.17 and 23.00 million, respectively, and the direct economic benefits calculated by the ratio of income to operating costs were 1.13, 1.18 and 1.49, which were greater than 1.00. It was showed that the benefits were greater than the costs, and the advantages of recycled bricks were obvious. Compared with gangue and fly ash, government subsidies accounted for 26.32% of the revenue from the recycled bricks made from construction and demolition debris, which could effectively guarantee the survival of construction and demolition debris recycling enterprises.The main reason for restricting recycled brick enterprises was that the low recovery rate of construction waste leaded to less recycled brick sources. And recycled bricks lacked competitive advantages with similar products in terms of social recognition, resulted in a lack of market competitiveness. Based on this, it was suggested that the government departments could improve the social recognition, product quality and competitiveness of recycled bricks by encouraging the use of recycled materials in new projects, issuing franchise operations and allocating special scientific research funds.

In order to solve the problem of large-scale resource utilization of phosphogypsum and consider the economy of engineering application. Sulfoaluminate high-activity material (SHAM) clinker prepared from total solid waste with advantages of early strength, high strength and low cost was used as the main cementing material. Phosphogypsum was modified by admixture such as distribution stone slag and mineral powder to prepare SHAM stable phosphogypsum mixture (SSPM), and the experimental research of SSPM used as pavement base material was carried out. The unconfined compressive strength test, water stability test and microstructure test of SSPM were carried out. The effects of carbide slag and mineral powder on the mechanical properties and water stability of SSPM were studied, and the action mechanism was analyzed. The effects of different SHAM clinker ratios on the mechanical properties of SSPM were studied. The results showed that the 7d unconfined compressive strength of SSPM was up to 6.02 MPa, which could be used as pavement base material. Admixture could promote the formation and stability of hydration products, adding 1% carbide slag and 3% mineral powder could improve the unconfined compressive strength of SSPM at any age. SSPM had good water stability, the softening coefficient was not less than 0.85, and the water-soaked strength could still meet the strength requirements of roadbed materials. With the increase of solid waste-based SHAM clinker content, the 7 d and 28 d strength of SSPM increased significantly, but the later strength of SSPM decreased when the content was more than 15%. This study could provide a feasible technological path for expanding the resource utilization of phosphogypsum and promote the development of low carbon cycle in society.

The PEST analysis method was adopted to analyze the development of construction and demolition debris treatment industry in china from four aspects of political environment, economic environment, social environment, and technological environment. The change process of construction and demolition debris from “filling and discarding materials in gullies” to “green construction hubs” was sorted out and summarized from different perspectives such as development stage, policy standards, and process technology. The release time of relevant policy documents in the construction and demolition debris treatment industry was taken as the historical coordinate axis, the development process of the industry was divided into four stages: embryonic stage, transitional stage, development stage, and deepening stage. Based on the time points of various planning periods in China, a detailed analysis was conducted on the development of the industry chain and investment operation mode, as well as the influencing factors and development trends of the social and technological environment. It was pointed out that with the promotion of the “dual carbon” strategy, China’s urban and rural construction had opened a new chapter led by green transformation, and the construction and demolition debris treatment industry would always be an important theme for the development of China’s circular economy.

Based on the construction background of “zero wastes city ”during the period of “14th Five-Year Plan”. The current status and development opportunities of urban construction and demolition debris recycle business were analyzed. The development model of construction and demolition debris resource industry was constructed, which supported multi-source solid waste collaborative disposal and was based on the dual circulation of matter and energy. And the relevant problems, supporting policies and development strategies that need to be solved urgently were put forward, which was expected to play a positive role in the healthy and well-organized development for China’s construction and demolition debris recycle business.

The solid waste was taken as research object. Three groups of anaerobic, aerobic and micro-aerobic landfill reactors were set up to analyze the three phase indexes of leachate, landfill waste, and landfill gas in landfill process, so as to study the stabilization process of landfill. The experimental results showed that the aerobic and micro-aerobic conditions could reduce the production of leachate and accelerate the degradation of pollutants in leachate. Compared with anaerobic landfill, the aerobic landfill reactor temperature was higher and the settlement rate of the waste pile was faster. In the process of micro-aerobic landfill, the concentration of O2 inside the landfill could be maintained at about 10%. The concentration distribution of O2 decreased from top to bottom. As the depth of the landfill increased, it became harder for the gas to disperse.

Landfill is the main application technology of rural domestic waste treatment in China. Based on the field survey of 15 small-scale landfills. The problems existed in most small-scale landfills in China were analyzed,and the characteristics of rural application miniaturization of landfill technology were clarified. The research showed that in terms of technology, the miniaturization of landfill technology currently had the practical problem of generally low construction and operation and maintenance level. In terms of economy, small-scale landfills that met the requirements of current standards had poor scale efficiency and high secondary pollution control costs. In terms of carbon emission, the existed small-scale landfills had high carbon emission intensity, so it was necessary to achieve the goal of reducing pollution and carbon by regulating the collection of landfill gas or reducing the direct landfill of primary waste. At the same time, the applicable areas of landfill technology in rural areas and relevant suggestions were put forward on this basis.

The membrane concentrate produced from landfill leachate has always been a technical problem in the industry. In order to explore a stable and reliable treatment process. The concentrated leachate from a typical domestic waste landfill in Guangzhou was taken as the research object, and conducted an experimental study on the full quantitative treatment technology of membrane concentration. The main technical routes included chemical softening pretreatment, two-effect negative pressure evaporation, centrifugal separation, deodorization and other process units. The research results showed that this concentrated liquid treatment technology could achieve continuous and stable operation at a concentration multiple of 10 times. After treatment, the condensed water could meet the standard for discharge. After solidification, the salt mud could meet the landfill requirements. The odor treatment effect was good. At the same time, the coreheat exchanger of the evaporation device had good anti scaling performance.

The “double carbon” goal is a significant strategic decision for China, aimed at building a community with a shared future and achieving sustainable development. Constructing a green, low-carbon circular economic development system and enhancing the recycling of renewable resources were the key components to achieve the goal of “double carbon”. Three research methods of field visit, qualitative induction, and quantitative analysis were employed to investigate the recycling modes of recyclables in Huangpu district, Shanghai. The results indicated that the district had established a “recyclables” system, and the "points and stations" of recyclables had been basically covered. However, several challenges persisted, including site limitations, notable NIMBY effects, inadequate public awareness, variations in categorization, and insufficient engagement from recycling enterprises. These factors hindered the overall development of the classification system. Based on the current state of recyclable collection and transportation in Huangpu district, several policy suggestions were proposed, such as enhancing public awareness of fine classification, implementing rational facility planning, establishing a comprehensive digital supervision system, and providing differentiated subsidies for various recyclable categories.

Assessment is an important measure to promote the classification of municipal solid waste(MSW). A quantifiable evaluation method system was proposed from five aspects, including system and mechanism construction, classified delivery, classified collection and transportation, classified treatment, and civilized habit formation, and had been applied to the evaluation of MSW classification in key cities.Through a comprehensive and systematic evaluation and analysis of 46 key cities, the effectiveness of MSW classification was studied, the innovative methods and experience of urban practice were summarized and extracted, the common problems in the implementation of waste classification were analyzed and defined.And suggestions were puts forward from the national level, local level and different levels of cities,to provide technical support for the competent departments of the sanitation industry to inspect and guide the promotion of MSW classification, and to provide demonstration and guidance for the national MSW classification.