AERATION IMPROVEMENTS TO SAVE ENERGY

摘要

The City of San Jose at its San Jose/Santa Clara Water Pollution Control Plant has embarked ona series of projects to reduce energy consumption and provide operational savings, and aerationsystem upgrading is one of the key projects. The plant was converted in 2000 from a coarsebubble, cross-roll in 2000 to fine bubble membrane tube diffusers, which produced significantsavings. In 2009 a second project was initiated to develop an even more cost effectivealternative using a greater number of diffusers in slightly different geometries. Off-gas testingwas performed to confirm aeration efficiency. An economic analysis was used to determine themost cost effective alternative. Upgrading the original year-2000 retrofit with diffusers havingmore active surface area provided a pay back of approximately one year. The economic analysisalso confirmed that the decision to upgrade the original coarse bubble system with fine bubblediffusers was sound and would provide a payback of 3 to 6 months using current costs. Onecounter-institutive result was the inadequacy of the original coarse bubble diffuser air piping.The in-tank headers were able to provide even air distribution for coarse bubble diffusers butwere unable to do so with fine pore diffusers, which operate at much lower air flow rate.Upgrading options are continuing and additional energy conservation activities will occur.