RIASSUNTO
Abstract
Commonwealth Petroleum (Submerged Lands) (Management of Environment) Regulations 1999, require an accepted Environment Plan (EP) for offshore production facilities to operate. The EP should contain a comprehensive risk assessment of the environmental effects and risks of the whole PW discharge. Compliance with maximum dispersed oil in water concentrations continue to apply but the regulatory focus has changed in recognition of potential chronic effects associated with dissolved aromatics and other potential contaminants. This paper describes Australian regulatory requirements for the environmental management of PW, assessment techniques, treatment technologies and likely trends in Australian PW management.
Introduction
In Australia, the majority of offshore production facilities discharge treated produced water (PW) to the sea. PW management is focused on maintaining compliance with dispersed oil in water maximum concentrations. New regulations came into effect for existing offshore facilities in Commonwealth waters on 1 October 2001. Operators are required to have an accepted Environment Plan (EP) in order to manage the facility The EP must include an assessment of the environmental effects and risks of the operation of the facility [Regulation 13(3)]. Operators are required to assess and mitigate any unacceptable risks. This paper provides information regarding regulatory requirements, PW risk assessment methods, treatment technologies and likely trends in PW management.
Australian Regulatory Requirements
The Commonwealth Petroleum (Submerged Lands) (Management of Environment) Regulations 1999 require oil and gas production facilities to have an accepted Environment Plan (EP). Regulation 13 (3) requires an assessment of environmental effects and risks of petroleum activity which is defined in Regulation 4 as the operation and maintenance of a facility. The assessment should provide a measure of the risks associated with dispersed and dissolved oil fractions, metals, radionuclides, added chemicals and relevant chemical or physical attributes of the whole fluid. The EP should provide an assessment of potential chronic effects and risks to marine biota associated with long term PW discharge. Field / laboratory chronic toxicity tests on selected species are used together with fate and effects modelling to support the risk assessment. For planned new facilities it is common for operators to conduct facility design and environmental HAZID studies with regulator participation to consider PW disposal options. The case for preferred PW disposal options is put forward in the EP submission. An industry benchmark performance level has been retained. The concentration of petroleum (dispersed) in any PW discharged to the sea is not to exceed 50 mg/l at any one time and average less than 30 mg/l during each period of 24 hours.