The airport has spent about $600,000 on the resource consent process and state-of-art plant to improve its quality of effluent discharge.
In a report to be presented at this week's compliance committee, ORC compliance manager Martin King said analysis of the performance monitoring results had revealed "dramatic improvement" since the membrane filtration plant came online.
There had been a series of commissioning problems but otherwise he described the plant's performance as "outstanding". Issues with high phosphorous and ammonia levels had been sorted, he said.
The work done by the airport to improve the quality of effluent had produced a standard of compliance that was "orders of magnitude better in every respect" than was generally indicated by historical data.
To continue to maintain a high level of compliance and a more sustainable, environmentally friendly approach, the airport had started a comprehensive testing programme over and above its consent requirements, Mr King said.
The testing, along with continued fine-tuning, should see results improve further.
Airport chief executive John McCall said it was not easy to get a "pat on the back" from a regulatory authority, so they were very pleased to achieve what they had.
"We're very, very proud."
Staff had worked closely with the regional council to achieve the result which had helped them to deliver more than was asked for, he said. The plant had a 20-year consent.
"It has set a new benchmark for water quality of discharge from sewerage treatment plants and a new benchmark for the Taieri."
Audit site visits were also held for Kaitangata, Balclutha, Kakanui, Oamaru, Moeraki and Palmerston sewerage plants, with the general level of compliance being good, he said.
