Membrane Bioreactor/Ultra Low Energy Reverse Osmosis Membrane Process for Forward Operating Base Wastewater Reuse
Dr. Hua Wang | GE Global Research
Forward Operating Bases (FOBs) require 25-60 gallons of potable water per soldier per day for essentials including drinking, hygiene, and food preparation, and they produce 35-50 gallons of wastewater daily per soldier. Wastewater treatment methods in FOBs include burn-out latrines, chemical latrines, sewerage lagoons, removal to off-site facilities by contractors, and rarely, a conventional wastewater treatment plant. Currently, a 600 soldier FOB requires 22 trucks per day to supply the base with fuel and water and to remove wastewater and solid waste, creating significant security risk to convoy personnel as well as a negative environmental impact.
The overall objective of this project was to develop an innovative, easily deployable membrane bioreactor (MBR) and ultra-low energy (ULE) reverse osmosis (RO) system for onsite wastewater treatment that produces high-quality water for potable and non-potable reuse, thereby minimizing the need to transport water and wastewater to and from the FOBs.
The approaches in this project include three integral components. The first was to develop ULE, high permeance membrane technology by incorporating highly engineered nanomaterials. These ULE nanocomposite RO membranes operate at low pressures and have a low energy requirement. The second was to build a laboratory-scale MBR/RO wastewater treatment system to demonstrate its ability to produce high quality water for reuse. The third was to perform a techno-economic feasibility assessment of a deployable MBR/RO system configuration based on laboratory-scale experimental data and suitable performance modeling.
The advanced ULE RO membrane, incorporating engineered nanomaterials, demonstrated a 2- to 3-fold permeance enhancement, while maintaining the 99.5% or higher salt rejection characteristic of current commercial RO membranes. MBR/RO wastewater treatment experiments were carried out using both synthetic wastewater and a mixture of on-site generated kitchen and laundry wastewater and tap water to simulate typical wastewater streams from FOBs. The integrated MBR/RO system produced high quality effluents that met potable reuse requirements when the MBR was operated at low Hydraulic Retention Time (2-4 hours) and high Sludge Retention Time (20-25 days). In addition, rapid biological seeding and start-up procedures were successfully developed to start the MBR system and generate high quality effluent in less than 5 days. The system performance and water quality data were used to design a low footprint, energy efficient, and deployable MBR/RO system for FOBs. The results indicate that the investment of the GE deployable, low energy MBR/RO wastewater treatment system pays back in less than 1 month after deployment in FOBs, offering tremendous cost savings for the U.S. military and an improved base environment and security.
The major benefits of the MBR/ULE RO wastewater treatment system to the Department of Defense and specifically its FOBs are:
- Greatly reduced potable water demand from off-base sources
- Greatly reduced need to transport wastewater away from the bases
- Potentially 80% less water traffic on roads (transport of potable water and wastewater)
- Potentially 50% less overall traffic on roads (transport of potable water, wastewater, and solid waste)
- Net annual potential cost savings of more than $30 million per 600-soldier FOB
- Improved base environment, security, soldier health, and stewardship of foreign lands.