Impact of Chlorine discharge


How much chlorine will be used in the waste water treatment process? Chlorine is designed to kill micro-organisms, can you advise the impact on marine life in Westernport Bay from the discharge of chlorinated water?

AGL Employee

Hi Mike61,


Marine life in Western Port is an important environmental asset that must be cared for and we recognise a major concern is about the potential marine impacts from the open loop regasification process – using seawater to warm the very cold LNG.


During the open loop process the ship’s system, like a filtration system in a salt water swimming pool, produces a small amount of chlorine, being approximately 0.1 of a milligram a litre at the release point, from the seawater to keep the system clean.


Early EES referral expert reports found that when the water returns to Western Port it will break down to an undetectable level within 20 seconds. In other words, the level of chlorine in the water that’s returned to the port would be significantly less than that allowed in our drinking water.


While these earlier reports show the chlorine breaks down very rapidly and the temperature differences quickly dissipate, we recognise this still concerns the community. The community have made their concerns known to the government and they have been successful in making sure they are now assessed independently through an environmental effect statement process. We hope the EES process being conducted by the government will carefully address the concern around chlorine.


Thanks for your response Lachlan.


So if I understand correctly, the Ships system is trying to keep it's equipment clean, but in the process, inadvertently trying to turn the bay into a swimming pool? Can you explain how the EES process addresses this specific concern?

AGL Employee

Hi @Mike61,


We’d just like to apologise for the delay in addressing your enquiry – we have received a large number of complex and detailed questions that we need to discuss with a few specialists.


This is not the way we want to deal with community concerns and we’re working to be more responsive in the future.


We’ll respond to your question shortly.




AGL Employee

Hi Mike61,


Again, my apologies for the delay in responding to you - this is not the way we want to deal with community concerns and we're working to be more responsive in the future.


Under s.4.2 of the EES Scoping Requirements, the biodiversity requires the assessment of impact such as, entrainment, discharges, noise in relation to flora and fauna and leaks or spills. This includes the discharge from the defouling system that includes an amount of chlorine.


To find the EES scoping requirements, see:


The technical studies relating to the chlorine discharge are currently underway, however once finalised the EES will be made publicly available and you will be able to make a written submission on the EES during the exhibition period.