There are many challenges to a good town-gown relationship in college towns, but here’s one that doesn’t get a great deal of press: urine overloads. On certain nights of the week, partying UNH students in Durham can overwhelm the town’s wastewater treatment plant. But NHPR’s Sam Evans-Brown reports a group of UNH students have teamed up with the town to get some of that nitrogen-rich urine out of the water, and put it where it could do some good.