Globally, the commitment of companies to Circular Economy (CE) is still limited. Mapping the circular practices performed by companies is a challenging and complex task and few empirical papers have explored CE implementation in companies. Based on interviews and analysis of company reports, we addressed in-depth the implementation of practices, targets, and assessment tools related to CE in ten Swedish companies. Only 10 circular practices out of 21 are implemented in at least 50% of the companies, indicating that the companies have just begun their transition to CE. The most common practices relate to waste reduction and resource efficiency (mainly energy). Barriers to collaboration are competition, keep confidentiality, small company size, lack of interest of other stakeholders, among others. So, there is a potential for increasing collaboration, especially with the municipality. The priority has been emissions reduction targets and the use of climate-focused tools (i.e., carbon footprint) while social aspects and circularity are less explored. We conclude that the monitoring of environmental performance is limited mainly to the use of resources and emissions. The low use of circularity tools is caused mainly by internal barriers such as lack of knowledge and shortage of resources. So, the companies should get more knowledge on CE assessment tools, include social indicators related to circular practices, and set targets for societal impact. © 2025 The Authors

The COVID-19 pandemic has brought the epidemiological value of monitoring wastewater into sharp focus. The challenges of implementing and optimising wastewater monitoring vary significantly from one region to another, often due to the array of different wastewater systems around the globe, as well as the availability of resources to undertake the required analyses (e.g. laboratory infrastructure and expertise). Here we reflect on the local and shared challenges of implementing a SARS-CoV-2 monitoring programme in two geographically and socio-economically distinct regions, São Paulo state (Brazil) and Wales (UK), focusing on design, laboratory methods and data analysis, and identifying potential guiding principles for wastewater surveillance fit for the 21st century. Our results highlight the historical nature of region-specific challenges to the implementation of wastewater surveillance, including previous experience of using wastewater surveillance, stakeholders involved, and nature of wastewater infrastructure. Building on those challenges, we then highlight what an ideal programme would look like if restrictions such as resource were not a constraint. Finally, we demonstrate the value of bringing multidisciplinary skills and international networks together for effective wastewater surveillance. © 2024. Published by Elsevier B.V.

Perception and awareness can affect behaviour and decision-making, for example, how companies implement Circular Economy (CE) practices. However, there is limited empirical research about this topic. Thus, we investigated the perception and awareness of representatives from water-intensive and bio-based sectors regarding the CE concept based on interviews and a survey with 10 companies in Sweden. Our results indicate that CE is understood mainly as zero waste and its key principles are resource efficiency and ecodesign. Missing (or partially addressed) important elements of CE are consumption, social aspects, regenerative role of CE, collaboration, and Industrial Symbiosis. The main benefit from implementing circular strategies is economic, and the main barrier is the lack of financial resources. The bio-based companies have a broader understanding of CE and its benefits than the water-intensive companies. Overall, more clarification and standardisation of the CE concept is necessary to avoid misunderstanding with other concepts such as sustainability. © 2024 The Authors

Sewage sludge (SS) can be applied in soil for its nutrient recycling in agriculture and forestry, but the presence of toxic substances may prompt environmental and human health risks. Brazilian Resolution (CONAMA 498/2020) establishes thresholds for biosolid (i.e., treated sludge) quality for application in soils. We have evaluated the (eco)toxicological impact potential of such practice regarding the mentioned thresholds, and the concentration of inorganic substances in sludge from three different Wastewater Treatment Plants (WWTP) in São Paulo, Brazil. The assessment relied on USEtox®, a model that estimates the potential toxicological impact on humans and ecosystems. According to the evaluation of the regulatory thresholds, Zn are responsible for an ecotoxicological impact potential of 2.33E + 02 PAF.m3.day/kg (potentially affected species), which represents 48.2% of the aggregated impact for the scenario, while Hg potential is of 1.25E-04 cases/kg for non-cancerous diseases in humans – corresponding to 54% of this scenario. The assessment of the SS samples has confirmed to be critical for Zn, Hg, and Cr, and indicated potential ecotoxicological risks for concentrations found of Fe and Al, which do not have regulatory thresholds. Results were discussed along with related literature and international regulation. The study supports sustainable management of sewage in Brazil, and the analytical framework is replicable in other regions. © 2023 Published by Elsevier B.V.

The discharge of nitrogen into nature results in environmental degradation and public health problems. Conventional processes applied in wastewater treatment plants (WWTPs) for nitrogen removal have high energy demand and chemical consumption. Hence, this chapter addresses the recent research development about more sustainable approaches involving bioelectrochemical systems (BES) focused on nitrogen. Among the content are novel and meaningful insights towards the main factors controlling nitrogen oxidation, reduction, and separation/recovery; potential applications in WWTP; limiting factors; and contributions towards the circular economy principles. Despite there are limiting factors such as costly materials, lack of knowledge on microbial ecology, and low removal rates, the current generated in autotrophic nitrifying and denitrifying BES ranges from 1.2 to 1175 mA/m² and 14 to 371 A/m³, respectively. This can potentially increase WWTPs self-sufficiency in terms of energy and external carbon. Alternatively, nitrogen can be recovered in BES (struvite, NH₄HCO₃ crystals or NH₄OH), but improvements in ammonia separation across ion exchange membranes are necessary. © 2023 Elsevier Inc. All rights reserved.

The measurement of progress towards Circular Economy (CE) within a company is crucial for identifying opportunities and designing circular practices. However, most of the existing tools do not consider the systemic view and principles of CE. The aim of this paper is to assess the contributions and limitations of CE assessment tools regarding the key elements: social dimension, stakeholder engagement, R-imperatives and industrial symbiosis. Also, the aim is to offer guidance for improvements towards a CE transition. The methodology was an integrative literature review; then based on the critical assessment of tools a guide was created. Thirty-eight tools were thoroughly analysed and our results show that there is a limited number of multidisciplinary tools (only 10), that is including all CE key elements, and in some cases partly. Social dimension is not fully explored; only 6 tools have indicators related to society, local community, customers, and workers. Recommendations for future tools development include to offer training for possible users of the tools and to develop tools for the service sector. Finally, we conclude that all the key elements of CE are interconnected. The proposed guide-ACTION (Assessing Circular Transition In Organisations Now)- includes the key elements, databases, tools, and indicators, and is aligned with the CE principles to help the assessment. © 2022 The Author(s)

There is great potential to apply energy recovery from municipal wastewater treatment plants (WWTP) to achieve better energy efficiency and greenhouse gas emissions abatement. However, in most of the wastewater treatment plants that produce biogas through sludge digestion, there is no thermal energy recovery or electricity generation, and the biogas is flared and wasted, particularly in developing countries. This paper discusses the recent technological advances related to biogas recovery from wastewater treatment besides identifying research gaps and local conditions, which affect implementation. Techniques for enhancement of biogas production such as co-digestion and microalgae systems for energy recovery were reviewed in terms of performance and context for application. This paper provides an assessment of how local conditions promote or hinder biogas recovery from WWTP in megacities of developing countries. The lack of government subsidies and a biogas market that is not well developed and regulated hinder biogas recovery implementation in the studied megacities. Infrastructure and electricity prices are also discussed. Strategies to promote energy recovery are recommended based on successful examples of energy self-sufficient WWTP. The findings may not only support planning on energy recovery but also guide technological development and research on this topic, aligned with the sustainable development goals.

Considering the current resources scarcity, Wastewater Treatment Plants (WWTP) should be adapted to become more sustainable. For example, it is possible to recover resources present in municipal wastewater. However, regional studies about integration of resource recovery processes at different scales or about the main barriers to implementation in developing countries are missing in the literature. Also, there is a need for planning methodologies to identify the most sustainable solution in each context. Understanding the current situation is an essential step to support planning and accelerate resource recovery implementation. To address these issues this thesis aims to guide planning, technology and policy development towards resource recovery from municipal WWTP in large cities of developing countries. This thesis presents a comprehensive knowledge base for wastewater treatment plant managers and decision-makers leading to a better understanding of resource recovery solutions and the actions needed to facilitate implementation. The methodology comprised critical literature reviews and two case studies. Secondary data from literature and primary data (obtained through questionnaires) were collected and analysed. Megacities in developing countries are analysed in the papers, with the focus on the Macrometropolis of Sao Paulo, which is the most populous area in the Southern Hemisphere. The current situation shows a low implementation of resource recovery practices in the region, and local conditions affect the implementation of water reuse, and nutrients and energy recovery. A framework consisting of eleven steps is proposed to support planning and decision-making on resource recovery from wastewater. This new tool was tested and can be applied by decision-makers in wastewater sector for better operation and management. Market, legislation, local economic development, and cooperation with stakeholders are relevant aspects covered in the analysis. There is a great potential to expand wastewater treatment integrated with nutrient and energy recovery strategies in developing countries. Potentials for phosphorus and energy recovery were estimated and some recovery scenarios are recommended. In conclusion, the findings can help planning and elaboration of resource recovery projects in wastewater treatment in urban areas and stimulate creation of public policies. The main research gaps identified in this thesis can guide further research and technological development in this field.

In developing countries, there is often a lack of a comprehensive data set that supports the development of coherent policies on resource recovery from wastewater treatment. This paper aims to contribute to the elaboration of resource recovery projects by providing accurate and updated data from wastewater treatment plants such as those located in the region of the Macrometropolis of Sao Paulo. The authors discuss possibilities of improvement of resource recovery for this illustrative example. Comprehensive analyses were performed based on data from 143 municipal wastewater treatment plants to understand the situation regarding resource recovery implementation in this region. The results show that just 26% of the plants perform at least one resource recovery practice. The predominant resource recovery practice is internal water reuse, and recovery is concentrated more in large plants than in medium and small ones. The sludge is disposed in landfills except for three plants, which perform sludge recycling for compost. Some plant managers reported interest in recovering energy from biogas, in expanding water reuse and in recovering sludge for fertilizer production or for building materials. Several aspects that have been regarded as relevant to the implementation of resource recovery processes in previous literature are discussed, such as the size of the plant, related legislation as well as treatment technologies and configurations. Finally, the authors propose a generic framework with several steps that can help to achieve resource recovery implementation. Therefore, the results can provide support for planning of resource recovery projects for large cities in developing countries. © 2020 Elsevier Inc.

Currently, it is important to develop strategic frameworks to support the selection of sustainable resource recovery solutions. This study applies a new framework for planning, implementation, and assessment of resource recovery strategies for a full-scale wastewater treatment plant (WWTP) in São Paulo megacity. The framework comprises several steps based on case study-specific data and information from current literature. Data were collected from various sources: a survey with a wastewater treatment utility, national and regional databases, and review of local regulations and international literature. Treatment configuration, wastewater and by-products composition, potential demand (for water, energy, and phosphorus), stakeholder identification, and local legislation were thoroughly discussed regarding decision-making on resource recovery. Scenario analysis was used to explore suitable nutrient and energy recovery measures based on indicators. Biogas recovery and sewage sludge composting showed more favorable conditions due to similar experiences in the area and robust legislation. The proposed framework is a simplified tool, and its application can support managers to get information on resource recovery and how to plan such initiatives in easier ways to facilitate wiser decision-making, and better operation and management. The results on framework use and refinement can guide potential applications in other contexts and stimulate public policy formulation and further research.