Metagenome-resolved global microbial diversity and function in activated-sludge wastewater treatment systems – Nature

Report on Global Microbial Diversity and Function in Activated-Sludge Wastewater Treatment Systems

Introduction

Wastewater treatment plants (WWTPs) serve as critical reservoirs of microbial diversity, playing a vital role in environmental sustainability and public health. This report presents a comprehensive global-scale metagenomic analysis of activated sludge from WWTPs across six continents, emphasizing the alignment with Sustainable Development Goals (SDGs), particularly SDG 6 (Clean Water and Sanitation), SDG 12 (Responsible Consumption and Production), and SDG 13 (Climate Action).

Global Metagenomic Catalogue Development

A total of 828 metagenomic datasets from WWTPs worldwide were selectively sampled and integratively analyzed. This effort resulted in the creation of a global metagenomic catalogue for activated sludge, comprising:

• 24,536 metagenome-assembled genomes (MAGs)
• Over 24 million non-redundant genes
• Identification of 12,563 MAGs without prior species-level classification

The catalogue includes a high-resolution, MAG-level relative abundance and distribution map, illustrating the global biogeographic patterns of microorganisms in WWTPs.

Functional Insights into Wastewater Treatment Microorganisms

This extensive collection enhances the understanding of functional microorganisms involved in nutrient removal processes, including:

• Polyphosphate-accumulating organisms (PAOs)
• Nitrifiers
• Denitrifiers

These microbial groups are essential for the efficient removal of phosphorus and nitrogen, contributing directly to SDG 6 by improving water quality and sanitation.

Gene Annotation and Metabolic Potential

Systematic annotation of genes related to key environmental functions was conducted, focusing on:

1. Nutrient removal pathways
2. Virulence factors
3. Plastic degradation
4. Biosynthesis of bioactive compounds

Phylogenetic analysis integrated with metabolic potential revealed previously under-characterized microbial taxa, expanding knowledge of microbial diversity and ecosystem functions in WWTPs.

Implications for Sustainable Development Goals (SDGs)

The study supports several SDGs by providing foundational knowledge and resources for sustainable wastewater management:

• SDG 6: Clean Water and Sanitation – Enhances nutrient removal efficiency, reducing water pollution and protecting aquatic ecosystems.
• SDG 12: Responsible Consumption and Production – Facilitates resource recovery from wastewater, promoting circular economy principles.
• SDG 13: Climate Action – Supports mitigation of greenhouse gas emissions through improved microbial processes in WWTPs.

Applications and Future Directions

The genome-resolved framework and extensive microbial catalogue provide essential resources for:

• Targeted genome-centric research
• Directed engineering of wastewater treatment processes
• Development of innovative and sustainable treatment technologies

These advancements align with global efforts to enhance environmental sustainability and public health.

Data and Code Availability

• Metagenomic datasets and MAGs are deposited in the NCBI BioProject No. PRJNA1204190.
• All MAGs, predicted genes, and analysis scripts are accessible via Science Data Bank at https://doi.org/10.57760/sciencedb.18043.

Conclusion

This global-scale metagenomic study of activated sludge in WWTPs significantly advances the understanding of microbial diversity and function, directly supporting the achievement of key Sustainable Development Goals. The findings provide a robust scientific foundation for enhancing wastewater treatment technologies, promoting environmental sustainability, and safeguarding water resources worldwide.

1. Sustainable Development Goals (SDGs) Addressed or Connected

1. SDG 6: Clean Water and Sanitation
   • The article focuses on wastewater treatment plants (WWTPs) and their microbial diversity and functions, which are crucial for effective wastewater treatment and sanitation.
2. SDG 12: Responsible Consumption and Production
   • The study includes analysis of plastic degradation genes, which relates to sustainable management and reduction of waste.
3. SDG 14: Life Below Water
   • By improving wastewater treatment and reducing pollutants such as plastics and nutrients, the research indirectly supports the protection of aquatic ecosystems.
4. SDG 15: Life on Land
   • Enhanced nutrient removal and pollution control in wastewater treatment contribute to ecosystem restoration and pollution control on land.
5. SDG 9: Industry, Innovation and Infrastructure
   • The article discusses genome-centric research and innovative wastewater treatment engineering, promoting sustainable industrial processes.

2. Specific Targets Under Those SDGs Identified

1. SDG 6: Clean Water and Sanitation
   • Target 6.3: Improve water quality by reducing pollution, minimizing release of hazardous chemicals and materials, halving the proportion of untreated wastewater, and substantially increasing recycling and safe reuse globally.
   • Target 6.6: Protect and restore water-related ecosystems.
2. SDG 12: Responsible Consumption and Production
   • Target 12.4: Achieve environmentally sound management of chemicals and all wastes throughout their life cycle.
   • Target 12.5: Substantially reduce waste generation through prevention, reduction, recycling, and reuse.
3. SDG 14: Life Below Water
   • Target 14.1: Prevent and significantly reduce marine pollution of all kinds, particularly from land-based activities, including marine debris and nutrient pollution.
4. SDG 15: Life on Land
   • Target 15.1: Ensure the conservation, restoration, and sustainable use of terrestrial and inland freshwater ecosystems.
5. SDG 9: Industry, Innovation and Infrastructure
   • Target 9.4: Upgrade infrastructure and retrofit industries to make them sustainable, with increased resource-use efficiency and greater adoption of clean and environmentally sound technologies.

3. Indicators Mentioned or Implied to Measure Progress

1. Indicators related to wastewater treatment effectiveness:
   • Relative abundance and distribution of microbial genomes (MAGs) in activated sludge globally, which can be used to monitor microbial community health and function in WWTPs.
   • Presence and annotation of genes involved in nutrient removal (phosphorus and nitrogen metabolic pathways), which serve as molecular indicators of treatment performance.
2. Indicators related to pollution and waste management:
   • Genes related to plastic degradation and biosynthesis, indicating the potential for biodegradation of plastics in wastewater systems.
   • Virulence factors annotated in microbial genomes, which can be monitored to assess potential health risks in wastewater treatment.
3. Data availability and genomic catalogues:
   • Global metagenomic datasets and genome catalogues (24,536 MAGs and over 24 million genes) provide a baseline for monitoring microbial diversity and function over time.

4. Table of SDGs, Targets, and Indicators

Source: nature.com