Increasing the amount of bacteria per ml in a suspension

[Moosh]

Hi

I've come here because I don't know what else to do to find an answer, I've looked through textbooks and typed every word combination I can possibly think of into google, but nothing. My question is this:

You are given a suspension of 10^4 bacteria per ml and need to produce 10^6 per ml (not by growth but by manipulating the suspension). How would you achieve this?

Seeing as growth is out of the question, it kinda stumped me. I don't know if I'm being stupid and missing a point, but I can't see a clear answer. I'm not even sure it it's a biology or a maths question anymore. I realise the amount per ml has to increase by 10,000%, but I have no idea how that's possibly without growth. Any help would be much appreciated.

[EnricoPallazzo]

Evaporation?

[JackBean]

What about to spin your bacteria and resuspend in 1/100 of volume?