Evac Evolution Ballast Water Management System – FAQs
The Evac Evolution system has a number of features which make it the ideal choice for shipowners who need to operate their vessels worldwide.
A. Based on space saving filtration and well proven UV technology – available skid mounted or in modular form for installation in confined areas.
B. Currently in the final stages of U.S. Coast Guard type approval to the live/dead standard.
C. Equipped with UV-Transmission feedback loop for accurate dosage and power savings in changing water conditions. We are the only manufacturer to supply a UV Transmission system as standard, with others it is charged as an extra.
D. Effective in marine, brackish and fresh water enabling ships to operate without restrictions.
E. Effective in the most challenging water conditions with high levels of sediment.
F. Made by Cathelco, a member of the Evac Group, who have over 60 years of experience in marine engineering and provide global support through a network of factory trained agents and service centres.
Taken together, these features provide an excellent combination of effectiveness, reliability and economy.
It is essential that the BWMS can respond rapidly to changing water conditions with different levels of sediment. This is vital to the effectiveness of the system, but is also important in saving power.
To achieve this, the UV-Transmission sensor measures the light transmittance through a sample of water taken after the filter, but before it reaches the UV reactors. This is measured at the same wavelength (UVC 254 nm) as the biocidal light emitted by the UV lamps. From this data, the automation unit control unit calculates the correct UV dosage.
In this way, the output to the lamps is continuously optimised, ensuring the correct level of irradiation and economising on power through the use of stepless power control.
UV intensity sensors mounted on the reactor walls measure the intensity of light received during irradiation. This relationship creates a feed-back loop in which the calculated dose is continuously compared with the actual dose. If the actual dose is within the prescribed range, ballast water treatment continues as normal. However, if the dose is less, then the automation system increases the power or initiates a lamp cleaning cycle.
The revised G8 Guidelines for IMO Type Approval and the U.S.Coast Guard Final Rule (Section162.060-38) on the treatment of ballast water state that the UV-Transmission level must be recorded together with the dosage during each ballasting operation.
We are the only company to provide a UV-Transmission sensor as standard. With systems obtained from other manufacturers it is necessary to purchase a UV-T sensor as an extra.
For new build applications, the Evac Evolution system can be supplied skid mounted or containerised saving on installation time.
However, we recognise that things are rarely as straightforward as this and have gained experience in supplying the system in modular form and fitting the individual components in confined spaces.
In some instances, this has resulted in a linear arrangement where the UV reactors are installed in one location and control cabinets some distance away. In retrofit applications, the key to a trouble-free installation is careful planning and co-ordination between all those concerned.
Customers who purchase an Evac Evolution system receive a comprehensive 13 month guarantee from the date of installation covering all the components supplied.
One of major strengths of the Evac Group is a well-established network of agents, service centres and stock locations based in shipbuilding and repair centres around the world. This is reinforced by offices in 14 countries over four continents and a network of more than 70 representatives. The agents have factory trained engineers who have received specific training covering the installation and servicing of BWMS.
Installing the system – FAQs
The vessel does not have to be drydocked, but it is preferable for a number of reasons. An over board discharge line has to be created for the filter and this is more complicated if the ship is in the water, although it can be achieved by creating a link to existing discharge pipework. Also, it is easier to break into existing pipework if it is already drained and not functioning. Therefore, in terms of speed and economy, drydocking is the easiest approach.
This will vary from one project to the next according to the complexity of the installation. However, from past experience installations usually take between 8 and 10 days.
Capacities from 34 to 250m³/hr:
Skid size: 1040 (L) x 820 (W) x 1589mm (H)
Capacities from 250 to 1,500m³/hr:
Skid sizes up to 3293 (L) 2733 (W) x 2375mm (H)
In retrofit applications, the components are supplied in modular form and distributed to make the best use of the available space within the engine room.
Operating the system – FAQs
Once the decision to ballast or de-ballast is made, virtually all of the operations are automatic. The automation control panel governs these operations and enables them to be monitored and logged.
At ‘over view’ level, the control panel shows a graphical representation of the system showing all of the major components. With the intuitive schematics showing sea water routing, read-outs showing the transition state of valves as well as instant information from sensors, engineers can easily see how the system is performing.
The automation control unit continuously logs all the data concerning the performance of the system for a period of up to two years. This includes the ballast tank number, time/date of event, mode of operation, flow rate, temperature, power to the UV lamps, UV transmission and calculated UV dose. The UV transmission rate is recorded at 32mm (the distance between the UV source and the edge of the reactor) and also at 10mm according to the Class Body requirements.
With the Evac Evolution system the quartz sleeves surrounding the lamps are automatically cleaned after every ballasting/de-ballasting operation using an efficient wiper system.
One of the advantages of filtration and UV systems is that there are relatively few consumable items, namely lamps and wiper blades.
Type Approval and Legislation – FAQs
What are the technical differences between an IMO Type Approved system and one that meets the USCG Type Approval criteria?
The IMO and the U.S Coast Guard have different ways of measuring water quality discharge standards. These differences revolve around the use of the words ‘viable/unviable’ (IMO) and ‘live/dead’ (USCG).
The IMO standard requires discharges of less than 10 viable organisms per cubic metre greater than 50 microns and less than 10 viable organisms per millilitre in a size range from 10 – 50 microns. In this case, ‘viable’ means that all of the other organisms in the sample are not capable of reproducing but may still be alive.
On other hand, the USCG requirement is a discharge of less than 10 living organisms per cubic metre greater than 50 microns and a discharge of less than 10 living organisms per litre in a size from 10-50 microns. In this instance, it means that all of the other organisms in the sample must be completely dead.
The Evac Evolution system is in the final stages of gaining U.S. Coast Guard Type Approval which is expected to be achieved before the end of 2018. We are also well on the way to gaining Type Approval to the revised IMO G8 standard which is likely to be attained early in 2019.