The water quality index (WQI) is an essential indicator to manage water usage properly. This study aimed at applying a machine learning-based approach integrating attribute-realization (AR) and support vector machine (SVM) algorithm to classify the Chao Phraya River's water quality. The...

The circularity of plastic packaging waste (PPW) material via recycling is critical to its circular economy towards sustainability and carbon neutrality of society. The multi-stakeholders and complex waste recycling loop of Rayong Province, Thailand, is herein analysed using an actor-network theory to identify key actors, roles, and responsibilities in the recycling scheme. The results depict the relative function of three-actor networks, namely policy, economy, and societal networks, which play different roles in PPW handling from its generation through various separations from municipal solid wastes to recycling. The policy network comprises mainly national authorities and committees responsible for targeting and policymaking for local implementation, while economic networks are formal and informal actors acting for PPW collection with a recycling contribution of 11.3–64.1%. A societal network supports this collaboration for knowledge, technology, or funds. Two waste recycling models are classified as community-based and municipality-based management, which functions differently by coverage areas, capabilities, and process efficiency. The economic reliability of each informal sorting activity is a crucial factor for sustainability, while empowering people in environmental awareness and sorting ability at the household level is also essential, as well as law enforcement that is effective in the long-term circularity of the PPW economy.

Sustainable waste management was introduced more than ten years ago, but it has not yet been applied to the Thai petrochemical industry. Therefore, under the philosophy of sustainable waste management, this research aims to apply the reduce, reuse, and recycle (3R) concept at the petrochemical factory level to achieve a more sustainable industrial solid waste management system. Three olefin plants in Thailand were surveyed for the case study. The sources and types of waste and existing waste management options were identified. The results indicate that there are four sources of waste generation: (1) production, (2) maintenance, (3) waste treatment, and (4) waste packaging, which correspond to 45.18%, 36.71%, 9.73%, and 8.37% of the waste generated, respectively. From the survey, 59 different types of industrial wastes were generated from the different factory activities. The proposed 3R options could reduce the amount of landfill waste to 79.01% of the amount produced during the survey period; this reduction would occur over a period of 2 years and would result in reduced disposal costs and reduced consumption of natural resources. This study could be used as an example of an improved waste management system in the petrochemical industry.