Ballast for ships | MEXEL®
The ships are stabilised by ballast water tanks. The ballast water could be sea water, brackish water or freshwater. According to the SEAM European Project, around 10000 millions of tons of water pear year are ballasted. For France only, the annual tonnage of ballast water is around 22 millions of cubic meters according to IFREMER (French Institute for the Research and Sea Exploitation).
The ballast waters and associated sediments contain hundreds of species of organisms and micro-organisms. The transport of non-endemic species in the ballast water through the world induces major negative effects. Notably, these species (virus, bacteria, algae …) can be directly or indirectly toxic for human or animal (fish, mollusc …) or can to become established in their new environment and therefore induced ecological and economical damages (cooling water systems, fishfarm…).
To fight against this problem, the International Maritime Organisation (IMO, 2004) recommend in the International Convention for the Control and Management of Ships’ Ballast Water and Sediments (Adoption: 13 February 2004):
- “Under Article 2 General Obligations. Parties undertake to give full and complete effect to the provisions of the Convention and the Annex in order to prevent, minimize and ultimately eliminate the transfer of harmful aquatic organisms and pathogens through the control and management of ships’ ballast water and sediments.
- Under Regulation D-2 Ballast Water Performance Standard. Ships conducting ballast water management shall discharge less than 10 viable organisms per cubic metre greater than or equal to 50 μm in minimum dimension and less than 10 viable organisms per milliliter less than 50 μm in minimum dimension and greater than or equal to 10 μm in minimum dimension; and discharge of the indicator microbes shall not exceed the specified concentrations.
The indicator microbes, as a human health standard, include, but are not be limited to:
- Toxicogenic Vibrio cholerae (O1 and O139) with less than 1 colony forming unit (cfu) per 100 ml or less than 1 cfu per 1 gram (wet weight) zooplankton samples ;
- Escherichia coli less than 250 cfu per 100 ml;
- Intestinal Enterococci less than 100 cfu per 100 ml.”
Mexel® 786B product drastically reduces the bacteria flora after 12 hrs of exposure at a concentration ranged between 5 and 15 mgL-1. This treatment permitted to reduce at the same time the sulphur-reducing bacteria. After 36hrs, the loss of the Mexel® 786B properties permits to discharge the ballast water.
Following this success, Mexel Company has developed a new product, the Mexel® 432/336, notably to be in accordance with the Directive 98/8/CE of the European Parliament and the Council of February 16, 1998, concerning the marketing of the biocidal products.
This product is an emulsion of alkylamines in aqueous phase. Taking into account its formulation and by analogy with the product Mexel 432/0, this emulsion has corrosion inhibitor, scaling inhibitor properties and reduces the mud adherence.
The used of this biocidal substance induces a reduction of 4 log and 5 log of fungi and bacteria respectively at a concentration ranged between 30 and 50 mgL-1.
