Municipal sewage treatment and organic industrial wastewater treatment usually use the activated sludge method. Activated sludge is a collection of microorganisms such as bacteria, mold, algae, protozoa, rotifers, nematodes, etc. After the pollutants are adsorbed by the activated sludge, they become a source of nutrition for these microorganisms, which are absorbed and removed.
The activated sludge method mainly makes these microbiota-sludge in contact with the drainage in a floating state and treats them. Contact aeration treats sewage by attaching these microbiota to the contact material.
Below we will introduce you to the actual appearance of the organisms related to wastewater purification. Since the chromosomes of microorganisms are very complex, we use a special illumination method to photograph the survival of microorganisms through a microscope. Activated sludge is a collection of various microorganisms (small particles, visible to the naked eye) that form around a bacterial population called the animal flora.
In the activated sludge method, the propagation of filamentous bacteria affects the drainage and separation effect of the sludge, which is called "accumulation". Filamentous bacteria in attached sludge are not problematic, and it is difficult to avoid the appearance of filamentous bacteria. In this case, the attached sludge has good adsorption of organic matter (polluting substances) in the drainage. Just like regular activated sludge. It takes only 30 minutes to remove 70 to 80 percent of the organic matter in drainage. apart. Through this adsorption, more than 90% of the organic matter is removed. The former (activated sludge) adsorption is considered a physical phenomenon caused by colloidal gravity, ion exchange, and the gravitational pull of different charged electrons, etc., while the latter (adhered sludge) adsorption is thought to be caused by the use of biochemistry. Various protozoa can be seen under a microscope. These protozoa can basically be divided into five categories, namely succulents, flagella, ciliates (free-swimming type), ciliates (stalked), and straw worms.
Meaty
Fleshy protozoa move mainly through pseudopods. And if this protozoa appears in large quantities in the activated sludge, it may reduce the cohesion of the activated sludge. Its nutritional intake form is mainly dependent nutrition.
Amoeba (genus name)
Pseudopods are leaf-shaped. It has a so-called amoeba shape. A large number of these protozoa can make the discharged water dirty. The prosthetic foot is leaf-shaped or finger-shaped. The shell is made of transparent chitin and ranges in color from colorless to brown. When viewed from above, the shell is round, and when viewed from the side, the shell is hemispherical. They can usually be seen in activated sludge.
Flagellates
Each individual of this protozoa has 1 to 4 flagella, and depending on the species, sometimes more than 4 flagellars are present. Usually they appear when the sewage treatment plant starts to operate. Its types are mainly independent nutrition and dependent nutrition.
Marsula spp. (genus name)
The slender body has flagella. It is mostly found in stagnant water areas and often in sedimentation tanks.
ciliates
The flagella of this protozoa is equivalent to the organ of a motor cell. For dependent nutrition, it is mainly found in sewage treatment plants. Two to three of these animals are known for their activated sludge cilia. Ciliates are very common in sludge, and certain ciliates can be used as biological indicators for judging the quality of sludge.
Worm (genus name)
Its shape is an oval body with no curvature and a flat surface of the abdomen. There are protrusions on the back and rippled stripes in the longitudinal direction. The circumference of the mouth is a very wide triangle with a flat groove in front. Occurs when the concentration of sewage is extremely low. The worm has cilia at the front end, which absorb food from the ear by stimulating an electric current. Usually survives by attachment, and the body opens or tapers as it unfolds. It is oval or pear-shaped when swimming.
Zori-moth (genus name)
The body of the worm is made up of cilia. This genus mostly occurs in the premature stage or initial sedimentation tank of activated sludge. In activated sludge, grasshoppers usually appear when the nature of the sludge is poor.
Monarch (genus name)
Its body consists of calves with discontinuous filaments and forms groups. The stem of the worm does not need to expand and contract at the same time, and each cell can expand and contract completely independently. Occurs when activated sludge has good performance.
Coverworm (genus name)
There is a small chamber at the front of the stem of the non-farsighted branch of the genus, and the perimeter of this chamber is unique. It can usually be detected in sewage with a large amount of feces and urine, or in activated sludge in the form of separated liquids.
Straw worms
The species is hairy. Depending on the type, the shape is spherical, conical, cylindrical, or irregularly branched trees. It is characterized by: adults have straws and cilia will be lost. Most worms have stems, but depending on the type, there may be worms with no stems. The handle structure does not have to be homogeneous, but it does not have to be telescopic. Depending on the raw water, some activated sludge will have a considerable number of of worms, so this protozoa as a water quality indicator organism will be of concern in the future.
Foot straw worm
Its shape is hemispherical and usually has a stem. The straw was completely scattered among insects, or may have settled in some places.
Hammer straw worms
Pear-shaped or triangular pyramid-shaped, shellless. The straw settles in 1 to 4 positions on the anterior surface of the worm body, and the stem is not raised.
Rotifers
Rotifers are more advanced animals than the above microbes and can only multiply under dissolved oxygen of a few ppm. The main source of nutrients is bacteria, but smaller organic particles can also be ingested. Rotifers can only breed in low-load processing equipment. Only when the quality of the discharged water is excellent, the rotifers will breed in the treatment plant.
algae
In the general activated sludge method, it is difficult to imagine that algae will multiply in the environment of an aeration tank. Even if it appears, it will fall off the sludge in the final sedimentation tank and end up only mixing into the returned sludge. Conversely, in the adhesion bioaeration method, a large number of diatoms and green algae can be attached to the contact surface of the surface part.
Microorganisms (decomposing fungi, cyanobacteria, green algae, protozoa) that appear in sewage treatment are used as indicator microorganisms for the maintenance and management of sewage treatment plants, or their relationship to the purification mechanism in the activated sludge method. It is often used for research. Research in this area is not mentioned at the moment, but it cannot be said that the classification or physiological study of microorganisms associated with wastewater purification is very comprehensive, and it is expected that further research will be carried out in the future. Due to the peculiarities of microorganisms attached to the contact material, the attached bioaeration method makes it a preferred microbial method different from activated sludge. The subsidiary bioaeration methods have also made many achievements in high drainage and intermediate waterway drainage. Qianjie Biological is a company specializing in sewage treatment, heat and environmental protection industry, agricultural and aquatic industry, thinking about uniqueness, keeping up with the development of society, science and technology is the purpose of creativity, into the test, research and development, and finally developed a variety of environmental sewage treatment, river treatment and so on