EVALUATION OF ALTERNATIVES FOR A GREENFIELD WATER RECLAMATION FACILITY, INCORPORATING CARBON-FOOTPRINT AND SUSTAINABILITY PERSPECTIVES

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.Wastewater treatment facilities are not considered to be among the top producers of GHGs from human activity; however, a more holistic view of wastewater management indicates that its impacts on GHG emissions spread into other sectors of GHG production. Because of their engineered nature, wastewater treatment facilities represent significant opportunities to reduce GHG emissions. It follows that when a municipality is planning new wastewater treatment facilities, the evaluation of treatment alternatives needs to consider the relative impacts of those alternatives on GHG emissions. Sustainability principles also need to be incorporated into the evaluation methodology.This paper presents a case study evaluation of wastewater management alternatives including GHG-emissions and overall “carbon-footprint.” This case study is for a future, greenfield-type wastewater treatment facility in Columbus, Indiana. The evaluation demonstrates how different wastewater management options present differing impacts on GHG emissions and carbon sequestration. Consequently, the impacts of GHG emissions and carbon management need to be part of the wastewater facility planning process.Using a decision science approach, the evaluation compares potential impacts of wastewater management alternatives for new wastewater treatment facilities (19-mgd design capacity). Five different treatment alternatives were evaluated, with three of those alternatives involving sub-options, for a total of eight treatment scenarios investigated:This paper summarizes the results of the evaluation and demonstrates how traditional and non-traditional wastewater management options are affected by their impacts on carbon management and their potential for reductions in GHG emissions. It is concluded that the evaluation of the GHG-emission impacts and “carbon footprints” of wastewater treatment can and should be considered when evaluating alternatives for the design and implementation of water reclamation facilities.