When Tom Szaky decided to become an entrepreneur at the age of 19, he picked something that most people in that “dot-com” era would probably have called a very unattractive business: waste management. For the past 16 years, Szaky’s company, Trenton, N.J.-based TerraCycle, has specialized in recycling hard-to-recycle materials, such as cigarette butts and dirty diapers, and has remained a little-known name to the wider public outside of the recycling industry.