In the operation of sewage plants, activated sludge poisoning phenomenon is occasionally encountered. Poisoned activated sludge exhibits many different forms. Usually, the poisoning of activated sludge is the same as that of humans and animals, and is divided into two cases: acute poisoning and chronic poisoning. Acute poisoning is difficult for the operation of integrated equipment. But for chronic poisoning, activated sludge has many forms of manifestation. The operation and maintenance personnel of the integrated equipment are like a doctor, and there are still many ways to solve the active sludge of chronic poisoning. However, in practice, after the operator found signs of chronic poisoning, he did not adjust the process in time, resulting in the death of activated sludge.
What are the main points for judging activated sludge poisoning?
1. Observe through a microscope. The first needs to observe the death of protozoa in activated sludge. Protozoa are represented by fibrals. If all the fibrinosis disappears, it can be determined whether there is toxic sewage flowing into the integrated equipment. 6 hours after the death of the fibrella, the body is hydrolyzed and disappears. Therefore, it is judged whether the activated sludge is poisoned by the disappearance of the protists.
2, judged by the sedimentation ratio of activated sludge. The first manifestation of poisoned activated sludge is that the sedimentation ratio of activated sludge is reduced, and the protozoan animal dies. In order to preserve the activity of the bacterial gel group, the activated sludge will sacrifice the bacteria on the periphery of the bacterial gel group, so the bacteria that die on the periphery will free up and distribute to the sewage of the equipment. At the same time, the coarse bacterial gel mass of activated sludge will also disintegrate and become thinner and smaller. At this time, we will find that there are many fine particles in the water that cannot be settled. The flocculation of activated sludge becomes worse and the flocculation takes a long time.
3, liquid level scum to judge. After activated sludge poisoning, the dead bacterial gelatin will form liquid surface scum under the action of aeration. The operator needs to observe the characteristics of the liquid surface scum to determine the toxicity of the activated sludge. For example: the liquid surface scum is thin and loose, the color is gray and dark, there will be no bright activated sludge color after the active bacteria are poisoned, and the dead activated sludge has no adsorption ability between each other, so the scum is also very loose.
4, detect the dissolved oxygen DO change state. When activated sludge poisoning, as the death of activated sludge bacteria continues to decrease, we will find that the dissolved oxygen DO of the aeration tank mixture gradually rises under the condition that the aeration amount is unchanged. At the same time, the removal rate of organic matter is gradually decreasing. This trend is also the main basis for our judgment of activated sludge poisoning.
5. Changes in the water outlet of the equipment. After activated sludge poisoning, the effluent detection will find that the COD concentration continues to rise, because the water is mixed with a large number of disintegrated activated sludge. And the water is turbid.
