Biosolids Master Planning from a Greenhouse Gas Perspective – How Different Options Affect the Carbon Footprint

In recent years there has been an exponential rise in concern and interest regarding global warming trends, with the evidence becoming increasingly stronger that climate change is a result of greenhouse gases (GHGs) emitted largely by human activity. The GHGs of most concern are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), ozone (O3), chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), perfluorinated carbons (PFCs), and sulfur hexaflouride (SF6). By far the most common of the GHGs is CO2, but several of the other GHGs have considerably stronger effects on global warming potential relative to their total mass, and at least two of them (CH4 and N2O) are common to wastewater treatment.The relative impact of human activities on Global Climate Change (GCC), in comparison to natural, planetary cycles, is still a matter of intense and ongoing debate that this paper is not intended to answer. It cannot be debated, however, that our global economy currently depends heavily on the use of fossil fuels that contribute large amounts of GHGs to the atmosphere. Increases in the costs of fossil fuels due to dwindling supplies will force more careful examination of the resource potential of biosolids, and thus more careful evaluation of biosolids management options from the standpoints of environmental, social, and economic impacts that define the general concept of sustainability.This paper will present new perspectives on the evaluation of traditional biosolids management options from GHG-emission and “carbon-footprint” standpoints. It will describe how different biosolids management options may pose widely differing impacts on carbon sequestration, and will establish the premise that the impacts of potential GHG emissions and resource management should be included in biosolids master plans.