Environmental Impacts of Concentrate Management Alternatives: Criteria for Comparative Assessment

Environmental impacts of concentrate management from desalination projects is a major consideration in deciding for an appropriate concentrate management strategy and mitigation methods. The concentrate management technology of each plant should be developed in view of the desalination plant location, potential environmental impacts, and possible mitigation options. This paper examines the advantages and disadvantages of different concentrate management strategies in view of the characteristics of the concentrates from desalination processes and potential environmental impacts for each concentrate management alterative. The quality of the concentrate depends on the amount of chemicals used (i.e., anti-scaling agents, surfactants, acids for pH adjustment, and salts removed from feed water). Therefore, concentrate produced by the desalination processes can impact the land, marine environment, energy demand and greenhouse gas emissions, groundwater quality as well as demands for chemicals, and noise emissions. The aim of this study is to develop an assessment method by analyzing the potential impacts in view of the criteria associated with each alternative. The general concentrate management options include discharge to oceans and bays, discharge to surface waters and sanitary sewers, deep well injection, land disposal, and evaporation ponds. In view of the potent toxicity and persistence of emerging contaminants, innovative and cost-effective treatment technologies are needed, especially for the emerging organic contaminants (EOCs) that may be retained in the concentrate. The results of this study can be used as a decision making tool for preliminary screening of options for concentrate management strategies appropriate depending on the location of the desalination plants.