atg UV gains NVI approval for disinfection of intake water and wastewater

The approval follows 45 weeks of field-testing onboard the Norsk Fisketransport operated well boat Namsos. The minimum required UV dose of 25 mJ/cm2 was ensured by operating with variable lamp power control according to the UV dose monitoring. UV intensity, flow rate, lamp operating hours, UV dose and chamber temperature were continuously monitored, recorded, and verified against a reference sensor. Water samples were collected weekly for heterotrophic bacteria and Vibrio species analysis which showed an average 2.5 log reduction.

Erling Lorentzen of Norsk Fisketransport, said: "The atg units meet the capacity, functionality and reliability requirements of our wellboats.

“We have used the UV systems during smolt transport and despite demanding conditions on the transport, the UV systems maintained the required UV dose. Service friendliness and ease of installation mean that we will use these UV systems in the future on our boats."

Fitted with lamp system

Namsos is used for the transport of live salmon from sea cages and for de-lousing operations as a service to fish farms on the Norwegian coastline. The vessel is equipped with three 1000m3 circular fish holding tanks with separate circulation systems each of which was fitted with a WF-850-20 medium pressure lamp system capable of three tank turnovers per hour.

Specifically designed for well boat and aquaculture applications, the compact units lend themselves to installation in the limited spaces available on a marine vessel whilst also featuring very low-pressure head losses.

The medium pressure lamps are low in operating cost and a UV dose alarm function can be interlocked with overboard valves, ensuring that no untreated water is discharged into the sea. For onshore aquaculture sites, atg UV’s Data Stream feature allows monitoring of UV operation at remote sites via an Ethernet connection.