Activated sludge, as the main carrier in the activated sludge process, appears as yellow brown flocs in appearance. This floc is composed of a large number of microbial communities, with a huge surface area and strong adsorption performance, making it easy to precipitate and separate water, thus purifying and clarifying wastewater. The application of micro nano bubble technology in activated sludge process has broad prospects, which can provide more efficient and environmentally friendly solutions for sewage treatment.
01 What is Activated Sludge Process
Activated sludge process is a method of biological treatment of wastewater. Under artificial oxygenation conditions, sewage and various microbial communities are continuously mixed and cultured to form activated sludge. Utilize the biological coagulation, adsorption, and oxidation of activated sludge to decompose and remove organic pollutants from wastewater. Then separate the sludge from water, with most of the sludge flowing back to the aeration tank and the excess being discharged from the activated sludge system.
02 Composition of Activated Sludge
1. Active microorganisms
2. Residue of microbial self oxidation
3. Composition of organic and inorganic substances adsorbed on activated sludge that cannot be biodegraded
Microorganisms are the main component of activated sludge. The microorganisms in activated sludge are an ecosystem composed of various microbial communities such as bacteria, fungi, algae, protozoa, and metazoa.
03 Properties of Activated Sludge
Color: usually yellow brown,
Odor: earthy smell,
Status: Like alum floc like particles,
Particle size: generally 0.02-2mm, moisture content is generally 99.2-99.8%, density varies depending on moisture content.
Specific surface area: 20-100cm2/ml
Bacteria are the center of the composition and purification function of activated sludge, and are the most important part of microorganisms.
04 Biological Species Involved in Wastewater Biological Treatment
There are many types of organisms involved in wastewater biological treatment, including the following:
① Bacteria ② Protozoa ③ Algae ④ Metazoa
Bacteria: Among the biological communities utilized in wastewater treatment, bacteria are the smallest in size. It can decompose and absorb various organic compounds under both aerobic and anaerobic conditions. There are several strains of bacteria that play a role in the biological treatment of sewage, including bacterial flocs, jersey bacteria, nitrifying bacteria, denitrifying bacteria, and polyphosphate accumulating bacteria.
Microbial flocs: In all aerobic biological treatments, they are the main organisms that form biofilms and biofilms.
Jersey bacteria: They multiply in large quantities in activated sludge, causing it to swell and posing a threat to wastewater treatment.
Nitrifying bacteria: bacteria (including ammonia oxidizing bacteria and nitrite oxidizing bacteria) that oxidize ammonia nitrogen to nitrite and nitrite to nitrate under aerobic conditions.
Denitrification bacteria: Under anaerobic conditions (without dissolved oxygen), they can use the oxygen in nitrate (bound oxygen) to oxidize and decompose organic matter, reducing nitrite or nitrate to nitrogen gas.
Polyphosphate accumulating bacteria: Under anaerobic (no dissolved oxygen, no nitrate and nitrite) and aerobic alternating conditions, they have an excess uptake capacity for phosphorus.
05 Process of Activated Sludge Degradation of Organic Matter in Wastewater
The removal (degradation) of organic matter by activated sludge during aeration can be divided into two stages:
Adsorption Stage 1
Due to the large surface area of activated sludge and the presence of viscous substances such as polysaccharides on the surface, organic matter in wastewater is transferred to activated sludge.
Stable Stage 2
The organic matter mainly transferred to activated sludge is utilized by microorganisms.
When using activated sludge method to treat sewage, it is necessary to pay attention to the effects of factors such as sludge load, suspended solids in the mixed solution, sludge settling ratio, and sludge volume index on the degree of sludge looseness (activity) and coagulation and settling performance.
The application of micro nano bubbles in activated sludge process is mainly reflected in the following aspects:
Improving aeration efficiency: The high specific surface area and slow rising speed of micro nano bubbles can significantly increase aeration efficiency, thereby improving the treatment efficiency of activated sludge process.
Improving gas-liquid mass transfer: Micro nano bubbles can improve gas-liquid mass transfer, promote microbial growth and activity, thereby enhancing the biodegradability of sludge.
Pollutant removal: Micro nano bubbles can effectively remove pollutants such as organic matter, heavy metals, and microorganisms from water, improving water quality.
Environmental remediation: Micro nano bubble technology can be used for ecological restoration of rivers and lakes, cleaning of marine oil pollution, and achieving rapid cleaning and remediation of polluted environments.
The XINOZONE micro nano bubble generator integrates current domestic and foreign micro nano bubble generation device technology and manufacturing processes. After years of practical testing and engineering applications, it fills the gap in domestic nano to micro bubble generation devices and achieves a breakthrough from laboratory to industrial promotion and application.
The principle is to make the gas and liquid highly miscible and mix, using a dynamic high-speed shear device to chop the bubbles in the gas-liquid mixture. Due to the strong shear force of these components, the bubbles can be chopped to tens of nanometers to several micrometers, ultimately forming milky white micro nano bubbles. This method can balance gas-liquid mixing and micro bubble generation, and has the characteristic of gas-liquid process enhancement.
The characteristics of XINOZONE micro nano bubble machine include adjustable flow rate, multiple external gas sources, and the ability to provide integrated machines (micro nano ozone integrated machine, micro nano oxygen integrated machine).
The bubbles are fine and the dissolved oxygen is high, the bubble concentration is adjustable, and it can work continuously for 24 hours.
