Page 81 - AGL Sustainability Report 2011

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Sustainability Performance Report 2011 79
Environmental risk
AGL’s projects and operations produce a variety
of different waste streams. Wastes represent
resources that have not been used for their highest
benefcial purpose.
AGL’s approach to waste is consistent with the waste management
hierarchy, where the approach taken, in order of decreasing
preference, is to avoid, reduce, reuse, recycle and dispose of wastes.
Waste collection processes at AGL’s offices involve segregation of
paper, cardboard, and common domestic recyclables such as glass,
plastics, aluminium and metal tins.
At AGL’s industrial sites, opportunities to reuse or recycle wastes are
sought, and hazardous wastes are disposed of using regulated waste
tracking systems and licensed waste management contractors.
Water-based waste streams are discharged either to sewer or to
the stormwater system under licence from the relevant Water
Authority or Environment Protection Authority (EPA). Discharge
quality is regularly monitored to confirm compliance with
regulatory requirements.
Produced water that is a by-product of upstream gas production
and exploration projects is discussed separately on
page 82
this report.
Hazardous waste
Approximately 32% of the hazardous waste generated by
AGL during FY2011 was recycled or reused. Almost all of this
comprised waste oil and oily waste that can be cleaned up and
reclaimed for use as an alternative fuel.
A significant proportion (70%) of the hazardous waste disposed
in FY2011 was contaminated soil from Torrens Island Power
Station, associated with AGL’s activities to address historical soil
contamination, and drill fines from Camden Gas Project.
In the late 1990s, soil excavated at Torrens Island during the
decommissioning of a former soot pond was found to be
contaminated with petroleum hydrocarbons, and was subsequently
stored in a lined pit on-site. In 2010, the soil was removed
from the site and bio-remediated before being disposed of at a
licensed landfill.
The drill fines from the Camden Gas Project were used in trials
which aimed to accelerate the drying of drill cuttings using sawdust
material. The result of this trial was such that AGL had to dispose
of the drill fines and sawdust mixture to landfill. This trial process
has now ceased and, as outlined below, AGL has resumed standard
drying procedures which enable suitable reuse of drill cuttings.
Non-hazardous waste
The majority (68%) of non-hazardous waste generated by AGL
during FY2011 was drill cuttings from the Camden Gas Project,
and 18% comprised ‘general waste’ disposed to landfill. In FY2011,
3,180 tonnes of drill cuttings from the Camden Gas Project were
dried and then diverted to a Sydney-based company which cleans,
screens, separates and uses the drill cuttings to make a variety of
construction materials, including bricks.
The majority of the wastewater discharged from AGL’s operations
comprises cooling water that is drawn from the Port Adelaide
River, passed through the Torrens Island Power Station to cool it,
and then discharged to Angas Inlet under licence from the South
Australian EPA. The water is discharged at a higher temperature than
it is taken in and an EPA licence sets limits on the temperature rise
allowable. Cooling water thermal discharge is monitored daily, and
this monitoring is verified by an external auditor every two years.
The last verification took place in December 2010, with the next
verification due in FY2013.
Waste streams
Hazardous waste disposed 68%
Hazardous waste reused 32%
Non-hazardous waste
Hazardous waste
Non-hazardous waste disposed 22%
Non-hazardous waste reused 78%