Horizontal waste trap fail?

[startstreamer8]

I have to run a waste pipe from 2 washing machines low down to allow for kitchen units. See the pic. there is no room for a P trap so the plumber put a horizontal trap as in pic. To me it looks like there is a big hump where the trap is. Will that not create an issue? There is  no fall into the trap from the pipe that comes from the machines. 

Or maybe horizontal traps need to be like this? It's the first time I've seen a horizontal trap.

 

Does anyone know? He's an experienced plumber so would be surprised if he made an error. 

[Mike]

That's waterless trap and the hump is normal. The pipe should, however, still be flowing downhill - it rather looks like it's flowing uphill; if so, that would be a fail.

[Russell griffiths]

There’s no clips holding that pipe, so surely it’s not finished, I would get it all clipped and secure first, the right hand corner presumably goes to the machines. 
 

if running two washing machines i would either want it in 50mm pipe, or two pipes.