It’s been 30 years since a pilot project in Miami-Dade County found that blasting wastewater with electrons could clean it up, removing all kinds of nasty stuff, from mircroorganisms to harsh chemicals. All that was needed was some intrepid scientist or engineer to come up with an accelerator that was cost-effective, compact and user-friendly enough to clean wastewater on an industrial scale. Many countries have been inching forward in using accelerators for environmental remediation – removing toxic dyes from wastewater at a textile factory in South Korea, for instance, or sulfur dioxides and nitrogen oxides from flue gases at a power plant in Poland. But such devices are still too big and unreliable. In this country, studies and technology demonstrations continue, but are making incremental progress. Fay Hannon is dreaming up a low-energy, portable accelerator for environmental cleanup, while Gianluigi “Gigi” Ciovati is figuring out how to use a commercial cryocooler to stabilize a more powerful accelerator he’s designing. “I’m of a generation where environmental protection really weighs on your mind,” said Hannon. “In this case, wastewater treatment is not my specialty,...