Industrial Wastewater Aeration and Energy Conservation at Millipore Corporation

Millipore Corporation operates an industrial wastewater pretreatment system (IWPS) at its Bedford, Massachusetts facility utilizing aerobic biological treatment technology. The system was designed and installed approximately 20 years ago with a direct drive blower and a series of coarse stainless steel bubble diffuser heads. The coarse bubble diffuser system was selected over a fine bubble system due to the presence of suspended solids in the wastewater. Since its installation, Millipore has made several system upgrades to improve the aeration and energy efficiency of its IWPS, including the addition of variable frequency drive blowers controlled by a series of dissolved oxygen meters capable of adjusting the volume of air flow. With advancements in aeration technology over the past several years, Millipore recognizes that there is an opportunity to further increase the aeration and energy efficiency by improving the oxygen transfer through improvements to the diffuser system. This paper provides a summary and in-depth review conducted by Millipore to upgrade the coarse air system with a fine air diffuser system. The review consists of an overview of existing operating parameters such as energy requirements, dissolved oxygen demand, and treatment parameters as well as a technical evaluation of alternative diffuser and aeration systems that can meet or exceed treatment needs. Each potential alternative is summarized and compared based on its technical feasibility, capital cost, operating costs, and expected life.