Advances in Organic Solid Waste and Wastewater Management, 2nd Edition

Dear Colleagues,

The sustainable management of organic solid waste and wastewater has become one of the most pressing challenges worldwide, driven by rapid urbanization, population growth, industrialization, and increasingly stringent environmental regulations. Organic waste streams and wastewater are major contributors to environmental degradation when improperly managed, leading to greenhouse gas emissions, water pollution, ecosystem deterioration, and public health risks. At the same time, these waste streams represent an important and largely underutilized source of valuable resources, including energy, nutrients, organic matter, and functional materials. Addressing this dual challenge requires integrated, multidisciplinary, and innovative approaches that move beyond conventional treatment strategies toward sustainable resource recovery and valorization. 

This Topic focuses on recent advances in the management, treatment, and valorization of organic solid wastes and wastewater, with special emphasis on technologies and strategies that support sustainability, circular economy principles, and climate change mitigation. Organic solid wastes such as food waste, agricultural residues, biosolids, and agro-industrial by-products are increasingly being recognized as valuable feedstocks for waste-to-energy and waste-to-value pathways. Similarly, wastewater is no longer viewed solely as a waste stream to be treated and discharged but rather as a resource that can be harnessed for the recovery of water, energy, nutrients, and other high-value products. 

A central theme of this Topic is the development and optimization of biological, physicochemical, and hybrid treatment technologies aimed at enhancing resource recovery while minimizing environmental impacts. Particular attention is paid to anaerobic digestion and related biological processes, which play a key role in organic matter stabilization, biogas production, and nutrient transformation. Advances in reactor design, operational strategies, microbial community analysis, and process integration are of special interest, as they directly influence process efficiency, stability, and scalability. In parallel, emerging biological processes for nutrient removal and recovery, including innovative nitrogen and phosphorus management routes, are highly relevant for achieving more energy-efficient and sustainable wastewater treatment systems. 

Another important focus of this Topic is the application of advanced materials and emerging technologies to improve the performance of waste and wastewater treatment processes. This includes the development and use of advanced adsorbents, catalysts, biochar-based materials, and nanomaterials for contaminant removal, resource recovery, and process intensification. Advanced oxidation processes and hybrid treatment systems that combine biological and physicochemical approaches are also within the scope of this Topic, particularly for addressing emerging pollutants such as pharmaceuticals, personal care products, and other persistent organic contaminants.

This Topic also emphasizes the importance of integrating waste and wastewater management strategies within broader sustainability and circular economy frameworks. This includes life cycle assessment, technoeconomic analysis, and environmental impact evaluation of treatment and valorization pathways. Contributions that address climate change mitigation through greenhouse gas reduction, carbon capture, and carbon valorization are especially encouraged. In this context, biochar production, biomass valorization, and the synthesis of functional carbon-based materials from waste streams represent promising avenues for closing material and energy loops. 

Overall, this Topic aims to provide a focused platform for disseminating recent scientific and technological developments in organic solid waste and wastewater management. Contributions are expected to address both fundamental and applied aspects, including process design, performance evaluation, and real-world implementation challenges. By bringing together studies from different disciplines and application contexts, this Topic seeks to support informed decision-making and advance practical solutions that contribute to more sustainable and resource-efficient waste and wastewater management systems. 

The following is a link to the first edition of this Topic:

https://www.mdpi.com/topics/JR057GW3V4

Prof. Dr. Alejandro Alvarado-Lassman
Prof. Dr. Carlos Velasco-Santos
Prof. Dr. Juan Manuel Méndez-Contreras
Topic Editors