Ocean Protection System OPS: Perfect Ballastwater Treatment

1^st stage: High-performance pre-filter

The self-cleaning automatic pre-treatment filter is a versatile, self-cleaning, low-maintenance filter unit for removing particulate impurities from highly contaminated water and process water. It works even at low operating pressures and has only low pressure losses during high flow rates. The system's other main features include simple and robust design, and a very small footprint. 

The concentrate rinse flows of the two pre-treatment phases – automatic pre-filter and automatic backflushing filter – are continuously pumped overboard on site, meaning that there is no hazard of spreading microorganisms.

2^nd stage: Continuous filtration

The ballast water is then cleaned with the aid of an automatic backflushing filter, which removes more particles. Standard solutions achieve flow rates of up to 2500 m³/h. Compared with conventional filters, the automatic filter has the considerable advantage of providing continuous filtration if required.

The combined pre-treatment has the advantage over a simple filter solution of allowing large volume streams to be treated. The highly effective pre-separation means that the ­sub­sequent phases only have to filter out the very smallest remaining particles and organisms. 

3^rd stage: Efficient UV sterilisation

The ballast water treated in the first phase contains only very low levels of suspended solids, thus ensuring that the low-pressure UV rays can penetrate sufficiently for maximum efficiency. The UV light hits the microorganisms in the water and damages their DNA. The DNA is damaged in such a way that the organism can no longer replicate and is thus rendered harmless.

The low-pressure radiation units in the OPS emit most of their light in the 254 nm range, which is in the spectral range of maximum germicidal effectiveness. In contrast, other methods generate a broadband spectrum which is mainly outside the relevant spectral range. 

The great advantage of UV sterilisation, which is widely used in drinking water treatment, is that the process dependably destroys even the tiniest organisms without needing chemical additives which would require subsequent removal. Che­mi­cal methods use chlorine or chlorine dioxide to deactivate the organisms. Both sub­stances require dedicated storage facilities on board, they must be handled by specially trained staff and the ballast water needs to be treated before it can be discharged.