In terms of throughput, not a problem at all. With proper GPU computing techniques you can do full color correction and so on at dozens of Gigapixels per second on a single desktop GPU (bound by memory bandwidth).

The problem is more with bandwidth and working memory. For example, if you'd stream the image to a GPU (at 6.4 GB per image, assuming it's greyscale 16 bit), you're just being bottlenecked by PCIe plain and simple. GPU memory sizes aren't favorable to these sizes, either, most models don't have enough memory to have one input and one output buffer (assuming you also want 16 bit out). So, with a single GPU the bus would limit you to around 1-2 pictures per second.

However, the quoted throughput is "30 TB per night", that's only one GB per second. So it's plausible (but unlikely they do) to process all of the data on a single desktop PC with a GPU and a dual 10 GbE NIC card.