The operational experience survey results, held from 2017 to 2018, were based on a sample of 500 installations. Systems in a regular operation and subject to monitoring or efficacy testing were up to 14% in 2017, while the last year was up to 25%. The systems that were inoperable in 2017 were 14%, while were down to half at 6% in 2018.


Operations with problems in 2017 were up to approximately 30% while it almost doubled last year. Furthermore, systems that are under regular operation but not subject to monitoring or efficacy testing was previously 43% compared to 2018 that was only 10%. Many more units are in operation but more challenges to overcome.

BWTS installations per different vessel types

  • Tankers and Bunkers share the 75%;
  • Containers 11%;
  • LNG carriers 6%;
  • The rest 7% refer to other vessel types like gas carriers, general cargo and other types of vessels.

The selection depends on many factors:

  1. Vessel type. In bulk carriers a single ERMA FIRST FIT BWTS is usually installed that treatment capacity covers 1 ballast pump, while the de-ballasting is conducted at full capacity. In tankers, full treatment capacity is required that is a single or double BWTS usually for flow rates that are more than 3000 m3/h. For the After Peak Tank, a filter-only-option or a secondary smaller system is installed that its size is according to GS&Fire pump. Same applies also to the LNG carriers, meaning treatment capacity to cover full ballasting. Other vessels that are not highly depended in ballasting like containers, Ro-Ro or other vessels, a single system is installed to cover one ballast pump capacity or lower.
  2. Operational habits. Meaning the duration of ballast voyages, in terms of holding time of the ballasting water, the areas of operation in terms of the quality of the water, speaking about the organic load and dirt, turbulent waters, brackish, sea water, salinity levels, and temperature.
  3. Vessel specific features. Like Top Side Tanks, gravity de-ballasting in bulkers and also in some smaller capacity tankers that Fore Peak Tank is served by an independent pump.

The pre-selection stage

Vendors specific criteria:

  • Reliability of Technology: In my opinion, a filter is a mandatory application that leads to a minimum energy needed for disinfection. Additionally, internal components and wetted parts are protected from mechanical failures. Nevertheless, we need to identify the balance between the filter type and the retention capacity, in order to avoid possible clogging risks.
  • Disinfection Stage: Life Cycle of components, maintenance and operation costs. The design, configuration and the redundancy of equipment.
  • Installation Requirements: A purchaser should take into consideration to look out for a vendor that offers flexibility and modularity, a cost-efficient installation and a vendor scope of supply that is 100% clear.  Hidden costs are avoided.
  • After Sales / Service Network / Lifecycle support: After purchasing and installing a system, vendor is required to have an extended service network in order to support operator in the after-sales level.

According to a typical retrofitting project, two weeks are needed for the technical, commercial offer and the onboard survey, another two for the technical review and within the next couple of weeks the proposal acceptance and contract signature.

This is the point where the actual project initiates. After that, 13 weeks are needed for the BWTS components production, at the same time Approval Drawings development need s 9 weeks. After drawings are finalized, 4 weeks by Class Review and 5 weeks to deliver the components to shipyard. Installation works by Shipyard take 3-4 weeks for and one week that is required for the successful commissioning of the system.

Consequently, a typical delivery time is 5-6 months after Purchase Order.

During fusibility stage we face the following challenges:

  • Identify the most suitable BWTS location
  • Have available maintenance space
  • Not to disturb vessel’s safe operation
  • Minimize modifications on the existing piping systems and structural elements
  • Minimize pressure losses
  • To provide the optimum cost-effective solution


Above text is an edited version of Mr. Konstantinos Dimopoulos’ presentation during the 2019 SAFETY4SEA Cyprus Conference.

View his presentation here


The views presented hereabove are only those of the author and not necessarily those of  SAFETY4SEA and are for information sharing and discussion  purposes only.

Mechanical Engineering graduate specialized in Energy, combined with an MBA degree. Holding an extended professional experience in high pressure hydraulic systems (filtration, fluids treatment etc.) and engineering, as worked with HYDAC a leading company in fluid technologies. At the same time, he attended multiple seminars and conducted researches. In middle 2015, he joined ERMA FIRST SA as a Technical Marketing Manager and be responsible for the technical support, vessels survey and provide assistance to the development and efficient in fast-paced multitasking environments; able to prioritize effectively and accomplish objectives. From January 2019, he was promoted to International Sales Manager, being responsible of global markets that require a strong combination of both technical and business skills and contribute to the overall success of the ERMA FIRST company.