About LeAF

We work for a better world

Who we are

LeAF BV is an independent research and consulting organization. We leverage our knowledge, expertise and research facilities to recover and safely reuse water, energy, nutrients and other valuable resources from solid and liquid waste streams. We ensure that remaining (secondary) waste streams are treated and purified to guarantee their safe discharge into the environment. Through these efforts, we contribute to the improvement of our society.

Our work propels you further

To recover and safely reuse resources from waste streams pose complex challenges in the circular economy. This also applies to treating (secondary) waste streams discharged into the environment. We bridge the gap from goals and ambition to practice. Through our work, you’ll receive an honest and complete analysis, providing answers that propel you forward.

Over LeAF
Wie wij zijn

Our team

We are LeAF. Every day, we commit ourselves to make the world a better place. As idealists, we dedicate ourselves to this. Yet, we remain grounded, separating fact from fiction. Our advice is always pragmatic and realistic. Driven by content, we commit fully to addressing your needs, ensuring thorough and complete solutions. Many of our projects tread new ground, pushing the boundaries of innovation. This demands flexibility and adaptability to achieve optimal outcomes. Communication is essential in our work. As our client, you’ll have direct and personalized access to our experts, ensuring effective and enjoyable collaboration.

Curious about our team? Visit our team page:

Discover our expertise:

Decentralized Sanitation

Recovery of valuable resources from domestic wastewater and efficient treatment are crucial in a circular economy. With over 25 years of expertise, LeAF is the primary expert in the field of decentralized sanitation.


With tailor-made laboratory research, LeAF provides you with the answers you need to move forward.


Pharmaceutical residues, PFAS, and other micropollutants receive considerable attention. LeAF provides you with insight into the latest developments and suitable removal technologies.

Organic waste

Organic waste contains valuable resources. However, its collection and recycling pose significant challenges. At LeAF, we’re dedicated to assisting you in finding the most effective strategies to achieve your goals.

Resource Recovery

Waste streams often contain valuable resources. At LeAF, we collaborate with you to ensure that you can take the next step towards a circular world.


LeAF fully delivers sustainable services. This means that our work always contributes to projects that aim for a better world. We understand that not everyone has the means to afford our expertise. That’s why we perform a number of advisory projects annually at a reduced cost or even pro bono. By doing so, we collectively take a step forward. We finance these initiatives from our profits, ensuring our commitment to positive change remains unwavering.

Our sole shareholder is the ANBI-registered Lettinga Foundation. Committed to water and sanitation projects with a focus on waste stream processing, resource recovery, and reuse, the Foundation also supports the education of future environmental technologists and fosters environmental technological innovations. One notable initiative is the biennial Lettinga Award, recognizing outstanding contributions in this field.

Contact LeAF

We gladly speak to you about our services and experience. Feel free to contact us about finding solutions for sustainable management of wastewater and organic waste.

Contact us