The Bill & Melinda Gates Foundation is giving $4.8 million to a project to identify new methods of on-site sanitation in developing countries.

The grant to the London School of Hygiene and Tropical Medicine supports a three-year project to research and develop new concepts for sanitation such as improving pit latrines, which are the only option for about 1.7 billion people without access to sewage systems. The London School will research how advances in biotechnology, using enzymes and micro-organisms to convert plant waste to biofuel, for example, might be applied to sanitation.

The London School also received the $1 million Gates Award for Global Health this year.

The Gates Foundation's program on water, sanitation and hygiene is only about three years old but has grown to 19 grants so far totaling about $160 million.

Unsafe water and poor sanitation and hygiene are leading causes of illness and death in the developing world. Improving them could prevent one tenth of global diseases, according to the World Health Organization. About 2.4 million people die from diarrhea and other water-related illnesses every year.

With its water-related grants, the Gates Foundation has funded low-cost, practical solutions that can be commercialized.

Among the recipients is Seattle-based PATH, which is exploring water quality through a $17 million, five-year grant to help develop low-cost filters, gadgets and other water-treatment products.

In 2008 the foundation gave $13 million to an international consortium led by the University of Bristol to develop Aquatest, a simple diagnostic tool that can give a reliable indication of whether water sampled is safe or not.

Since little research has focused on the development and use of pit latrines, the London School said it aims to build knowledge about decomposition processes and evaluate the potential of biotechnology and improved design to accelerate decomposition.

Its goal is to find solutions that can be turned into affordable, sustainable products available on the market. Researchers say such innovations can improve health and reduce costs for sanitation in an environmentally safe manner. The project will combine academic and industrial expertise and provide an innovation fund to turn promising ideas into prototypes.

Locally another non-profit, Seattle-based Water 1st, has been working on projects that integrate water supply, sanitation and health education in four countries, taking safe water as the basis for ending poverty.