Discharge criteria

排放标准

Any type approved ballast water treatment system shall comply with the discharge criteria regulation D2 and they are;

Capacity discharge for organisms;

1. Less than 10 organisms per m3, for organisms> 50 micrometers,
2. Less than 10 organisms per ml, for organisms between 10 and 50 microns.

Capacity of indicator microbes; ( cfu – colony forming unit)

1. Toxigenic vibrio cholera: 1 cfu per 100 ml
2. Escherichia coli: 250 cfu per 100 ml
3. Intestinal enterococci: 100 cfu per 100 ml

任何经过批准的 ballast water treatment system 都必须符合排放标准规定 D2，它们是：

生物容量排放要求：

对于大于 50 微米的生物，每立方米不得超过 10 个生物；

对于介于 10 和 50 微米之间的生物，每毫升不得超过 10 个生物。

指示微生物容量要求（cfu - 菌落形成单位）：

霍乱弧菌毒素原性菌：每 100 毫升不得超过 1 个 cfu；

大肠杆菌：每 100 毫升不得超过 250 个 cfu；

肠道肠球菌：每 100 毫升不得超过 100 个 cfu。

General structure of a Ballast Water Treatment (BWT) System

– The ballast water is generally passed through a filter for physical treatment to remove living organisms and dirt of size 50 microns and above. Some systems use cavitation devices as physical treatment.

– Later, the ballast water is sterilized to kill microbes by chemical treatment using chemicals and the treated water is filled in ballast tanks. Methods include emitting ultra-violet rays in water, reducing the oxygen content in water, adding active substances such as ozone and using its sterilizing ability, sterilizing water by using chemicals etc.

– Subsequently, the water is discharged overboard, but for a system in which re-treatment or neutralization is necessary, the water is discharged overboard after such treatment has been performed.

• Ballast water 通常通过过滤器进行物理处理，以去除大于 50 微米的生物和污垢。一些系统使用空化设备进行物理处理。
• 然后，通过化学处理将 ballast water 进行消毒*菌，以*死微生物，然后将处理后的水填充到 ballast tanks 中。方法包括在水中发射紫外线、降低水中的氧含量、添加致活性物质如臭氧并利用其消毒能力、使用化学物质进行消毒等。
• 随后，水被排放到海上，但对于需要重新处理或中和的系统，水在进行此类处理后排放到海上。

Different types of ballast water treatment system

There are 4 different types of ballast water treatment system commonly used. They are;

1. UV treatment method
2. Gas Treatment method
3. Electrolysis method
4. Magnetic Separation method.

目前常用的 ballast water treatment system 有 4 种不同类型，它们是：

1.紫外线 (UV) 处理法
2.气体处理法
3.电解法
4.磁分离法

a) UV Treatment method

• 图中展示了 UV 处理法的概览。在第一阶段过滤器中，大型水生生物会随着污垢一起被去除。随后，钛白粉上会释放出光，在光的作用下产生的自由基能够灭菌水生生物和其他真菌。
• 未成对电子的原子或分子称为自由基。通过辐射特定波长的光，钛白粉能够产生活性氧和羟基自由基（OH 自由基），从而具有强大的消毒能力。
• 另外，一些系统使用紫外线进行消毒灭菌。由于此处理系统不使用化学药品，微生物、真菌等可能会在 ballast tank 中再生长。因此，在排放前需要再次通过 BWT 系统对 ballast water 进行处理。

b) Gas Treatment method

– Figure shows an overview of the gas treatment method. When filling ballast water, Inert gas is blown into the ballast water using a Venturi tube, the oxygen concentration of water is reduced, and ballast water is sterilized.

– The oxygen concentration of inert gas is lower than 0.1%, and this is lower than inert gas used for oil tankers (lower than 5%). In addition, some system uses ozone which has strong disinfection. These treatment methods may need neutralization process or water quality adjustment during discharge of ballast water.

• 图中展示了气体处理法的概览。在填充 ballast water 时，使用 Venturi 管向 ballast water 中吹入惰性气体，降低水中的氧浓度并对 ballast water 进行消毒。
• 惰性气体的氧浓度低于 0.1%，低于用于油轮的惰性气体的氧浓度（低于 5%）。此外，一些系统使用具有强大消毒能力的臭氧。这些处理方法在排放 ballast water 时可能需要中和过程或水质调整。

c) Electrolysis method

Figure shows an overview of the electrolysis treatment method with filtration & cavitation. The uptake ballast water is passed through filters and large aquatic organisms and dirt more than 50 microns are removed. – Cavitation damages the cell membranes of organisms, and nitrogen gas purified onboard and hydroxyl ions generated by electrolysis are added to sterilize and to kill aquatic organisms and fungi. – There are no active substances that are brought into the ship from outside the ship.

• 图中展示了带有过滤和空化的电解处理法的概览。吸取的 ballast water 通过过滤器，去除大于 50 微米的大型水生生物和污垢。- 空化会损坏生物的细胞膜，电解产生的氮气和氢氧根离子会被添加到 ballast water 中进行消毒灭菌。- 没有从船外带入船舶的活性物质。

d) Magnetic Separation method.

– Figure shows an overview of the magnetic separation treatment method. This is a treatment system for aquatic organisms, micro-organisms, and microbes in which magnetic powder is fed to the ballast water during its filling, water is agitated and magnetic separation performed.

– No chemicals for sterilization are used. The aqueous ingredients in ballast water are also unchanged, and re-treatment of discharged water, neutralization, etc., are not necessary.

• 图中展示了磁分离处理法的概览。这是一种用于水生生物、微生物和微生物的处理系统，在 ballast water 填充过程中向其中添加磁性粉末，水被搅动并进行磁分离。
• 该系统不使用消毒灭菌的化学药品。ballast water 中的水分成分也不会改变，因此不需要对排放的水进行重新处理、中和等操作。



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