The Gates Foundation funded container-based sanitation — a sanitation model using portable, sealed toilet containers that are collected and serviced like waste bins, then emptied at centralized treatment facilities. The model requires no sewage infrastructure, no water, and no digging, making it deployable immediately in dense urban informal settlements where conventional sanitation is impossible. Sanergy in Nairobi and SOIL in Haiti pioneered the model with Foundation support, demonstrating that container-based sanitation could be financially self-sustaining through the conversion of collected waste into fertilizer and biogas.