The link above doesn’t really answer the original post. I can’t think of a way to automate it, but you can burn, say, five or ten dban disks and set up an assembly line, booting and nuking several computers at once. Another alternative is one of the commercial services that will wipe or physically destroy your drives for you.
The duplicate question referenced above mentioned “there is also a product called eBan that will network boot the machines and wipe them that way”
The user could also customize the DBAN disk to do the wipe automatically without user intervention. Dangerous of course.
I think with the cost of drives so low these days, especially if they are old enough to be decommissioned and wiped, you might as well just contact the maintenance department, ask for a few drills and batteries, and drill away!