Plumbing / Building Question - Add garage sink

[lookitsjonno]

I want to add a small sink into our garage for hand washing. My plan for fresh water is to T off an outside tap which should be easy enough, but i'm struggling with waste. Thankfully the waste inspection chamber is only about 3 meters away. How can I run my waste into the chamber (image below)? Can I just drill a hole through the black plastic at the side a couple of feet down and slope a 1.5inch waste pipe into it?

 

[lookitsjonno]

Thanks guys opted to do the job properly and hook it into a blank on the chamber directly. Killed me yesterday digging the 1 meter deep hole mind.

 

[lookitsjonno]

Thanks for that, did exactly as you said and laid in pea shingle above and below. Just finished filling it back up. Pipe work fought me every step of the way so ended up with an adjustable jobby. Queue several trips to Toolstation and lots of swearing I'm pretty pleased with the result. We plan to patio the area for an outdoor kitchen later in the year but most from halfway onwards is 450mm or deeper.