Submitted
2025 Global Climate Challenge

Pooloop: zero waste sanitation

Team Leader
Miranda Zhong
We provide a completely decentralized wastewater solution that removes human waste directly at the source—using a smart, dry toilet that operates with no water, no smell, and no residual waste, forming a closed-loop circular sanitation system. Our system consists of two components: Pooloop and Wooloop. Pooloop is our product-ready core sanitation unit, which includes an electric-powered dry toilet and a...
What is the name of your organization?
Novotheme
What is the name of your solution?
Pooloop: zero waste sanitation
Provide a one-line summary or tagline for your solution.
A decentralized wastewater system with smart dry toilets that turns waste into fertilizer, eliminates sewage needs and recycles greywater on-site.
In what city, town, or region is your solution team headquartered?
Dongguan, Guangdong Province, China
In what country is your solution team headquartered?
USA
What type of organization is your solution team?
For-profit, including B-Corp or similar models
Film your elevator pitch.
What specific problem are you solving?
Over 3.5 billion people – almost half the world’s population – use sanitation leaving human waste untreated. This crisis causes 1.4 million preventable deaths annually, mostly from diarrheal disease (UNICEF, 2023). Poor sanitation is a leading cause of child mortality, malnutrition, and school absenteeism, especially for girls who lack safe, private toilets. In low-resource settings—urban slums, refugee camps, and extreme cold/drought-prone areas—centralized sewage systems are often technically unfeasible and expensive. As a result, communities rely on open defecation, pit latrines, or chemical toilets, which pollute water sources, emit methane, and increase disease outbreaks. Further, conventional sewage systems are not only water-intensive, but also economically and environmentally unsustainable. Standard toilets use an average of 1.6 gallons per flush, and older models can use up to 7 gallons (US EPA). Globally, this adds up to over 37 billion gallons of freshwater flushed away each day—at a time when more than 2 billion people live in water-stressed regions. To build a more sustainable and inclusive future, we urgently need a new sanitation model—one that is operationally feasible in off-grid settings and complementary to existing infrastructure where it exists—a system that reduces emissions, protects public health, conserves freshwater, and eliminates reliance on costly centralized infrastructure.
What is your solution?
We provide a completely decentralized wastewater solution that removes human waste directly at the source—using a smart, dry toilet that operates with no water, no smell, and no residual waste, forming a closed-loop circular sanitation system. Our system consists of two components: Pooloop and Wooloop. Pooloop is our product-ready core sanitation unit, which includes an electric-powered dry toilet and a local post-processing reactor. The toilet features an automated sealing system that encloses waste in biodegradable PHA film after each use—while also providing a fresh, sanitary seat cover. This ensures a waterless, odor-free, and hygienic experience. The sealed waste packages are collected weekly and processed in the Pooloop reactor to produce organic fertilizer safe for agricultural use. Wooloop, currently in development, is our greywater recycling module. It uses a compact membrane bioreactor to treat water from handwashing, bathing, and cleaning. Designed to meet WHO and domestic reuse standards, Wooloop filters out pathogens, organic pollutants, and solids, enabling safe on-site reuse for any non-potable domestic purposes. Together, Pooloop and Wooloop form a modular, off-grid, low-carbon sanitation platform, ideal for areas without sewage infrastructure—urban, rural, or emergency.
Who does your solution serve, and in what ways will the solution impact their lives?
Our solution serves three core user groups based on infrastructure availability and climate vulnerability. First, we target infrastructure-poor and climate-vulnerable areas—including urban slums, rural communities, refugee camps, and disaster zones—where safe sanitation is often nonexistent. These locations are ideal for full implementation of both Pooloop (toilet + post-treatment reactor) and Wooloop (greywater recycling), delivering a fully off-grid, closed-loop sanitation and water reuse system. Second, we serve communities with existing but overwhelmed sewage infrastructure, particularly in urban public settings such as parks, schools, markets, and transportation hubs. In these cases, Pooloop operates as a decentralized relief system, alleviating pressure on outdated infrastructure without requiring connections to sewers or septic systems. Third, we support temporary, mobile, and transitional contexts—such as construction sites, emergency response zones, and large public events—where conventional toilets are unfeasible. Our portable, low-maintenance solution offers clean, odor-free sanitation that can be deployed in days. By offering a modular, scalable approach, our system improves health, conserves water, and builds climate resilience for underserved populations, while adapting to diverse use cases. It empowers users with safe, dignified, and sustainable sanitation wherever infrastructure is limited or failing.
Solution Team:
Miranda Zhong
Miranda Zhong
Founder
Azie Zong
Azie Zong
Mir Qi
Mir Qi
Junkai Huang
Junkai Huang
Student Researcher
George Shi
George Shi
Yuchen Zhang
Yuchen Zhang