The characteristics of activated sludge are judged by biological phase

Water world (WeChat chinaacitywater) introduction: In the activated sludge method, microorganisms bear the responsibility of decomposing and transforming pollutants, and there are many types, of which bacteria dominate, and the number can account for 90%-95% of the total weight; in addition, there are some protozoa and offspring. However, when observing the characteristics of activated sludge, bacteria can generally not be used as observation objects, and the more mature method is to observe the native and epiphytic animals in the activated sludge through the microscope, and use the type, quantity and activity of the proto-epizoan animals to judge the state and development of the activated sludge, so as to ensure the orderly operation of the process and adjust it in time.

In the activated sludge system, the proto-epizoan animals exist in the form of monomers, so when the impact load and the operating conditions of the activated sludge change, it usually fluctuates in activity, quantity and type, and it is of great significance in practice to judge the state of the activated sludge and the operation status of the process through these fluctuations.

1. Overview of protozoans of activated sludge

In the activated sludge system, according to whether the activated sludge is beneficial, the protozoa can be divided into: non-activated sludge, intermediate activated sludge protozoa, activated sludge protozoa. The first is usually the activated sludge system that fails during operation, and the parameter control is unreasonable before it will multiply and dominate. The second type generally exists in the transition stage from the early stage of systematic culture to the maturity of sludge or in the stage of activated sludge from improvement to improvement and from difference to good.

The number of offspring animals in the activated sludge system is generally not too large, and its presence has an indicative effect. In practice, when the epizoans are dominant, the activated sludge is often in an aging state.

The following is a simple collation of relevant exchange Q&A examples for your reference to study, exchange, classification is inappropriate and needs to be supplemented and improved, and I hope you will point it out more.

2. Exchange example Q&A

Question 1: In order to observe the sewage treatment situation, microscopic examination is necessary, so how many microorganisms (flagellar, nematode, bell worm, rotifer) are observed in the lml liquid during the test to indicate that the operation is good? Or does it work poorly?

Reply:

(1) The number of microorganisms is not key, because it fluctuates with MLSS value, temperature, and water composition; the focus is on whether the population proportion is coordinated.

(2) In addition, the quality of water quality treatment is not determined by a single index, and it is necessary to consider other indicators comprehensively, so as to enhance the accuracy of judgment.

Question 2: Biological phase observation: The absolute superiority of rotifers can explain any problems?

(1) Rotifers are offspring, which generally appear in the case of good water quality.

(2) If the rotifer appears in excess, it means that the activated sludge shows mild sludge aging, and the degree of aging can be determined with the sedimentation ratio supernatant.

Question 3: In the A2/O process, a large number of frills are generated in the biological filler, and the filling is a black polyethylene biological filler. What is the reason for the emergence of this creature? How to remove?

(1) Normal epizoans, which are also needed in the biological phase of the entire biofilm.

(2) There is no need to deliberately cope. Its presence facilitates the renewal of biofilms. Otherwise, the biofilm is too thick and the removal rate of pollutants is not high.

Question 4: I would like to ask you, is there a lot of fibrella worms and tired branch worms in the biochemical pool, and there are few bell worms, is it a precursor to sludge expansion? If so, could it be related to insufficient aeration?

(1) There are many bell worms or many tired branches, which is related to the composition of sewage.

(2) As long as the above two types of protozoa are dominant, the possibility of sludge expansion is unlikely.

(3) Lintels are sensitive organisms, and whether they grow dominantly or not has little to do with sludge expansion.

(4) As long as the aeration volume is not too high or too low, and lasts too long, it is not directly related to the expansion of sludge.

Question 5: What does the presence of caster worms in the sludge phase mean? Will the water quality deteriorate?

(1) The caster worm has not been heard of, and the common rotifers in the wastewater treatment process are rotifers, saddle beetles and pig-kissed rotifers.

(2) As far as rotifers are concerned, a small number of them appear to indicate that the sludge is in good condition, and if there is too much, it indicates that the sludge tends to age.

Question 6: What does it look like for a bell worm to grow a bag? Is it because it grows when it is attacked with poison?

I don't quite understand whether the sac is a bubble coming out of the bell worm's head. Usually for the following reasons:

(1) When microscopic observation, the coverslip is pressed too hard, which is caused by the compression of the bell worm body.

(2) The sample stays too long. After the death of the bell worm, the content is delivered.

(3) Caused by activated sludge poisoning.

Question 7:1 Can it be assumed that the presence of animal flagellars is a high load on the system? 2, I remember that when it is generally extremely aging, due to the defling of the bacterial gel group, it will also lead to an increase in the number of flagellar. 3, the aging situation should be increased to increase the discharge of mud to increase the water load, so that the number of flagellats will only be more, at this time the operation should generally be how to adjust? 4, in addition, the current system of ferrets and amoeba is also more, combined with the number of flagellar is very large, can it be considered that the sludge deflation is more serious, rather than high inlet water load?

(1) Yes, in general, the appearance of non-activated sludge flagellars is usually caused by high loads, and there are a few cases where the sludge disintegrates and the system deteriorates or recovers on the way.

(2) There are very few non-activated sludge flagellats that appear at this time, and they are not dominant.

(3) Generally there will be no situation you said, even if it appears, it is not dominant, and some can be tested sporadically.

(4) This is best combined with the load to judge, from the situation you said alone, I tend to load high caused, aging, non-activated sludge flagella is not dominant special supplement, flagellar is divided into non-activated sludge and activated sludge, if it is activated sludge, then there is no need to worry.

Question 8: When the activated sludge is made of SV30, if the supernatant is very turbid for a day, how to determine whether it is "sludge poisoning, sludge expansion, sludge aging, overload, excessive aeration"? In particular, how is "sludge poisoning" determined by observing SV30 and microscopy?

Inside the parentheses is the content judged by SV30

(1) Sludge poisoning: protozoa disappear, especially shield fibrella and bellworm (the whole is turbid, accompanied by scum, starting with most of the sinking, the remaining part sinks slowly)

(2) Sludge expansion: microscope can see filamentous bacteria (supernatant clear)

(3) Sludge aging: check the sludge concentration and observe the microscope for epiphytic animals. (Turbid, but the water between the particles is clear)

(4) Excessive load: check the sludge load and observe whether there are non-protozoans and vivid appearances according to the microscope. (Turbid, but the interparticle water body is also white and hazy)

(5) Excessive aeration: the on-site DO value to judge. (Fine particles).

Question 9: A month ago, a large number of foam appeared on the surface of the biochemical pool ditch, according to the amount of water, DO value, combined microscopy (more than 4-5 rotifers, 2 nematodes, fewer bellworms, more tubular worms, more filamentous bacteria and protruding bacteria outside the glue mass), the index is close to 120, inferred that the sludge is aging and the load is low. Gradually, the sludge performance is slightly improved by increasing the discharge, reducing the aeration, and increasing the load. After 5 days, the groove foam begins to disappear. However, after 10 consecutive days of high load impact, resulting in dissolved oxygen not rising, long-term maintenance of less than 1.5mg / L, microscopic examination found that the filamentous bacteria outside the bacterial gel group decreased, microorganisms from straw worms to nematodes all existed, SVI value rose to between 160-190. Are the active dots that appear on microscopy at high loads free bacteria? Is it possible to assume that the sludge swelling caused by the filament army in front of it is the expansion of non-filamentous bacteria caused by high loads? Is the increase in the number of tubeworms indicative of sludge aging?

(1) Not free bacteria, but protozoa (side jumpers or trichomoniasis), indicating a high load.

(2) It can be considered that the sludge expansion caused by the filament army in front of it is not easy to settle due to the high load and high sludge activity.

(3) Do not know which kind of barrel worm refers to, the general sludge aging microorganisms usually have epiphytes, shell worms and so on.

Question 10: How does the presence of a large number of case worms indicate the operating state of the system? Our project is now sludge age is certain, the load is about 0.1, some time ago due to long-term low-load operation problems, has now recovered, but the number of shell worms has increased a lot, what is the reason?

Generally, the system is characterized by low dissolved oxygen and low load, but the efficiency of the system organic matter processing will not have much impact.

Copyright notice: Please indicate the source, author; water world subscription number; WeChat ID: chinacitywater. If you do not add the source and author, you will do a plagiarism report!