Hengshui’s “zero-waste city” initiative demonstrates synergistic pollution reduction and climate action through agricultural waste innovation

Tsinghua University Press

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The diagram illustrates the closed-loop system converting agricultural waste into biogas, electricity, heat, and fertilizer.

 

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Credit: Circular Economy

The full paper, titled Ecological Circular Disposal of Agricultural Waste: Integrated Production of Gas, Electricity, Heat, and Fertilizer for Achieving Synergistic Effects of Pollution Reduction and Carbon Emission Reduction, was published on March 18, 2025, in Circular Economy.

 

Key Innovations and Findings

The study focuses on Hengshui City, a national pilot for China’s “zero-waste city” initiative, which generates 4 million tons of livestock manure annually. By carrying out the construction of the “zero- waste city”, improving the technical system, institutional system, and market system for solid waste from agricultural sources, and adopting advanced anaerobic digestion technology, the city has established a circular model that integrates biogas production, electricity generation, heat recovery, and organic fertilizer manufacturing. Key outcomes include:

1. Annual GHG Reduction: The project of combined production of gas, electricity, heat and fertilizer in Anping County, Hengshui City reduces the local greenhouse gas emissions by 87,208.5 tons of carbon dioxide equivalent every year. This is mainly achieved by carrying out the resource utilization of manure, reducing the methane emissions from manure management and replacing the use of fossil fuels.
2. Economic Growth: Since 2020, driven by the construction of Hengshui’s “zero-waste city”, the utilization rate of agricultural waste has increased to over 90%. The regional gross domestic product has increased by 21%, and the fixed-asset investment in agriculture, forestry, animal husbandry, and fishery has increased by more than 15%.
3. Policy Synergy: The “1+N+13” institutional framework for the construction of the “zero-waste city” has been established. By combining centralized planning with localized solutions, it has promoted sustainable biogas projects and cross-sectoral cooperation.

Dr. Wang Zhihua from the Research Institute for Environmental Innovation (Suzhou), Tsinghua, who is also the first author of this article, said that this study tried to conduct a reduction in pollution and carbon emissions analysis of the Hengshui “zero-waste city” construction based on the DPSIR model from 2020 to 2023. Under the background of “zero-waste city” Construction in China, the case study is very essential for understanding the details and major implication of the policy. It can provide some useful information for effective management of livestock and poultry manure waste.

 

Methodology and Analysis

In this study, based on the “driving force-pressure-state-impact-response” (DPSIR) model, an analysis of pollution and carbon emission reduction in the construction of Hengshui’s “zero-waste city” was carried out. From the three dimensions of economy, environment and society, 19 indicators were selected for evaluation. Moreover, the entropy weight-technique for order preference by similarity to an ideal solution (TOPSIS) method was used to standardize the data from 2020 to 2023, quantifying the impacts of factors such as the growth of gross domestic product (GDP), the scale of livestock farming, and the growth rate of fixed asset investment in agriculture, forestry, animal husbandry and fishery. In addition, the study adopted the approved Clean Development Mechanism (CDM) method (AMS.Ⅲ.D.ver.21) to analyze the greenhouse gas emission reduction effect of the comprehensive biogas utilization project in Anping County, Hengshui City. The results show that:

(1) Core Drivers: The driving factors for pollution and carbon emission reduction in the agricultural sector during the construction of Hengshui’s “zero-waste city” mainly include economic and social development, the employment situation of residents, as well as social response factors such as fixed asset investment in agriculture and the construction of standardized and large-scale breeding and livestock facilities. A large amount of agricultural waste in Hengshui and the environmental governance pressure brought about by air pollution control seriously restrict the work of pollution and carbon emission reduction in the construction of Hengshui’s “zero-waste city”.

(2) Emission Hotspots: The implementation of the project of co-production of “gas, electricity, heat and fertilizer” can effectively reduce greenhouse gas emissions by 87,208.5 tons of carbon dioxide equivalent per year, with a reduction rate of over 64%. The emission reduction amount of this model is significantly affected by three factors: biogas leakage, emissions during the storage of livestock and poultry manure, and emissions generated during equipment operation. Among them, the emissions during the storage of livestock and poultry manure have the greatest impact on the emission reduction amount, accounting for 59% of the emissions after the implementation of the biogas project.

(3) Comprehensive Efficiency: Using the technique for order preference by similarity to an ideal solution (TOPSIS) method, the comprehensive evaluation index of pollution and carbon emission reduction in the agricultural sector during the construction of Hengshui’s “zero-waste city” from 2020 to 2023 was calculated. The results show that the comprehensive evaluation index of pollution and carbon emission reduction in the agricultural sector during the construction of Hengshui’s “zero-waste city” has been increasing year by year from 2020 to 2023, with an 87% growth in 2023 compared to 2020. This indicates that remarkable achievements have been made in pollution and carbon emission reduction during the construction of Hengshui’s “zero-waste city”

Challenges and Global Implications

While the model succeeds in reducing emissions, challenges persist. Dr. Lyu Pu, the corresponding author of the paper and an environmental policy expert, pointed out that, “Nutrient runoff from biogas-derived fertilizers risks eutrophication if mismanaged. Precision application and monitoring are critical.”

This study emphasizes the role that the circular economy plays in achieving the United Nations’ sustainable development goals. Through the ecological circular model of combined production of gas, electricity, heat, and fertilizer, Hengshui has created green jobs. It has reduced the use of chemicals by replacing synthetic fertilizers with organic ones, and has decreased the use of fossil energy by incorporating biomethane into the natural gas network.

Globally, the findings align with circular economy strategies in the EU, Japan, and Singapore. For instance, Surrey, Canada, uses similar anaerobic digesters to power municipal fleets, while Thailand’s “3Rs” policy (reduce, reuse, recycle) mirrors Hengshui’s approach.

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About Circular Economy

Circular Economy (CE) is an international fully open-access journal co-published by Tsinghua University Press and Elsevier and academically supported by the School of Environment, Tsinghua University. It serves as a sharing and communication platform for novel contributions and outcomes on innovative techniques, systematic analysis, and policy tools of global, regional, national, local, and industrial park's waste management system to improve the reduce, reuse, recycle, and disposal of waste in a sustainable way. It has been indexed by Ei Compendex, Scopus, Inspec, CAS, and DOAJ. At its discretion, Tsinghua University Press will pay the Open Access Fee for all published papers from 2022 to 2026.

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Journal

Circular Economy

DOI

10.1016/j.cec.2025.100130 

Article Title

Hengshui’s “Zero-waste City” Initiative Demonstrates Synergistic Pollution Reduction and Climate Action Through Agricultural Waste Innovation

 

Nature-based activity is effective therapy for anxiety and depression, study shows

University of York

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Researchers evaluating a nature-based programme of activities for patients with mild to moderate mental health conditions have shown that improvements in mood and anxiety levels can be seen in as little as 12 weeks. 

As part of the UK government’s commitment to transform mental health services, seven ‘test and learn’ green social prescribing sites were identified across England, which included a programme in Humber and North Yorkshire - the first of the seven sites to publish results from the national programme. 

Green social prescribing is a practice whereby a healthcare professional refers a patient to community-based nature activities to help improve health and wellbeing beyond medical treatments. Currently these programmes are in a testing phase, but evidence is now pointing to the need for investment in this area to make it an additional option for patients across the country.

More than 220 participants from across Humber and North Yorkshire were included in the programme, and their mental health status was evaluated before and after exposure to an organised programme of nature-based activities, such as horticultural and care farming, sport and exercise, and outdoor mindfulness and craft-based activities.

The majority of participants took part in the programme weekly between one and four weeks, five to eight weeks, and others between nine and 12 weeks.  The team used the Office of National Statistics  measures of personal well-being, as well as the hospital anxiety and depression scale (HADS) to understand if participants had made improvements.

Across the board, participants reported improvements in wellbeing and mental health. But participants  who took part in longer programmes - typically nine to 12 week - or took part in activities related to horticulture and care farming, showed greater improvements in mood and anxiety levels compared with those involved in shorter programmes - one to four weeks - or in activities such as outdoor crafts, creative and mindfulness-based sessions, or sport and exercise.

The signs of improvement were similar to those seen in short-term cognitive behavioural therapy (CBT), where someone might meet one-to-one with a therapist over a period ranging from six weeks to a year or more 

Professor Peter Coventry, from the University of York’s Department of Health Sciences, said: “We have known for some time that nature has a positive impact on health and wellbeing, but in more recent years, a stronger evidence-base has grown that proves this to be true for mental health in particular.

“The fact that activities such as gardening, tending allotments, and care farming had the most impact on the participants in our study, demonstrated that it is not just about being passive in nature, but connecting with it in a meaningful way.  

“There is also something to be said for connecting with nature in the company of other people who live in the same place as you.  Anxiety and depression can often be born out of loneliness and feelings of disconnectedness, so it makes sense that taking part in shared activities close to home  - especially those that involve caring for and improving your local environment - can help lift mood and reduce anxiety.”

The study showed that these positive impacts were seen in all ages, which ranged from age 18 to age 85, and across genders.  Researchers are now calling for more investment to be made to support these community activities and the employment of green social prescribers that GPs and other health and social care professionals can refer their patients to.

Trish Darcy, research associate from the University’s Mental Health and Addiction Research Group, said: “This intervention might not work for everyone, but through an initial exploratory conversation a social prescriber will discuss with a patient or user of the service if nature-based activities would be suited to them, and for that choice to happen we need more investment to support these community-based activities”. 

“In our study 65% of participants were from low socioeconomic groups and we now know that not only can it help improve their mental health, but participation was high for  horticultural based activities in particular, meaning that not only is it good for the individual, but for the local community environment too.”

The evaluation, published in the journal Health & Social Care in the Community, was conducted in partnership with The HEY Smile Foundation and NHS Humber and North Yorkshire Integrated Care Board (ICB).

Dr Hannah Armitt a Clinical Psychologist and Clinical Lead for the Humber and North Yorkshire ‘test and learn’ programme said: “The research conducted in our region has the potential to enhance service delivery by connecting statutory services with local providers of nature based and outdoors activities. 

“It is important to evidence the potential of green space and nature to ensure clinicians and patients alike can harness the benefits of this wonderful free natural resource we have in abundance in Yorkshire and Humber.”

The study formed part of a national cross-government project on green social prescribing, managed by DEFRA with support of national partners, including Department of Health and Social Care, the Department for Levelling Up, Housing and Communities, Natural England, Sport England and National Academy for Social Prescribing.

Anthony Hurd, Humber and North Yorkshire Green Social Prescribing Programme Manager, said “This work has not only shown the positive outcomes that nature-based activities have on mental health, it has also highlighted the role that community-based organisations play in supporting the health and wellbeing of communities. 

“As healthcare begins to move more into the community, and with a focus on prevention, the community-based organisations delivering activities such as gardening, care farming and walking groups need to be recognised as key players in our national health service and be resourced appropriately.”

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Journal

Health & Social Care in the Community

 

Living fungus-based building material repairs itself for over a month

Cell Press

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Engineers have developed a building material that uses the root-like mycelium of a fungus and bacteria cells. Their results, publishing April 16 in the Cell Press journal Cell Reports Physical Science, show that this material—which is manufactured with living cells at low temperatures—is capable of self-repairing and could eventually offer a sustainable alternative for high-emission building materials like concrete. 

“Biomineralized materials do not have high enough strength to replace concrete in all applications, but we and others are working to improve their properties so they can see greater usage,” said corresponding author Chelsea Heveran, an assistant professor at Montana State University. 

Compared to other similar biomaterials, which typically are only usable for a few days or weeks, Heveran’s team’s materials—which are made using fungal mycelium and bacteria—are useful for at least a month. 

“This is exciting, because we would like for the cells to be able to perform other functions,” says Heveran.  

When the bacteria live within the material longer, their cells are able to perform several useful functions, including self-repairing when damaged and cleaning up contamination. 

Materials made from once-living organisms are beginning to enter the commercial market, but those made with organisms that are still alive have proven challenging to perfect—both because of their short viability periods and because they tend to lack the complex internal structures needed for many construction projects. 

To address these challenges, the team, led by first author Ethan Viles of Montana State University, explored using fungal mycelium as a scaffold for biomineralized materials, inspired by the fact that mycelium had previously been used as a scaffold for packaging and insulation materials. The researchers worked with the fungus species Neurospora crassa and found that it could be used to craft materials with a variety of complex architectures. 

“We learned that fungal scaffolds are quite useful for controlling the internal architecture of the material,” said Heveran. “We created internal geometries that looked like cortical bone, but moving forward, we could potentially construct other geometries too.” 

The researchers hope their new biomaterials can help replace building materials with high carbon footprints like cement, which contributes up to 8% of all carbon dioxide emissions produced from human activities. As a next step, they plan to further optimize the materials by coaxing the cells to live even longer and figuring out how to manufacture them efficiently on a larger scale. 

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This research was supported by funding from the National Science Foundation. 

Cell Reports Physical Science, Viles et al., “Mycelium as a scaffold for biomineralized engineered living materials.” https://www.cell.com/cell-reports-physical-science/fulltext/S2666-3864(25)00116-X

Cell Reports Physical Science (@CellRepPhysSci), published by Cell Press, is a new broad-scope, open access journal that publishes cutting-edge research across the spectrum of the physical sciences, including chemistry, physics, materials science, energy science, engineering, and related interdisciplinary work. Visit: https://www.cell.com/cell-reports-physical-science/home. To receive Cell Press media alerts, please contact press@cell.com. 

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Journal

Cell Reports Physical Science

DOI

10.1016/j.xcrp.2025.102517 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Mycelium as a scaffold for biomineralized engineered living materials

Article Publication Date

16-Apr-2025

 

Bite-sized chunks of chicken with the texture of whole meat can be grown in the lab

Cell Press

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Chicken produced with 1125-fiber HFB

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Credit: Shoji Takeuchi, The University of Tokyo

A bioreactor that mimics a circulatory system can deliver nutrients and oxygen to artificial tissue, enabling the production of over 10 grams of chicken muscle for cultured meat applications. These results are publishing in the Cell Press journal Trends in Biotechnology on April 16.

“Our study presents a scalable, top-down strategy for producing whole-cut cultured meat using a perfusable hollow fiber bioreactor,” says senior author Shoji Takeuchi of The University of Tokyo. “This system enables cell distribution, alignment, contractility, and improved food-related properties. It offers a practical alternative to vascular-based methods and may impact not only food production but also regenerative medicine, drug testing, and biohybrid robotics.”

A significant obstacle to the reconstruction of large-scale tissues is the creation of well-distributed vascular networks because diffusion alone cannot sustain cells across considerable distances. The thickness of tissues without an integrated circulatory system has generally been limited to less than 1 mm, making it challenging to produce centimeter-scale or larger tissues with densely packed cells.

“We're using semipermeable hollow fibers, which mimic blood vessels in their ability to deliver nutrients to the tissues,” Takeuchi says. “These fibers are already commonly used in household water filters and dialysis machines for patients with kidney disease. It's exciting to discover that these tiny fibers can also effectively help create artificial tissues and, possibly, whole organs in the future.”

The authors demonstrated the biofabrication of centimeter-scale chicken skeletal muscle tissues using a Hollow Fiber Bioreactor (HFB) consisting of an array of 50 hollow fibers. In addition, they implemented a robot-assisted assembly system for the fabrication of a 1,125-fiber HFB and produced whole-cut chicken meat weighing more than 10 g using chicken fibroblast cells, which make up connective tissue.

“Cultured meat offers a sustainable, ethical alternative to conventional meat,” Takeuchi says. “However, replicating the texture and taste of whole-cut meat remains difficult. Our technology enables the production of structured meat with improved texture and flavor, potentially accelerating its commercial viability. Beyond food, this platform may also impact regenerative medicine and soft robotics.”

According to Takeuchi, additional challenges for future research include determining the long-term effects of perfusion on tissue quality, adapting the technology for organ fabrication and biohybrid robotics, and further improving the mechanical properties and structural integrity of the tissue to better mimic the characteristics of natural muscle tissue.

“We overcame the challenge of achieving perfusion across thick tissues by arranging hollow fibers with microscale precision,” Takeuchi says. “Remaining challenges include improving oxygen delivery in larger tissues, automating fiber removal, and transitioning to food-safe materials. Solutions may include use of artificial oxygen carriers to mimic red blood cells, bundle-removal mechanisms that efficiently remove fibers in a single operation, and edible or recyclable hollow fibers.”

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 The authors have patent applications (PCT/JP2022/047671 and WO2023120710A1) related to this work.

Trends in Biotechnology (@TrendsinBiotech) is a multi-disciplinary Cell Press journal publishing original research and reviews on exciting developments in biotechnology, with the option to publish open access. This journal is a leading global platform for discussion of significant and transformative concepts across applied life sciences that examine bio-based solutions to real-world problems. Trends in Biotechnology provides cutting-edge research that breaks new ground and reviews that provide insights into the future direction of the field, giving the reader a novel point of view. Visit https://www.cell.com/trends/biotechnology. To receive Cell Press media alerts, contact press@cell.com.    

Trends in Biotechnology, Nie et al. “Scalable tissue biofabrication via perfusable hollow fiber arrays for cultured meat applications” http://cell.com/trends/biotechnology/fulltext/S0167-7799(25)00085-X

Perfusion in the bioreactor

Credit

Shoji Takeuchi, The University of Tokyo

Journal

Trends in Biotechnology

DOI

10.1016/j.tibtech.2025.02.022 

Method of Research

Experimental study

Subject of Research

Cells

Article Title

Scalable tissue biofabrication via perfusable hollow fiber arrays for cultured meat applications

Article Publication Date

16-Apr-2025

 

Sex-based differences in binge and heavy drinking among US adults

JAMA Network

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About The Study: 

This analysis found that past-month binge drinking among young adult females in 2021-2023 was higher than males, reversing 2017-2019 patterns, whereas males in other age groups continued to binge and heavy drink at higher rates. These findings may be due to more rapid decreases in binge drinking over time among young adult males relative to females, or to plateauing or increases in binge drinking among females. Further investigation using other nationally representative surveys is needed to elucidate these explanations.

Corresponding Author: To contact the corresponding author, Bryant Shuey, MD, MPH, email bryant.shuey@pitt.edu.

To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/

(doi:10.1001/jama.2025.2726)

Editor’s Note: Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.

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Embed this link to provide your readers free access to the full-text article This link will be live at the embargo time https://jamanetwork.com/journals/jama/fullarticle/10.1001/jama.2025.2726?guestAccessKey=d47ec1d7-0eea-48ee-a6ad-a9356c6b5f85&utm_source=for_the_media&utm_medium=referral&utm_campaign=ftm_links&utm_content=tfl&utm_term=041625

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Journal

JAMA