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The apparatus for the aeration method is mainly a segment of clear PVC pipe that is about 9.75" long and has an inner diameter of 4". One end of the pipe is connected to a ---- base that has four evenly placed metal rods attached to it. The rods run freely along the length of the clear PVC pipe and penetrate an ---- lid, which is held in place with butterfly screws at each rod. There are five adapters in the contraption. An adapter in the center of the lid joins the apparatus to a pump via a 3/8" tube. Water can be pumped out from this location when the container is completely full to cause a partial vacuum or air can be pumped in to pressurize the container. Two adapters are located near the base of the contraption that function as a water inlet and air inlet. The air inlet also has an air stone connected to it on the interior of the pipe. The pressure in the contraption is measured with a pressure sensor attached to an adapter near the base, and the dissolved oxygen probe is connected at the bottom of the apparatus near a magnetic stir bar to prevent bubble formation on the probe. O-rings are used to seal the contraption at each adapter location and at the interface between the pipe and the lid.
This contraption is used to simulate the interface between the distribution pipe exit and the grit chamber at the AguaClara plants. The container is filled with water and sealed off and water is pumped out of the lid causing a partial vacuum. The environment created is similar to that in segments of the distribution pipes of actual the transmission line bringing water to the plants. After the water is put under negative pressure, the pump clamp is released to open the container to atmospheric pressure, which simulates the grit chamber conditions.
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