Facts Behind Fears in Scrubbers’ Washwater Discharge

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Safety Debate: Exhaust Gas Scrubber’s Washwater
April 30, 2020
Facts - Scrubbers’ Washwater | Environmental Impact of Scrubber Systems

Scrubbers are a recognised solution to comply with the IMO 0.5% Sulphur Cap but recent local bans on washwater discharges from open-loop scrubber systems have increased a widespread misconception that there are no safeguards against their environmental impact.

Kamelia Cleantech offers some background and observations to help clarify the situation, which can be summarised as follows:

The Misinformed Fear

There is a pervasive misconception asserting that open-loop scrubber systems are dealing with air pollution but creating a new “environmental mishap” by dumping wastewater into the sea.  Safety concerns are also raised around the possible machinery dysfunctions under the case of using open-loop scrubber systems. In rare circumstances, the system may break down and could result in leakages or failure of pumps. Due to the extensive nature of components, this could be an obvious fact.

The Unknown Fact

The International Maritime Organization (IMO) has set out guidelines for Exhaust Gas Cleaning Systems (EGCS) that includes washwater discharge and monitoring criteria to safeguard against possible environmental damage. This guideline safeguards vessels from discharging harmful components into the seawater by setting strict limits for a set of measured parameters. The criteria include the following:

  1. Turbidity (to safeguard against heavy metals and ash)
  2. Polycyclic Aromatic Hydrocarbons (PAH)
  3. pH Levels

Washwater has to be treated before it is discharged to remove solids such as metals and oily waste. In an open-loop system, Sulphur Oxides (SOx) scrubbed out of the exhaust gas from sulphates which dissolve in the washwater. The acidity in the exhaust gas is neutralised by seawater, but if the natural alkalinity of seawater is low, the efficiency of the scrubbing itself may be reduced and it takes more water to neutralise the gases before scrubbing washwater can be discharged.

IMO has also made it clear that regulatory decisions about the environmental impacts that are being called out against scrubbers should be based on sound science. Local authorities may take a precautionary stance but a global open-loop washwater discharge ban is currently not on the cards. Scrubbers still play an important role in global fuel availability to comply with the 2020 Sulphur limit.

The Confident Choice

The recent bans and misinformed negative sentiment expressed in the press has created uncertainty about the viability of open-loop scrubber solution at a time when the market is already under a lot of stress to cope with the 0.50% Sulphur limit taking effect at the start of 2020. With exhaust scrubbers’ ability to safely remove SOx and the elaborate EGCS guidelines set out by the IMO, ship owners and operators can count on high-quality scrubber systems like Kamelia Cleantech. Our exhaust scrubbers offer the best solution in terms of effective SOx removal, advanced control systems based on AI, and a minimal opportunity cost due to our ability to install on-voyage. Our systems are robust and require minimal maintenance because of the built-in safeguards in the system.

Do you want to know more about the washwater discharge from scrubbers? Please contact us at info@kameliacleantech.com

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