GLOBAL — Carnival Corporation & plc, one of the world’s largest cruise companies, employs more than 150,000 people from nearly 150 countries and collectively serves around 13 million guests annually.
Combining over 225,000 daily cruise guests and 100,000 shipboard employees, more than 325,000 people are sailing aboard the Carnival Corporation fleet every day.
With so many people onboard, a cruise ship is similar to a floating city. Like any major city, there are high amounts of waste generated. Unlike cities however, cruise ships lack the space to contain food waste for long periods of time. Cruise ships in the past have used solutions such as food pulpers; recently many of these have been outlawed due to non-compliance with MARPOL regulations due to accidental plastic entering waste streams.
In 2019, Carnival Corporation piloted biodigesters from three manufacturers to improve environmental compliance and the disposal of food waste onboard its ships. Biodigesters from three manufacturers were tested on 15 ships to evaluate a variety of parameters and track data, such as the weight and volume of food waste digested and the net volume of CO2e reduced. After extensive testing and trials over a three year period, Carnival chose the LFC biodigester from Power Knot as their main biodigester due to reliability of maintenance, service and support and long term savings.
Fighting cruise food waste with fines
The International Convention for the Prevention of Pollution from Ships (MARPOL) is the international convention covering prevention of pollution of the marine environment by ships from operational or accidental causes. It was adopted in 1973 and is enforced by the International Maritime Organization (IMO, a specialized agency of the United Nations). MARPOL Annex IV and V holds all ships accountable for the disposal of their sewage and garbage.1
MARPOL Annex IV contains a set of regulations regarding the discharge of sewage into the sea from ships, including regulations regarding the ships’ equipment and systems for the control of sewage discharge, the provision of port reception facilities for sewage, and requirements for survey and certification.2
MARPOL Annex V prohibits the discharge of all garbage into the sea, except as provided otherwise in regulations 4, 5, and 6 of the Annex, which are related to food waste, cargo residues, cleaning agents and additives and animal carcasses.
Over the years, various cruise ships have been fined for non-compliance which have ultimately led to the ocean being contaminated with food waste mixed with plastic. Food waste and plastic entering the ocean stream creates a number of issues, from eutrophication to contamination of natural habitats and resources.
Cruise ships swim towards modern solutions
In 2019, Carnival Corporation piloted biodigesters onboard fifteen of their ships. At that time, biodigesters were an emerging technology in comparison to food pulpers which were originally the primary method of food waste disposal. Food pulpers are garbage disposer made specifically to break down cardboard, paper, and food waste. They grind down waste into a slurry which is piped into a tank.
However, food pulpers are delicate and require extremely careful handling to prevent the device from breaking and plastic from accidentally entering the waste stream. Common food scraps such as banana and orange peels cannot be placed inside pulpers because they can potentially damage the equipment. Subsequently, it requires multiple touches and oversight for usage.
As mandated by MARPOL, Carnival began exploring more sustainable and economical alternatives such as biodigesters.
“Think of a food waste biodigester as a large, stainless steel stomach that digests food waste – if you can feed it to people, you can feed it into a digester,” said Chris Donald, senior VP of Corporate Environmental Compliance at Carnival Corp. “Since we serve meals to millions of guests each year, this new green technology can help us significantly reduce our environmental impact and carbon footprint, while also greatly improving our ability to manage non-food waste, including plastics. We have already seen positive results and significant benefits from these systems, which are technologically advanced yet simple to use. We are evaluating different digesters and are currently planning to expand the use of these systems across our fleet as part of our commitment to environmental excellence.”
The biodigesters were strategically placed in areas where food waste was typically produced, such as the ship’s galleys. Mesh filters at the bottom of the machine prevented debris and any plastic from accidentally leaving the machine.
Uninterrupted operation and steady service
After the initial pilot in 2019, Carnival selected two different models of biodigesters to run in depth testing on. Power Knot was selected for Carnival UK, Holland America, and several Princess Cruise ships. After extensive third party testing, the LFC biodigester was found to be in compliance with all regulations by the Carnival UK legal team. The LFC biodigester was found to be the most reliable amongst all biodigester machines with minimal maintenance issues.
Although the initial price of other biodigesters was cheaper than that of Power Knot, Carnival found themselves spending much more in the long run in maintenance and spare parts costs due to the cheap build quality of other machines. Carnival also found issues with obtaining spare parts for other biodigester machines as supply chain issues arose. Due to strong supplier relations, a reliable inhouse manufacturing team, and careful planning, Power Knot has been able to offer uninterrupted maintenance and support without issue through the pandemic.
After extensive testing and trials over a three year period, Carnival has chosen the LFC biodigester from Power Knot as their main biodigester due to reliability of maintenance, service and support and long term savings. In 2022, Carnival pushed forward with a large-scale implementation of the LFC biodigester across many of their fleets.
Works Cited
- International Maritime Organization. (n.d.). International Convention for the Prevention of Pollution From Ships (MARPOL). International Maritime Organization. Retrieved April 11, 2022, from https://www.imo.org/en/About/Conventions/Pages/International-Convention-for-the-Prevention-of-Pollution-from-Ships-(MARPOL).aspx
- International Maritime Organization. (n.d.). Prevention of pollution by sewage from ships. International Maritime Organization. Retrieved April 11, 2022, from https://www.imo.org/en/OurWork/Environment/Pages/Sewage-Default.aspx
