Tankers Could be Converted into Water Makers

water drop

Published May 20, 2015 8:09 PM by The Maritime Executive

Like many of the world’s resources, water is not distributed equally. Some parts of the world have all the clean water they need, while others are fighting a constant water shortage. Globally, there has been a growing focus on water access over the past decade, prompted by statistical extrapolations for world population growth, which indicate that water-related challenges will only continue to increase.

In developing countries, up to 90 percent of wastewater is discharged into the environment without being properly treated. At the same time, the increasing global population is driving greater water scarcity and more competition for fresh water. More efficient management of the world’s current water resources is the key. Treated wastewater is becoming a critical resource, which can be used to fill most of a community’s industrial and agricultural needs.

Two years ago, the company approached DNV GL with an innovative idea: could old oil tankers be repurposed into floating wastewater treatment plants? 

“We have to think differently if we want to solve the global challenges related to water supply and pollution from discharge of untreated wastewater,” argued EnviroNor CEO Sigmund Larsen. 

An Extraordinary Innovation project team was set up, and has now developed three solutions: The Changemaker, The Reliever, and The Water Factory. These solutions for recycling wastewater offshore are based on proven technology, but applied on board a ship or a floating unit. The solution is flexible in terms of size and can be designed according to requirements at the location.

The Changemaker

The Changemaker is a vessel engineered to turn wastewater coming from the shore via pipelines into clean water, safe to use for irrigation and industry purposes.

The Changemaker would be able to recycle around 2,100 cubic meters (550,000 gallons) of wastewater per hour, serving up to 250,000 people. It would house primary, secondary and tertiary water treatment units, and could also supply large volumes of bio-solids to form the basis for fertilizer. By combining known technologies in a new way, the floating plant could be tailored to different locations with specific water needs.

As a secondary benefit, converting ships into a wastewater treatment centers could add 20 years to a vessel’s life cycle. And it need not be limited to tankers. “Ships from super tankers to river barges can be converted to provide dry coastal cities with much needed clean water for irrigation, industry purposes and even providing safe drinking water for humans”, says DNV GL’s chief sustainability officer, Bjørn K. Haugland.

“It’s hugely exciting that there is creative thinking about new solutions to help resolve a global problem,” says Nina Jensen, CEO of the WWF Norway. “If we can treat water for irrigation and industry, that relieves the pressure on the drinking water resources. Large-scale reuse of water is essential to a sustainable future. A solution that also reuses phased out ships is spot on environmentally.” Both WWF and Red Cross Norway support the project.

The Reliever

Another vessel, The Reliever, has also been designed to take over the processing of shore-based treatment plants when they need to be upgraded or repaired. The energy needs of these offshore wastewater recycling plants can be partly met by their own processes. Renewable sources such as biogas can be extracted as waste is treated onboard.

The Water Factory

The third element the team developed is The Water Factory: a plant that treats slightly polluted river water so it becomes safe to drink. Designed for use in densely populated places, barges could travel up rivers where clean drinking water is in short supply. It’s a cost effective and mobile solution that can meet acute needs much more quickly than building onshore plants.

Economic Sense

The idea of offshore recycling also makes economic sense. In a timeframe of 20 years, the capital expenditure needed to create this offshore wastewater recycling plant is estimated to be about 25 percent less than for an onshore plant with equivalent capacity.

Offshore wastewater treatment is both possible and profitable, and can be used in most coastal areas around the world, says DNV GL. Floating wastewater treatment plants are an exciting potential market that can help tackle a pressing sustainability issue.