IMO #6 - BWM 压舱水管理法 (Part 2)

2008-04-22 13:29  浏览次数 23

BWM 压舱水管理法 (Part 2)

2007.01.20

虽然这个 Ballast Water Management (BWM) 国际公约还没有正式通过和生效,但世界上很多国家为了保护自已的水域不受到外来水中生动物的侵犯都己开始执行压舱水处理法.尤其是美国和加拿大共有和共用的大湖区 (The Great Lakes), 这几个大湖从大西洋的圣劳伦斯海道 (St. Lawrence Sea Way) 进入之后便无其他出口,湖跟湖之间因水平不同均采用船闸 (图片 1,2 and3).

         

因此整个大湖区就像一个封闭不通的湖 所以当地政府对外来船舶带来的压舱水特别敏感.

大湖区的北岸属加拿大,南边归美国. 二个国家各订有自己的BWM法律,到达该地的外国船舶二边政府的法律都要应对,可说是有点吃不消.

下边是BWM 最新条例:

1.美国加利福利亚州 - 2006/5/9 开始要求外来船舶必需在抵达港口之前于离开陆地50海哩外和水深200米处更换压舱水.

2. IMO - 2006/11/07 发表一份 (Circular BWM 2, Circular 7) 有关压舱水处理法之检验和证明文件.

3. 美国华盛顿州 - 2007/7/1开始禁止船舶把没有处理过的压舱水排入他们的水域.

4. 美国密歇根州 2007/1/1开始,任何船舶在进入该州任何港口之前船上必需

         (1). 备有BW Control general permit

          (2).   BW必需用下列四种BW处理法其中的一种, 处理后方可排出.

                 Treatment method:

 

                           a.  Hypochlorite treatment

                           b.  Chlorine dioxide treatment

                           c.  De-oxygenation treatment        

                           d.  Ultra violet radiation  

上述4种处理法其中的 Chlorine Dioxide 方法已由美国 Ecochlor公司发明,生产并在 Matson 航运公司的 “Moku Pahu” 轮上开始试用. 这种处理方法

Technology:

Chlorine Dioxide is unique in its effectiveness against all organisms. It can be safely and economically generated in dilute solutions on commercial vessels.

Chlorine Dioxide (CIO2) is a gas with strong oxidation properties and a high antimicrobial activity over a wide pH range. The mechanism of action of CIO2 on organisms is not entirely understood, but it is believed that CIO2 goes across the cell wall and inactivate organisms by acting on sulfur containing amino acids within the organism. The concentration of CIO2 rapidly decrease, known as the initial oxidant demand, is dependent on the specific characteristics of the water mass.

Treatment

Ecochlor’s treatment system injects a dilute solution of chlorine dioxide into the ballast water piping as ballast water is loaded. The chlorine dioxide solution strength is determined by operational parameters (flow rate, target dosage) and adjusted automatically during the ballasting operation.

The chemical concentration is sufficient to neutralize any invasive species in the ballast water entering the system. Chlorine dioxide will remain active for several hours in the ballast tanks to neutralize any biofilm in the ballast water tanks. The biofilm is a source of re-inoculation of the ballast water and must be neutralized for proper control of invasive species. The chlorine dioxide will decay over time and there will be no residual in the ballast water tanks at the time of discharge.

Result

The “Moku Pahu” has 13 ballast tanks and can carry up to 17,000 tons of ballast. The vessel performs the flow-through method of ballast water exchange when calling at U.S.

This technique consumes considerable manpower and increases greatly the operational hours on the two ballast pumps. The system used by Matson is designed, fabricated and installed by Ecochlor. Overall the system has the capacity to treat a maximum ballast water flow rate of 2,500 tons per hour.

根据加州环保局最近的报告说旧金山湾区是全世界最受到侵害的港湾因政府当局已查出该港湾共有250种外来具有侵害性的生物, 所以我们可以预测加州对 BWM 的限制将会更加严格.

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