Southern Wales-based First Milk, the largest UK supplier of whey ingredients for the cheese industry, spent £3m (€3.77m) on the upgrade, including a £1.25m (€1.57m) government contribution.
The investment improved the quality of the whey produced at First Milk's Haverfordwest creamery, delivered substantial energy savings and reduced CO2 emissions, the company said.
The new arrangement is set to deliver more than £500,000 (€628,000) of energy savings at the site each year.
"In addition to improving the returns the creamery can command for our whey products, this new equipment also enables us to achieve significant energy savings and reduce our CO2 emissions by over 3200 tonnes," said general manager Paul Rowe.
"Between reduced heavy fuel oil usage, effluent treatment and the recovery and re-use of condensate water, we are delivering benefits in the region of half a million pounds per annum."
On time, on budget Work on the project began in March 2007 and was completed on-time and within budget, in ten months, and followed an additional £3m (€3.77m) investment made in 2006.
Charles Morrish, managing director of First Milk Ingredients, said the Welsh government had supported the project because of its green credentials and because of First Dairy's strong commitment to more than 300 dairy farmers in the area.
"It's a win-win situation for the region and for First Milk," he said, adding the upgrade would help First Milk better deliver its range of functional ingredients that included sweet whey, lactose and whey/lactose concentrates.
Its ingredients are being employed by sectors such as confectionery, ready meals and infant formulas across Europe.
Morrish wouldn't reveal pricing structures but said in general, they were "firming".
Elin Jones, the minister for rural affairs said: "The Welsh Assembly Government is keen to support First Milk, which is a major outlet for milk produced by dairy farmers in South West Wales."
Rowe said the increasing competitiveness of the dairy industry meant such investments were necessary "to maintain our leading position."
"The grant support we have received from the Welsh Assembly Government has been instrumental in enabling us to undertake this latest project," Rowe added.
First Milk produces more than 35,000 tonnes of whey products as well as 20,000 tonnes of cheese for UK retailers such as Morrisons, Tesco and ASDA.