Developments to Watch
CHEAPER CLEAN WATER FROM MANURE-LOVING MICROBES
Some people look at the piles of steaming horse droppings that dot the British countryside and see only the obvious. Not Professor Emeritus S. John Pirt of King's College in London. Thanks to the unflagging curiosity of this semiretired microbiologist, sewage treatment may soon get less costly.
Pirt has found a microbe in horse manure that both dines on sludge and generates heat--up to 80C (176F), enough to kill harmful bacteria in sewage. By teaming the new bugs with other microbes, Pirt is developing a fermentation process that digests raw sewage, leaving behind only treated water and trace minerals. The process also gives off carbon dioxide, which he hopes to collect for sale to greenhouses. Pirt predicts that his "biocombustion" technology will be 40% cheaper than incineration, now the preferred method of disposing of sludge. And it can be scaled to suit any size community. Pirt says it will take three years and $5 million--which he's soliciting from interested water companies--to finish development. EDITED BY OTIS PORT