Along with the food from the wastes the bacteria need oxygen, supplied as compressed air that also aids in mixing the bacteria with its nourishment. All of this works very well, as long as there is a steady supply of waste and as long as nothing toxic to the bacteria finds its way into the process. Unfortunately for the wastewater treatment facility at the Laboratory, both of those problems exist. About 400,000 gallons of wastewater enter the treatment facility daily, a third of it is clean process water, the rest is sanitary waste. On the weekends, however, the sanitary waste portion of wastewater influent drops to zero, leaving only the clean process water.
Shut downs are terrible for the plant.
Over the Christmas break we have to feed the system with about 50 pounds of dog food every day or the entire bacterial population will starve and die off. When the bacteria are vulnerable, even a small amount of the wrong thing put down the drain can completely kill off the bacteria. Arsenic, heavy metals in general and strong acids or bases with pH of below two or above 12. And another incident where a green-colored high pH liquid resembling automotive antifreeze entered the facility and killed most of the ciliate bacteria. These folks will let you know what is acceptable to the wastewater treatment plant and what is not.