Patent ID: 8025795

Claim:
A ballast water treatment system for treating water for a vessel having a ballast tank and a ballast pump, comprising: pathway means defining a water pathway having a main inlet for connection to a body of navigable raw water for the vessel, the raw water containing sediment and marine organisms, the pathway also having a main outlet for connection to the ballast tank and a discharge for discharging water to the body of navigable raw water, the pathway including ballast water piping for supplying raw water from the main inlet to the main outlet for the ballast tank; a back washable filter in the pathway, the filter having a filter inlet for receiving the raw water from the main inlet, the filter screening sediment from the raw water to produce initially processed water which contains at least some marine organisms, the filter having a first outlet for supplying initially processed water to the pathway, a second outlet for supplying back washing water to the discharge, and a third outlet connected to said second outlet for supplying pre-screened water from the filter to the discharge and wherein said pre-screened water from said third outlet and back washing water from said second outlet do not enter the ballast tank; biocidal means connected between the first outlet of the filter and the main outlet to the ballast tank, for receiving initially processed water from the filter and for disabling or killing the marine organisms in the initially processed water to produce treated ballast water for the main outlet to the ballast tank; the pathway being adapted for connection to the ballast pump of the vessel, so that the ballast pump is in line with the filter and biocidal means and in line with the ballast water piping for pumping water along the pathway between the main inlet and the main outlet, and through the filter and the biocidal means; and a sensor along the pathway for at least sensing the rate of light transmission through the water and control means connected to the sensor for regulating the flow rate of raw water for the vessel in response to the sensing by said sensor.