First, you have to buy the powder, you know; it mustn't be wet, and it mustn't be that coarse stuff that they load cannons with--it must be pistol powder.
Waste material is put into a grinder on the factory floor and the coarse stuff left over is sucked through a pipe into the furnace where it is burnt, generating thermal energy.
That way you remove much less grass each time, which makes the job easier, and the low-growing grasses will thrive while many of the taller, coarse stuff will die off.