GREENVILLE — The 25 students in Rochelle Eggebrecht’s fourth-grade classroom at Greenville Elementary School are learning how to turn trash into treasure. And they’re asking their peers and the community to join in the effort. The students have organized Project Upcycle, a district- and community-wide project that collects plastic waste such as drink pouches and Ziploc bags and sends it to TerraCycle, a company based in New Jersey. TerraCycle uses the plastics to create useful, eco-friendly products like tote bags, purses, kites, fencing, coolers, school pencil cases and binders.