Upgrade of a High Purity Oxygen Plant for Improved Energy Efficiency and Process Control

Post Point Wastewater Treatment Plant
Bellingham, Washington

The paper describes an approach to design and control of high purity oxygen (HPO) activated sludge treatment systems incorporating anaerobic zones for settleability control, efficient oxygen transfer, and control of dissolved oxygen concentration through variable speed drives. A case study from an upgrade project in Bellingham, Washington is used as an example of the approach. Results from upgrade of the Post Point WWTP provide proof that significant improvements can be made in the process control and energy efficiency of HPO plants. Improvements to sludge settleability can result from conversion from fully aerobic to anaerobic selector operation. Continuing improvements in oxygen transfer can make upgrade of impellers economical. Provision of variable speed drives reduces waste of DO, drive power, and HPO gas. Source: WEFTEC 2009 Proceedings

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Posted: August 27th, 2010 | Filed under: Waste Water Treatment | Tags: Energy Savings, Improved Oxygen Transfer, Improved Plant Efficiency, Improved Sludge Settleability, Reduced Loss of DO in the Effluent | No Comments »

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Suitability of Extended Aeration Plants for BNR Retrofits: A Case of Tripling Rated Capacity

North Perth WWTP
Perth, Ontario Canada

The conversion of an extended aeration plant to modified Ludzack-Ettinger (MLE) process coupled with the construction of a dedicated septage receiving facility required the tripling of the plant contaminant processing capacity. Conversion to the MLE process affected a 55% reduction in annual average SVIs to about 126 ml/g, 75% reduction in alum dosage (on a molar basis), and 23% reduction in electrical power consumption. Biological nitrogen removed increased from 27 tons N in 2006, comprising 34% of the influent total nitrogen to 136 tons N or 67% of the influent nitrogen in 2008. The MLE achieved more stable nitrification throughout the year than the former extended aeration plant. Source: WEFTEC 2009 Proceedings

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Posted: August 27th, 2010 | Filed under: Waste Water Treatment | Tags: Cost Savings, Energy Savings, Improved Sludge Settleability, Increased Capacity, Reduce Alum Dosage | No Comments »

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