San Jose Treatment Plant, California

Every community generates sewage that needs to be treated, and San Francisco Bay is ringed with dozens of sewage treatment plants, all of which discharge into the Bay. The largest of these is the San Jose Water Pollution Control Plant (also known as the San Jose-Santa Clara Regional Wastewater Facility) which treats the effluent from most of Santa Clara County, serving a population of around 1.4 million people. Though it operated for many years as only a primary treatment plant, the facility now has secondary and tertiary systems, which make the discharge reasonably clean when it flows through Artesian Slough and into the southern end of the Bay. The sludge drying ponds next to the plant are said to be the world's largest. Solids extracted in the treatment process are trucked to 600 acres of ponds next to the plant, where the muddy waste dries, aided by trucks that break the crust that forms on the surface. When dry, it is delivered to the nearby Newby Island Landfill where it is mixed with layers of household waste.