Fumigator reports recapture results that exceed EPA controls

May 5, 2023

Genera, a leading provider of fumigation solutions and the company responsible for fumigating log exports from Northport, has introduced an advanced activated carbon recapture system for methyl bromide fumigation at the port.

The move comes in response to updated controls specified by the Environmental Protection Agency in 2021 for the use of methyl bromide for fumigation.

One of the updated controls involves the use of recapture technology. It states that half of all under-sheet fumigation involving methyl bromide must have recapture technology applied by 1 January 2022, moving to 100 percent by 1 January 2025.

’Recapturing’ means preventing a minimum percentage of methyl bromide from being released to air after fumigation. For under-sheet fumigation this started at 30 percent on 1 January 2022 and increases to 99 percent by January 2035.

Genera, a 100 percent New Zealand-owned company headquartered in Mount Maunganui, has been at the global forefront of methyl bromide fumigation and recapture technology for decades. Over the past 10 years, in particular, considerable investment and effort has gone into improving the capacity and efficiency of methyl bromide recapture systems. It has been using its new recapture technology on all log rows at Northport, and recapturing to 90 percent, since 2022.  

Genera uses activated carbon, a porous material with a vast surface area, to recapture the methyl bromide gas from under impervious sheets at the end of fumigation. The activated carbon adsorbs and removes the gas from under the sheets. The purified air is then released back into the environment.

The solution Genera has devised for large-scale port operations uses a 20-foot ISO (container-sized) tank to house the activated carbon. This makes it highly mobile and transportable, particularly within a port environment. It is encased by a high-strength steel frame capable of withstanding the rigours of transportation and heavy use.

It allows Genera to recapture up to four large log rows at a time in less than an hour to a high percentage.

One of the important innovations of the new system is the ability to re-use the carbon that becomes saturated with methyl bromide during the recapture process, as opposed to traditional systems that require the saturated carbon to be disposed of at an authorised landfill at significant cost. 

Given the volumes involved, Genera never considered using a system that required disposal of the methyl bromide saturated carbon as this would have resulted in environmental problems far worse than the ones it is addressing.

Instead of dumping the carbon, saturated carbon pods are transported to Genera’s regeneration facility.  A 24-hour process takes place that involves heating the carbon to desorb the methyl bromide and remove it from the pod. This is then run through a liquid treatment system that ‘chemically destroys’ the methyl bromide, preventing it from making its way back into the environment. 

The carbon pods can then be used again for recapturing methyl bromide. Genera says it has yet to see any significant loss of recapture efficiency of the ‘regenerated’ carbon, meaning the carbon has not needed to be replaced as yet.

Genera says that this system and the associated technology have already reduced by 90 percent the amount of methyl bromide being ‘vented’ into the atmosphere without creating other harmful downstream impacts. The system has proven to be a technically and economically feasible and a safe option for use by the forestry industry for treatment of export logs.

More information and some common questions and answers about methyl bromide fumigation can be found on the Northport website.

In addition to EPA, Worksafe and other legislative requirements, Genera or any other fumigation company working at the Northport facility are also subject to Northport’s requirements for fumigation operations.