Hydro Tasmania aims to improve its measurement and performance in resource use, waste and emissions by auditing the Hobart office and implementing strategies to minimise consumption and waste levels, and by consolidating data from across the business. We appreciate that our performance will impact on local environments and communities through effects on water quality, landfill and contamination, and also the perception of the community on our claims to be a sustainable business.

Resource use
Some ad hoc resource use initiatives were implemented at some power stations and in the Hobart office. Efficient plumbing fixtures continued to be installed in the Hobart office to reduce water consumption. A small group of dedicated staff have initiated the Clean Biz program, which aims to coordinate activities targeting resource use in the Hobart office and which ultimately may be adopted by other sites.

Operational waste management is specified in the environmental management plan for each project.
It specifies how the waste is to be handled and disposed and refers to any other specific plans for controlled waste, such as oil or asbestos. A data tracking system has been implemented to document waste disposal in preparation for implementing a formal business-wide process.

	Figure 5 NPI Atmospheric Emission Profile Comparison 2004/05 to 2006/07 Click to enlarge

Data showed Bell Bay power site waste emissions returned to 2004/05 levels and Bass Strait islands waste emissions were close to 2005/06 levels due to similar usage of diesel and similar input from wind turbines.

Spills
Altogether there were 20 severity-1 spills with negligible or insignificant environmental harm or nuisance and seven severity-2 spills where environmental harm was likely and/or a regulatory requirement breached.
The seven severity-2 spills are listed here.

• An oil spill at Poatina Power Station, where up to approximately 150 litres of oil were lost via the tailrace to water. No environmental impact was observed when the incident was reported and investigated. No stakeholder complaints were received.
  
• 200 litres of the chemical C-Treat-6 were lost to the waterway from Reece Power Station. There was
• 60 litres of oil were lost to ground from a transformer at King Island’s Huxley Hill Wind Farm. All contaminated soil was removed.
  
• At least 200 litres of oil were lost to soil and possibly water from a transformer at Liapootah Power Station. While soil contamination is evident, an independent investigation considered that it did not present a significant risk to soil ecosystems or human health.
  
• An unknown quantity of diesel leaked to soil from a bowser at Wayatinah. The faulty equipment has been replaced and soil contamination remediated.
• Effluent overflowed from the Strathgordon sewage system on four occasions, with two of these being severity-2 events, despite an upgrade of the plant.
  After the first overflow, a cut-off drain was built to prevent discharge into Stinky Creek. The plant is currently operating but still has capacity problems with heavy rain conditions. The capacity of the sewage system is under review. The in-ground infrastructure has been assessed and repairs are required to limit inflows. During 2007/08 these repairs will be requested and completed, subject to funding approval.
  

All environmental incidents are reported and managed in accordance with environmental incident management procedure in the environmental management system, ESMS, certified to ISO 14001.

Non-compliant discharges

Water discharge from Bell Bay
Cooling water is drawn from the Tamar River and discharged to Donovans Bay on the northern side of the Bell Bay Power Station. Studies conducted for Hydro Tasmania have determined that the warm water discharge is acceptable and within the limitations allowed by the site Environmental Protection Notice (EPN) and has no significant impacts on biodiversity value of water bodies and related habitats. The gas turbine facility does not require water for cooling.

During 2006/07 at the Bell Bay Power Station, monitoring of cooling water indicated a non-compliance with limits specified under the Environment Protection Notice. Following site maintenance work and a problem with caustic flows, the coalescing filter became clogged.
As a result, the released cooling water did not meet the requirements of the EPN for pH and suspended solids.
The release period was reported as being less than 10 hours, and when identified, immediate action was taken to rectify the situation. A contributing factor to the incident appears to have been an oversight in handing over operation and maintenance requirements to a new contractor a few days prior to the incident. Monthly sampling since the incident has shown discharge within the required limits.

Gowrie Park sewage pond
At the Gowrie Park sewage pond, sampling results for a downstream site indicated a level for non-filterable residue (NFR) higher than that permitted under the EPN. Inflow and outflow sampling for the pond did not indicate the same result as the downstream site. It therefore appeared to be a result of external factors rather than the operation of the pond itself.