Alfa Laval recovers all reusable oil from oily wastewater and cuts waste disposal costs

When Atlantic Islands Electricity (AIE), a privately owned power station located on Madeira Island, needed new, more sustainable ways to optimize performance, the company turned to its current fuel-conditioning equipment supplier, Alfa Laval, for answers. With the combination of an Alfa Laval PureDry waste fuel recovery system and an Alfa Laval PureBilge oily water cleaning system, AIE now turns 45 tons of oily waste per month into 30 tons of cleaned water that can be released directly into the ocean and recovers 15 tons of usable fuel from oily waste.

DATE 2023-11-28

An autonomous region in the Portuguese archipelago of Madeira Islands, Madeira – the largest island in the group –must be completely self-sufficient with regard to electricity production due, in part, to the fact that it lies completely off the European power grid and, in part, to its commitment to the sustainable development of its energy sector.

From fuel conditioning to fuel recovery

Located about 25 kilometres south of the capital city of Funchal, the 6 300-square-meter AIE power station is a fossil fuel-powered electricity generating plant. The plant produces 60 kV of electricity and 22 000 tons of steam each year for use by the Electricity Company of Madeira, which handles electric power transmission and distribution on the island.

Before the plant went operational in 2000, AIE was in contact during the planning stages with Alfa Laval for the supply of fuel conditioning equipment. Based on this long-term business relationship, Alfa Laval approached in 2012 AIE with a unique opportunity to install and test Alfa Laval PureDry, an innovative waste fuel recovery system that effectively separates waste oils into three phases:

• Water containing less than 1000 ppm oil

• Oil containing less than 5% water for reuse

• Super-dry solid cake

After a successful two-year pilot test, AIE bought a new Alfa Laval PureDry system. Upon Alfa Laval’s recommendation, AIE also bought an Alfa Laval PureBilge oily water cleaning system to address the plant’s oily waste handling issues.

Waste fuel recovery and recycling

According to Philippe Staehli, technical director and one of AIE’s owners, the investment in Alfa Laval PureDry and PureBilge has delivered fast payback. Instead of shipping oily waste to the mainland every month for processing at a cost of 200 euro per ton, AIE can handle oily waste processing on site and reap considerable environmental benefits, too.

To generate electricity, the plant’s six 12 MW four-stroke engine use more than 130 tons of fuel oil each day. Besides fuel oil, there is soot, particles, lube oil, leakage and spillage in water and fluids from operational sources, such as the machinery spaces, internal drainage systems, and a wide variety of other areas throughout the plant.

“We’ve now been using Alfa Laval PureDry for fuel recovery and Alfa Laval PureBilge for cleaning oil in water for more than a year, with good results,” says Staehli.

On the one hand, PureDry removes the fuel oil from the oily water in the plant’s fuel oil waste tank and returns it to the main oil tank for reuse. On the other hand, PureBilge generally reduces the content of oil in water from various operational sources throughout the plant to less than 5 ppm – without the use of filters or chemicals.

“The combination of PureDry and PureBilge ensures that our operations are as efficient and environmentally sound as possible,” explains Staehli. “This is very important to us, as the oily waste cannot be treated locally in Madeira and must instead be shipped to Portugal.”

Through combination treatment, AIE now turns 45 tons of oily waste per month into 30 tons of cleaned water that can be released directly into the ocean, recovers 15 tons of usable fuel from oily waste and has eliminated mainland waste processing costs, only requiring solid waste disposal of a single 150-kilogram sludge cake.

“I haven’t done the math,” Staehli goes on to say. “But it sure adds up to big savings for AIE and for the environment.”

Easy to operate and maintain

Self-sufficiency is also AIE’s mantra when it comes to equipment operation and maintenance. AIE plant manager Alberto Rodrigues strives to manage all aspects of operation and maintenance.

“It’s difficult and expensive to have a service engineer come to Madeira,” says Rodrigues. “So I appreciate that PureDry and PureBilge are fully automated and very low maintenance. That lets me to focus on other aspects of plant operation.”

Recognized for sound environmental practices AIE is committed growing its business responsibly. To ensure sound environmental practices are employed, the power station established its own eco-efficiency system. In 2010, AIE won first prize in the Industrial Free Trade Zone of Madeira Environmental Awards presented by Sociedade de Desenvolvimento de Madeira (Regional Development Board of Madeira).

“We are committed to growing our business responsibly and optimizing our processes,” says Staehli. “The use

of Alfa Laval PureDry and PureBilge supports our core principles of environmental sustainability as well as sustainable business practices. To us, it’s win-win.”



AIE owner and technical director Phillipe Staehli.

Alfa Laval PureBilge

Alfa Laval PureBilge: A fully automated centrifugal bilge water treatment system that cleans oily wastewater for safe discharge into the ocean.

Alfa Laval PureDry

Alfa Laval PureDry: This fully automated waste oil treatment system separates the waste oil into three phases: cleaned oil, water and super-dry solids.