Ocean Protection System OPS

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MAHLE Industrial Filtration is protecting the world’s oceans with their chemical-free NFV ballast water treatment OPS.

“Stowaways” in ballast water – an international problem
Almost 90% of the commodities traded worldwide are transported by ship, and that figure is steadily rising. Ballast water tanks give vessels stability and the necessary draught required for cost-effective operations. Ballast tanks are filled with sea water, fresh water and a mixture of the two, pumped in from the world's oceans and discharged again as required. Every year, around 12 billion tons of ballast water are used, water that contains countless “stowaways”. Every time a ship takes in ballast water, it also involuntarily takes in masses of tiny aquatic organisms and distributes these on the world's waterways. Although a large proportion of the microorganisms, such as bacteria and viruses, do not survive being transferred in the ballast tanks, a sufficiently large number of organisms are released when the ballast tanks are emptied. Once these invasive species (fish, small invertebrates, worms, bacteria, viruses and other microbes) settle in their new habitat, they can potentially cause considerable ecological and economic damage. In extreme cases, they can become a hazard for humans.

Overview of the system
The Ocean Protection System OPS is three-stage ballast water treatment system and operates in-line during up-take and discharge of ballast water. The system is based on well known technologies from the industrial applications and combines mechanical and physical cleaning and disinfection principles. While up-taking the ballast water flows sequential through two self-cleaning filter stages followed by one low pressure UV irradiation (LP-UV) stage before it ends in the tanks. On the contrary during discharge all filters are bypassed and the ballast water is treated once again with high performance LP-UV. Due to this two-way treatment-method the duration of the voyages is no longer a significant issue. That means as well that shortest holding times are sufficient to assure the compliance with the IMO D-2 standard at the discharge of ballast water.

Details of the system
The OPS is a three-stage ballast water treatment system. The system works as an in-line system during uptake and discharge of ballast water. During uptake the first step of treatment is a pre-filtration for separating particles larger than 200 µm, followed by a second filtration for separating particles larger than 50 µm. With this pre-treatment most parts of sediments are removed from the ballast water. The sludge from the self-cleaning process will be discharged at the same place where it was taken on board. The uptake treatment finishes by disinfection via ultraviolet light. Figure 1 shows the principle operations (flow chart). During discharge only the UV disinfection is in operation, while the other stages are bypassed.

Functionality of the Ocean Protection System OPS
The ballasting process starts and the medium flows axially against the first filter stage. Filtration takes place from the inside to the outside of the filter element and the cleaned medium leaves the filter through the radially-mounted outlet flange. When the filter element reaches a defined differential pressure (the filter element is packed with solids) an axially slidable disc moves up and down during the reversible flow by the help of a pneumatic cylinder within the filter element. All operating conditions are monitored by the control unit. After passing the first filter stage the medium flows into the second filter stage: an automatic self-cleaning screen filter designed specifically for ballast water treatment application. The filter is offering a high level of compliance within the IMO’s D-2 standard as well as an efficient solution for filtering sea water containing large quantities of dirt. The filtration process creates differential pressure across the screen that rises as the “cake” enlarges, until a predetermined value is reached (normally 0.5 bar) to activate the flushing process. In cases of low operating pressures and generated suction forces not reaching the required minimum level, a small suction pump is added to the flush line to assist the cleaning process. This is a reliable and inexpensive addition to the system, enabling the filter to operate under extremely low pressures of only 1.2 bar. This low operating pressure is crucial, in particular for retrofit’s, because the low operating pressure meets the parameters of existing ballast water pumps and therefore save costs and potential reconstruction.

Further advantages are:

• due to anti-corrosion coating, the operating time of the filter is extended
• the system is a fully automatically self-cleaning system, which efficiently handles heavy dirt load in raw water
• filtered water is continuously supplied during the self-cleaning process §
• the second filter stage generates very low costs per cubic meter of filtered water

After the fine filtration of the medium it becomes treated by ultraviolet light. The ultraviolet light is a natural component of the electromagnetic spectrum. One of the most effective disinfecting wavelength and the one most often used for disinfection is at 254 nm. The ultraviolet light necessary for disinfection is generated in low pressure-high output amalgam lamps. Each lamp is housed and protected against water pressure by a special quartz sleeve. A watertight quartz tube surrounds each lamp. The ballast water to be disinfected is turbulently conducted through the reactor chamber. The gas plasma generated in the lamp emits light with a primary wave length of 253.7 nm. This intensive ultraviolet light reaches organisms in the water and impacts directly on their DNA. By changing the DNA the cell division of the organism is interrupted – it can no longer reproduce itself. With this technology it is possible to kill or inactivate harmful microorganisms in water, without adding chemicals, without harmful side effects, inexpensively, highly efficient, and reliable. UV disinfection is an entirely physical process. Microorganisms such as plankton, viruses, yeast that are exposed to the effective UVC radiation are inactivated within seconds. UV disinfection of wastewater has become an accepted alternative to chemical methods of disinfection for secondary and tertiary quality wastewater. For, reportedly over 1,000 UV systems are in operation throughout North America, Europe, and Asia. The many advantages over chlorination result in a continued increase in interest and use of ultraviolet light as a disinfectant. The disinfection by UV requires no chemicals and therefore causes neither corrosion problems, reaction tanks or secondary pumps, risk of over-dosage, need of special storage or handling, nor environmental problems. The de-ballasted water remains alive and enables further organisms to life in the water. Furthermore it retains its natural flavour and smell without any by-products that might endanger health.

In addition to that, UV reactors require minimum operation costs, due to low power consumption and little maintenance by maximum operating safety.

Process for type approval

Land based test
In spring 2009 land based test trials were carried out successfully at the Royal Netherlands Institute for Sea Research (NIOZ), on the island Texel in the Netherlands, in accordance with the required IMO D-2 standard and the G8 guidelines (Resolution MEPC.174(58)).

In each of the official test runs the numbers of organism were well down below the IMO D-2 standard; therewith the OPS fulfills also the different requirements of the United States, amongst others the California-Standards.

The above-average performances demonstrated that the OPS operate in a reliable and environmentally safe way of treating ballast water.

An additional G8 requirement to show that the discharge of ballast water is environmentally acceptable was also achieved during land based tests. At the same time misc. ecotoxicological studies proved that no potentially toxic changes in chemistry occurred during the UV irradiation. The treated water did not contain any toxic or growth inhibiting substances nor were chemicals produced as a by-product.

Shipboard tests
Currently shipboard testing is executed in accordance with the IMO standards. Several tests for mechanical functionality and biological effectiveness were accomplished successfully. The first successful test confirms and partially exceeds the positive results of the land based tests.

Hereby a containerized OPS unit was installed on a 1100 TEU Container Feeder Vessel in one of the cargo holds. The container was delivered as a plug-and-play version especially designed for use as a retrofit unit. For this purpose only the BW piping system was adapted for the inlet- and outlet connections of the OPS, so that an exchange of the existing pump was not necessary.

A new and fast installation method with minimized welding reduced the complexity of integration significant whereby the installation workings could be executed within 5 days without interrupting normal ship operations. All workings were supervised from ship´s classification society and approved thereafter.

Experiences from ship owner
The ship owner confirmed that the full service package offered by MAHLE Industriefiltration is very beneficial. Under consideration of the customized and modular design of the BWTS an implementation in the whole fleet (vessel from feeder up to Post-Suezmax size) would be possible.

Advanced features and design
The fully automated OPS can be completely integrated into the vessels ballast water control system. If any of the logged operating parameters of the BWTS are not within the acceptable and predetermined tolerances, the control system will shut down the OPS and not allow untreated ballast water to pass. When the system is not in operation or in an improbable emergency case the pneumatically activated inlet- and outlet- butterfly valves separate the OPS from the vessel´s ballast system.

Installations on-board ships with hazardous areas, such as tankers, can also be accomplished with the OPS. However there are limitations as to the location of the individual system components. By adapting some system components, it can be made into an explosion proof system, such as required for use on oil and gas carriers and chemical tankers.

The OPS will not cause corrosion of the vessel´s structure. The filtration step is a solid liquid-separation system only and the UV disinfection treatment does not change the treated water by any means. Official chemical water analysis during land bases testing approved that there is no effect on corrosion.

Additional advantages for ship owner and operators of civil, marine and special vessels are the low power consumption of the Ocean Protection System, low operation and maintenance costs, as well as no need of chemicals, as a result maximum safety for all involved.

Besides the standard design as a skid-mounted unit (Fig. 2) the OPS is optional available as container system or in single components. The filtration system can be installed separately from the disinfection system. Both systems can be installed either vertically or horizontally as this has no effect on the operation or the efficiency of the system. This individual design for misc. flow rates and the fact of fast and low cost installation make the OPS for new buildings as well as for existing ships equally interesting.

Current situation
MAHLE Industriefiltration expects the IMO type approval in fourth quarter of 2010. Based on the outstanding test results and the convincing technology the OPS attract increasing attention in the market. MAHLE Industriefiltration receives in the last month several OPS orders for 2010 and 2011from renowned shipping companies.

MAHLE Industriefiltration GmbH
develops and builds advanced filtration and separation technology for use in a wide range of industrial applications and in power plants, civil and military shipbuilding. The company is part of the MAHLE Group and thus is backed by the strength of a worldwide market leader. The MAHLE Group is one of the top 30 automotive suppliers and the globally leading manufacturer of components and systems for the internal combustion engine and its peripherals. Around 43,000 employees work at over 100 production plants and eight research and development centers. In 2009, MAHLE generated sales in excess of EUR 3.9 billion.

For almost 50 years, NFV products have been relaible systems for shipping companies in the field of deoiling, membrane filtration and fuel treatment. Our products help our partners to successfully balance economy and ecology. By focusing our maritime and petrochemical activities in the new Hamburg facility, we are able to concentrate research, planning and production in one site. MAHLE Industriefiltration provides its products a wide range of customised and highly efficient filtration and separation systems for a wide variety of applications: from bilge water separation over ballast water treatment to engine maintenance, the protection of hydraulic systems and pipelines, transfer and circulation systems. This comprehensive portfolio is rounded off by customer support services precisely tailored to customers’ needs. Ten of the world’s top 15 shipping companies and the world’s three largest shipyards as well as several navies around the world (e.g. German, Turkish, Russian and U.S. Navy) equip their ships with our environmentally friendly, high quality systems, placing their trust in the outstanding operating security of NFV- systems. The NFV-products have been the German Navy’s partner of choice for deoiling, membrane filtration and fuel treatment systems for over 30 years.

Hamburg, 09/2010