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  • Graeme Warnell

How To Reduce Bilge Waste Using Nature Based Solutions ?

I have written this blog after reading a fantastic article in the Guardian online that revealed ships dump oily waster into European seas up to 3000 times a year.

The article stated:

“Up to 3,000 cases of oil dumped by commercial ships may be happening every year in European waters, according to a new investigation, which found the scale of illegal “bilge dumping” is likely to be far higher than publicly acknowledged.

Dealing with this oily wastewater – by treating it to remove pollutants or by offloading it at port – is expensive. To cut down on operational costs, some ships simply dump it directly into the ocean, where it can pose a serious threat to marine life”

When I look at how ships operate, I ask the question: Why are we not reducing the amount of oily waste ships create whilst at sea to mitigate this problem?

Is this simply a case that there is a lack of appetite to embrace simple innovative solutions because change is just too difficult or perceived to be too expensive?

What is bilge waste is composed of?

Typically, it’s a blend of liquids from the engine room containing toxic substances such as fuel, oil, lubricants, solvents and other toxic chemical cleaning products.

How can bilge waste be treated to reduce its volume and toxicity?

The answer to this is two-fold:

1) Reduce the amount of toxins you put into the bilge

2) Treat the oily waste that enters the bilge

Reducing Toxins – the engine room often needs cleaning and components of the engine room need degreasing. This is required to reduce both slip hazards and the risk of fire by ignition of flammable substances. However, the cleaning and degreasing often use harsh toxic chemical products including solvents, which are also flammable.

So why do we not replace the toxic chemical cleaning products and solvents with nature based eco-friendly solutions. The cleaning processes do not need to change just the cleaning products. By adopting this simple approach, we have reduced the toxicity of the bilge already by eliminating dangerous chemical cleaners and solvents.

Treating the bilge waste in situ – nature-based products for cleaning and degreasing can be fortified with harmless bacteria that eat the lubricants, oils and fuels that are being washed from the engine room into the bilge.

Once in the bilge these bacteria form a biomass that actively removes the oily components of the waste converting them into water and naturally occurring Co2.

A ships bilge creates one of the best environments there is for bioremediation. The ships cleaning and maintenance processes provides a natural food source for the bacteria via oil and grease whilst the movement of the ship always ensures everything is sloshed around almost like a washing machine.

To further boost the process, bioremedial dosing agents can be added directly to the bilge if required.

The benefits of switching to these nature-based products for cleaning and maintenance is not just restricted to the engine room. Using non-chemical products anywhere on a ship reduces the risk of accidental spillage into the marine environment

As nature-based solutions are Ph neutral, non-caustic and non-toxic they are ideal for use in confined spaces or where natural air circulation is poor.

The use of nature based bioremedial products in the galleys of ships ensures cleanliness, the creation of slip free floors and the removal of grease and fats from the associated wastewater tanks and within the ships drainage system. This prevents unwanted blockage and foul smells.

At GW Environmental we took our theory to a UK passenger ferry company and asked to see the array of cleaning products they typically used on a day-to-day basis.

We were amazed to find that nearly 80% of the 13 different chemical cleaning products used on the ship were acutely toxic to aquatic life. Furthermore, over 60% of these products could have been replaced with no more than 2 nature based bioremedial products.

Reducing the number of cleaning products needed to maintain the ship could lead to a far less complicated procurement, storage and handling processes. The nature-based products also presented far less risk of the wrong products being mixed resulting in an adverse chemical reaction. From a safety perspective the use of nature-based products meant there would be far less exposure to both employees to harmful chemical cleaning products by inhalation of skin absorption.

The question remains if the toxicity and volume of dangerous bilge waste can be reduced by just changing your cleaning regime why is the shipping industry not doing it?

If you found this article interesting and would like more information on using nature-based products for cleaning instead of toxic chemicals, please email the author Graeme Warnell at

By implementing environmentally responsible cleaning practises, you could help reduce the pollution of our rivers and oceans, create a safer workplace for your employees, reduce your carbon footprint and put something good back into the environment so why wouldn’t you?

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