Do you know about Microscopic examination of microorganisms?

Do you know aboutMicroscopic examination of microorganisms?

1. The systematic state of biological reaction

Its principle is to use microorganisms in activated sludge, protozoa and metazoa and other biological phases in the aeration condition of sewage organic matter decomposition into CO2+H2O.  For some inorganic substances, such as NH3-N, the energy generated during decomposition is used to grow and reproduce the microbes themselves.

Continuous sewage into the biological phase in the sewage growth and reproduction, and eventually formed a relatively stable with a certain degradation function of the ecosystem.  The formation of the stable ecological system from biofacies good growth environment, including organic load, temperature, ph, concentration of antibiotics, oxygen supply, etc., when the control factors in the sewage treatment system of change, all kinds of activated sludge biofacies, number and activity of so will change accordingly.

To a certain extent, the change of activated sludge biophase in the treatment system reflects the quality and state of the sewage treatment system.

Therefore, by observing the changes of biophase population and activated sludge quantity in sewage treatment system, the operation status and quality of the treatment system can be understood, and the operating conditions of the treatment system can be adjusted in time to change the biophase, so as to ensure the normal operation of the treatment system.  Biofacies observation in wastewater treatment system has been widely used in water treatment field.

2. Observation techniques of biofacies

1) Settling performance of activated sludge

Take fresh activated sludge, put it in 1000 ml measuring cylinder, stand for a certain time, carefully observe the sedimentation rate of sludge, whether the muddy water interface is clean, whether the supernatant is transparent, etc.

2) Biological phase observation of activated sludge

Before observation, the observed samples were mixed evenly, and 0.05ml samples and slides were absorbed with a large-caliber quantitative pipette (to ensure easy access to activated sludge). Cover the slides and place them under a microscope for observation.  At the beginning, the observation was made under the 100-fold field of vision, and the whole field of vision was looked around to have a preliminary understanding of the general situation of the biological phase of the sample, as well as the state, particle size, compression density of the flocs and the observed proto and metazoan populations.

Understand the largest species in the biofacies. To some extent, the largest species indicates the residence time of sludge.  When 100 times field observation is not clear, use 400 times field observation.  In particular, the position and number of the mouth, flagella, ciliate ciliate growth mode and filamentous bacteria growth of the biophase must be observed in a field of more than 400 times.

3. Observation details of biofacies

1) Structure of activated sludge

The physical and biological properties of activated sludge can objectively reflect the running state of sewage treatment process.

If the activated sludge is found to have large floc size, clear edge, compact structure and good adsorption and settlement performance during observation, it indicates that the sewage treatment operation is in good condition, mud and water can be separated well in the subsequent treatment process, and the effluent effect of sewage treatment is good.

Observe whether there is suspended matter SS in the water between the floc and the floc. If there is more suspended matter, it indicates that there is a lot of suspended matter in the sewage.  When the abnormal situation processing system, the structure of the sludge is loose, grain size, a large amount of the original, such as winding type ciliates metazoan, including paramecium, bean worm belongs to type, kidney worm, amoeba, trichomonad belongs to such as biological, shows that the processing system sludge settling performance is poor, spate separation effect is not good, affect the effect of water.

2) protozoan and metazoan indicators

Inlet load indication:

In the normal operation of activated sludge, the biofacies remained relatively stable, and the protozoa and metazoa were mainly in the genus Pelagida, Paestoma and rotifer.  When there are advanced metazoans such as bear worm and ladle worm, it indicates that the sewage inlet load is low. When the treatment system runs under low load for a long time and enters aging, rotifers, nematodes and other micro metazoans will appear.

At this point, the sludge load should be increased.  When the number of protozoa in activated sludge decreased significantly compared with the normal state, and some protozoa appeared in the low load state, such as zooids, disappeared without metazoa, it indicated that the influent load was too high, and amoeba and some small flagellates were dominant.  At this time, measures should be taken to reduce sewage inflow and sludge discharge to reduce sludge load and maintain the normal operation of the system.

Dissolved oxygen indication:

The protozoa of atoelia, sulfur bacteria, scutellaria and neozoa often occur when dissolved oxygen in activated sludge is insufficient.  At the same time, under the condition of high load and insufficient aeration, a large number of flagellates appeared.  At this time, measures such as increasing aeration should be taken to increase dissolved oxygen.  When dissolved oxygen is high, organisms such as amoebas, succulents and rotifers often occur.  At this time, measures such as reducing aeration and increasing sludge reflux ratio should be taken to improve sludge concentration and reduce sludge load.

Sewage acid alkaline indicator:

When the alkaline sewage is strong, turbidity of effluent water, disintegration of activated sludge, death and disintegration of protozoa and reduced treatment efficiency often occur, so acid should be timely added to neutralize.  When the acidity is too strong, the activated sludge treatment tank often has a sour taste, the treatment efficiency is reduced, and the activity of various biological phases is reduced. At this time, alkali should be added in time to adjust.

3) The indicator function of population changes of the same species

Sewage treatment system in the normal state of operation, the number and type of organisms contained in it is relatively stable, on the contrary, when the species and number of organisms occur large fluctuations, indicating that the sewage treatment system environment in the corresponding changes.

When the filamentous bacteria contained in the sludge appear in large numbers, it indicates that the sludge has expanded or will expand, including rhizobacteria, bescheri sulfur bacteria, Nocardia, mold, etc. Relevant measures should be taken in time to inhibit the growth of filamentous bacteria, adjust the treatment conditions of the system, and maintain the stable operation of the treatment system.

When the flocs are loose, the flocs become food for some rotifers.  With adequate feed, rotifers overreproduce.  In this case, sludge aging, the corresponding sludge disposal measures should be taken to eliminate the damage caused by sludge aging water treatment effect.  Protozoa and some microscopic animals are more sensitive to toxins than toxins.  Shielding fiber is an important index in activated sludge.  When this type of domestic sludge is rapidly reduced, it indicates the toxic substances in sewage.  It needs to be pretreated in time.

4) Combined with the actual analysis of working conditions

Activated sludge is a relatively stable ecosystem with certain degradation function. The formation of this stable ecosystem benefits from the good growth environment of biological phase. When the environmental conditions in the sewage treatment system change, the corresponding biological phase will also change.  The change of biofacies reflects the quality and state of sewage treatment system to a certain extent.

In the operation and management of sewage treatment system, the operation state of the treatment system can be studied by observing the biological phase change of activated sludge, and the problems existing in the treatment system can be found in time, and measures can be taken to ensure its continuous and stable operation.  Of course, in different regions and different sewage treatment plants, water quality and processing technology are different, sewage is various, and the biological phase of activated sludge will also be very different.

Therefore, in the work practice, we should refer to the specific situation, study the relationship between water quality change and biological phase change suitable for specific cases, so as to better guide the operation and management of sewage treatment plant by observing the change of biological phase.

4. Summary of the practice of biofacies

The structure (loose or not), state (normal or not) and color (brown is the best) of activated sludge in water samples were observed by microscope, while the number (how many), activity (active or not) and state (young, normal or old) of microorganisms in sludge were observed.  Generally, when the activated sludge is in a good state, there are more clock worms, tired branchworms, rotifers and nematodes with strong activity. If the volume is too small, it is young, and if the volume is too large, it is not conducive to the sludge performance.

1) purification performance of active sludge microorganism has the branch such as clock, insect, projecting fiber, fiber insect, pinch off and all kinds of metazoan and straw insect sessile organisms or prostrate creatures, such as when these several reached more than 1000 / mL, accounting for more than 80% of the whole biological individual number, can be concluded that the activated sludge with high purification effect.

2) When the purification performance of activated sludge deteriorates, the organisms that appear are polybosoma, trichomonad, house trichomonad, pea worm and other fast swimming organisms.  At this time the flocs are very broken about 100um laugh.  Only polybosoma and house trichomonad appeared in severe deterioration.  In extreme deterioration neither protozoa nor metazoa appear.

3) When the activated sludge recovered from the deteriorated state, the organisms appeared to be slow-swimming or creeping organisms such as macrosperms, oblique leaf worms, oblique tube worms and spiky caterpillars.  These microorganisms have been observed to become dominant for about a month.

4) During the disintegration of activated sludge fraction, the organisms appeared as slug metamorphosis, radiamoeba and other sucopods.  When these organisms appear more than tens of thousands of floccules become smaller, so that the treatment water turbidity.  When these organisms are found to proliferate, they can be curbed to some extent by reducing the amount of sludge returned and the amount of gas pumped.

5) The microorganisms that appear when the activated sludge bulges are jerseys and various molds, etc. These filamentous microorganisms cause the sludge bulges. When the SVI is above 200, these filamentous microorganisms are filamentous.  There were fewer micro animals in expanded sludge than in normal sludge.

6) When the dissolved oxygen is insufficient, the microorganisms are thiobacillus bainiensis and so on.  These microorganisms thrive at low concentrations of dissolved oxygen.  These microorganisms appear as black, putrefying and smelly activated sludge.

7) Microorganisms that appear when overaeration, if the overaeration time lasts for a long time, various amoebas and rotifers are the dominant organisms.

8) When the concentration of wastewater is too low, a large number of microorganisms appear, such as migratory worms.

9) Microorganisms that appear when BOD load is low.  Topshell worms, scales, rotifers and oligocaterpillars were the dominant organisms, and these organisms were also the indicators of nitrification for a long time.

10) Organisms that appear when shock loads and poisons enter.  Because protozoa react faster to the change of environmental conditions than bacteria, the impact of shock load and poison on activated sludge can be seen by observing the change of protozoa.  The most sensitive of the protozoans to impact load and toxicity is the projection worm; when the projection is drastically reduced, the impact load and a small influx of toxins occur.