Abstract:Biological treatment of sewage is a method of water treatment that utilizes the metabolic reactions of microorganisms. Microbial monitoring is an important means of analyzing pollution conditions, assessing treatment effectiveness, and conducting emission testing during the treatment process. This article introduces the application example of our M500 multifunctional biological monitoring instrument in microbial monitoring in sewage biological treatment, and elucidates the important significance of our multifunctional biological monitoring instrument in microbial monitoring.

Keywords:Wastewater treatment; Colony count; Microbial microscopy examination; Algae; Zooplankton; biological monitoring

Wastewater treatment plays a crucial role in maintaining the ecological environment. At present, the commonly used methods for sewage treatment can be classified into physical methods, chemical methods, and biological methods. Physical methods are often used as a pretreatment method in wastewater treatment; Chemical treatment refers to the process of adding chemical agents such as alum to wastewater, which react with pollutants to produce harmless substances; The biological method mainly focuses on the treatment of sewage by microorganisms, using the decomposition effect of microorganisms to convert organic matter in sewage into simple inorganic substances, thus purifying the sewage. Compared with physical and chemical methods, microbial treatment has the advantages of economy and can achieve harmless and resourceful treatment, so it has always played an important role for a long time^[1].

In sewage treatment, microbial monitoring can not only analyze the pollution status and the basis for discharge water quality testing, but also indicate the effectiveness of activated sludge. Based on the biological characteristics of protozoa and their species, quantity, activity, and other performance under different environmental conditions, the analysis of their composition and quantity can provide useful indicator information for activated sludge treatment processes.

For the monitoring of microorganisms in wastewater treatment, the fully automatic colony counting analysis software, microscopic image analysis system software, algae intelligent identification and counting software, and planktonic animal counting software in the Xunshu M500 multifunctional biological monitoring instrument can effectively assist in the observation, counting, analysis, and monitoring of bacteria, algae, protozoa, rotifers, crustaceans, and other microorganisms in wastewater treatment.

1Application of Bacterial Detection

At present, the current national water quality standards mainly use total coliform bacteria or fecal coliform bacteria as biological indicators, and there are also various pathogenic microorganisms in sewage. example

For example: Salmonella, Shigella, mold, yeast, Toxoplasma gondii, etc^[2]The number of bacteria in activated sludge is about 108-109 per mL. The most commonly occurring dominant populations are: alkali producing bacteria, Bacillus, and Flavobacterium, followed by Nocardia, nitrifying bacteria, Escherichia coli, etc. The main methods used in sewage bacterial detection include pouring method plate, coating method plate, filter membrane method plate, air settling method plate, etc. The rapid counting colony counting software can support various types of colony plates mentioned above.

1.1 Application of rapid colony counting technology

The instrument adopts a variable light ratio wide band floating dark field technology, equipped with a 10 megapixel CMOS and high-definition lens. Using optical principles, it forms an extremely clear spatial stereoscopic image effect of colonies, improving the contrast between colonies and the background, the recognition of small colonies, and the differentiation of impurities. Widely used in disease control, inspection and quarantine, food and drug safety inspection, environmental water quality monitoring, scientific research and other fields.

1.2 software application

1.2.1colony counting

Xunshu's Colonfast colony image intelligent recognition technology can identify complex colonies and quickly detect bacteria such as Escherichia coli and Staphylococcus aureus that have specific colony colors and shapes on color media. It achieves fully automatic colony counting, colony morphology analysis, adhesive segmentation, automatic color recognition, automatic impurity removal, as well as advanced functions such as morphology analysis, automatic conversion, measurement, and calibration. The speed of automatic colony counting is higher than 500 colonies per second, and the smallest distinguishable colony diameter can reach 0.01mm.

2 Application of Microbial Microscopy Inspection

In the laboratory of sewage treatment plants, microbiological microscopy testing has become one of the increasingly important projects in recent years. Counting and observing microorganisms, especially indicative microorganisms, is particularly important. Indicative microorganisms refer to microorganisms that are easy to observe under a microscope in wastewater treatment and have a good reflection of the state of activated sludge. Due to the different processes of sewage treatment plants and the varying composition of incoming wastewater, the dominant indicative microorganisms in each plant and process are also different^[3]The microorganisms in activated sludge mainly include bacteria, protozoa, and algae, as well as fungi, pathogens, and so on. Bacteria are the main actors in decomposing organic matter in microorganisms, followed by protozoa who also have a certain degree of decomposition. The Xunshu multifunctional biological monitoring device is equipped with a powerful microscopic image analysis system, which can help users observe and count microorganisms in sewage and activated sludge.

2.1 Application of Rapid Numerical Microscopy Technology

The Xunshu Microscopic Image Analysis System consists of high-sensitivity color CMOS, powerful microscopic image analysis software, and

The microscope is widely used in various application fields such as microscopic cell image analysis, industrial metallographic structure analysis, dust and particle detection, and material microstructure observation.

2.2 software application

2.2.1High definition dynamic and static dual channel observation

The system has "dynamic and static dual parallel observation technology", which can conveniently adjust the microscope and CMOS to synchronize and intuitively display dynamic microscopic images with the computer, and also observe high-definition static images at the same time. In addition, the system also has 27 image processing functions, allowing users to obtain high-quality microscopic images of target objects.

2.2.2Cell particle count

The software has the function of automatic counting of cell particles (automatic statistics, classification statistics, color recognition statistics, region statistics, adhesion segmentation statistics, etc.). For cells or particles with clear contours (such as cocci, bacilli, spores, etc.), it can achieve automatic counting of the entire field of view within 1 second. It makes up for the shortcomings of the traditional manual counting method with the naked eye, improves statistical efficiency, and makes cell and particle counting work simple and easy, achieving twice the result with half the effort.

2.2.3measurement

The system comes with measurement tools that can automatically analyze parameters such as diameter, area, perimeter, and roundness of the target object, as well as measure characteristic parameters such as lines, angles, circular area, arc length, and arbitrary curves. Especially the arbitrary curve measurement function has brought great convenience to the research of actinomycetes, molds, and algae. The system can also achieve editing and embedding functions for both Chinese and English text as well as various graphics.

3 Observation and Counting Application of Algae

With the intensification of human activities, a large amount of industrial wastewater, domestic sewage, and agricultural wastewater containing nutrients such as nitrogen and phosphorus enter the water body, leading to eutrophication of the water body. This causes algae, especially some planktonic algae, to proliferate in large numbers, forming algal blooms or red tides, which have a serious impact on fisheries and human life^[4]Therefore, the role of algae in biological monitoring is increasingly being valued by people. Algae, as the primary producers of ecosystems, make significant contributions to water quality monitoring and sewage treatment. They can sensitively and accurately detect changes in the external environment, and based on community characteristics such as the types and quantities of aquatic algae, they can determine the pollution situation of water bodies. At the same time, in sewage treatment, algae can absorb and remove harmful substances from sewage, purifying water quality.

Algae monitoring in sewage treatment is not only an analysis of water pollution status, but also a test of sewage purification effect. The algae intelligent identification and counting software of the multifunctional biological monitoring device can observe, identify, count, and analyze algae in detail, providing a convenient channel for experimenters and researchers to detect algae.

3.1 Application of Fast Counting Algae Technology

3.1.1Algae observation and counting process

3.1.2Algae software functions

The algae software contains an information rich algae database, which includes textual descriptions, characteristic images, and exquisite microscopic photos of 11 phyla, 672 genera, and 3350 species of algae. The freshwater algae library basically covers common species in China's seven major water systems and 28 key lakes and reservoirs, while the marine algae library mainly focuses on common planktonic algae in the East China Sea, Bohai Sea, Yellow Sea, and South China Sea.

The software has taxonomic search, common algae search, and keyword search functions. The intelligent search and identification function can quickly compare and identify the algae that need to be identified with the algae in the image library through two levels of morphological search, and achieve precise analysis of parameters such as algal population area, cell diameter, algal filaments, branching angle, etc

Accurate measurement; Fully automatic recognition and counting of certain single celled algae, such as Chlorella vulgaris.

The software includes an independent analysis module for Microcystis and other clustered structured algae. The analysis module can automatically detect and calculate the number of cells in Microcystis aeruginosa and other clustered algae, and accurately count and analyze the clustered algae species.

4 Observation and counting application of planktonic animals

Most sewage treatment plants improve their secondary sewage treatment process through activated sludge process. Activated sludge is a complex ecosystem composed of various bacteria, fungi, algae, and protozoa, among which protozoa play a role in improving water quality, evaluating and indicating the operation and treatment efficiency of sewage plants. Directly observing the composition, quantity, and physiological changes of protozoa can reflect the growth and changes of bacteria, indirectly evaluating the quality of sewage treatment processes and treatment effects, and thus guiding production operations^[5].

The Xunshu multifunctional biological monitoring device includes professional zooplankton counting software, which can observe zooplankton in detail. The software integrates more than 1500 types of microscopic photos, hand drawn images, and textual introductions of planktonic animals, which can assist in the identification of planktonic animal species and quickly achieve high-definition imaging, classification and counting, automatic total accumulation, and dominant species sorting of planktonic animals.

4.1 Application of rapid counting zooplankton detection and analysis technology

4.1.1Counting process of planktonic animals

4.1.2Function of zooplankton counting software

The software's process based counting can achieve classification and statistics, total count statistics, automatic calculation and sorting of dominant species, and abundance conversion of planktonic animals. The database has 6 major categories, 460 genera, and 1500 species of planktonic animals with characteristic text descriptions and images. It can be quickly searched based on class, genus, and species classification, as well as Chinese and Latin names. By using a digital ruler, the length, width, and other numerical values of planktonic animals can be intuitively measured, making it convenient for operators to directly observe and conduct preliminary morphological analysis of planktonic animals.

5 Conclusion

Wastewater treatment is a long-term and arduous task. The observation and detection of microorganisms, algae, and planktonic animals are important aspects of wastewater biological treatment, which can provide an objective and truthful evaluation of the treatment effect. The Xunshu multifunctional biological monitoring instrument helps detection personnel simplify tasks, enabling observation and counting of bacterial colonies, microscopic analysis of microorganisms, and monitoring of algae and planktonic animals. It effectively ensures the smooth progress of sewage treatment work and provides stable and reliable data and information for water environment safety assessment and sewage quality purification.