Improving Combustion Efficiencyin Remote Alaska Community MSW-Burn Units

Approximately 180 to 225 very remote communities, the bulk inaccessible by road, with populations averaging 200 to 500 people, are located in Alaska for which the open burning of municipal solid waste is prevalent, inevitable, and necessary to minimize environmental health concerns. Other waste management options, including conventional incinerators, are not feasible for this unique population group, overwhelmingly comprised of Alaska Native Villages. A decade ago, open dump burning and household barrel burning dominated waste management practices. Today, contained communal burning in what are termed “burnboxes” is the accepted combustion method. These units have proven affordable and adaptable to challenging village operational needs and unique operating conditions. It is well established that even contained and designed open burning presents a significant potential health risk, but in the absence of a feasible alternative, waste burning will continue. In fact, without burnboxes, open dump burning, burning in barrels in town, disposal in drinking and food source water bodies, increased disease transmission and contact risks, increased in-town waste storage, and increased fire danger will present in their place. For the foreseeable future, the resultant cumulative environmental health risk of eliminating burnboxes would be considerably higher. Thus, this project seeks to improve the emissions performance of the burnbox while maintaining its target community usability. While not measured in situ, burnboxes are thought to operate at temperatures between 600°F and 1200°F. Conventional incinerators operate at temperatures in excess of 1600°F (typically higher). The burn temperature of burnboxes is thus considered to be a primary factor in their poorer emissions. In Phase I, Tok Welding and Fabrication seeks to develop a higher temperature waste combustion unit via the manufacture of a composite chamber wall of steel-sandwiched Insulfrax, a bio-soluble calcium-magnesium-silicate insulative material designed to withstand continuous temperatures of up to 1000°C (1832°F). To evaluate the results, a pilot longitudinal comparative study will be performed, with the single- and composite-wall units operated side-by-side under village field conditions. Ambient weather will be recorded via a Davis field weather station, and burnbox temperatures will be measured via high temperature monitoring probes and a hand-held laser unit as backup. The resulting heat retention of the innovation is anticipated to produce substantially higher burn temperatures compared to the current unit. The improved emissions and reduced potential exposure duration (reduced burn time) will incur only a nominal increase in capital cost, with expected zero impact on the current ultra-low operational and maintenance design.