Impacts of garbage classification and disposal on the occurrence of pharmaceutical and personal care products in municipal solid waste leachates: A case study in Shanghai

Identifying ESG types of Chinese solid waste disposal companies based on machine learning methods

In the context of China's efforts to combat climate change and promote sustainable development, the solid waste treatment industry's environmental, social, and corporate governance (ESG) performance is receiving significant attention. To comprehensively assess the ESG performance of the solid waste treatment industry and identify company types, this study constructs a targeted ESG evaluation index system based on existing literature, SASB industry standards, and company reports and utilizes a random forest approach combined with K-means clustering to determine indicator weights. Based on this index system, the paper evaluates the ESG performance of 71 solid waste disposal companies (SWDCs) from 2013 to 2021 and identifies their ESG types from static and dynamic perspectives. In the static view, company types are determined based on annual ESG performance, while the dynamic view considers time-series changes to observe the evolution of company ESG types. The results show that the overall ESG performance of SWDCs falls within the 2-8-point range, indicating a noticeable high-low imbalance. Key initiatives to improve ESG performance in this industry include enhancing waste management measures, developing emergency plans, and reinforcing ESG disclosure. From a static perspective, this paper can identify companies into three categories: delayed development, single-wheel-driven, and coordinated development. Finally, from a dynamic perspective considering the time factor, companies are further subdivided into five types: continual leading, growth catch-up, slow progress, fluctuating change, and retrogressive inertia. This study not only provides targeted recommendations for different types of ESG companies but also helps various sectors of society better understand the ESG conditions of this high environmental risk industry, thereby enhancing the regulation and support for its sustainable development.

A picture of pharmaceutical pollution in landfill leachates: Occurrence, regional differences and influencing factors

Municipal solid waste (MSW) landfill sites have been identified as a significant source of pharmaceuticals in the environment because unused or expired pharmaceuticals are discarded into MSW, which eventually percolate into leachates. However, the contamination of pharmaceuticals in landfill leachate in China is not comprehensively understood. Previous research into factors influencing pharmaceutical concentrations focused on a limited number and type of target pollutants or restricted study area. In the present study, 66 pharmaceuticals were analyzed (including 45 antibiotic and 21 non-antibiotic pharmaceuticals, also categorized as 59 prescription and 7 non-prescription pharmaceuticals) in leachate samples from landfill sites with various characteristics in different regions of China. The results indicated that non-antibiotic pollutants were present at significantly higher concentrations than antibiotic pollutants, with median concentrations of 1.74 μg/L and 527 ng/L, respectively. Non-antibiotic pollutants also presented a higher environmental risk than antibiotic pollutants, by 2 to 4 orders of magnitude, highlighting that non-antibiotic pharmaceuticals should not be overlooked during the assessment of landfill leachate. Pharmaceutical concentrations in landfill leachate samples exhibited regional differences; the population size served by the landfills was the dominant factor contributing to the observed differences. In addition, landfill characteristics such as the solid waste composition and MSW loading can also affect pharmaceutical concentrations in landfill leachate. Despite the implementation of the classification and disposal policy of MSW in Shanghai, China since July 2019, specifying that unused or expired pharmaceuticals should be discarded as hazardous waste, high levels of pharmaceutical contaminations were detected in leachate from the main components of classified MSW (i.e., residual and food waste). These findings emphasize the importance of pharmaceutical management in solid waste systems.

Release potential, neglected leakage and reduction countermeasures of COD and Ammonia in MSWLs

In order to eliminate the impact of the industrial revolution on the environment and improve the water ecological environment, pollutant discharge reduction is imperative. With the acceleration of global discharge reduction process, the huge pollutant release potential and potential environmental effects of municipal solid waste landfills gradually appear, but its release amount and intensity have not been quantitatively revealed. We propose a coupling method of parameter stochastic simulation and physical process model simulation to estimate the hidden leakage of large-scale regional municipal solid waste landfills, and provide a methodology for estimating the hidden leakage of landfills in other countries and even in the whole world by taking China, which has the largest amount of waste generation among developing countries, as an example. Prior to the implementation of stringent construction quality control and assurance management requirements, the average annual leachate generation potential over the entire life cycle of 2600 landfills in China was estimated to be 4.66 × 108 m3, in which the concentrations of COD and NH3-N are 5.38 × 102-6.48 × 104 mg/L and 6.10-3.50 × 103 mg/L, respectively, and the total amounts are 5.21 × 103-7.81 × 108 t and 8.09 × 102-6.65 × 107 t, respectively. About 14 % of these pollutants may leak into the environmental media through the landfill liner with the average number of holes of 21.5/ha. For different regions, the overall release, discharge and leakage of COD and NH3-N in East China account for 35.70 %, 36.68 % and 29.60 % respectively, making it the region with the highest potential for discharge and risk of leakage. Meanwhile, the implementation of mandatory regulations related to leachate generation and control has led to a significant reduction in the leakage of pollutants. For instance, comprehensively detecting and repair of holes in the impermeable liner has reduced the number of holes to 2/ha, resulting in a reduction of >90 % in the leakage of pollutants.

Functionalization strategies of metal-organic frameworks for biomedical applications and treatment of emerging pollutants: A review

One of the representative coordination polymers, metal-organic frameworks (MOFs) material, is of hotspot interest in the multi field thanks to their unique structural characteristics and properties. As a novel hierarchical structural class, MOFs show diverse topologies, intrinsic behaviors, flexibility, etc. However, bare MOFs have less desirable biofunction, high humid sensitivity and instability in water, restraining their efficiencies in biomedical and environmental applications. Thus, a structural modification is required to address such drawbacks. Herein, we pinpoint new strategies in the synthesis and functionalization of MOFs to meet demanding requirements in in vitro tests, i.e., antibacterial face masks against corona virus infection and in wound healing and nanocarriers for drug delivery in anticancer. Regarding the treatment of wastewater containing emerging pollutants such as POPs, PFAS, and PPCPs, functionalized MOFs showed excellent performance with high efficiency and selectivity. Challenges in toxicity, vast database of clinical trials for biomedical tests and production cost can be still presented. MOFs-based composites can be, however, a bright candidate for reasonable replacement of traditional nanomaterials in biomedical and wastewater treatment applications.

Exorbitant signatures of pesticides and pharmaceuticals in municipal solid wastes (MSWs): Novel insights through risk analysis, dissolution dynamics, and model-based source identification

Studies on the occurrence and fates of emerging organic micropollutants (EOMPs) like pharmaceuticals and pesticides in MSWs are scarce in the literature. Therefore, MSWs were sampled from 20 Indian landfills and characterized for five widely consumed EOMPs (chlorpyrifos, cypermethrin, carbofuran, carbamazepine, and sodium diclofenac), physicochemical, and biological properties. The pesticide (median: 0.17-0.44 mg kg-1) and pharmaceutical (median: 0.20-0.26 mg kg-1) concentrations significantly fluctuated based on landfill localities. Eventually, principal component and multi-factor (MFA) models demonstrated close interactions of EOMPs with biological (microbial biomass and humification rates) and chemical (N, P, K, Ca, S, etc.) properties of MSWs. At the same time, the MFA resolved that EOMPs' fates in MSWs significantly differ from bigger cosmopolitan cities to smaller rural townships. Correspondingly, the concentration-driven ecological risks were high in 15 MSWs with EOMP-toxicity ranks of diclofenac > carbofuran = chlorpyrifos > cypermethrin > carbamazepine. The EOMPs' dissolution dynamics and source apportionments were evaluated using the positive matrix factorization (PMF) model for the first time on experimental data, extracting four anthropogenic sources (households, heterogeneous business centers, agricultural, and open drains). The most significant contribution of EOMPs to MSWs was due to heterogeneous business activity. Notably, the aging of soluble chemical fractions seems to influence the source characteristics of EOMPs strongly.

A comprehensive review on food waste anaerobic co-digestion: Research progress and tendencies

Food waste (FW) anaerobic digestion systems are prone to imbalance during long-term operation, and the imbalance mechanism is complex. Anaerobic co-digestion (AcoD) of FW and other substrates can overcome the performance limitations of single digestion, allowing for the mutual use of multiple wastes and resource recovery. Research on the AcoD of FW has been widely conducted and successfully applied to a practical engineering scale. Therefore, this review describes the research progress of AcoD of FW with other substrates. By analyzing the problems and challenges faced by AcoD of FW, the synergistic effects and influencing factors of different biomass wastes are discussed, and improvement strategies to improve the performance of AcoD of FW are summarized from different reaction stages of anaerobic digestion. By combing the research progress of AcoD of FW, it provides a reference for the optimization and improvement of the performance of the co-digestion system.