Environmental Impact Assessment of the Davis Sewage Outfall

Untreated, macerated wastewater effluent has been discharged to the sea at Davis Station since 2005, when the old wastewater treatment infrastructure was removed. This environmental assessment was instigated to guide the choice of the most suitable wastewater treatment facility at Davis. The assessment will support decisions that enable Australia to meet the standards set for the discharge of wastewaters in Antarctica in national legislation (Waste Management Regulations of the Antarctic Treaty Environmental Protection Act - ATEP) and to meet international commitments (the Madrid Protocol) and to meet Australia's aspirations to be a leader in Antarctic environmental protection. The overall objective was to provide environmental information in support of an operational infrastructure project to upgrade wastewater treatment at Davis. This information is required to ensure that the upgrade satisfies national legislation (ATEP/Waste Management Regulations), international commitments (the Madrid Protocol) and maintain the AAD's status as an international leader in environmental management. The specific objectives were to:1.    Wastewater properties: Determine the properties of discharged wastewater (contaminant levels, toxicity, microbiological hazards) as the basis for recommendations on the required level of treatment and provide further consideration of what might constitute adequate dilution and dispersal for discharge to the nearshore marine environment2.    Dispersal and dilution characteristics of marine environment: Assess the dispersing characteristics of the immediate nearshore marine environment in the vicinity of Davis Station to determine whether conditions at the existing site of effluent discharge are adequate to meet the ATEP requirement of initial dilution and rapid dispersal.3.    Environmental impacts: Describe the nature and extent of impacts to the marine environment associated with present wastewater discharge practices at Davis and determine whether wastewater discharge practices have adversely affected the local environment.4.    Evaluate treatment options: Evaluate the different levels of treatment required to mitigate and/or prevent various environmental impacts and reduce environmental risks.