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Zero-Cost Operational Modifications Reduce Effluent Nitrogen and Chemical Consumption at the OWASA Mason Farm WWTP

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OWASA owns and operates the 55 ML/day Mason Farm Wastewater Treatment Plant, which will be required to meet strict TN mass load allocations starting in 2018. The existing secondary process provides limited denitrification, and OWASA will be dependent on denitrification filters to meet the standard under historical operations. Operation of the aeration basins as a step feed process, which could be made at zero capital cost, was identified to reduce secondary effluent TN and chemical consumption. Step feed operation commenced in June 2010, and OWASA immediately observed a 50% reduction in effluent TN. Alkalinity feed has been reduced by 55%, and alum and acetic acid feed have been reduced by 25% and 33%, respectively, since implementation of step feed, resulting in 260,000/year of chemical savings. Operation in the step feed mode of operation is expected to save over 800,000 per year over 20 years once the strict TN limit is in force.

Document Type: Research Article


Publication date: January 1, 2012

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  • Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed.

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