Methods and apparatus for compact and easily maintainable waste reformation. Some embodiments include a rotary oven reformer adapted and configured to provide synthesis gas from organic waste. Some embodiments include a rotary oven with simplified operation both as to reformation of the waste, usage of the synthesized gas and other products, and easy removal of the finished waste products, preferably in a unit of compact size for use in austere settings. Yet other embodiments include Fischer-Tropsch reactors of synthesized gas. Some of these reactors include heat exchanging assemblies that provide self-cleaning effects, efficient utilization of waste heat, and ease of cleaning.