Evaluation of the environmental implications to include structural changes in a wastewater treatment plant

The environmental implications of including structural changes in a wastewater treatment plant to decrease effluent concentrations of nitrogen were evaluated in this study. Environmental effects from these structural changes were assessed by using the Life Cycle Assessment theoretical framework. The wastewater treatment plant selected as a reference scenario had an activated sludge configuration. The Ludzack-Ettinger and Oxidation Ditch configurations were selected as modifications of the reference scenario. Results from this study show that the inclusion of nitrogen removal mechanisms in the configuration of the plant reduces the effect of the plant on the eutrophication, but simultaneously increases the effect on the consumption of abiotic resources, global warming, acidification and human toxicity. These general trends, however, vary depending on the configuration selected to remove nitrogen. Taking all the impacts together, the Oxidation Ditch configuration would cause less environmental impact than the Ludzack-Ettinger configuration, given the characteristics of the selected scenarios. (C) 2002 Society of Chemical Industry.