New Delhi, India — The Ganvie Light Tower, a biowaste-to-energy infrastructure project, has been named the winner of the international design competition “Waste Not – Innovative Solutions for Human Excreta Management,” hosted by UNI and co-organized by Design x Design. Selected from a highly competitive international pool, the project offers an innovative model for sanitation and energy resilience in underserved floating communities and was recently showcased at the Alliance Française de Delhi during the 2025 Design x Design Exhibition.

The proposal was developed by designers Sangji Han and Tian Xu in the advanced design studio of renowned architect Francis Kéré. It addresses complex environmental, infrastructural, and social challenges by reimagining human waste as a valuable resource. The award jury commended the project for its innovative clarity, cultural sensitivity, and real-world applicability.

From Waste to Resource: A Community-Centered Infrastructure

The Ganvie Light Tower offers a design-driven response to the lack of safe and sustainable sanitation infrastructure in water-based settlements. Located in Ganvie, a stilt village on Lake Nokoué in Benin, West Africa—home to over 20,000 residents—the project envisions a decentralized infrastructure that transforms organic waste into biogas and light.

At its core, the design introduces a floating public platform that offers:

• Sanitation facilities 
• Biogas collection and distribution 
• A light-emitting community tower powered by waste-derived energy

Residents are encouraged to contribute waste by receiving biogas in exchange, creating a closed-loop ecosystem that provides both ecological and economic benefits. The system promotes hygienic practices, reduces reliance on firewood and fossil fuels, and helps improve indoor air quality, thereby lowering carbon emissions.

The Light Tower serves as both a visual and communal beacon, functioning as a public gathering space—redefining sanitation infrastructure as a site of empowerment and interaction, rather than marginalization.

Global Exposure at Design x Design Exhibition, New Delhi

Photo Courtesy: Sangji Han

The project gained international recognition through its inclusion in the prestigious Design x Design 2025 Exhibition at Alliance Française de Delhi, held from February 1–22, 2025. The exhibition, known for showcasing innovative works in architecture and interdisciplinary design, featured the Ganvie Light Tower as a significant solution to global challenges.

Photo Courtesy: Sangji Han

Sangji Han delivered a virtual opening address, discussing the project’s mission and broader implications for climate resilience and sustainable urbanism. The address emphasized the importance of design interventions that connect environmental systems with social equity, positioning the Light Tower as a potential model for other communities beyond Ganvie.

The exhibition attracted significant attention from sustainability experts, architects, researchers, and public policy professionals. Documentation shared by attendees—including photos, videos, and feedback—helped amplify the project’s reach and highlighted its international relevance.

Jury Commendation: Design with Empathy and Precision

The judging panel, composed of respected figures in architecture and environmental design, praised the Ganvie Light Tower for its technical sophistication and socio-cultural insight. Jurors Iftikhar-mulk Chishti, founder of StudioiF, and Monish Siripurapu, principal architect of ANT Studio, offered formal commendations on behalf of UNI and Design x Design.

In a statement, the organizers noted:

“Given the challenging nature of the theme, we recognize that it required a sensitive understanding to address it. While many might have been cautious about engaging with this subject, this project offers a valuable perspective and aligns well with the competition’s objectives.”

The jury acknowledged the proposal’s ability to combine ecological logic with architectural sensibility, noting its potential as a replicable model for equitable infrastructure in climate-vulnerable regions.

Designing for the Circular Economy: Core Themes and Impact

The project reflects a growing global movement to reimagine waste—especially human excreta—not as a final product, but as the starting point of sustainable cycles. Through an integrated system of collection, conversion, and distribution, the Ganvie Light Tower fosters circularity in five key domains:

• Public Health: By providing hygienic sanitation and eliminating open defecation, the platform helps reduce the spread of disease and improve overall well-being. 
• Social Equity: The design ensures safe, accessible infrastructure for all genders and ages, particularly in marginalized communities. 
• Cultural Sensitivity: Responding to Ganvie’s water-based context, the structure utilizes floating foundations and community-centered placement. 
• Economic Development: Biogas production reduces reliance on traditional fuels, lowering household costs and stimulating local micro-economies. 
• Environmental Regeneration: The system minimizes pollution in the lake ecosystem and reduces methane emissions through controlled anaerobic digestion.

With the growing demand for off-grid sanitation systems, the Ganvie Light Tower offers a potential template for inclusive urbanism and decentralized sustainability.

About the Competition: UNI’s “Waste Not” 2024

Launched by UNI in April 2024, the “Waste Not” competition addressed one of the most pressing but often overlooked global design challenges: human excreta management. While traditional sanitation solutions have focused on containment and disposal, this initiative sought innovative strategies that incorporate waste repurposing into the circular economy.

Participants were invited to submit interdisciplinary proposals addressing waste across various scales—from individual households to entire cities—and across diverse global contexts. Submissions were evaluated based on innovation, feasibility, cultural alignment, and potential for systemic change.

The competition culminated in September 2024 with the announcement of the Ganvie Light Tower as the winner—a rare distinction that reflects the project’s exceptional merit.

A Platform for Future Collaboration and Implementation

Following its exhibition and recognition, the Ganvie Light Tower has attracted interest from architectural and sustainability organizations for further development and field testing. Discussions are ongoing with ANT Studio, led by juror Monish Siripurapu, to explore prototyping and scaling the design for implementation in similar floating or peri-urban settlements.

The project exemplifies a shift in the design discipline toward interdisciplinary, impact-driven practices, with far-reaching implications for public infrastructure, renewable energy, and environmental justice.

Summary: A Beacon for Design-Led Resilience

The Ganvie Light Tower stands as a significant achievement in socially responsive architecture and ecological innovation. By transforming waste from a byproduct to a resource for empowerment, the project introduces a compelling model for future infrastructure—rooted in dignity, sustainability, and shared value.

Its recognition as the winner of UNI’s Waste Not competition and its feature at the Design x Design Exhibition in India position the project as both a thought leader in circular design and a practical proposal for real-world impact. As global sanitation challenges intensify and climate resilience becomes increasingly important, the Ganvie Light Tower marks a significant step forward in reimagining how design can meet basic needs with intelligence, humility, and vision.

Project Title: Ganvie Light Tower
Designers: Sangji Han, Tian Xu
Studio: Advanced Studio by Francis Kéré
Award: Winner, “Waste Not – Innovative Solutions for Human Excreta Management,” UNI 2024
Exhibition: Design x Design, Alliance Française de Delhi, February 1–22, 2025
Jury: Iftikhar-mulk Chishti (StudioiF), Monish Siripurapu (ANT Studio)
Host: UNI, Design x Design
Competition Page: https://uni.xyz/competitions/waste-not/entries