Pureco—No-flush toilets for cold and arid areas

What it does

Our design targets ecological toilets for cold, arid rural regions. Using solar/wind energy, it separates waste, powers lighting/heating, removes odors, composts waste into fertilizer, ensuring sanitation without water/electricity and prioritizing user comfort

Your inspiration

As of 2022, 3.5 billion people lack access to safe sanitation, and 400 million practice open defecation daily. Poor sanitation causes diseases killing 800 children under five daily. Annual global costs reach US$223 billion. In rural China, 25% of households use unhygienic toilets in cold, arid regions. These areas face water shortages, frozen conditions, and high costs for sewer systems, making flush toilets impractical. Farmers abandon new toilets due to the cost of water use and cleaning burdens. Lack of inclusive designs reduces acceptance, slowing progress.

How it works

This waterless composting toilet system employs feces-urine separation. Feces are mixed with rice husks, sawdust, and probiotics, fermented via manual stirring and solar heating to decompose efficiently and reduce volume. For a family of three, cleaning is required biennially, lowering maintenance costs. The stabilized compost serves as a soil amendment for farmers. Urine is stored, aged, diluted, and reused as organic fertilizer. A flexible bag prevents winter freezing. The trapezoidal urinal backplate allows versatile installation—on flat walls or corners—maximizing space efficiency. A solar fan and passive ventilator remove odors continuously. Footrests aid safe use for children and elderly. EPP foam seats provide winter comfort, while gravity-driven self-closing lids direct men to the urinal, reducing compost chamber mess. An optional dual-chamber bin processes kitchen and garden waste, enhancing fertilizer output.

Design process

Our design has undergone over a year of iterative optimization. Initially, the back panel used a pipe-type solar collector, later upgraded to more efficient vacuum glass tubes. This reduced the collector’s volume for easier transport and installation, while modular assembly lowered production labor costs. The fecal-urine processor evolved from a double-layer nested structure (urine outer chamber, feces inner chamber with a heater) to a simpler mold-free design: a two-compartment fiberglass tank paired with a flexible urine storage bag. This shift prioritized cold-climate reliability beyond freeze prevention. Field research in rural communities revealed elderly residents’ resistance to hygienic toilets due to long-standing perceptions of odor and uncleanliness. We shifted outreach to emphasize emotional connections—e.g., “Improved toilets keep grandchildren visiting longer”—to motivate adoption.

How it is different

This rural sanitation system offers an integrated solution balancing environmental sustainability, user-friendly design, cultural relevance, and economic feasibility. Tailored to rural households in challenging climates, it improves public health and environmental outcomes. The system uses a waterless feces-urine separation design. Feces are composted with rice husks and sawdust via solar heating. Urine is aged and reused as fertilizer. Low-cost urine storage bags resist freezing. EPP foam toilet seats provide insulation. Gravity-based lid closures reduce odor. Footrests ensure safety, and self-closing lids maintain hygiene. The project aligns with traditional composting practices and emphasizes family aspirations in public engagement. Locally produced components keep costs low, while compost and urine reuse offset chemical inputs. This low-cost, culturally grounded design improves rural sanitation and offers a replicable model for underserved regions.

Future plans

In mid-August 2025, a prototype eco-toilet will be installed at a Beijing eco-farm. Four staff will simulate rural usage for data collection. Over 2 months, the design will be refined. By late October, 2 pilot units will be deployed in rural China. Scaling involves rural project partnerships. For consumer markets, sustainable toilets will be developed for homestays, eco-farms, parks, and greenways. Using recycled materials promotes sustainability. Internationally, partnerships with UNICEF, NGOs, and corporate ESG departments will be pursued. Leveraging cooperation initiatives will accelerate global adoption of sustainable sanitation solutions

Awards

UNICEF imaGen Ventures 2024/2025 Winner