To redistribute the construction waste properly and optimize the existing collection and transportation system, the construction planning of construction waste redistribution sites in a city was studied by using cluster analysis and particle swarm optimization algorithm. Taking the four districts of a city as the research objects, the cluster analysis was used to obtain the classification results of construction waste generation points for different redistribution site construction plans. By comparing the total cost of each plan, the results showed that the number of redistribution sites in optimized construction scheme was four and the lowest cost was 177.959 5 million yuan. On this basis, the particle swarm optimization algorithm was applied to optimize the construction waste redistribution route planning with the objective of minimizing the cost. The optimal site selection results for the construction of each redistribution site were obtained, which could minimize the redistribution distance and cost of construction waste in the city. Additionally, guiding recommendations for the construction of the redistribution sites were provided.

Influenced by the differences in domestic waste composition, calorific value and flue gas purification process, the water emission control objects and elements of waste incineration plants in European Union, United States, Japan and China are significantly different. Based on the relevant water discharge standards and regulatory requirements in domestic and foreign, the differences and reasons of domestic and foreign standards were discussed from the perspectives of control objects, discharge limits and implementation standards. The analysis showed that the wastewater treatment object of domestic waste incineration plants in European Union and Japan was wet flue gas process wastewater, and the key control factor was dioxins. In United States, there was no waste water to be treated in domestic waste incineration plants, so no sewage treatment facilities were equipped. The wastewater treatment object of domestic waste incineration plant in China was mainly leachate, and the key control factors were organic pollutants and heavy metals. In the control of wet flue gas process wastewater, European Union controlled more factors than Japan, but the concentration limit of dioxin emission was relatively relaxed. Japan only controlled the concentration of dioxins discharged into natural water from domestic waste incineration plants, but the limits were relatively strict. In terms of the standard determination of the quality of wastewater discharged into natural water, United States and European Union standards allow the emission concentration of pollutants to fluctuate reasonably within a certain range for a short time. Standards in Japan and China are more emphasis on non-discriminatory environmental regulation to reflect the principle of justice and equality, and once the concentration exceed the limit value， it is considered to exceed the emission. Finally, in view of the water emission management of domestic waste incineration industry in China, suggestions were put forward to reasonably determine the control factors and emission requirements, further optimize and expand more flexible emission limits and regulatory measures.

The basic material properties and potential environmental risks of fecal sludge from urban public toilets were preliminary discussed. Taking five public toilets in Shanghai as the research object, various methods were used to determine the nutrient, pathogenic microorganism, heavy metals, and antibiotic content in its fecal sludge, in order to provide specific data support for the subsequent resource utilization of fecal sludge. The results showed that the fecal sludge was rich in organic matter and nutrients, while could be used as the fertilizer raw material, but the carbon-nitrogen ratio (C/N) was significantly lower than the C/N ratio required (15~25) for general conventional composting treatment processes. All samples contained fecal coliform, fecal enterococci, and salmonella, with fecal coliform levels ranging from 53 700 n/g to 92 100 n/g. The content of heavy metals in fecal sludge was much lower than that in municipal sludge, and the environmental risk indexes of Zn, Cu, Cr, Cd, Pb, and Ni were all below 10. The composite risk index was 19.36, indicating low eco-risk. The ecological risk levels of tetracycline, chlortetracycline and sulfamethoxazole detected in the five groups of fecal sludge were the second risk level, that is, although the ecological risk of antibiotics in fecal sludge for direct agricultural use was low, it could not be ignored. Therefore, urban fecal sludge from septic tank has a high potential for resource utilization, but appropriate treatment technologies need to be selected to cope with the above potential risks.

The total design scale of a waste sorting collection and treatment center in Wuxi was 510 t/d. The main construction contents included domestic waste transfer system, other kitchen waste treatment system, and associated odor and wastewater treatment systems. The “horizontal pre-compression” process was adopted for the transfer of domestic waste, while the “pretreatment + aerobic composting” process was adopted for the disposal of other kitchen waste. According to the area and concentration of wastewater and odor produced in the processes of waste compression and treatment, high and low concentration treatment systems were set up respectively to achieve environmental protection requirements through zonal and quality-based treatment. The construction of the project has realized the classification， transportation and disposal of domestic waste, and greatly reducing the impact of domestic waste transfer and treatment facilities on the surrounding environment,which can provide reference for the design of waste sorting and transfer stations in economically advanced regions in China.

Qingdao city is one of the core areas to promote ecological protection and high-quality development in the Yellow River basin. It is of great significance to study the status, sources and potential risks of heavy metal pollution in the surface soil of this region. Based on the content and pollution characteristics of 6 heavy metal elements (As, Cd, Cu, Pb, Hg, Ni) in the surface soil (0-20 cm) of an industrial park in Qingdao,the correlation analysis and positive definite matrix factorization (PMF) model were used to analyze the source of heavy metals in soil. The results showed that all heavy metal elements in surface soil did not exceed the second type of construction land screening values in GB 36600—2018 Soil Environment Quality Risk Control Standard for Soil Contamination of Development Land. However, compared with the background value in Shandong province, all heavy metal elements were enriched to different degrees, Cd and Hg were 6.38 and 4.85 times of the background value, respectively, showed obvious enrichment. The variation coefficients of Cd and Hg were greater than 100%, which belonged to strong variation, the other heavy metals showed moderate variation. The variation coefficients of As, Cu and Pb were slightly more than 50%, and the variation coefficient of Ni was the smallest (32%). The evaluation results of the local accumulation index showed that Ni, Cu and As were pollution-free (Igeo<0), Pb and Cd were mildly polluted (0≤Igeo<1), and Hg was moderately polluted (1≤Igeo<2). Source analysis results showed that the sources of heavy metals in the surface soil in the park were affected by pesticide and fertilizer production activities, industrial emissions, atmospheric subsidence and natural sources, and their contribution rates were 15.99%, 37.32%, 30.35% and 16.34%, respectively.

The changes in composition and characteristics of terminal municipal solid waste (MSW) were analyzed based on the monitoring data which collected in the last decade from a city in South China. The results indicated that food waste consistently constituted the highest proportion of wet-based components in MSW, ranged from 45.9% to 55.1%; followed by rubber and plastic, paper, and textiles, which were 21.1%-27.8%, 5.6%-14.5%, and 4.0%-10.5%, respectively; the proportion of all other wet-based components accounted for no more than 5.0%. The bulk density of MSW ranged from 197 kg/m3 to 278 kg/m3, and the moisture content ranged from 53% to 60%. The content of wet-based combustible changed little overall in the last 10 years, with an average value of 37%; the wet-based content of ash decreased from 11% to 6%. In the past 10 years, the wet-based low calorific value of MSW showed an overall upward trend, which increased from 5 571 kJ/kg to 6 361 kJ/kg. The content of carbon, hydrogen, and oxygen in the dry basis all showed an increasing trend in the last decade, the carbon content increased from 37.6% to 44.6%, the hydrogen content increased from 5.51% to 6.51%, and the oxygen content increased from 24.5% to 25.4%. Meanwhile, the content of nitrogen and chlorine in the dry basis both decreased, the nitrogen content decreased from 2.95% to 1.45%, and the chlorine content decreased from 0.51% to 0.45%, while the sulfur content increased from 0.15% to 0.22%. The research results could provide a reference for the selection of terminal treatment method of MSW and the optimization of terminal treatment facilities in this study area.

Aerobic composting is an effective way for resource utilization of digestate and kitchen waste. Co-composting of digestate and kitchen waste can effectively improve the physicochemical properties of the compost pile and thus increase the composting efficiency, but the compounding ratio of the two co-composts still needs to be explored. In this study, five treatment groups were set up for co-composting with the mass ratio of digestate to kitchen waste of 10.0∶0, 7.5∶2.5, 5.0∶5.0, 2.5∶7.5, and 0∶10.0. The physicochemical indexes in the composting process as well as the degree of humification of the final product were used as the evaluation indexes in order to determine the optimal ratio of co-composting of kitchen waste to digestate, which could provide a reference for the improvement of the efficiency of the joint resource utilization of digestate and kitchen waste. The results showed that when the mass ratio of digestate to kitchen waste was 2.5∶7.5, it could enter the high-temperature period quickly and maintain for seven days in the high-temperature period, which met GB 7959—2012 Hygienic Requirements for Harmless Disposal of Night Soil. The pH, organic content, and seed germination index of the five treatments were all in line with the requirements of NY/T 525—2021 Organic Fertilizer. The lower water-soluble NH4+ in the compost product with the mass ratio of digestate to kitchen waste of 2.5∶7.5 indicated that it had less plant toxicity. Results analysis of humic acid content and ratio of humic acid and fulvic acid showed that the final product with mass ratio of digestate to kitchen waste of 2.5∶7.5 had the highest degree of humification, but it contained high levels of Na+ and Cl-, and the adverse effects of salts on plants should be taken into account in land application. In conclusion, the mass ratio of digestate to kitchen waste of 2.5∶7.5 was the optimal ratio for co-composting， which had the highest humification efficiency, the better quality of final product, and a high potential for land application.

Under the background of “dual carbon”, the preparation of biodiesel from kitchen waste oil would play an important role in achieving “turning waste into treasure”and the green and low-carbon transformation of energy. The energy consumption and greenhouse gas emissions of kitchen waste oil throughout its lifecycle from production to the production of biodiesel were analyzed. And it was compared with the entire process of petrochemical diesel production. The greenhouse gas emissions contribution of each stage in the preparation of biodiesel from kitchen waste oil, as well as the energy consumption and CO2 emissions comparison of biodiesel production between enzymatic and traditional ester exchange methods were analyzed. The results showed that compared with petrochemical diesel, the energy consumption of biodiesel produced by enzymatic method was reduced by 71.43%, and the GWP of CO2 and greenhouse gas were reduced by 60.09% and 59.79%, respectively. The pre-treatment of trench oil and frying oil, as well as the deep processing of waste oil and fat, were the main stages of energy consumption and greenhouse gas emissions throughout the entire life cycle of waste oil and fat. The greenhouse gas emissions caused by methanol and steam production was the main reasons. Compared with the ester exchange method, the energy consumption of biodiesel process using bioenzyme method was reduced by 4.58%, and the GWP of CO2 and greenhouse gas were reduced by 38.53% and 38.52%, respectively. It was recommended to develop a biodiesel processing technology using kitchen waste oil as raw material in China, to prevent kitchen waste oil from flowing back to the dining table, save fossil energy consumption, and reduce greenhouse gas emissions.

With the maturation of anaerobic digestion technology in the treatment of wet waste projects, the resource utilization of anaerobic biogas has become a significant method for the resource recovery of wet waste. The principles, processes and characteristics of four utilization technologies for anaerobic biogas were summarized, including biogas purification for natural gas production, biogas cogeneration, direct combustion of biogas for heating, and hydrogen production. Based on the data from four typical engineering cases, an economic model was established for cost and benefit analysis with the biogas utilization scale of 3 000 m3/h. The comprehensive benefit ranking of the four typical cases was biogas cogeneration (with electricity price subsidies)>biogas purification for natural gas production>biogas cogeneration (without electricity price subsidies)>direct combustion of biogas for heating. The final selection of the biogas resource utilization schemes for wet waste projects should fully consider various factors such as the scale of the wet waste project, site boundary conditions, project investment, electricity and steam costs, product market consumption and prices, and comprehensive economic benefits. The research results indicated that the product price was the most critical factor affecting the comprehensive benefits of biogas resource utilization schemes. When the sales price of natural gas exceeded 2.28/2.68 yuan/m3（under the conditions of collaborative low-cost power and heating in the park）or the sales price of steam exceeded 191.50/229.30 yuan/t, the comprehensive benefits of the corresponding biogas utilization scheme were higher than those of the cogeneration scheme without/with grid electricity price subsidies.

Food waste pretreatment slurry can theoretically be used as a carbon source in the biological denitrification process of wastewater treatment due to its high COD concentration. However, direct dosing of food waste pretreatment slurry in these processes was limited as its high SS content could easily lead to membrane fouling in follow-up processes. In order to solve this problem, a new type of dish centrifuge was used to treat food waste pretreatment slurry, and the treatment performance was analyzed under different feed temperatures, nozzle pore sizes and slag discharge intervals. The results showed that the optimal operating parameters were under the temperature of 60 ℃, the nozzle aperture of 0.6 mm and the slag discharge interval of 5 minutes, with a suspended solids removal rate of 85.95%. Engineering application results showed that food waste-originated carbon source could partially replace commercial carbon source in biochemical treatment process. While the equivalent ratio of food waste-originated carbon source to methanol was about 24∶1, and methanol dosage could be reduced by up to 30%.

With high-density polyethylene (HDPE) and sawdust as the research objects, combined with thermodynamic analysis and experimental research, the influence rule of input power, HDPE mass ratio and steam-to-carbon ratio (S/C) on hydrogen production rate, gas product composition, and chlorine release behavior in the process of plasma gasification were investigated. Moreover, thermodynamic calculations was conducted based on the Gibbs minimum free energy principle. Simulation analysis revealed that increasing input power from 7.5 kW to 34.0 kW resulted in a maximum hydrogen proportion rate of 59% at 20 kW (corresponding temperature at 800 ℃). As HDPE mass ratio increased from 0 to 100%, the hydrogen production rate decreased from 65% to 56%. When S/C was 0, the proportion of hydrogen was the highest (80%), and with S/C increased from 0 to 3.0, the proportion of hydrogen showed a decreased trend. Chlorine products in the gas phase mainly comprised KCl(g) and (KCl)2(g). Experimental results confirmed the consistency between the effects of input power, HDPE mass ratio, and S/C on hydrogen production with thermodynamic analysis. When the input power was 22 kW, the proportion of HDPE raw material was 80% and S/C was 1.0, the optimal hydrogen production were 1.52 m3/kg, 1.51 m3/kg and 1.38 m3/kg， respectively. Gas-phase chlorine distribution reached the highest when the input power was at 22 kW, HDPE mass distribution of 20% and S/C of 1.4. Comparison of the experimental results validated the potential of thermodynamic simulation for qualitative and quantitative analysis of plasma gasification products. The feasibility of using thermodynamic calculation to simulate the co-gasification of biomass and HDPE plasma was explored, which could provide reference for the operation optimization and chlorine control of plasma gasification.

The harm of smoking mainly comes from the harmful substances produced by the combustion of cigarettes, such as tar, polycyclic aromatic hydrocarbons, carbon monoxide, and cyanides. These substances could lead to various diseases including cardiovascular diseases, respiratory system diseases, cancer, and chronic inflammation. Therefore, it was urgent to reduce the harm of cigarettes and decrease the content of tar and other harmful substances. To this end, the generation patterns of harmful substances in cigarette smoke and the mainstream technologies for harm reduction and tar reduction were extensively explored. The application of numerical simulation techniques in cigarette combustion and harm reduction were introduced. Thereby providing both theoretical foundations and practical guidelines for a comprehensive understanding of cigarettes and related issues, as well as for reducing the health hazards of smoking.

At present, the deacidification process of flue gas of established sludge incineration projects in China mostly adopts the wet process-based route. For the projects constructing in the “isolated island” mode, the cost of zero discharge of deacidification wastewater is high, while the operation cost of the wet-based deacidification route has no advantages. The deacidification process of an “isolated island” sludge incineration project was taken as the research object, the characteristics of the commonly used deacidification process were analyzed. Meanwhile, seven schemes were set up from the aspects of deacidification agent selection, deacidification efficiency allocation, fly ash chelation and so on, in order to contrast the operating cost of different process combination schemes, and demonstrate the rationality of the selection of deacidification process route for this project. Finally, suggestions on the selection of flue gas deacidification process for sludge incineration projects were put forward combined with the feasibility of wastewater discharge and fly ash chelation, which could provide reference suggestions for the design of new sludge incineration or process transformation projects.

A MSW landfill in Guangdong province had reached the limit of storage capacity, and had environmental pollution and safety risks, which need to be rectified. The comprehensive remediation of the project phased closure was implemented by taking engineering measures such as landfill shaping, mid-term covering, leachate collection and drainage, rainwater interception and drainage, groundwater vertical barrier,contaminated groundwater pumping and groundwater (surface water) pollution monitoring. After the remediation of the project, groundwater and the settlement rate of landfill pile were regularly detected, which could availably prevent environmental safety risks after the phased closure of the landfill and minimize secondary pollution. Meanwhile, the average leachate treatment capacity of the landfill decreased from 966 t/d in 2019 to 380 t/d in 2023, and the leachate production gradually stabilized. The settlement rate of landfill pile gradually decreased from 2.41 mm/d (87.97 cm/a) in April 2021 to 0.76 mm/d (27.74 cm/a) in September 2023, and the settlement rate gradually slowed down after a rapid decline. According to GB/T 25179—2010 Technical Requirements for Site Utilization after Stabilization in Municipal Solid Waste Landfill, the project is still in the uneven settlement period (10~30 cm/a) at this stage, and continuous dynamic monitoring is required. The main pollution indicators of groundwater including CODMn and NH3-N concentration basically met the requirements of the Class IV standard limit in the GB/T 14848—2017 Standard for Groundwater Quality. The implementation of engineering measures for this project could provide powerful data support for the safe utilization of the landfill site after the phased closure, while it also could provide reference for similar projects in the future.

Taking an informal landfill in Zhejiang province as an example, the landfill gas content, leachate concentration, organic matter content and biodegradability of waste was investigated, to analysis the pollution status, stabilization level and environmental risk of the landfill. The results showed that the CH4 volume fraction in landfill gas ranged from 2.41% to 44.94%, with an average of 25.64%. While 87% of drilling sites CH4 volume fraction exceeded the gas limit value (5%) above the landfill in GB 16889—2024 Standard for Pollution Control on the Landfill Site of Municipal Solid Waste. 12 indexes such as color scale, SS, COD, BOD5, Hg and Cr in landfill leachate exceeded the standard value in GB 16889—2024, and the exceeding standard rate were all more than 30%. The contents of organic matter and biodegradability in the waste pile were both high, ranging from 30.50% to 70.70% and 7.10% to 19.40%, respectively, so the degree of waste decay was low. In short, although the landfill had been closed for a long time, it had high methane production, organic matter content, biodegradability and leachate concentration, which was still in an unstable state. In addition, the pollution risk index of the stock garbage was 90.93 points, which belongs to the high level pollution risk, indicating that the informal landfill has great environmental risks and security risks due to its large scale and pollution-free prevention and control measures.

The mechanical properties of waste humus soil are of great significance to its reuse in geotechnical engineering. The humus soil retrieved from the landfill site was used as the object, based on saturation permeability test, unconfined compressive strength test, direct shear test and consolidation compression test, the influence of landfill age and compaction degree on the mechanical properties of humus samples was analyzed, and discussed the influence mechanism. The results showed that the permeability coefficient of the compacted humus was in the order of 10-5-10-7 cm/s, and with the increase of landfill age and compaction degree, the permeability coefficient all decreased and tended to a stable value. The mechanical properties of compacted humus soil were significantly affected by landfill age and compacted degree, the unconfined compressive strength, elastic modulus, cohesive force and compression modulus all increased with the increase of landfill age and compaction degree. While the compression coefficient decreased with the increase of landfill age and compaction degree. The above results provided key theoretical support for the reuse of humus soil.

he regulation of informal waste dumps is an inevitable move to promote the construction of ecological civilization. Combining with the project case, the regulation methods of the informal landfill sites through excavation and screening were discussed. The screening process is very complex, and the screening quality would be affected by the screening material characteristics, the screening equipment and other factors. Through the field test, the effect of natural drying and adding different proportion of quicklime on moisture content, and the effect of roller screen speed on screening quality under the optimal moisture content were analyzed. The results indicated that the moisture content of refuse soil could be improved effectively (24.2%) with the addition of 4% quicklime, the refuse soil was overturned and exposed to sunlight for 1 hour followed by covering for 2 hours. When the rotary speed of the drum sieve reached 25 r/min, the optimal screening efficiency （87%） was obtained, which met the requirements for project implementation.