This seems to be the question of the day; "Will this routine work?"
That's an impossible question to answer.
Losing 30 lbs comes primarily from being in a caloric deficit. Said deficit is a product of eating less and moving more.
On the moving more side of the equation, the possibilities of what will expend calories are endless. That said, it becomes more than a matter of simply burning energy though, when you're talking about optimizing body composition.
By that, I mean, most don't simply want to lose weight. They want to lose fat while preserving muscle to leave them looking and feeling healthy.
With that in mind, sure, some calorie wasting stuff is great for aiding the deficit. That said, the muscle preserving side requires a strong stimulus that says, "Hey body, even though we aren't eating enough energy to maintain what we currently have, this exercise is tough stuff and if it's going to continue, we need to keep this muscle stuff around."
The sort of exercise that sends this signal is weight training. You say you're circuit training which doesn't tell us a whole lot. In general, circuit training entails low weights and low rest. That generally doesn't send a very strong signal for muscle maintenance. In fact, in many cases that sort of weight lifting can fall into the calorie wasting camp from above.
If you're brand new to weight lifting, circuits are fine for now but you'll want to progress onto something a bit more fitting given your goals.
