Environmental Comparison of Biosolids Management Systems Using Life Cycle Assessment

Abstract

To fill a gap in the information available to nonmetropolitan policy makers, eight scenarios combining processing technologies and end-uses for biosolids products associated with a 40,000 equivalent-person town were modeled using environmental life cycle assessment (LCA). An uncertainty analysis examined several key assumptions. The results showed that the reuse of biosolids products can be environmentally beneficial but transportation distances can change the preferences between technologies, and drying biosolids using petrochemical methane rather than biogas (produced endogenously in the wastewater facility) significantly worsens environmental performance. System scale can also invert option preferences. This work demonstrates an application of LCA to a strategic engineering question. We also examine the methodological feasibility of considering carbon sequestration and water offsets beyond those typical of previous studies. As the development of scientific data regarding the benefits of biosolids recycling develops,there may be potentialto reward agricultural businesses that choose to reduce their environmental burdens using biosolids. A life cycle management approach to this will be necessary.