How is the wastewater treated at the Huntingburg wastewater plant?

The wastewater arrives at the plant after traveling through the collection lines. First, the wastewater runs through a bar screen (metal rack with evenly placed rods) which removes large items such as trash, plastic, rags,etc. Next, the wastewater flows slowly through settling tanks where floating material such as oil and grease are skimmed off and where solids settle to the bottom. The solids then form primary sludge that is pumped through a solids treatment process. Then the wastewater, which still contains some solids, is sent through a secondary, aerated treatment process involving microorganisms. The solids are used as the food supply for the microorganisms. Eventually, the microorganisms also settle to the bottom as they move through large basins called clarifiers. It is possible to recirculate some of them back through the process to continue their cleaning work. However some are removed as the microorganism growth expands. The removed solids that have been through the primary and secondary treatment processes then enter a solids digestion process. After digestion occurs, the remaining material is dried and disposed of in a state certified manner. Finally, the clarified water travels from secondary treatment through a holding tank where chlorine is added for disinfection. The final product of clean, disinfected water can now be returned to the environment from which it came.