Reasons for low dissolved oxygen in wastewater
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Why is the dissolved oxygen level in the wastewater from our aeration tanks always so low, or even undetectable? But even with three blowers running in the wastewater treatment plant, the pressure remains very low. They suspect there is a problem with the samples we prepared. What are the main factors affecting this? Why, after adding sulfuric acid, does the sludge in the bottle sometimes settle at the bottom and sometimes remain on the surface?
Do you do laboratory analysis or online analysis? If it is a laboratory analysis, it may be due to the dissolved oxygen in the water being consumed by microorganisms during sampling and sample transfer, or there might be something incorrect with your testing method. If a wired method is used, it is possible that the dissolved oxygen probe has failed or become contaminated. If it is an electrochemical probe, the electrode must be repolished and the electrolyte replaced; after re-calibration, it can be put back into use ； In the case of the fluorescence method, it may be that the organic substances in the wastewater have poisoned the fluorescent film, or the probe is damaged.