A *slightly* smelly outing to the Tacoma Wastewater Treatment Plant showed us the major process that sewer water goes through before being added to Commencement Bay. The students got to see how the water is combed for particles bigger than a half-inch before going to large tanks where it is again sifted on top and bottom. The sludge is then added to a large tank with pure oxygen (also created on site) and turned to methane gas. The city is going to start selling the methane gas to Puget Sound Energy to offset the cost of running the plant. The students learned that the water that looks cloudy towards the end of the process is just filled with good bacteria, and they were able to see just how clean the water gets before being gradually piped into the bay. It was a little smelly, but the students quickly adjusted!