Straw density board vs. conventional density board: Is straw density board more sustainable?

Abstract

The widespread use of density boards in various industries has caused a series of environmental issues. The results of this study can inform policy-making and facilitate the sustainable development of density boards. The research focuses on the comparison between 1m3 conventional density board and 1m3 straw density board, with the system boundary defined as "from cradle to grave." Their life cycles are evaluated across three stages: manufacturing, utilization, and disposal. To facilitate environmental impact comparisons, the production stage was divided into four scenarios based on different power supply techniques. To identify the environmental break-even point (e-BEP), variable parameters for transport distance and service life were incorporated into the usage phase. The disposal stage evaluated the most prevalent disposal method (100 % incineration). Regardless of the power supply method, the total environmental impact of conventional density board throughout its life cycle is always higher than that of straw density board, owing to the large amount of electricity consumption and the utilization of urea-formaldehyde (UF) resin adhesives in the raw material stage of conventional density boards. During the production stage, while the conventional manufacture of density boards results in environmental impacts ranging from 57 % to 95 %, which surpasses those of straw-based alternatives at 44 % to 75 %, modifying the power supply technique can alleviate such impacts by 1 % to 54 % and 0 % to 7 %, respectively. Thus, altering the power supply technique can effectively mitigate the ecological footprint of conventional density boards. Moreover, when assuming a service life, the remaining eight environmental impact categories exhibit an e-BEP at or prior to 50 years, with the exception of the primary energy demand (PED) values. Based on the environmental impact results, relocating the plant to a more judicious geographical location would indirectly increase the break-even transport distance and consequently mitigate the environmental impact.