Until the early 1970s, in the United States, wastewater treatment mostly consisted primarily of the removal of suspended and floating material, treatment of biodegradable organics, and elimination of pathogenic organisms by disinfection. Standards were not uniformly applied throughout the country. In the early 1970s until about 1980,

At this Wastewater Treatment Plant in Glendale Heights, IL, an aluminum slide gate had to be forced open using a front-end loader and a chain after seizing in place due to inevitable corrosion. The corrosive bond was so severe that the chain snapped upon the first attempt.