The Department of Defense’s overseas contingency operations generate significant amounts of solid waste that requires proper treatment and disposal. Poor waste management practices (open burn and taking waste off base) can create health and safety hazards, security vulnerability, logistical challenges, and the long term legacy of pollution. Deployable incinerators can address these issues, but do not produce energy. Recovering thermal and electrical energy from on-site produced solid waste, can provide an important component in the overall camp energy system to reduce reliance on off-base energy resources.

The objectives of this project were to design, build, and demonstrate an innovative, state-of-the-art prototype incinerator package that will 1) be contained in one 20’ International Organization for Standardization (ISO) container with the 3 TRICONs to not exceed 10,000 pounds each (2) reduce waste volume by >95 % (3) require 25 gallons of diesel fuel per burn cycle 4) produce 10kW per burn 5) produce 13 gallons/minute (GPM) of hot water 6) analyze air emissions to understand impact of energy recovery on quality of air emissions.

Technology Description

The Deployable Waste to Energy Convertor (DWECX) is a variant on the design of the Expeditionary Solid Waste Disposal System, a system developed by Eco Waste Solutions for the U.S. Army. The DWECX design expands on the proven waste disposal capability of the Expeditionary Solid Waste Disposal System (ESWDS) by adding an integrated energy recovery feature. Like the ESWDS, the DWECX waste conversion process is one of starved-air gasification of waste, followed by excess-air oxidation of the gaseous byproducts generated in the conversion process. The Thermal Energy to Electrical Power System (TEEPS) was designed to capture waste heat from the DWECX exhaust using a heat-pipe type of Heat Exchanger and then circulate the thermal oil to the Organic Rankine Cycle (ORC) engine to produce electricity. A second heat exchanger condenses the working fluid using cooling water which can be used for hot water.

Demonstration Results

Performance results 1) the final logistical footprint produced was two 20’ ISO containers with the individual 6 TRICONs not exceeding 10,000 lbs. (2) Waste disposal efficiency was estimated at >95% (3) Fuel efficiency was not addressed in order to optimize Air Emissions quality 4) 3.8 kW of net electrical power was generated. Future system optimizations are expected meet the 10kW per target. 5) 13 GPM of hot water was generated 6) The analysis of air emissions yielded a good understanding of the impact of energy recovery on the quality of air emissions and an understanding of where improvements could be made. The analysis of Capital and Operating Costs provided an estimate of return on investment of five months for capital cost investment return and a net present value of $8 M, assuming 20-year life expectancy of the incinerator package. In addition, there are a number of indirect benefits related to environmental, social, safety and health when compared to burn pits or taking waste off-site.

Implementation Issues

This project will provide camp planners with data and reports that detail system performance, connections and integration with camp infrastructure required to take advantage of the energy produced. Subsequent research and development will be required to adapt the concept further to make it operationally viable. In particular the ORC engine technology requires an off the shelf equipment vendor to assist in ORC integration into the DWECX-TEEPS system. Operational testing of the equipment, by soldiers, will be required to refine the package for eventual deployment. As development work matures project performance will be monitored against the Technology Transition Plan which will encompass operational, logistic, environmental, energy and financial performance data.