Gemi Balast Suyu İle Yayılan İstilacı Türlerin Bertarafı İçin Alternatif Yöntemler

Abstract

Dünyada ticari eşyaların %80’i deniz taşımacılığı ile taşınmaktadır ve her yıl yaklaşık olarak 3-5 milyar balast suyu uluslararası denizlerde bu şekilde transfer edilmektedir. Balast suyunun bu şekilde taşınması geminin dengesi ve stabilitesinin sağlanması için gereklidir. Dünyada farklı limanlarda yapılmış olan birçok çalışmada balast suyu sucul organizmaların, bakteri ve virüsleri de içeren insan patojenlerinin transfer edilmesinde önemli bir role sahiptir. Balast suyunun alımı sırasında kıyı sularına deniz istilacı türlerinin girişi ve daha sonra sediment ve biyofilmler ile birlikte uzak limanlarda gemi balast tanklarından tahliyesi kıyı ve deniz ekosistemi için önemli bir tehdit oluşturmaktadır. Balast suyunun yönetimi için ‘Gemi Balast Suları ve Sedimanlarının Kontrolü ve Yönetimi Uluslararası Sözleşmesi’ Uluslararası Denizcilik Örgütü tarafından 2004 yılında kabul edilmiştir. Bu sözleşmede, balast suyu değişimi için D-1 standardı, balast suyunun performansı için D-2 standardı, güvenlik, test gereklilikleri ve prosedürleri ile birlikte istisnai durumlar tanımlanmıştır. Yeni balast suyu kurallarına uyum sağlanması, önümüzdeki yıllar içinde denizcilik endüstrisinin en önemli maliyet güçlüğü olarak karşısına çıkacaktır. Balast suyu yönetimi sözleşmesine göre, 2009 yılından önce inşa edilmiş, balast kapasitesi 1500 m3’ten küçük olan gemiler ile 2012 yılından önce inşa edilmiş, balast kapasitesi 5000 m3’ten büyük gemilerde 2016 yılı sonuna kadar ve 2009 yılından önce inşa edilmiş, balast kapasitesi 1500 – 5000 m3 arasında olan gemilerde 2014 yılı sonuna kadar D-2 standardının sağlanması gerekmektedir. Bu sebepten tüm ilgililer Uluslararası Denizcilik Örgütü kurallarına göre alternatif sistemler araştırmaktadır. Tank sedimanlarının yönetim masraflarına ek olarak sözleşmenin D-2 performans standartlarını karşılamak için oluşan masrafları ve operasyonel düzenlemeleri azaltmak veya kaçınmak için balast suyu yönetimi alternatiflerine olan ilgi gün geçtikçe artmaktadır. Bazı armatörler yerel standartlara sahip özel bölgelerde balast suyunu tahliye etmek için yeterli sisteme sahip değildir veya arıtım sistemleri bulunmamaktadır. Bu yüzden balast suyu yönetimi kurallarını karşılayabilmek için liman balast suyu alım tesislerinin mevcut bulunması balast suyunu tahliye etmek için alternatif çözüm olacaktır. Fakat bu liman balast suyu alım tesislerinin, kurulumunda ve işletilmesinde yaşanabilecek zorlukların değerlendirilmesinin yapılması gerekmektedir. Bunun için mevcut atık alım tesisleri ele alınabilir. Türkiye özelinde 2013 yılında 1717 geminin uğrak yaptığı Borusan limanı değerlendirildiğinde mevcut atık alım tesislerinden çok daha fazla elleçleme kapasitesine sahip alım tesislerine ihtiyaç bulunmaktadır. Balast suyunun alternatif yönetiminde, gemi dizaynları ile balast suyunun tahliye edilmemesi, balast suyunun kullanılmaması, konteyner gemilerinde balast suyu olarak katı balast kullanılması ve akış yöntemleri ile kaldırma kuvvetinden yararlanılan yöntemler bulunmaktadır. Bu çalışmada, balast suyu ve arıtım sistemleri tanıtılarak, balast suyunun yönetimi için alternatif yöntemler ile birlikte balast suyunun liman tesislerine alınması konusunda bilgilere ve değerlendirmelere yer verilmiştir.

Shipping moves over 80% of the world’s commodities and transfers approximately 3 to 5 billion tons of ballast water internationally each year that is necessary to provides ships’ trimming and stability. Many studies signified in different parts of the world have shown that ships’ ballast water has very important role for the transfer aquatic organism, human pathogens, including bacteria and viruses. Therefore, the marine environment is at risk to happen a serious ecological problem during discharging ballast water. The introduction of marine invasive species to coastal waters when ships take on ballast water at one port and then discharge with water, sediments, and biofilms from ships’ ballast water tanks it at other, ports is a significant threat to coastal and ocean ecosystems and economies. And, impacts on human and animal health, the environment and socio-economic activities appear. For example, the European zebra mussel has infested over 40% of internal waterways in United States. In 2004, with ‘International Convention for the Control and Management of Ships' Ballast Water and Sediments’ is adopted by International Maritime Organization, that describes D-1 standard for ballast water exchange, D-2 standard for ballast water performance, including the safety, testing requirements and procedures together with exceptional cases. Complying with the new ballast regulations is one of the most significant cost challenges the shipping industry can except to face over the next few years. According to the Ballast Water Management convention, D-2 standard must be provided for the ballast water capacity less than 1500 m3 (built from 2009) and the ballast water capacity greater than 5000 m3 (built from 2012) until the end of 2016 and the ballast water capacity between 1500 – 5000 m3 (built from 2009) until the end of 2014. For this reason, all parties have been researching alternative systems as per International Maritime Organization regulations. This study describes ballast water treatment systems together with ballast water and invasive species description. The ballast water treatment technology used to treat ballast water has generally been derived from other treatment systems, in which forms of solid-liquid separation and disinfection processes were applied. There are three treatment technology types, which are generally combined that are mechanical, chemical and disinfection. Most systems employ a two-stage approach involving mechanical separation at the first stage, followed by a second stage physical or chemical treatment. At this stage some systems use a combination of two or more treatments. In this study summarizes some systems which were approved or designed and tested. Chemical treatment use active substances to treat microorganisms, and for this, sufficient stocks will have to be carried on board. Therefore, this treatment would not be preferred by shipowners due to producing by-products with their chemical reactions to cause environmental threat. There are so many treatment systems on the market. The existing vessels can be integrated and retrofitted with these systems. Following adoption of the Ballast Water Management Convention, interest in these alternatives to conventional Ballast Water Management has increased since they offer ways to avoid, or substantially reduce, the operational issues and costs of treating compartmentalized ballast water to meet the Convention’s respective D-2 discharge standards, plus the cost of managing tank sediments. There is limited information in evaluating of these new technologies in reducing the transfer of harmful species in accordance with the goals of the Ballast Water Management Convention. This study gives informations and perspectives about intaking ballast water in the port reception facilities together with alternative methods related with the ballast water management. Ships that cannot meet this requirement for onboard ballast water treatment may be allowed to discharge ballast water to a port-based ballast water reception facility, which is generally understood to mean either a shore-based or barge-based ballast water treatment facility. This system has some disadvantages such as potential delays, sufficient space and equipment suitability. For this, in this study gives case study of port of Baltimore as an example to analyze economically and logistically port reception facilities. According to this case, port reception facility are feasible. On the other hand, technically that can be challenges. Additionally, port reception facilities evaluate in Turkey from this perspective and compared with the port of Baltimore for space situation. Some shipowners have not ballast water treatment system or, have treatment system but their system performance is not enough to discharge of ballast water at the special zones where exist a local standard. Therefore, complying with ballast water regulations, port reception facilities will be alternative solution in order to discharge ballast water. In this study gives information about waste reception facilities in Turkey to analyze challenges that can be occurred in port reception facilities. For this, when Borusan port where called 1717 vessels in 2013 is evaluated, it appears that ports need a port ballast water reception facilities which has more capacity than present waste reception facilities. Additionally, there are many concepts have been designed zero or minimal discharge (such as storm ballast, internal ballast and potable water), no ballast or continuous flow methods that are longitudinal trunks, ship buoyancy control and enhanced ballast water exchange concepts. All continuous flow systems readily exceed the performance required by the D-1 exchange standard but this standard is to be withdrawn at the end of 2014/2016. In regard to other zero ballast methods that may include their high build costs and relatively large wetted surfaces when loaded. The amount will vary according to the design cargo type and capacity, cargo loading and unloading requirements and other trading factors. At the same time, solid ballast method can be alternatively used for the container vessel. As container vessels can be arranged for solid ballast with empty positioning in export and import leg on their rotation. This method would be more attractive for retrofits or new builds than modified container ships. Results of this study underline that alternative system is very crucial for removing invasive species. In the future studies, numeric analyses and assessments of port reception facilities and the other alternative systems such as ballast free and no ballast can be proposed.