Waste treatment and disposal
Annex III of the Madrid Protocol outlines the obligations of national programs for waste disposal and management. Antarctic research stations generate a variety of wastes, including liquid waste (human waste, water from kitchens and bathrooms, and from operational activities in workshops) and solid waste (e.g. materials for landfill and recycling). Burning of fossil fuels for power generation, powering of vehicles and waste incineration at the stations contributes to emissions into the environment.
Wastewater effluent is discharged directly to the sea adjacent to the stations. At Davis and Macquarie Island, sewage is macerated and released. Maceration is the minimum level of sewage treatment required under the Madrid Protocol. At Macquarie Island, sewage is discharged into a high-energy environment where the macerated particles are quickly diluted and dispersed. The AAD has recently installed a new wastewater treatment facility at Davis. The plant was commissioned during the 2015–16 summer (Box ANT7). This new facility will greatly improve the environmental outcome for the area. During the project’s second stage, an advanced wastewater treatment plant will be installed, which will have the capacity to produce potable water.
At Casey and Mawson stations, treatment plants process the sewage before it is released into the ocean. Biological oxygen demand (BOD) measurements assess how effective waste treatment plants are in removing organic matter from the sewage and how much organic matter is being released into the ocean. Figure ANT14 provides an annual summary of BOD measurements for each of these stations since 2001, from measurements made at approximately monthly intervals. The values for 2011–15 are 24 milligrams per litre (mg/L) for Casey (from 49 measurements) and 11 mg/L for Mawson (from 53 measurements). By comparison, the marine emissions limit for accepted modern technology in Australia is 10 mg/L (DPIWE 2001). A value of 60 mg/L for an individual measurement indicates poor efficiency in the treatment plant, and this threshold is occasionally reached when occupation of the stations is highest. For 2011–15, the threshold was exceeded on 8 occasions at Casey and 4 occasions at Mawson.
The quantities of suspended solids are also measured at the 2 stations. Suspended solids indicate how efficiently the waste treatment plants break down organic matter, and the amount of organic matter that is released into the ocean because of human occupation. Figure ANT15 provides an annual summary of suspended solids measurements for the 2 stations since 2001, from measurements made at approximately monthly intervals. The values for 2011–15 are 3 mg/L for Casey (from 50 measurements) and 20 mg/L for Mawson (from 56 measurements). Similar to BOD measurements, a value of 60 mg/L for an individual measurement indicates poor efficiency in the treatment plant, and this threshold is occasionally reached when occupation of the stations is highest. For 2011–15, the threshold was exceeded on 3 occasions at Casey and 9 occasions at Mawson.
Waste is minimised wherever possible—for example, reducing packaging waste by delivering goods to Antarctica in minimal packing. Substances such as washing powders and dishwashing liquids are biodegradable.
As with any community in Australia, the Australian Antarctic and subantarctic research stations generate a volume of waste in proportion to the station population and level of activity. This waste has been generated since the stations were established. However, how the waste has been managed over time has changed as the organisation has moved into a more enlightened era in terms of environmental management and Antarctic stewardship.
When stations were first established, the practice of ‘return to Australia’ was not considered necessary, and waste was disposed of at localised tip sites near the stations. This was in keeping with the way waste was handled in Australia and elsewhere in Antarctica at that time. These practices ceased when the Madrid Protocol came into effect. However, the tip sites and related waste disposal practices, although abandoned, have left an ongoing environmental legacy (see Contaminated sites and pollution). Through the Australian Antarctic strategy and 20-year action plan (2016), the Australian Government has committed to developing a plan to remove legacy waste and continue the remediation of contaminated sites (Australian Government 2016).
Clean-up operations have already started. In 2011, the remaining legacy waste at the Thala Valley waste site at Casey was returned to Australia. The site is being monitored, and results will be validated in terms of environmental impacts. Tip sites at the Mawson, Davis and old Wilkes stations remain unresolved, and continue to present an environmental legacy and ongoing impact.
Waste generated annually and materials no longer required on station are returned to Australia for recycling, re-use or disposal. Waste typically includes general landfill and commingled recycling, such as paper, glass, aluminium and plastic (polyethylene terephthalate [PET] and high-density polyethylene [HDPE]), sewage sludge, paint, oil, steel, copper, brass, building materials and laboratory chemicals.
Some waste cannot be returned to Australia for quarantine reasons and is incinerated at the station. This includes kitchen scraps, medical waste and human waste returned to the station from field activities. Incineration results in a range of emissions to the environment, and Australia aims to minimise the amount of materials incinerated on the stations by diverting materials from incineration to re-use or recycling. The ash from incinerators is stored on station and returned to Australia for disposal. Data are collected on the amount of material incinerated, as well as all waste returned to Australia. New wastewater treatment facilities under construction have been designed to process food waste, and have the potential to greatly reduce the amount of material incinerated on station. The AAD regularly reviews the environmental impacts of waste activities, the extent of station community compliance with waste-management guidelines and the economics of recycling.
Waste is returned to Australia by ship, usually during the resupply of the stations. The amount of waste returned to Australia each year is highly variable and dependent on the availability of cargo space on the ship, shipping schedules, and sea ice and weather conditions during station resupply. Figure ANT16 shows the total mass of waste returned to Australia and incinerated at the stations from 1999–2000 to 2014–15.