It appears to me that the limited size of the existing treatment plant site is being used to drive to the selection of the treatment process. I would like to see the possibility of building a new plant on a new location that would allow for future expansion to a regional treatment concept. I believe that Packy Cronin actually addressed that idea during the meeting when he talked about the gravel pit property along Hwy. 191. A new plant with room for regional expansion could use a less expensive process than the proposed MBR, on a larger footprint. A more conventional activated sludge process with tertiary treatment or microfiltration could be designed in lieu of the MBR system. The study identifies the MBR equipment cost at $7,182 million, with annual cost of membrane replacement at $142,700 and annual chemical costs at $224,600. This process results in the highest annual OM+R cost, with the only advantage that I can find being a smaller plant footprint. When Mr. Buecker addressed a more conventional system on the existing site in his presentation, he cited a cost of $8 million for two 60 ft. Diameter clarifiers and associated pumping and reactor volumes. I believe this estimate to be too high.
See Response to Comment 63. Relocating a wastewater treatment plant is typically extremely expensive and takes several years to implement. The District WRF needs expansion and upgrades to be completed within the next three years. The utilization of IFAS, with secondary clarifiers, a RAS and WAS pump station, and associated site access and yard piping modifications is estimated at $8M based on engineer’s experience with similar projects, including the same contingencies, engineering/administration, and contractor markups as utilized in the MBR cost estimate spreadsheet (i.e., an apples to apples comparison). This cost is before filtration is addressed, which would require a new building or expansion of the existing filter building.