A Robust, Energy-Positive Wastewater Treatment System for Forward Operating Bases
Dr. James Dusenbury | US Army Combat Capabilities Development Command Ground Vehicle Systems Center
The goal of this project is to integrate solar, biological, electrochemical, and membrane technologies to create and demonstrate a deployable, robust, and energy-positive wastewater treatment/utilization system for forward operating bases (FOBs) that can convert both blackwater and food wastes into potable water and renewable energy for on-site uses. The technology is scalable and would also be suitable for fixed facilities. Three specific objectives will be carried out by the study:
- Designing and fabricating a mobile, robust, energy-positive wastewater treatment system for a 150-soldier FOB;
- Testing and demonstrating the system under real-world operational conditions;
- Conducting techno-economic and life cycle analyses of the system, and
- Transitioning the technology.
The system will include five unit operations: electrocoagulation (EC), upflow fixed film reactor (UFFR) anaerobic digestion (AD), membrane treatment, thermoelectric generation (TEG), and photovoltaic (PV). The process starts with the EC treatment of combined blackwater and AD effluent. A newly developed EC unit will be used first to efficiently and quickly treat the high-strength wastewater and generate reclaimed water. The reclaimed water will be treated using ultrafiltration and reverse osmosis membranes with chlorination for potable water production. A small portion of the potable water will be used as the cooling water for the TEG. The rest of the water will be used for other potable applications on-site. The majority of the EC sludge will be mixed with food wastes and the concentrate from the membrane treatment to feed the UFFR for biogas generation. A small amount of EC sludge will be discharged to maintain the nutrient balance of the system. The high-efficiency and robust UFFR will convert carbon in the wastes into biogas to power a simple TEG unit for co-generation of electricity and heat. The PV panels are for additional electricity generation and will be integrated with the TEG to satisfy the power demand of the entire system.
The robust and energy-positive blackwater and food wastes treatment system will provide an all-new concept for FOBs to sustainably treat waste streams, reclaim water on-site, and generate renewable energy. The preliminary mass and energy balance analysis predicts that the proposed system can handle both blackwater and food wastes for a 150 soldier FOB without external fossil fuels. The success of the proposed project will clearly address the wastewater treatment issues that FOBs currently encounter. Consequently, it becomes considerably more likely that the system will be adopted not only as a waste management practice but also as an on-site energy generation solution. The technology developed by this project will combine and advance military base wastewater treatment and energy utilization if fully deployed, which will significantly improve the sustainability of contingency base operations and turn an environmental liability into a valuable asset. In addition, beyond the military operations, it is intended to extend the energy-neutral wastewater treatment technology to a wide range of wastewater management systems from fixed facilities to distributed systems for both municipal and agricultural applications. The use of this new concept will dramatically change the landscape of wastewater treatment in the future.