Cherokee Metropolitan District (CMD) outside of Colorado Springs, CO currently operates a 4.8 mgd maximum month flow water reclamation facility (WRF) with sequencing batch reactors (SBRs) and ultraviolet disinfection. The WRF effluent is discharged to several rapid infiltration basins. The facility has a permit limit of 400 mg/L total dissolved solids (TDS) based on a 30 day average and has experienced rising levels above 600 mg/L, of TDS in the raw wastewater. The WRF is being retrofitted with reverse osmosis (RO) membranes to treat a side stream of the treated wastewater to comply with the effluent permit. However, brine disposal options are costly or not feasible in this part of Colorado resulting in the need for the WRF RO process to obtain high recoveries and limit the quantity of brine in order to make evaporation ponds feasible for disposal. In early 2021, construction began on a retrofit of the WRF involving fine and coarse screening, grit removal, conversion of the SBRs to membrane bioreactors (MBR), high recovery reverse osmosis (HRRO), and evaporation ponds. The headworks of the facility is designed to treat up to 9.4 mgd peak hour flow. Two of the four existing sequencing batch reactors will be retrofitted to continuous flow bioreactors with pre-anoxic, aerobic, and post-anoxic zones. Four trains of MBR and three trains of HRRO will be added. The HRRO system is designed to operate between 90 and 95% recovery and will treat a side stream of MBR filtrate in order to blend down to the required effluent limit of 400 mg/L TDS. Reject brine will be sent to over 50 acres of evaporation ponds. This paper will review several unique aspects of the project since this will be the first municipal wastewater facilities to utilize membrane bioreactors and high recovery reverse osmosis.
This presentation is available to AMTA Members only.
- Karla Kinser
- Burns & McDonnell
- AMTA/AWWA Membrane Technology Conference, West Palm Beach, FL
- AMTA/AWWA Membrane Technology Conference
- Membrane Bioreactors, Reverse Osmosis, High Recovery