Wastewater Collection System (Sewer): usually a larger town or city, like Cheyenne, Casper, or Rock Springs, where operators specialize in working in the collection system. You never work at a treatment plant. You are responsible for the collection system, including installation, repair, and maintenance of sewer mains, manholes, lift stations and pumps. Collection Systems come in Levels 1 and 2. Begin with the Level 1 Collection System exam. Doesn’t sound like the right exam?