What happens after you flush your toilet? For 2.6 million county residents, the answer to that question can be found at a 110-acre plant in Fountain Valley operated by the Orange County Sanitation District.

The industrial site, along with a similar setup in Huntington Beach, is where approximately 185 million gallons of sewage is treated in a complex process that essentially digests biologic material into its basic components.

Byproducts of that process include drinking water — about 130 million gallons per day, thanks to a groundwater replenishment system — methane gas and carbon dioxide, salt, nutrient-rich fertilizer that’s trucked off to commercial farms and a small amount of plastic, debris and grit that winds up in a landfill.