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the IHS Ballast Water Guide - RWO Marine Water Technology

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Sponsored by <strong>IHS</strong> Fairplay Solutions <strong>Guide</strong> to <strong>Ballast</strong> <strong>Water</strong> Treatment Systems<br />

residual oxidants in <strong>the</strong> water coming from<br />

<strong>the</strong> ballast tanks are neutralised by sodium<br />

thiosulphate, which is injected from <strong>the</strong><br />

neutralisation module.<br />

The system is compact, can be designed as<br />

a skid-type version and straightforward to<br />

configure and install in a limited ed spa space. pa pace. pa pace ce.<br />

Ocean Protection<br />

Mahle<br />

2 3<br />

The Ocean Protection System (OPS) is a<br />

modular product that makes use of filtration<br />

and ultraviolet.<br />

The two-phase pre-treatment filtration<br />

system is described by <strong>the</strong> company as<br />

low maintenance and configurable for<br />

different flow volumes from 250m 3 /h up<br />

to 2,000m 3 /h. It can be operated ei<strong>the</strong>r as<br />

a compact, container-housed unit or can be<br />

adapted to suit <strong>the</strong> vessel’s design and layout<br />

making use of available space. The filtration<br />

stages have automatic self-cleaning.<br />

The first filtration phase uses <strong>the</strong> pressure<br />

differential of around 1.2bar induced in<br />

<strong>the</strong> ballast water stream by means of a disc<br />

attached to a pneumatic cylinder. This forces<br />

any coarse sediment and organisms to <strong>the</strong><br />

outer edges of <strong>the</strong> flow, where <strong>the</strong>y are<br />

removed by means of a flush valve.<br />

The cleaned water is <strong>the</strong>n redirected to<br />

<strong>the</strong> second stage of <strong>the</strong> filtration system . In<br />

this <strong>the</strong> smaller particles are removed using<br />

a 50µm filter element, which is regularly<br />

backflushed to keep it clean.<br />

The ballast water passes to a low-pressure<br />

UV radiation unit where <strong>the</strong> DNA of any<br />

remaining organisms is destroyed. The UV<br />

light is mostly in <strong>the</strong> 254-nanometre range.<br />

Treated ballast water passes back and forth<br />

between <strong>the</strong> ultraviolet radiation unit and<br />

<strong>the</strong> ballast tanks before being passed out of<br />

<strong>the</strong> OPS system.<br />

BAWAC<br />

Maritime Assembly Systems 3<br />

Germany-based Maritime Assembly Systems<br />

followed <strong>the</strong> G8 process with its BAWAC<br />

system. Land-based testing took place in a<br />

testing station in Singapore. The prototype<br />

500m3 /h BAWAC used seven fluid-cooled,<br />

metal steam UV lamps.<br />

A helix structure around <strong>the</strong> lamps ensures<br />

<strong>the</strong> water remains in <strong>the</strong> UV treatment area<br />

for longer than in straight-pass systems,<br />

distributes <strong>the</strong> light evenly. It also provides<br />

vibration damping for <strong>the</strong> quartz components.<br />

The seven burners are composed of<br />

three components. First, <strong>the</strong>re is <strong>the</strong> highperformance,<br />

long-life burner itself, which<br />

has low energy consumption. The burner is<br />

surrounded by quartz glass, which supplies<br />

it with cooling fluid. The rotating helix<br />

component distributes <strong>the</strong> light. It is driven<br />

by ballast water, providing indirect cooling of<br />

<strong>the</strong> burner and mechanical damping of <strong>the</strong><br />

quartz glass body. Wiper blades in <strong>the</strong> helix<br />

are pressed against <strong>the</strong> quartz glass cylinder<br />

hydraulically as water passes through th <strong>the</strong><br />

BAWAC, cleaning <strong>the</strong> system.<br />

MH Systems<br />

California-based MH Systems uses a<br />

combination of two treatment systems,<br />

deoxygenation and carbonation.<br />

An inert gas generator (IGG) is at <strong>the</strong> heart<br />

of <strong>the</strong> BWTS from MH Systems. The inert<br />

gas – which consists of 84% nitrogen, 12-<br />

14% CO 2 and around 2% oxygen – is bubbled<br />

through <strong>the</strong> ballast water by means of a row<br />

of diffusers with downward-pointing nozzles<br />

placed at <strong>the</strong> bottom of <strong>the</strong> tank.<br />

IGGs infuse <strong>the</strong> ballast water with inert<br />

gas bubbles until it attains a state of hypoxia,<br />

with a pH of nearly 5.5. The gas infusion<br />

© <strong>IHS</strong> Global Limited 2012 23<br />

012_037_CorrectedBW1204.indd 23 01/08/2012 15:33:45<br />

3

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