Design-Build Concept and Unique Startup Plan
Quechan Paradise Casino, a newly constructed gaming facility located in Winterhaven, Calif., began its wastewater treatment operations in January 2009. The project was a design-build concept allowing plant start-up prior to the Casino’s grand opening. Early into the project's development, the Aqua-Aerobic membrane bioreactor (MBR) was selected on the basis that it offered a small footprint, high-quality effluent and low energy consumption. Aqua-Aerobic Systems, Inc. worked closely with Clear Solutions Environeering, Inc. and Roel Construction to get the treatment plant built within a several month period so the casino could be fully operational before the influx of people attending the grand opening.
A typical Aqua-Aerobic MBR schematic.
The Aqua-Aerobic MBR system was actually started up a month before the casino opened in order to get the biomass to necessary levels for treatment of the grand opening flows. The flow was expected to go from < 2% to nearly 100% capacity virtually overnight. Because of Aqua-Aerobic’s unique, early startup plan, Quechan avoided significant expense from hauling excess amounts of seed-sludge. On opening day, the plant processed nearly 100,000 gallons, and the effluent quality was superb.
Design Characteristics
Quechan's Aqua-Aerobic MBR system consists of two batch biological reactors and two membrane tanks, each containing one PURON submerged membrane. The system resides inside a building with separate rooms housing process equipment, pumps, chemical feed equipment, blowers and controls. The building size is minimal because the Aqua-Aerobic MBR system, with vertically integrated equalization, offers the smallest footprint among equivalently designed membrane treatment technologies.
One of Quechan's batch biological reactors.
The treatment facility was designed to treat an average daily flow of 0.15 million gal per day (mgd). The design flow reflects weekend operation when peak flows are anticipated, therefore representing full-strength conditions. The plant's treatment objectives meet California's strict Title 22 reuse requirements, although not required since the casino is located on Native American-owned land. The casino reclaims its wastewater effluent for supplying drip irrigation for its resort landscaping and future onsite golf course. The plant's treatment objectives are listed below.
| Influent | Effluent | |
| BOD | 400 | 5 |
| TKN | 50 | -- |
| TN | -- | 5 |
| TSS | 400 | 5 |
| TP | 12 | -- |
Operating Data
Despite significant fluctuations in daily flow and loads, Quechan continues to record exceptional operating data, with effluent TN levels of 3 mg/L, turbidity below 0.1 NTU and TSS concentrations below detectable limits.
One of Quechan's membranes in air scour mode.
Future Expansion
Quechan's location and available land will also accommodate a second hotel and gaming facility as part of its planned expansion. The Aqua-Aerobic MBR system is designed to treat a future flow of 0.25 mgd with only the addition of two membrane modules. The reactors, membrane support equipment and biological treatment equipment are sized to meet this future flow for easy expansion. The Aqua-Aerobic MBR system will easily handle the plant’s future demands while continuing to provide sustainable water management for the facility.
