How are we tracking?
Indicator: Percentage of biosolids beneficially used
In 2011–12, we produced 40,521 dry tonnes. Yearly totals are affected by changes in wastewater treatment processes, population and wastewater flows. We may also include amounts we produced in the previous reporting period, as amounts are not included in totals until removed from storage facilities.
In 2011–12, we again met our target of beneficially using 100% of biosolids produced at WWTPs. Biosolids are beneficially used in agriculture and horticulture.
Table 42 – Percentage of biosolids beneficially used 2007–08 to 2011–12
Indicator: Percentage of solid waste recycled or used
In 2011–12, we maintained our overall recycling rate at 72%.
Construction and demolition waste
The Office of Environment and Heritage target for recycling construction and demolition waste is 76% by 20142. In 2011–12, the percentage of construction and demolition (C&D) waste Sydney Water and our contractors recycled was 69%. This is six per cent less than last year and is the lowest in recent years. This was partly due to excavating 5,500 tonnes of potential acid sulfate soils (PASS). PASS is required by legislation to be sent to landfill. Without the disposal of this PASS material, the overall C&D recycling rate would have been 72%.
We maintained recycling of C&D waste generated by external contractors at 71%. This category of waste remains the largest single source and affects total C&D waste.
Several projects had high recycling rates in 2011–12:
Priority Sewerage Program (98%)
Hoxton Park recycled water project (96%)
Warriewood Wastewater Treatment Plant upgrade (99%).
We recycled 81% of office waste in 2011–12, compared with 47% the year before. This reflects good waste management practices at our Parramatta and Potts Hill facilities and greatly improved recycling rates from other facilities.
We increased recycling of process waste from 48% in 2010–11 to 88% in 2011–12. This offset our C&D recycling. The increase was the result of improved contract management across all areas of operations. The largest increase was in silt and debris recycling, where the contractor improved recycling of sediment from maintaining sewer and stormwater networks from an average of less than 50% to an average of over 90%.
We still have difficulties in recycling litter captured from stormwater devices, due to the costs involved in separating contaminants and sorting the recyclable material.
We maintained recycling rates at 90% for grit and screenings from wastewater treatment plants. During 2010, we introduced a new contract for grit and screenings to improve the recycling rate.
Table 43 – Percentage of solid waste recycled or reused 2007–08 to 2011–12
22007, NSW Waste Avoidance and Resource Recovery Strategy 2007,
Department of Environment and Climate Change NSW, Sydney.