Sludge doesn't have many microorganisms. What does that mean?

Answer 1

The low number of microorganisms in the sludge may have the following meanings:

** 1. Sludge is in a special stage **
1. ** Initial adaptation period **
- During the adaptation period of the growth process of activated sludge microorganisms, especially in the early stage, the microorganisms had just come into contact with a new environment and a new substance. They first absorbed but did not decompose. At this time, the microorganisms had not proliferated in large numbers, and the fermentation system was adjusting and changing. Although the individual had a tendency to increase, the number was small. This stage was the adaptation process of microorganisms to the new environment. The time was relatively short, usually 5 - 15 minutes, and because the number was too small, the increment was negligible in some cases.
2. ** Late stage of the intrinsic respiratory stage **
- During the intrinsic respiratory stage, F/M (the ratio of organic matter to the amount of microorganisms) was very small. The nutrients in the mixture were exhausted, and almost all microorganisms could only decompose the nutrients in the body to maintain life. As this process continued, the number of microorganisms continued to decrease, their activity became worse, and their cohesion and settling became better. Protozoa also appeared, and the amount of sludge gradually decreased. The treated water became clear.

** 2. Suppressed by environmental factors **
1. ** Nutrient imbalance **
- The growth of microorganisms in activated sludge required a balance of various nutrients, such as carbon, nitrogen, phosphorus, mineral salt, and growth hormone. Among them, carbon sources (CODs, BODs) were the most demanding. The nitrogen source was used to form the protein and the nuclear acid in the cells of the microorganisms. The phosphorus source was essential for the synthesis of phosphorus compounds such as protein and lysin, as well as metabolism, material and energy transfer. There were also some mineral salt involved in the composition of cell structure, energy transfer, control of protoplasts, and so on. If the nutrient ratio was not appropriate, such as the ratio of BOD5: N: P deviated from 100:5:1, the growth and reproduction of microorganisms would be inhibited, resulting in the number of microorganisms being difficult to increase or even decrease.
2. ** Dissolved oxygen deficiency or excess **
- For activated sludge microorganisms in an Aerobic environment, the dissolved oxygen concentration needed to be maintained at an appropriate level. If the dissolved oxygen is insufficient (less than 2 milligrams per liter), such as the presence of microorganisms that are adapted to low dissolved oxygen concentration such as Bayes 'sulfur bacteria, the growth of normal airborne microorganisms is limited, which may lead to a decrease in the number of microorganisms. If the dissolved oxygen was excessive and persisted for a long time, the activated sludge environment would change, which might also affect the survival and reproduction of microorganisms, resulting in the abnormal growth of the number of microorganisms.
3. ** The pH value is not suitable **
- The suitable pH value for the growth of activated sludge microorganisms is generally 6 - 9. Under special circumstances, the highest ph value of the incoming water can be 9 - 10.5. If it went beyond this range, it would affect the living environment of the microorganisms and suppress the activity of the microorganisms, thus affecting their growth and reproduction, resulting in a decrease in the number of microorganisms.
4. ** Abnormal water temperature **
- Microorganisms have their optimal growth temperature range, generally 10 - 45°C, and the optimal temperature is 15 - 35°C. If the water temperature was not within this range, for example, if the water temperature was too low or too high, it would affect the metabolism speed of the microorganisms, which would affect the growth and reproduction of the microorganisms, causing the number of microorganisms in the sludge to decrease.
5. ** Toxic substances exist **
- When toxic substances exist in sewage, protozoa react faster than bacteria to changes in environmental conditions. The impact of shock load and toxins on activated sludge can be observed by observing the changes of protozoa. Toxic substances would suppress the activity of microorganisms and pose a threat to the survival of microorganisms, resulting in a decrease in the number of microorganisms.

** 3. Other possible factors **
1. ** Sludge source or special nature **
- If the sludge came from some special treatment process or industrial waste water treatment, such as dangerous leather sludge with excessive heavy metal content, the microorganisms in this sludge may be difficult to survive and reproduce due to the toxicity of heavy metals, resulting in a small number of microorganisms. In addition, some sludges may have been specially treated, causing the original microorganisms to be removed or lose their activity, and the number of microorganisms would be very small.
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