Taking a look at the contact tank in our system involves removing about a foot of earth on top of the 24" diameter concrete tank lid, and of course, removing the lid itself. The expert recommended we pump the contact tank, which if everything is working correctly, should only contain relatively clean and clear water. Ours was pretty muddy. After pumping about 40 gallons of water out of the tank, it was apparent that our pump was ingesting sediment, and that we needed a different method to remove water and muck from the tank. Being short on industrial pumping equipment and long on dim wits and energy, yours truly took a bucket into the hole. Even though water continued to trickle into the hole from the inlet and outlet tubes, I was able to stay ahead of the inflow and remove most of the sediment on the bottom of the tank. Photographic evidence of the adventure is included below for your enjoyment.
This was our routine: I would gather as much sediment and water in my little bucket as I could, while Karen's dad lowered a larger bucket into which I could empty mine. Because of the tight quarters, he would need to raise his bucket above my head so I could stoop back down to get another collection, stand up, direct the second bucket down in front of me, empty into it, repeat ad nauseum.
This demonstrates how far I could bend over inside the contact tank: just far enough to scrape my pail on the bottom while wedging my body against the sides of the tank, and trying to keep the inflowing water from running into my boots.