Six new grantees from India have joined the ranks of people who the Bill and Melinda Gates Foundation believes could change the future of toilets, the Seattle-based non-profit announced today.

The six recipients will split a $2 million purse from the Foundation and the Indian Department of Biotechnology in the pursuit of the next great design for a safer, more affordable toilet.

The winning designs include a toilet that replaces water with a sand-like substance and an air blower, and another that uses ultrasound in order to reduce water usage. They join sixteen other grantees from the program, which began in 2011, and includes teams from Stanford, Caltech and Unilever.

It’s all a part of the Foundation’s Reinvent the Toilet Challenge, a move to provide grants to inventors creating the next generation of safe, efficient and cheap toilets. Inventors need to produce a toilet that ideally runs without water, or a connection to a sewer and power grid.

“Our goal is to fund the development of complete solutions – solutions that are affordable, that work, and that people want to use,” Brian Arbogast, the director of the Foundation’s Water, Sanitation and Hygiene team, said in a press release.

While toilet innovation may sound like the setup for a joke told around a middle school playground, good sanitation is a key part of global development. Better toilets can help reduce the risk of disease, and creating a more efficient, lower-cost commode means that it’s easier to spread better sanitation to a country’s poorer residents.

Bill Gates called out the toilet program as a key part of the foundation’s development work in a recent interview, saying that the Foundation’s success rate with development projects outpaces that of venture capital.