What happened when the high-density pond turned over?

Mud and temperature. According to the query of China Sewage Treatment Engineering Network.

1, sludge accumulated under high-density pond sewage for too long, and the bubbles released by biogas slurry sludge fermentation turned over the pond.

2. The inlet temperature of the high-density pond is too high, which causes the convection of the pond water and produces a large number of bubbles to turn over the pond.