I read in a past thread that its trial and error to get the vacuum the right distance away from the sand where the suction will only take away the waste and not the sand.. besides vacuuming, you also need to poke the sand so that air bubbles/gases do not build up in pockets within the sand... this can be dangerous to your fishy friend if left unchecked.
If you're using a syphon vac a lot of people stir up the water to get the waste floating then they suck it out with the syphon vac. As DiiQue stated you'll need to be careful of gas building up in the sand. You're putting this in a bowl? What size bowl & how do your do water changes? If you do 100% water changes weekly I personally wouldn't go with sand. When I used a small container I always dumped everything out each week to rinse it all well, sand wouldn't be easy for that.
I have sand in my tank, and I just use the siphon vac. Move the vac in small, quick circles above the sand and it will stir it up enough to siphon up the waste, but the sand is heavy enough that it floats back down and doesn’t get sucked up. You can even "stab" the sand with it to get out the air bubbles/waste, and it still won't suck up the sand. J
What I did with my gravel was after I vacuum it, I get one of my plant base and kind of hammer it on the gravel to make it all tidy and compact. I guess you can do the same with sand but I'm not sure since I haven't tried it on sand (Soon tho lol).
I have petco sand, which is larger than playground sand. It is a full bag of orange and 1/4th bag of grey and it shows poop really bad, but all I do is use my hands and dig down half way and fluff the sand. It's heavy enough that it falls down right away and the *stuff* floats then lands on the top. Your filter should be picking up some of it. After about 5 minutes you can syphon gently about an inch off the sand if it's super fine sand. Mine i can put the syphon into it and pick up quickly and 99% falls back down since I am using a long syphon. I only have a 5.5 gallon tank though. I then dump outside in my garden because sand and a garbage disposal don't mix :)