Horner & Shifrin is providing professional design engineering services to Rock Creek Public Sewer District for the replacement of their Sequencing Batch Reactor (SBR) aeration blowers at the Kimmswick WWTP. The existing 100 hp multistage centrifugal blowers have reached their expected life, and a need for replacement was determined during the Facility Plan update developed on a previous H&S project. The existing blowers only allow for on/off cycling to provide a basic DO control in the SBR reaction tanks and can only be throttled by a manual intake valve.
New replacement 100 hp air-cooled magnetic bearing turbo blowers have been chosen as the basis for design to provide a more efficient compression and allow for tighter DO control in the reaction tanks by utilizing VFDs to maximize turndown. Recent control upgrades to the plant have enhanced the overall automation and allow for enhanced biological nutrient removal in the SBR tanks. The turndown will reduce energy consumption and allow for nitrification/denitrification to help optimize the energy usage of the plant. The blowers will be designed to meet full operating range of the SBR tanks so as to account for minimum mixing air requirements as well as the variable water level in the tanks throughout the cycling process.