Household hazardous waste quantification, characterization and management in China's cities: a case study of Suzhou

Data-driven models applying in household hazardous waste: Amount prediction and classification in Shanghai

Precisely predicting the amount of household hazardous waste (HHW) and classifying it intelligently is crucial for effective city management. Although data-driven models have the potential to address these problems, there have been few studies utilizing this approach for HHW prediction and classification due to the scarcity of available data. To address this, the current study employed the prophet model to forecast HHW quantities based on the Integration of Two Networks systems in Shanghai. HHW classification was performed using HVGGNet structures, which were based on VGG and transfer learning. To expedite the process of finding the optimal global learning rate, the method of cyclical learning rate was adopted, thus avoiding the need for repeated testing. Results showed that the average rate of HHW generation was 0.1 g/person/day, with the most significant waste categories being fluorescent lamps (30.6 %), paint barrels (26.1 %), medicine (26.2 %), battery (15.8 %), thermometer (0.03 %), and others (1.22 %). Recovering rare earth element (18.85 kg), Cd (3064.10 kg), Hg (15643.43 kg), Zn (14239.07 kg), Ag (11805.81 kg), Ni (4956.64 kg) and Li (1081.45 kg) from HHW can help avoid groundwater pollution, soil contamination and air pollution. HVGGNet-11 demonstrated 90.5 % precision and was deemed most suitable for HHW sorting. Furthermore, the prophet model predicted that HHW in Shanghai would increase from 794.43 t in 2020 to 2049.67 t in 2025.

An Analysis of the Factors behind Rural Residents' Satisfaction with Residential Waste Management in Jiangxi, China

With the increasing environmental and health problems caused by residential solid waste (RSW), upgrading waste disposal services has become a key priority in rural areas of developing countries. Waste disposal services can be improved by incorporating the end-user evaluation of the services and the infrastructure. This study aims to analyze the respondents' satisfaction with waste disposal services and infrastructure in rural China, which has not been well documented in the previous literature. For this purpose, we applied the ordered probit model on survey data of 1064 rural residents of Jiangxi, China. In two separate models, two independent variables, i.e., users' ranking of waste disposal management services and waste disposal management infrastructure, were regressed on five sets of policy, personal, social and demographic, environmental, and village characteristics of the respondents. Our results show that rural residents have relatively high satisfaction (level four out of five) with RSW services. We found a significant correlation between all five investigated characteristics (personal, social and demographic, environmental, and village characteristics) and respondents' satisfaction with RSW management. However, the correlation differs in magnitude and direction among different respondent groups, where gender, minority status, the sanitary condition of household toilets, and treatment of toilet waste at the village level have the largest influence on satisfaction. It was found that male respondents, ethnic minorities, residents with non-farming status, and respondents with more sanitary household toilets have higher satisfaction levels. Our results provide crucial references for decision-makers to effectively promote the further optimization and improvement of rural waste disposal systems in the future.

Towards a Circular Economy Development for Household Used Cooking Oil in Guayaquil: Quantification, Characterization, Modeling, and Geographical Mapping

The objective of the present study was to quantify, geo-locate, model, and characterize domestic used cooking oil (dUCO) generation for the city of Guayaquil. For this reason, and as a prerequisite for the proper planning of municipal cooking oil waste management in the city, we carried out 14-day fieldwork involving 532 households from different parishes of Guayaquil, combined with a survey to acquire data on their demographic and socioeconomic statistics. The artisanal characterization was further executed to 40 subsamples of dUCO to determine the density, moisture, solids content, and the volatile-matter characteristics present. Additionally, the Geographic Information System (GIS) was used to map the used cooking oil generation hotspots for the city, adding the Geographical Position System (GPS) of each participating household during the data acquisition. Finally, a multiple-regression model was proposed to establish correlations between the dUCO generated and five independent variables, such as household size, socioeconomic group, tenure status, education level, and income. Results showed that the per capita daily dUCO-generation rate was found to be 4.30 g/day/c or 4.99 mL/day/c, with a density of 0.86 g/mL. Filterable solids represented 0.37% for the entire dUCO collected sample, while separable water and grease represented 1.58% and 0.014%, respectively. In addition, the percentage of the volatile matter was found to be 7.7% ± 2.1% of the filtered dUCO. Using GIS mapping, we found that the areas near tourism sites have a higher dUCO generation value, considering the household survey. Following the developed multiple-regression model developed, it was found that household size and the socioeconomic group have the maximum effect on generating used cooking oil.

The Influence of Message Framing on Residents' Waste Separation Willingness-The Mediating Role of Moral Identity

With serious environmental problems increasing, waste separation has drawn much attention. Message framing is an important way to popularize separation knowledge and increase people's separation willingness. Message framing was classified into positive and negative frames in this study, and then based on moral identity theory from the social cognitive perspective, two dimensions of moral identity were introduced as mediating variables to construct a mechanism model of the influence of message framing on waste separation willingness. After a comparative study of three groups of subjects (N = 604), the following conclusions were drawn: (1) message framing positively influenced moral identity and waste separation willingness; (2) both positive and negative message framing positively influenced waste separation willingness through the partial mediating role of moral identity symbolization and internalization; and (3) the mediating role of symbolization was stronger in the effect of positive message framing on waste separation willingness, while the mediating role of internalization was stronger in the effect of negative message framing on waste separation willingness. The findings provide significant information for organizations to effectively carry out message strategies.

Promoting Chinese urban residents' participation in source separation and recycling

Source separation and recycling (SSR) for municipal solid waste is an important strategy for the transition to a circular economy and requires broader resident participation. How can residents' participation in SSR be promoted? Here, we consider 13 cities in Jiangsu as microcosms of China. We quantify residents' intentions to participate in SSR by distributing a validated questionnaire to 2,963 urban residents, analyze the results through structural equation modeling, and propose localized policy recommendations. We find that residents have positive attitudes toward SSR, although 92.6% of residents in southern Jiangsu were more willing to participate than those in northern Jiangsu (84.6%). Additionally, the influencing factors and their degree of influence on resident SSR participation intentions exhibit disparities across cities. "Accessibility of SSR facilities" simultaneously affects the 13 studied cities and is a key factor. "Environmental knowledge" and "environmental attitudes" are important impact factors, with occurrence frequencies of 84.6% and 69.2%, respectively. However, laws and regulations have no significant effect on residents' SSR participation intentions. We recommend that the government create favorable external conditions related to facilities and services, promote extensive publicity and educational activities through various channels, and improve the effectiveness of SSR laws and regulations. Future SSR management strategies should be localized, flexible and comprehensive. This research could help decision makers in China and other countries design policy guides to promote SSR and help link current research areas to social development.

Reverse logistics research of municipal hazardous waste: a literature review

The reverse logistics of municipal hazardous waste (RLMHW) have received close attention from researchers and practitioners alike, given the essential impact of safe transportation and effective management of hazardous waste on public health and environmental sustainability. There are a great number of studies in the extant literature on RLMHW, with many and diverse research topics; however, a concise and complete overview of the research works already conducted in this particular area is conspicuous by its absence. This paper strives to fill the gap through the conduct of rigorous systematic literature review of RLMHW in the past three decades, and then establish a framework of studies on RLMHW. The main contributions of this study are as follows: (1) to identify the trend of journals publishing research papers on RLMHW; (2) to extract the main topics in studies on RLMHW; (3) to locate the most popular research areas of RLMHW; (4) to summarize the methods adopted in studies on RLMHW; (5) to identify research deficiencies in certain categories of RLMHW; and (6) to establish the future research directions of RLMHW. The main implications of the study are to offer a better understanding of RLMHW by systematic crystallization of archival data in a systematic chronological order across central issues. This study contributes to scholarly debate in this field by serving as a snapshot paper to document the development of the field and gives input to policymakers in process design and policy making in the domain of RLMHW.

Household hazardous waste characterization and quantification at source in Thailand

Thailand is facing a management crisis of both urban and rural household hazardous waste (HHW). The collection and disposal of these wastes threaten both the environment and human health. The objective of the study was to investigate the characterization and quantification of household hazardous waste at source by all local administrations in Nakhon Nayok province, Thailand. The quantity of HHW in the household waste stream constitutes 2.53% of total household wastes (about 2.90 t/day). Most HHWs were generated in the local administration level (3.2%) followed by the subdistrict (2.9%) and municipality level (1.2%). The characterization of HHWs included paint products (20.1%), household batteries (17.4%), and unused medicines (14.1%). HHW characterization can be grouped as automobile products from municipalities (38.5%), paint and its containers from the subdistricts (43.08%), and pesticides from the more rural local administrations (24.73%). Albeit the amount of HHW waste found in the household waste stream is relatively small compared to the overall waste stream, it can still cause significant damage to human health and environment. This is because the elements and compounds that comprise hazard wastes are toxic at very low levels. Programs are needed to increase appropriate management of HHW to mitigate human health and environmental contamination risks. Reducing and separating HHW at source can minimize these problems during both normal and pandemic situations.Implications: The study of household hazardous waste (HHW) characterization and quantification is very importance for HHW management, especially study at source. In this study we found the smallest province in Thailand can produce HHW volume nearly three tons per day. The trend in consumption of household products may be increase. The government should therefore be more focused on HHW at source management in both normal and pandemic situations.

Optical, magnetic and electrical properties of new ceramics/lead silicate glass composites recycled from lead crystal wastes

Nowadays, the disposal of industrial wastes is an ablaze issue worldwide, especially those containing hazardous materials. Lead silicate glass waste (LSG) produced during lead crystal glass manufacturing, which contains about 30% of toxic lead compounds, belongs to this category. This work aims to adopt an innovative clean method to convert this waste into novel advanced ceramic materials via an environmental friendly method. Chromia Cr₂O₃ and hematite Fe₂O₃ ceramics with different content (0, 5, 10, 15%) are added separately to the solid wastes of LSG recovered from national crystal glass industry to obtain various ceramics/LSG composites by pressureless sintering methods. Different properties of the produced composites are evaluated in terms of phase's identification and microstructural features. Optical properties in terms of absorbance, reflectance, band gap (E_g), refractive index (n) and photoluminescence (PL) are investigated. Magnetic and electrical properties are inclusively studied. Results indicated that, an addition of chromia and hematite as well as increasing their content to 15% has enhanced the microstructural features, optical, electrical and magnetic properties of the obtained composites. Cr₂O₃/LSG composites are considered as promising optical and electrical materials. However, Fe₂O₃/LSG composites showed the highest optical and magnetic properties. They are strongly recommended in optoelectronic and magneto-optical applications.

Environmental impacts characterization of packaging waste generated by urban food delivery services. A big-data analysis in Jing-Jin-Ji region (China)

Controversies on food delivery services environmental impacts have been sparked due to the growth of this economic sector. This study focuses on the environmental impacts generated by packaging waste related to urban food delivery services. In particular, the Python based web-crawling and sample survey methods are used for big data mining, and LCA-based environmental impacts evaluation and Kernel density analysis methods are combined to determine the positioning trend of food delivery service providers and expansion direction of environmental pollution load in Jing-Jin-Ji region (North China). Results indicate that (1) food delivery service packages presently account for a very small proportion (<0.1%) of municipal solid waste (MSW). However, this study also evidences that food packaging accounts for 15.7% of the total MSW generated in this region. Even if this growing market sector might have a relatively low impact, households' lifestyle might affect the results. (2) In terms of consumption quantity, plastic bags are the most used packages, accounting for 35.08%; wooden chopsticks account for 32.21% and plastic boxes account for 27.43%. Among all environmental impact categories resulting from the process of production of packages, greenhouse effect is the most distinct one. Paper boxes generate the most serious environmental pollution. (3) The distribution of environmental pollution loads resulting from food delivery service packages positively correlates with the distribution of food delivery service providers in Jing-Jin-Ji. Shijiazhuang has the highest degree of pollution resulting from food delivery service packages with the interrupt value ratio of 80%, followed by Baoding City and Chengde City, which have the interrupt value ratios of 65.1% and 48.6%, respectively. Finally, as bridges between food delivery service providers and consumers, food delivery service platforms should improve their environmental protection mechanisms. Meanwhile, the government should define a standard concerning food delivery service packages to consolidate the concept of environmental protection in the society to change the ways people consume, in order to achieve a harmonious co-existence between resource utilization and environmental protection.

New Policy and Implementation of Municipal Solid Waste Classification in Shanghai, China

To promote sustainable development, the Chinese government launched a new municipal solid waste (MSW) classification strategy in 2017. Shanghai was selected as one of the first pilot cities for MSW classification. The Shanghai municipal government first established the new MSW classification policy in 2017. The Shanghai Municipal Solid Waste Management Regulation was published in 2019 and came into effect on 1 July 2019. This short communication reports on Shanghai's new MSW classification policy and its implementation. The main content and measures adopted by Shanghai's government to ensure the effective implementation of the new MSW classification policy are introduced. Besides, a SWOT (i.e., strengths, weaknesses, opportunities, and threats) analysis on the present policy and measures is conducted, and based on the results, some discussions and suggestions regarding the implementation of MSW classification in Shanghai and the whole of China are presented.

Endoscopic findings and outcome in caustic ingestion of acidic and alkaline agents in adults: A retrospective analysis

Caustic ingestion in adults is a rare but potentially life-threatening problem. It remains controversial whether endoscopic findings and mortality differ between acid and alkali ingestion. We compared ingestion of these agents and evaluated prediction parameters for survival and complications.Adult patients who presented with caustic ingestion were analyzed from 2005 to 2016. Mucosal injury was graded endoscopically by Zargar's score. Age, gender, intent of ingestion, caustic agents, comorbidities, management, complications, and mortality were examined.Thirty-one patients met inclusion criteria and were divided into acid (n = 10) and alkali group (n = 21). Ingestion of alkali resulted in higher grades (≥III) of esophageal (56% vs 24%, P = .01) and stomach injuries (43% vs 13%, P = .05) and was mostly done with suicidal intent (76% vs 30%, P = .003). Patients in the alkali group received more often surgical interventions, mechanical ventilation and tracheotomy. Overall complications including Zargar's-score ≥ grade III, mediastinitis, and aspiration pneumonia were higher in alkali group but all showed no statistical significance (P = .73). Mortality (acid: 1 (10%), alkali: 4 (19%), P = .52), age, gender, comorbidities, and intensive care management did not differ significantly between the groups. Chronic renal failure and mediastinitis were promising prediction parameters for mortality but did not reach statistical significance. No independent risk factors for the development of esophageal stenosis were identified.Alkaline agents caused a higher mucosal injury severity and were more often used in suicidal intent. Mediastinitis and chronic renal failure might be potential prediction parameters for survival but need to be evaluated in larger studies.

Methodological aspects of modeling household solid waste generation in Japan: Evidence from Okayama and Otsu cities

This paper presents a quantitative methodology and two empirical case studies in Japan on modeling household solid waste (HSW) generation based on individual consumption expenditure (ICE) and local waste policy effects by using the coupled estimation model systems. Results indicate that ICE on food, miscellaneous commodities and services, as well as education, cultural, and recreation services are mainly associated with the changes of HSW generation and its components in Okayama and Otsu from 1980 to 2014. The effects of waste policy measures were also identified. HSW generation in Okayama will increase from 11.60 million tons (mt) in 1980 to 25.02 mt in 2025, and the corresponding figures are 6.82 mt (in 1980) and 14.00 mt (in 2025) in Otsu. To better manage local HSW, several possible and appropriate implications such as promoting a green lifestyle, extending producer responsibility, intensifying recycling and source separation, generalizing composting, and establishing flexible measures and sustainable policies should be adopted. Results of this study would facilitate consumer management of low waste generation and support an effective HSW policy design in the two case cities. Success could lead to emulation by other Japanese cities seeking to build and maintain a sustainable, eco-friendly society. Moreover, the methodologies of establishing coupled estimation model systems could be extended to China and other global cities.

Characterization, quantification and management of China's municipal solid waste in spatiotemporal distributions: A review

Municipal Solid Waste (MSW) is a heterogeneous waste stream, which is harmful for human health and the ecological environment if it is not well managed. Based on results from different authors by analyzing the generation, physical components and management of MSW from different cities, this paper presents an overview of the temporal trends and spatial variation characterization of MSW generation and its physical components in China. Total MSW generation has increased from 31,320 thousand tons in 1980 to 178,602 thousand tons in 2014, and MSW generation per capita has also increased from 448.3g to 653.2g. The distribution of MSW generation is mostly concentrated in the coastal southeastern region, as well as large point sources of more than 200 thousand tons per year are mostly distributed in Jiangsu, Zhejiang, Shandong, Hebei and Guangdong provinces. The review shows that the largest proportion of food waste, plastics and paper is 61.2% (54.2-65.9%, 95% CI), 9.8% (7.2-14.0%, 95% CI), 9.6% (6.7-12.3%, 95% CI), respectively, in 2014; the best estimates of other waste were as follows: 3.1% textile, 2.1% glass, 1.1% metal, 1.8% wood and grass, 1.3% rubber and leather, 1.8% ceramic, 2.5% ash, 1.2% hazardous waste, and 4.5% miscellaneous. To better manage China's MSW, several possible and appropriate solutions (e.g., concentrating on key regions, intensifying source separation, promoting green lifestyle, and establishing specialized regulations and policies) should be adopted, which might facilitate the application of China's 13th Five, and identify gaps in our knowledge of MSW management subject.