It doesn't come as live anyting. It has internal pores and baffles where nitrifying bacteria can grow. If you look closely at the diagram of the pellet internals you can see that it contains 'eddys' where anerobic bacteria can grow. So basically it acts like a deep sand bed (which does remove nitrates) by allowing anerobic bacteria to grow.
I still see bubbles of nitrogen coming up from my DSB
(that's nitrAte converted back to nitrogen by anerobic bacteria.
I'm intrigued by the idea of these pellets, but at $43.00 for 1kg I'm not ready to be the guinea pig. Besides, my trates are at <=1 as of yesterday's test.