Depends on where the weed seeds and pathogens are.
Heat is a relatively simple, poison free way of doing it.
For pathogens in the soil mixing in Mustard as a green manure crop as soil
cleansing properties and it supposedly helps suppressing weeds as well. You
can grow it somewhere else, harvest the tops or pull the whole plants out
and mix them in where you want them if you don't have the time to grow a
green manure in situ/where it's needed.

You will not achieve complete eradication though.
Cheers
Holger

Thank you for your reply to our question.

We failed to mention that we are worm farmers and are trying to make a more user friendly product from the worm castings. We are not thermophylic composting the feed, instead we are cold composting (mesophylic) which does not remove any of the weed seeds or plant/animal pathogens. We are currently considering solar pasteurizing using a heat box. We have read information which suggests that to remove most of the pathogens we need to heat the worm castings to a temperature of 60 degrees Celcius for 30 minutes. What effect will this heating process have on microbial activity generated from the worm casting process? Also we cannot find any information on how long it will take to kill the weed seed.

Any information regarding the above would be very much appreciated.

Thank You

With the wormcasts, you are producing a soil-humus complex of superior quality together with billions of beneficial micro-organisms. Don’t destroy them, unless absolutely unavoidable. Screen your material for diseased plants and weeds before the worms process it. Or heat the material before the worms do their job!

Holger