Understanding metal dissolution from solar photovoltaics in MSW leachate under standard waste characterization conditions for informing end-of-life photovoltaic waste management

Pyrolytic homogeneity enhancement of municipal solid waste using a clustering-based sorting strategy

Heterogeneity of pyrolytic parameters in municipal solid waste (MSW) significantly hinders its waste-to-energy efficiency. So far, hardly any light has been shed on current pyrolytic heterogeneity conditions or feasible pyrolytic homogeneity enhancement approaches of MSW. Accordingly, pyrolytic properties (Ea and logA) of 130 MSW samples in 6 categories were collected from literature. A kinetic parameters clustering-based sorting strategy for MSW was proposed. A so-called C index was established to compare their sorting performance for Ea and logA against two traditional sorting strategies (substance categorization and density clustering). Results showed that the proposed sorting strategies outperformed the traditional ones in pyrolytic homogeneity enhancement, where the optimal C_Ea and C_logA reached 1578.30 kJ/mol and 93.11 -log min. Among investigated clustering methods, k-means clustering outperformed hierarchical clustering, which could be attributed to its adaptability to the sample structure. Future perspectives involving data set expansion, model framework development, and downstream technologies matching were also discussed. The index C established in this study can be used to evaluate other clustering models.

A review of toxicity assessment procedures of solar photovoltaic modules

Environmental management of solar photovoltaic (PV) modules is attracting attention as a growing number of field-operated PV modules approach end of life (EoL). PV modules may contain small amounts of toxic metals, and the procedures for assessing and regulating the toxic metal content and release of such materials at EoL differ widely across nations. This paper provides an overview of the metal composition of PV modules and common procedures for toxicity assessment through extensive research and review of technical literature and legislative documents. This review focuses on three primary aspects: first, it explores the distribution of toxic elements within current and emerging PV module designs, with a specific focus on obtaining representative samples for proportional toxicity testing within different module laminate areas. Second, it examines a sampling standard and the diverse toxicity testing methods and regulations employed in various regions, encompassing standards like the Environmental Protection Agency (EPA) Test Method 1311 (Toxicity Characteristic Leaching Procedure, TCLP) in the U.S., Restriction of Hazardous Substances (RoHS) in Europe, and the Waste Extraction Test (WET) in California. Third, the review examines the sources of variability in toxicity testing outcomes, including techniques for securing homogeneous samples from non-uniform PV modules, selecting particle sizes representative of landfill conditions in extracted samples, determining appropriate leachate characteristics such as leaching agents and pH levels, and considering factors like test duration and temperatures. In summary, this review summarizes relevant regulations and offers a comprehensive overview of the strengths and limitations associated with several toxicity assessment procedures currently in practice.

Geographic information system and system dynamics combination technique for municipal solid waste treatment station site selection

The rapid growth of municipal solid waste put pressure on the end treatment facilities, and the site selection of MSW treatment facilities needs to be carefully conducted. This study aims to develop a Standard Operational Procedures (SOP) for municipal solid waste (MSW) treatment station site selection based on GIS and system dynamics combination. System dynamics was used to establish a forecasting model for MSW simulation followed by the spatial analysis method to generate a geographic information system. The MSW simulation in Xiamen city using the system dynamics model proved that the model was with high prediction accuracy. An SOP for GIS-based MSW treatment station site selection was developed. The site selection for MSW comprehensive treatment in Xiamen using GIS and system dynamics screened the locations of the comprehensive solid waste treatment stations in Xiamen and eliminated unsuitable lands using the mapping function of the geographic information system, thus validating the SOP.