When starting the new municipal wastewater facility in Burley, Veolia Water North America was able to produce Class A reuse water. The state of Idaho designates Class A reuse water as municipal reclaimed wastewater verified to contain extremely low levels of potential disease-causing organisms. It is therefore suitable for reclaimed water supply to residential properties for non-potable uses (not for human consumption) such as garden/lawn watering and toilet flushing. Currently the facility reuses the Class A water in-house for seal water, wash water, and other uses throughout the facility. As a result, the facility went from averaging more than 15 NPDES¹ violations a month to zero violations.

The municipal wastewater facility is run on variable frequency drives (VFDs), which are programmable and allow the electrical equipment throughout the facility to be run in optimal conditions, thus reducing electrical consumption. VFDs allow the frequency of the electrical power that runs motors to be varied, depending on need.

One application of VFDs in the facility involves blowers. At the facility, wastewater moves through oxidation ditches, where oxygen is added to the water by blowers and aerobic bacteria break down organic matter.  Blowers at the oxidation ditches run at very low speeds during the day and are shut down late in the evening to conserve energy. In the morning, the blowers begin delivering the needed air to the oxidation ditches and run at low speeds to keep the microbiology working while minimizing energy use.

The solid materials that are removed from wastewater and treated are called biosolids. They must meet strict standards to allow reuse as a soil amendment.

Part of the wastewater treatment process involves dewatering biosolids, which takes the water out of the solids. At the municipal wastewater facility in Burley, dewatering is kept to a minimum, resulting in fewer solids sent to the sludge drier, which is the equipment that dries the solids after dewatering. Minimized use of the sludge drier means less natural gas is needed to run it.

When the sludge dewatering system is used, the facility reduces their total solids by 16 to 20%. These total solids then go to the sludge drier and produce Class A biosolids, which are designated by the U.S. Environmental Protection Agency to contain no detectible levels of disease-causing organisms. When the biosolids leave the sludge drier, they have gone from a 16 to 20% solid to at least a 95% solid, which could be compared to dirt.  This is an unregulated biosolid which can be used as soil amendment, or as fertilizer.