Papers

61,005 results
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Article Tier 2

Circular Economy in Wastewater Treatment Plant—Water, Energy and Raw Materials Recovery

This review proposes a conceptual framework for future wastewater treatment plants operating as resource recovery facilities within a circular economy, focusing on technologies for recovering water, energy, and raw materials including nutrients and biopolymers.

2023 Energies 51 citations
Article Tier 2

Wastewater Valorization: Practice around the World at Pilot- and Full-Scale

This review summarizes pilot- and full-scale wastewater valorization practices globally, focusing on how water resource recovery facilities recover nutrients, energy, and bio-based materials from sewage and sludge to contribute to a circular economy. The authors identify effective technological strategies that are being implemented or scaled up worldwide.

2021 International Journal of Environmental Research and Public Health 33 citations
Article Tier 2

Wastewater and sludge valorisation: a novel approach for treatment and resource recovery to achieve circular economy concept

This review highlights novel approaches for wastewater and sludge valorisation within a circular economy framework, focusing on recovering value-added products including biopolymers, nutrients, and energy to achieve sustainable development goals and combat water scarcity.

2023 Frontiers in Chemical Engineering 48 citations
Article Tier 2

Redefining Water Treatment: Identification of WWTPs as an Earth System Problem and Circular Economic Eco-Bog System to Challenge It

This paper argues that wastewater treatment plants should be reconceptualized as Earth system problems rather than isolated infrastructure, because the daily discharge of microplastics and other contaminants creates complex, poorly understood ecological effects at a planetary scale.

2021 European Journal of Environment and Earth Sciences 1 citations
Article Tier 2

Process simulation of co-HTC of sewage sludge and food waste digestates and supercritical water gasification of aqueous effluent integrated with biogas plants

Researchers modeled a system that combines wet waste from sewage sludge and food scraps into a biorefinery process, using hydrothermal carbonization (heating waste under pressure) followed by supercritical water gasification to recover nutrients and generate surplus energy, potentially transforming biogas plants into multi-product facilities.

2024 Energy 16 citations
Article Tier 2

Water reuse: a pillar of the circular water economy

This review argues that water reuse is a foundational pillar of the circular water economy, shifting the paradigm from dissipative pollutant removal toward resource recovery and closed-loop water management. The authors examine how conventional wastewater treatment approaches must be reimagined to enable sustainable water circularity.

2022 IWA Publishing eBooks 7 citations
Article Tier 2

Phosphorus removal and recovery in wastewater biological treatment from the perspective of phosphine: Current status, action mechanisms and future potential

This comprehensive review examines phosphorus removal and recovery from wastewater via biological treatment processes, using bibliometric analysis to map research trends and highlighting the emerging role of phosphine gas generation in phosphorus cycling within treatment systems.

2025 The Science of The Total Environment 3 citations
Article Tier 2

Wastewater Reclamation – opportunities and challenges

Researchers evaluated the potential of reclaimed municipal wastewater to supplement agricultural fertilizer demand by analyzing nitrogen, phosphorus, potassium, and total organic carbon in treated effluent disinfected by chlorination, ozonation, and UV irradiation, framing wastewater reclamation as a sustainable nutrient recovery solution within the ReNutriWater project.

2025 Global NEST International Conference on Environmental Science & Technology
Article Tier 2

Sewage Sludge Quality and Management for Circular Economy Opportunities in Lombardy

Researchers analyzed sewage sludge production and management in Lombardy, Italy, finding that most sludge met quality thresholds for agricultural recovery after stabilization but had low energy value, with circular economy opportunities depending heavily on sludge composition and regional treatment capacity.

2022 Applied Sciences 36 citations
Article Tier 2

Potential Nutrient Conversion Using Nature-Based Solutions in Cities and Utilization Concepts to Create Circular Urban Food Systems

This review examines how nature-based solutions in cities—like constructed wetlands and green infrastructure—can help recover nutrients from wastewater for reuse in agriculture. These systems can also help filter out microplastics and other contaminants before they reach waterways.

2021 Circular Economy and Sustainability 18 citations
Article Tier 2

Environmental Performance of Nitrogen Recovery from Reject Water of Sewage Sludge Treatment Based on Life Cycle Assessment

This study used life cycle assessment to evaluate nitrogen recovery from sewage sludge reject water via air stripping and biochar adsorption, finding that both methods can reduce environmental impacts compared to conventional fossil-based fertilizer production.

2023 Recycling 12 citations
Article Tier 2

Phyco-remediation of swine wastewater as a sustainable model based on circular economy

Researchers reviewed the use of microalgae to treat nitrogen- and phosphorus-rich swine wastewater, finding that phyco-remediation not only cleans effluent but generates commercially valuable biomass products like lipids, pigments, and biogas, making it a circular economy alternative to conventional waste stabilization ponds.

2020 Journal of Environmental Management 95 citations
Article Tier 2

Fate of microplastics in a centralized biogas plant treating mainly sewage sludge

Researchers tracked the fate of microplastics through a centralized biogas plant treating sewage sludge, examining how anaerobic digestion and subsequent dewatering partition microplastics between solid and liquid digestate fractions. The study informs efforts to develop safer digestate-based recycled fertilizers that minimize microplastic introduction to agricultural soils, where 20-55% of microplastics entering wastewater treatment plants are estimated to end up in sludge.

2025 Journal of Environmental Management
Article Tier 2

Removal of microplastics from wastewater: available techniques and way forward

This review surveys available techniques for removing microplastics from wastewater within a circular economy framework, discussing innovative treatment technologies, integrated risk-based approaches, and regulatory and economic guidelines needed to advance water resource recovery facilities beyond conventional pollutant removal.

2023 IWA Publishing eBooks 3 citations
Article Tier 2

Countering the porcelain dream: key findings from an evaluation of the global nitrogen cycle, a fundamental characterization of fresh faeces, and a campus composting toilet

This thesis examines global sanitation challenges through a sustainability lens, focusing on nutrient recovery and the need to close elemental cycles to reduce long-term environmental burdens. Proper sanitation infrastructure is foundational to reducing the pollution that reaches waterways, including microplastics.

2019 UVic’s Research and Learning Repository (University of Victoria) 2 citations
Article Tier 2

Microplastics pollution from wastewater treatment plants: A critical review on challenges, detection, sustainable removal techniques and circular economy

This review critically examines the challenges of detecting and removing microplastics from wastewater treatment plants, evaluating sustainable removal technologies and circular economy approaches to address this persistent source of aquatic microplastic pollution.

2022 Environmental Technology & Innovation 134 citations
Article Tier 2

AI Applied to the Circular Economy: An Approach in the Wastewater Sector

This review explored how artificial intelligence can be applied to circular economy objectives in the wastewater sector, examining AI-driven approaches for optimizing water treatment, resource recovery, and system efficiency. The paper identified opportunities and challenges for integrating machine learning into water utility operations within an ecological transition framework.

2024 Sustainability 6 citations
Article Tier 2

Material and energy flows of industrial biogas plants in Switzerland in the context of the circular economy

Researchers modeled material and energy flows through industrial biogas plants in Switzerland, finding that anaerobic digestion (breaking down organic waste without oxygen) could replace up to 14,000 tonnes of chemical fertilizers annually — but currently allows about 70 tonnes of plastic per year to end up in farm fields. Addressing that plastic contamination is essential if biogas expansion is to support a true circular economy.

2022 Bioresource Technology Reports 8 citations
Article Tier 2

Circular Economy in Wastewater Management—The Potential of Source-Separating Sanitation in Rural and Peri-Urban Areas of Northern Finland and Sweden

Researchers evaluated regional-scale source-separation sanitation scenarios in sparsely populated northern Finland and Sweden, finding that black water separation and urine diversion can substantially improve nutrient recovery compared to conventional wastewater treatment, particularly in rural and peri-urban areas.

2022 Frontiers in Environmental Science 24 citations
Commentary Tier 3

Editorial: Emerging approaches for sustainable management for wastewater

This editorial introduces a research collection on emerging approaches for sustainable wastewater management, highlighting advances in nutrient recovery, contaminant removal, and resource valorisation within circular economy frameworks.

2023 Frontiers in Environmental Science 18 citations
Article Tier 2

Utilization of Microalgae for Urban Wastewater Treatment and Valorization of Treated Wastewater and Biomass for Biofertilizer Applications

Researchers explored using microalgae to treat urban wastewater by recovering phosphorus and nitrogen, then repurposing the resulting biomass as a biofertilizer. The study suggests that this approach offers dual benefits of wastewater remediation and sustainable agriculture, as the nutrient-rich algal biomass promoted plant growth when applied to soil.

2023 Sustainability 33 citations
Article Tier 2

Retrieval of carbon and inorganic phosphorus during hydrothermal carbonization: ANN and RSM modeling

Researchers studied the recovery of carbon and inorganic phosphorus during hydrothermal carbonization of biomass feedstocks, optimizing conditions to maximize nutrient and carbon retention in the resulting hydrochar. Recovered hydrochar was proposed as a soil amendment combining carbon sequestration with phosphorus recycling.

2024 Heliyon 8 citations
Article Tier 2

Biomass valorization via pyrolysis in microalgae-based wastewater treatment: Challenges and opportunities for a circular bioeconomy

Researchers reviewed how microalgae grown in wastewater treatment systems can have their leftover biomass converted into useful products — biochar, bio-oil, and gas — through a heating process called pyrolysis. While promising for a circular economy, major challenges remain including high energy demands and potential harmful emissions that need to be addressed before the approach can be widely adopted.

2023 Journal of Applied Phycology 30 citations
Article Tier 2

A nanotechnology roadmap for circular wastewater management

This review paper summarizes research on using tiny particles called nanoparticles to make wastewater treatment more efficient and environmentally friendly. The technology could help clean water while also recovering valuable materials like nutrients and energy, but scientists still need to solve problems like how to use it safely on a large scale. Better wastewater treatment matters for human health because it helps ensure our water supply stays clean and reduces pollution in the environment.

2026 Frontiers in Environmental Engineering