Municipal Wastewater Treatment Automated Oxygenation and Mixing of Aeration Basins – Saving up to 60% on Energy

Energy is one of the major costs in wastewater treatment with power expenses representing the first or second largest line item of the operating budget for a plant. Aeration basins, with their high horsepower blowers, are most often the plant's single largest consumer of electrical power. Aeration basin operators at wastewater treatment plants often utilize their blower/diffuser systems not only to facilitate oxygen transfer, but to mix solids within the basin. While fine bubble diffusers are efficient at transferring oxygen, they are relatively ineffective at suspending solids. Operators utilizing fine bubble diffusers to mix their basins must maintain a minimum air flow to keep solids suspended, even if oxygen demand does not warrant the level of air flow. This results in an overshoot of dissolved oxygen (DO) targets and wastes energy.An integrated system is one in which each system can be optimized for the function for which it was designed and intended; each system is de-coupled from all others. To achieve a high rate of energy savings, three changes to the plant's aeration basins may be required:1) Installation of smaller, modular, high– efficiency blowers to replace existing centralized blowers.2) Installation of high– efficiency pulsed air mixers.3) Installation of aeration and mixing automated control with on line TSS and DO sensors in the aeration basins.PHi has designed such an integrated — decoupled system.