Multiple ant hills with dead grass, what do I do?

I have a problem with ants. There is so much information out there on various ants its hard to know what to do but I'd rather not call a professional yet if its a species that's easy enough to identify.

I live in Calgary, Alberta. My front lawn gets full sun in the morning and partial sun in the afternoon.

When I moved in in August the front "flower beds" were over grown weed and grass pits which had been previously covered with the black tarp material and red crushed stones. When I pulled it all up there was an ant hill on the end of each (there's two like this). I dug up much of the nest and poured boiling water down the big holes. I "boiled" the ones I saw running with eggs. I waited a day or two and saw no evidence of ants so I planted my flower beds and everything died... ants.

In the front yard there are 3 patches of dead grass; yellow and dry about 6"x6' which is not really piled into a hill but SWARMING with ants and holes everywhere. These patches are about 3 feet apart. If anything distrubes them they rapidly swarm with black ants (appear black, I haven't looked really closely) 1/2 cm - 1 cm big (different sizes). I assume these are the soliders as the regular ants I see in the yard are 1/2 cm and a bit smaller. So many swarm it looks like someone tossed a bag of peppercorns on there and is shaking them around. Some parts of the yellow grass blacks out. These ants bite when the dead grass area is disturbed.

Today I was mowing with the lawn mower set to the highest grass setting. I cut the top off an ant hill (I last mowed 3 weeks ago) and not only did they swarm the ground but me and the mower. The ground was very spongy with some grass starting to die when I looked closer. This site was about 10 feet from the other three but the ants looked the same, though about 3 feet from one of the flower beds.

Any idea of a) what kind of ants they might be? b) best way to kill them? I have small children who I'd like to be able to have play in the front yard and two dogs who go there rarely c) do you think all sites are connected underground?

The people who here before barely tended the yard and the thatch was so thick in the spring it was growing moss underneath. It been power raked twice but still has some thatch in the area around where most ants are, this could be contributing.