How do these 7 representative protozoa guide the regulation of activated sludge systems?

Today, let's talk specifically about how the more representative 7 microorganisms in the activated sludge system guide the control of the activated sludge system.

1. Side jumper

As we said before, side jumpers are non-activated sludge protozoa. In other words, the appearance of side jumpers indicates poor water quality. Friends with operational experience may find that when the mirror has side jumpers, the number is usually huge, which indicates that your activated sludge system has the following failures:

(1) The load of the activated sludge system is too high

Usually, when the sludge load exceeds 0.25, the food of microorganisms is sufficient and it is in a logarithmic growth period. A large number of new bacteria are less flocculatory and free in water. These free bacteria happen to be the prey objects of protozoa such as side jumpers, so at this time, side jumpers multiply in large quantities.

(2) Activated sludge culture process

In the process of cultivating bacteria in activated sludge, when going through the transition stage (the proliferation stage of bacteria not affected by the amount of food source), a large number of inactive sludge protozoa are also generated, and the side jumper is a typical representative.

At this time, if a large number of side jumping insects is observed, it is not necessary to judge it as system deterioration or unqualified, but on the contrary, it can be understood as the active sludge is developing towards the normal stage, indicating that the culture is progressing smoothly.

(3) Activated sludge aging

In actual operation, microscopic observation sometimes reveals that in the case of extreme aging of activated sludge, a large increase in side jumpers will also occur. The reason is still related to the presence of free bacteria in the activated sludge, but the free bacteria at this time are generated due to the disintegration of the sludge.

To sum up, when a large number of side jumpers appear in the activated sludge, it can be concluded that the system is in an abnormal state, we need to change the control parameters of the operating system to adjust the operation of the system, and often observe the number of non-activated sludge protozoa in the activated sludge to judge its specific change trend.

2. Market insects

Epitustomers are mostly round and do not actively move, and observing a small amount under the microscope does not have special implications, but if more than 3 can be observed in a field of view, it is considered to be an abnormal increase in epidermis. At this time, it is necessary to check the operation status of the activated sludge system. The specific operating failures of the activated sludge are as follows:

(1) Low load

When there are large numbers of shell worms, it is usually the activated sludge under low load, especially when the sludge load is less than 0.05. Because the epidermal worm does not move autonomously, it has minimal energy consumption and is more able to maintain its reproduction under low load; at the same time, the activated sludge under low load is easy to dissolve the flocculent, which provides convenience for the feeding of epidermal worms. On the contrary, in practice, the presence of shell worms cannot be seen in several flats under high load of activated sludge.

(2) Activated sludge aging

The occurrence of activated sludge aging corresponds to the high probability of epiderma, and at the same time, the epidermal worm often shows a slight tan color, which is obviously different from the color transparency of the simple breeding of epituss under low load. The above is the performance of the activated sludge system when the epidermal insects are breeding in large quantities, mainly concentrated in the two points of low load and activated sludge aging, and the accurate functional state of the activated sludge can be comprehensively judged by combining the food micro ratio and the activated sludge sedimentation ratio.

3. Bean worms

Beanworms are precisely the least likely class of non-activated sludge protozoa we want to see, especially when they proliferate in large quantities, which are often accompanied by extreme deterioration of activated sludge.

To this end, even if a small number of bean worms appear, it is necessary to pay higher attention to it, confirm the control parameters of the activated sludge, and correct the wrong control parameters in time. At the same time, the inlet wastewater should also be monitored to confirm whether there is a situation that inhibits the growth of activated sludge. The specific operating failures of the activated sludge are as follows:

(1) The water quality of inlet wastewater fluctuates frequently

Where the proliferation of non-activated sludge protozoa in large numbers is dominant, it is related to the abnormal operation of activated sludge. The large number of beanworms is also related to abnormal fluctuations in inlet water, mainly in terms of water quality, such as the flow of chemical inhibitors and the concentration of low inlet organic matter. The main mechanism is that the minimum life limit of bean worms is better than other activated sludge organisms, when other protozoa are inhibited, often bean worms can still grow dominantly, on the contrary, when the system is stable, bean worms are excluded by the dominant growth of other protozoa, and their number will be quite rare.

(2) Activated sludge is extremely hypoxic

As explained in the first point, if the activated sludge is in an extremely hypoxic state, it can also be understood that most of the protozoa growth in the activated sludge will be extremely inhibited. We have found that beanworms are extremely tolerant of low dissolved oxygen states, so the presence of large numbers of beanworms can still be seen in low dissolved oxygen and extreme hypoxia. Here, not only bean-shaped insects, but among the non-activated sludge protozoa, the head-turnworm, the dark-tailed filaria, the kidney-shaped worm, etc. are all dominant protozoa that tolerate low dissolved oxygen and extreme hypoxia.

Here also need to extend a basic concept, that is, the ability of bacteria to tolerate extreme hypoxia conditions is much stronger than that of protozoa, often before the activation of activated sludge due to lack of oxygen and disintegration, most of the protozoa have disappeared, especially the disappearance of activated sludge protozoa is more obvious, and the non-activated sludge protozoa represented by beanworms can see its advantages.

Combining the above two points, the presence of beanworms often indicates that the system is in a poor operating state, and the key issue is whether the dissolved oxygen value and the water quality composition of the inlet wastewater are inhibitory substances or the concentration of substrates is too low.

4. Zori-moth

Grasshopper is a protozoa that we learned in middle school textbooks, and its body size characteristics are obvious, but in the microscopic observation of activated sludge, it belongs to a larger category compared with other protozoa, which is related to the general small size of non-activated sludge protozoa. However, we still classify it as a non-activated sludge protozoa. Its characteristics indicate activated sludge are as follows:

(1) Low dissolved oxygen state

The growth environment of grasshoppers tends to be low dissolved oxygen, and when we sample and analyze water samples in the field, we can often observe more grasshoppers in slightly blackened water, and blackened water bodies often indicate that we have insufficient dissolved oxygen. Therefore, when it is multiplied in large quantities, it is necessary to confirm whether there is insufficient dissolved oxygen in the activated sludge system.

(2) Low load state

In the case of activated sludge under low load and low dissolved oxygen, it is still relatively common for grasshoppers to multiply in large numbers. In practice, we have not found that there are cases where grasshoppers are dominant under excessive load conditions. Considering the above two points, we still regard grasshoppers as non-activated sludge protozoa, and their dominant reproduction often indicates that the activated sludge is in a state of low dissolved oxygen and low load.

5. Cowardly tube leafworms

As a typical representative of intermediate activated sludge protozoa, the cowardly tube leaf insect has a variety of characteristics of intermediate activated sludge protozoa, such as cilia around the body, soft body shape, moderate swimming speed and no bristles. As an intermediate activated sludge protozoa, the concept of its definition as intermediateness has been described in detail before, and it is mainly summarized as follows in terms of its specific corresponding operating state of activated sludge:

(1) Activated sludge is in the non-optimal operating stage

The conditions for the presence of intermediate activated sludge tell us that its presence is related to the presence of a large number of free fine bacterial micelles in the activated sludge mixture, and such an environment is an environmental condition for the proliferation of intermediate protozoa. Of course, if there is a large number of fine activated sludge flocs in the activated sludge mixture, the system is usually in a stage of deterioration or beginning to improve. Therefore, the presence of a large number of intermediate protozoa in the activated sludge mixture is a bad sign.

(2) The inevitable performance of the bacteriocultural stage

The cultivation stage provides conditions for the presence of intermediate activated sludge protozoa due to the dispersion of bacteria to the initial flocculation stage, and intermediate activated sludge protozoa can be observed in the bacterioculture stage for about 2 weeks (referring to non-inoculated culture bacteria).

Combining the above two points, the presence of cowardly tube leafworm is more accurate to judge that the activated sludge is in an abnormal state, and it is also an important reference for judging that the activated sludge will develop to an improved or deteriorating state, and it is also conducive to our early detection of problems at the level of activated sludge microscopy, and the necessary analysis is carried out accordingly to eliminate system failures.

6. Lintels

Liner fibrella is the first representative organism of activated sludge protozoa, because its body size belongs to the smaller class of activated sludge protozoa, it is extremely sensitive to changes in the environment, which is very beneficial to our use of linguide to judge the fluctuation direction and health status of activated sludge. The operating state of the activated sludge it is mainly manifested in the following aspects:

(1) Activated sludge operation state embodiment

When a large number of linguides are observed with a microscope (more than four in one field), the activated sludge is often in a better operating state, and the activated sludge at this time has good sedimentation, the supernatant is clear, the liquid level is free of scum, and the discharge water is clear without defusculating particles. In short, through the confirmation of the main control parameters of the activated sludge, it will be found that most of them are in a normal control state.

(2) Whether the impact load is reflected or not

The impact load, especially the impact of the sludge load, has a greater impact on the lintel worms, and the number usually decreases or disappears sharply, mainly due to changes in the operating environment. The environmental changes are mainly due to the presence of a large number of free bacteria in the mixture after the activated sludge is under impact load, which is not beneficial to the activated sludge protozoa, on the contrary, it will make the non-activated sludge protozoa multiply in large quantities. Therefore, the change in the number of linguides is very indicative for us to determine whether the activated sludge is subject to impact load. Of course, through the confirmation of the food micro-ratio, combined with the observation of cibrella, we can naturally accurately determine whether the activated sludge is affected by the load.

(3) Toxicity, inert substances affect the performance

It should be said that under a certain concentration, the inert or toxic substances flowing into the activated sludge system will cause greater or smaller effects on the protozoa, but in practice it can be found that the sensitivity of linguide to toxic and inert substances is particularly large, and often before other protozoa are inhibited, the lintelworm has been significantly reduced or disappeared, so it is used as a reference for judging whether the activated sludge is affected by inert and toxic substances.

Combining the above three points, the indication of the normal state of activated sludge is very obvious and operable, mainly manifested in the weak ability of linguide to tolerate the parameter change of the activated sludge system, and its number, activity, etc. will have a greater impact or even disappear directly when the system does not fluctuate much.

7. Bell worms

As a typical representative of the attached class in the activated sludge protozoa, the bell worm also has a good indication effect on the operating state of the activated sludge. This is mainly reflected in the attachment requirements of attachment protozoa and food sources. The operating state of activated sludge targeted by bell worms is mainly manifested in the following aspects:

(1) Flocculation of activated sludge flocs

The flocculation of activated sludge flocs directly affects the growth of attached protozoa represented by bell worms. The necessary basic condition for the growth of attached protozoa is the presence of their attachments.

We already know that the attachment of the attached protozoa is the fungal glue group, then, the morphology of the fungal glue group directly affects the growth of the attached protozoa on the glue group, and the typical situation is that when the bacteria glue group is dissolved, the attached protozoa will not be able to attach to the fungal glue group.

Especially when the fungal gel mass is small, it is not conducive to the reproduction of attached protozoa. When there is a small phenomenon of fungal glue, we find that its sedimentation is also very poor, such an operating environment is more common when the activated sludge is impacted by loads or the food micro ratio is too high, so the protozoa that dominate the growth at this time are non-activated sludge protozoa, rather than attached protozoa.

(2) Equilibrium performance of free bacteria in activated sludge mixture

From the morphology of the attached protozoa represented by the bell worm, it can be found that the cilia of its head are constantly active, the mixture around the body flows through its mouth, and the fine bacteria gum mass in the mixture is filtered, and the fine bacteria glue mass that is filtered and intercepted is swallowed and used as food.

However, attached protozoa have higher requirements for the activated sludge mixture around them. When free bacteria appear in the activated sludge mixture rather than fine bacterial micelles, the attached protozoa will not be able to use it as food, and the end result is that the attached protozoa will reduce their dominant number due to insufficient food sources.

Therefore, when the attached protozoa predominate, there must be fewer free bacteria in the activated sludge mixture, and there are a large number of fine bacteria micelles formed by flocculation of free bacteria. Then, the performance of activated sludge determines whether free bacteria can floccinate into fine bacterial gels.

It can be clear that a large number of free fine infested by the impact load, due to its extremely high activity and not easy to floccinate into fine bacterial micelles, only when the activated sludge is in a normal state, the new bacteria can gradually floccinate into fine bacterial micelles, and the fine bacteria mice can continue to floccinate into larger bacterial micelles, and the activated sludge generated according to this is judged to be normal activated sludge.

(3) Indications of toxic and inert substances

Attached protozoa can grow and reproduce well in their suitable environment and achieve their dominant growth. Attached protozoa are also more sensitive to inert and toxic substances. When the activated sludge is impacted by toxic and inert substances, the initial manifestation is weakened or inactive, and the bell worm is manifested as the cessation of cilia in the mouth, followed by the expansion of the in vivo expansion bubble, and the content flow out of the body. This is the initial performance of the bell worm on the toxic, inert substance, and later can be found that the number of clock worms declines rapidly, and if the microscopic observation period is long, it can be manifested as the sudden disappearance of the bell worm.

Based on the above three points, the special indication of the role of bell worms on activated sludge is mainly manifested in the flocculation performance of the bacterial glue mass, the number of free bacteria and fine bacteria micelles in the activated sludge mixture, and the influence of toxic inert substance flow on the attached protozoa, which has a high reference value for us to observe the status of the protozoa by using the microscope to observe the functional state of the activated sludge.