How to remove concrete lump from yard floor?

[SSW83]

OP,
If you will persist with me - I'd like to go on a little because I'm simply interested in solving a puzzle.

Does your drainage run straight back into a rear ginnel or back entry alley way?
Is there a manhole cover visible in the ginnel - one of a number of manhole covers going on to the end of the alleyway?

How do your kitchen wastes discharge - straight down into the concrete?
Presumably, your down spout does likewise unless the gutter is drained by the neighbour's down spout?
And, as above, does your bathroom waste(s) discharge into a hopper head?

Apologies for the delay in replying to this. In the yard there are several drains. There is a drain for the bathroom sink wastewater, which is in close proximity to the concrete lump. This does drain into a hopper head, as you suggest. There is a second drain, which serves the kitchen sink, washing machine and dishwasher wastewater, and that is at the foot of the outrigger. The third drain is at the bottom of the yard (at the foot of the wall, on the other side of which is the alleyway). This is to catch rainwater in the yard, I presume. As for manhole covers in the alleyway, I haven't seen any. There are rainwater drains, however.

 

[Ian H]

The third drain is at the bottom of the yard (at the foot of the wall, on the other side of which is the alleyway). This is to catch rainwater in the yard, I presume.

10p says that's an interceptor trap