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How This Tofu Factory Turns Its Food Waste Into Energy: Food Processor Case Study

6 min read

As environmental consciousness and sustainable practices gain momentum, industries across the globe are seeking innovative solutions to reduce their carbon footprint and minimize waste generation while still generating a positive return on investment. Food processors in particular are grappling with the challenges of managing organic waste effectively. Enter anaerobic digestion—an eco-friendly and resourceful process that holds immense promise for food processors in their pursuit of sustainable circular solutions.

In this case study we look at one company, Island Spring Organics, a tofu factory selling at Whole Foods, PCC Community Markets and other fine supermarkets and restaurants in the Pacific NW. Island Spring Organics manages their organic waste with Chomp’s on-site anaerobic digester, which converts the food waste into biofertilizer–distributed for use to area farms–and biogas–used onsite to produce heat for the factory. 


Benefits of Anaerobic Digestion For Food Processors

From tackling waste management challenges to generating renewable energy and contributing to a circular economy, anaerobic digestion offers a range of advantages that align seamlessly with the goals of modern food processing facilities. Some of the main benefits include: 

1. Renewable Energy Generation

One of the most significant benefits of anaerobic digestion is its ability to generate renewable energy in the form of biogas. As organic waste decomposes, it produces biogas, primarily consisting of methane and carbon dioxide. This biogas can be captured and utilized as a valuable energy source for heat and electricity generation. Food processors can install combined heat and power (CHP) systems or use biogas directly in boilers or other heating equipment, reducing their reliance on fossil fuels and lowering energy costs.

2. Efficient Organic Waste Management That Complies with Regulations

The regulations on organic waste management are expanding as states and cities strive to meet sustainability goals and lower overall emissions, with 12 states currently enforcing regulations. Since food processors generate substantial amounts of organic waste, it’s critical for the industry to be proactive and implement long-term organic waste management solutions. Anaerobic digestion can be an ideal solution for managing this waste while also converting it into valuable resources. By diverting organic waste from landfills, food processors can minimize environmental impacts and comply with waste reduction regulations.

3. Cost Savings

By implementing anaerobic digestion systems, food processors can experience substantial cost savings in waste management and energy expenses. The reduction in waste disposal costs, such as landfill fees and transportation, can lead to significant financial benefits. The production of renewable energy through biogas can offset traditional energy costs, resulting in long-term savings. Moreover, there are various tax incentives available, which promote anaerobic digestion projects, further enhancing the financial viability for food processors. Learn more. 

4. Nutrient-Rich Fertilizer Production

Anaerobic digestion produces a nutrient-rich byproduct known as digestate. This digestate can serve as a biofertilizer, packed with essential nutrients for agricultural applications. The biofertilizer can be shared with local farms and gardens, returning valuable nutrients back to the soil, improving soil quality, and reducing the need for chemical fertilizers. By closing the loop and supporting a circular economy, food processors can contribute to community sustainable agricultural practices.

5. Environmental Stewardship & Circular Solutions

By capturing and utilizing biogas, the process prevents the release of methane, a potent greenhouse gas, into the atmosphere. Moreover, diverting organic waste from landfills reduces the production of harmful leachate and the release of greenhouse gases from decomposing waste. Companies using anaerobic digestion can contribute to community resiliency by making use of locally generated renewable energy and by sharing biofertilizer with neighboring farms.

How Island Spring Organics Utilizes Anaerobic Digestion

Located on Vashon Island, just outside of Seattle, Island Spring Organics faces unique logistical challenges in terms of waste management, which they are addressing through a remarkable solution with Chomp. Rather than incur expenses and logistical complexities associated with transporting food waste to distant landfills, Island Spring Organics partnered with Chomp to help take an innovative, proactive approach with an on-site anaerobic digester seamlessly connected to their facility. 

All the food waste generated during Island Springs Organic’s tofu production process is conveniently directed to Chomp’s on-site anaerobic digester. Water is added to the fibrous waste, resulting in a smoothie-like consistency. This mixture is then fed into the digester at regular and consistent intervals, ensuring a continuous and efficient process.

Inside the anaerobic digester, a remarkable transformation occurs as the resident microorganisms and microbes begin their work to convert the food waste into two valuable resources: biogas and biofertilizer. This process not only addresses the waste management challenges faced by Island Spring Organics but also unlocks opportunities for a local circular economy.

Chomp's Anaerobic Digester located next to Island Spring Organic's factory

The Use of Biofertilizer 

The biofertilizer generated through the anaerobic digestion process holds immense value for local agricultural practices. This nutrient-rich byproduct acts as an organic fertilizer, ensuring sustainable soil health and reducing reliance on synthetic fertilizers. By repurposing their waste into a valuable resource, Island Spring Organics showcases its commitment to environmental stewardship while actively contributing to a more regenerative and sustainable agricultural ecosystem.

The biofertilizer is distributed each week among local Vashon Island farms. (The truck responsible for distributing the biofertilizer to area farms runs on the very biogas produced by the anaerobic digester!) The results? Astonishing crop yields that surpass those achieved when conventional, petrochemical fertilizers were used. The benefits of this nutrient-rich biofertilizer are undeniable, contributing to healthier soils, enhanced plant growth, and circular, sustainable agricultural practices.

Chomp Delivering Biofertilizer on Vashon Island

The Use Of Biogas 

The biogas produced by the digester serves as a renewable energy source.  Some of the biogas is conditioned and utilized by the tofu factory for their energy needs. This upgraded gas is directly delivered to the tofu factory, reducing the amount of grid natural gas being used. By providing this renewable energy service, we are reducing the dependency on traditional fossil fuels, contributing to a greener and more sustainable operation. 

The biogas is also used to fuel cars on the island. The trucks used to transport the biofertilizer are fueled with this renewable natural gas (RNG). And this environmentally conscious local resident converted her vehicle to run on tofu waste-generated biogas.


Island Spring Organics exemplifies the power of anaerobic digestion to address logistical challenges and promote sustainable practices. By harnessing the potential of their organic waste, Island Spring Organics not only reduces their waste management costs but also creates the opportunity to produce renewable energy and biofertilizer, which are used on-site and in the local community. Through their innovative approach, Island Spring Organics sets a remarkable example for other food processors, demonstrating the transformative impact of anaerobic digestion on both operational efficiency and environmental responsibility.

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