Hyrax v1.0 ( branch: 1.0-stable )
Documentation for Versions:

In lib/hyrax/configuration.rb, there is a method to set the poll interval for notification updates:

   def notifications_update_poll_interval
    @notifications_update_poll_interval ||= 30.seconds

You could set this to never (effectively).

The setting is referenced in the view partial app/views/hyrax/users/_notify_number.html.erb also, providing another place you could set it.

data: { 'update-poll-url' => hyrax.user_notify_path,
        'update-poll-interval' => 30 } do %>
        'update-poll-interval' => Hyrax.config.notifications_update_poll_interval }  

Hyrax commit with these settings