Guest Author - Aaron Kirley

The cruise industry is making great strides to lessen its impact on the environment. This article will highlight some initiatives that cruise ships employ to reduce pollution and protect the seas in which they sail.

The days of dumping garbage in international waters are behind us and in its wake is a cruise industry with state of the art green capabilities. So what is a green cruise ship? One example is fully enclosed water systems. Some cruise ships have three separate water systems, one for fresh water, one for gray water, and the third for brown water. Fresh water is used for showers and faucets. The fresh water waste is treated and used in the gray water system for washing laundry and decks. Finally the toilet water and used gray water is collected in the brown water system which is treated on board and either dumped into the ocean or removed at shore. Before dumping water, green cruise ships have advanced treatment systems which remove virtually all bacteria and solids so that it is non-toxic to the environment and humans. However, this treated water creates the perfect environment for blooms of bacteria to grow and this is why cruise lines have signed an act to prevent them from dumping within 12 miles of any shore.

Cruise ships are taking special precautions to preserve the environments near ports. Special low sulfur fuel with 5% or less sulfur is used to reduce harmful emissions. Cruise ships also participate in Vessel Speed Reduction Programs which limit speeds to less than 12 knots within 40 miles of shore in an effort to limit air emissions. Burning diesel to generate electricity at port generates unnecessary pollution so some ships are converting to an Alternative Maritime Power (AMP) system which will allow them to plug directly into shore power while at port. Depending on the size of the ship, the AMP system can reduce nitrogen oxides (NOx) by more than one Ton and reduce sulfur emissions by 50% each day a cruise ship is at port.

These are positive changes but the sheer size and volume of consumables needed to support a mega cruise ship is staggering and waste remains a problem for cruise lines. Many ships have on board incinerators that are used to burn consumable solids. Some ships even have the ability to burn waste sludge oil as fuel. Still much of the waste from consumables such as dry cleaning chemicals, photo lab solutions, paint, and maintenance chemicals are stored in sealed containers and disposed of in landfills.

Cruise lines are certainly getting greener, but more work is required before the cruise ships can be considered environmentally “friendly”. Bon Voyage!