So-called holding time is the interval between the completion of ballast water uptake and the start of ballast water discharge. Under IMO legislation, no holding time is required for vessels with UV-based ballast water treatment systems. But due to technicalities in the USCG legislation, owners of UV solutions must wait to deballast when moving from one Captain of the Port Zone to another.
“Long USCG holding times have caused some ship owners to shy away from UV technology,” says Peter Sahlén, Head of Alfa Laval PureBallast. “By reducing holding time to just 2.5 hours for PureBallast 3, we’ve removed that barrier.”
Two different testing methods
“Holding time for UV ballast water treatment systems is the result of the different test methods used to verify biological performance by the USCG and IMO,” Sahlén explains. “Although the USCG testing regime is more complicated for UV systems, we’ve made it possible for PureBallast 3 users to keep their operations simple and efficient.”
The updated USCG type approval, issued on 4 April 2019, makes the USCG holding time for PureBallast 3 almost negligible. “By far, PureBallast 3 now offers the shortest USCG holding time of any UV system,” Sahlén says.
Competing without chemicals
In fact, the minimized USCG holding time also gives PureBallast 3 advantages over electrochlorination. Electrochlorination systems have de facto holding times for the minimization of total residual oxidants (TRO), which can only be shortened through the use of neutralization chemicals.
“Whereas PureBallast 3 is chemical-free, electrochlorination involves active substances that must be neutralized before discharge,” says Sahlén. “That requires either time or more chemicals.”
The USCG legislation may change
In the future, all UV systems may see their holding times eliminated. The recent signing into law of the Vessel Incidental Discharge Act (VIDA) paves the way for the USCG to re-evaluate the IMO-endorsed testing method.
“If the USCG decides to accept the same testing principle as IMO, suppliers will probably be able to reapply for USCG type approval based on the IMO testing method,” says Sahlén. “Alfa Laval chose not to wait.”
High expectations on PureBallast 3
“Since its launch in 2006, PureBallast has led the way in ballast water treatment,” says Sahlén of pursuing the updated USCG type approval. “The market expects more from Alfa Laval than from other suppliers, and making life simple and secure for our customers is first priority.”
“It’s the same reason we were first with IMO revised G8 type approval,” he concludes. “Whatever the legislation, we want to keep our customers ahead.”
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