To intercept large floating objects (such as branches, plastic bags, cloth) and suspended solids in sewage, preventing clogging of subsequent pipelines and equipment. Classified by bar spacing: coarse grilles (50-100mm), medium grilles (10-40mm), fine grilles (1-10mm). Classified by installation method: planar grilles, curved grilles.
To remove inorganic particles (relative density > 2.65) such as sand, gravel, and cinders with high density in sewage, avoiding wear on water pump impellers and clogging of aerators. Common types: horizontal flow grit chambers, vortex grit chambers, aerated grit chambers (with pre-aeration function).
A process that aerates sewage to cultivate a large number of suspended microbial communities (activated sludge), which adsorb and decompose organic matter in sewage. It is currently the most widely used and technologically mature aerobic biological treatment technology.
Aeration tank (core site for microbial growth and organic matter decomposition), secondary sedimentation tank (separates activated sludge from treated water), aeration system (provides oxygen and mixes sewage with sludge), sludge return system (returns part of the sludge to the aeration tank to maintain microbial concentration).
The process of introducing air (or oxygen) into the aeration tank. Core purposes: 1. Provide oxygen required for microbial metabolism; 2. Fully mix sewage with activated sludge to ensure sufficient contact between microorganisms and pollutants; 3. Maintain the suspended state of activated sludge to prevent sedimentation.
A²/O process, SBR process, CASS process, oxidation ditch process, CAST process, AAO-MBR process, etc.
Anaerobic-Anoxic-Oxic process. It can simultaneously remove organic matter, nitrogen, and phosphorus from sewage (i.e., "simultaneous nitrogen and phosphorus removal"). With compact structure and high treatment efficiency, it is one of the mainstream processes in municipal sewage treatment plants.
Sequencing Batch Reactor (SBR) operates cyclically in a single reactor, integrating five stages: influent, aeration (reaction), sedimentation, effluent, and idle. Advantages: small footprint, strong shock load resistance, no need for separate secondary sedimentation tanks and sludge return systems. Suitable for small and medium-sized sewage treatment plants and decentralized sewage treatment (such as towns and scenic areas).
The tank body is in the shape of a closed ditch, and sewage flows cyclically at a low flow rate (0.3-0.5m/s) in the ditch, combining the characteristics of plug flow and complete mixing flow. Advantages: stable process, strong shock resistance, simple operation and management, good sludge settling performance. Suitable for large-scale sewage treatment plants (daily treatment capacity > 100,000 tons).
The core difference lies in the existence form of microorganisms: In the biofilm process, microorganisms attach to the surface of carriers (such as fillers, filter media) to form a "biofilm", and pollutants are decomposed when sewage contacts the film. In the activated sludge process, microorganisms are suspended in sewage in the form of "sludge flocs". Additionally, the biofilm process has stronger shock resistance and less sludge production, but its treatment efficiency is slightly lower than that of the activated sludge process.
Biological filters (ordinary biological filters, high-load biological filters), rotating biological contactors (RBC), biological contact oxidation tanks, biological aerated filters (BAF), biological fluidized beds, etc.
Combines the advantages of the activated sludge process and biofilm process: Microorganisms attach to fillers in the form of biofilm, while sewage is in a flowing state through aeration, and some microorganisms are suspended. Advantages: high treatment efficiency, strong shock resistance, less sludge production, no need for sludge return, stable operation. Suitable for small and medium-sized sewage treatment.
Microbubbles (diameter 10-100μm) are introduced into sewage, and the bubbles adhere to the surface of suspended solids, making the density of suspended solids less than that of water, so they float to the water surface and are scraped off by a scum scraper. Applicable to treating suspended solids with density close to or less than water (such as oil, algae, fibers, fine flocs), especially suitable for oil separation of catering wastewater and decolorization pretreatment of printing and dyeing wastewater.
Chemical agents (such as lime, aluminum sulfate, ferric chloride) are added to sewage to react with pollutants to form insoluble precipitates, which are then separated by sedimentation or filtration. Commonly used to remove phosphorus (chemical phosphorus removal), heavy metals (such as copper, lead, zinc), and part of suspended solids, and can also be used for acid-base neutralization.
Further removes fine suspended solids, colloids, biofilm fragments, etc., from water, reduces effluent SS and turbidity, and improves water quality. Common filter media: quartz sand, anthracite, activated carbon, ceramsite, zeolite, etc. Classified by filtration method: rapid filters, slow filters, filter tanks.
Utilizes the strong adsorption capacity of the porous structure of activated carbon (specific surface area up to 500-1500m²/g) to remove trace organic matter, color, odor, heavy metal ions (such as mercury, chromium), and residual chlorine from water. Commonly used in advanced treatment (such as reclaimed water reuse) or treatment of refractory industrial wastewater.
Utilizes the selective permeability of semipermeable membranes (pore size 0.1-1nm) to allow water to pass through the membrane under pressure, retaining ions, organic matter, microorganisms, etc., in water. It can treat secondary effluent into high-quality reclaimed water (conductivity < 50μS/cm) for industrial circulating cooling, ultrapure water preparation in the electronics industry, landscape water supplementation, etc. It is one of the core processes of advanced treatment.
To kill pathogenic microorganisms (bacteria, viruses, parasite eggs, etc.) in sewage, preventing water pollution and disease transmission after sewage discharge. Common methods: chlorine disinfection (liquid chlorine, sodium hypochlorite), ultraviolet disinfection, ozone disinfection, chlorine dioxide disinfection.
An integrated process combining biological treatment (activated sludge process) and membrane filtration, using ultrafiltration (UF) or microfiltration (MF) membranes instead of secondary sedimentation tanks to separate sludge and effluent. Advantages: excellent effluent quality (SS close to 0), small footprint (30%-50% savings compared to traditional processes), high sludge concentration, strong shock resistance. Disadvantages: membrane fouling (regular cleaning required), high operating cost, high energy consumption.
Main products: biogas (main components: methane 50%-70%, carbon dioxide 30%-40%), digested sludge, and a small amount of digestive fluid. Biogas can be used as clean energy (power generation, heating, civil gas). After dewatering and stabilization, digested sludge can be landfilled, incinerated, or used for land application (must comply with the "Standard for Sludge Disposal from Municipal Wastewater Treatment Plants - Quality of Sludge for Land Improvement").
Upflow Anaerobic Sludge Blanket (UASB) reactor is an efficient anaerobic treatment equipment. Sewage rises from the bottom and fully contacts the anaerobic granular sludge in the reactor, where organic matter is decomposed. Suitable for high-concentration organic sewage (COD 5000-50000mg/L), such as beer wastewater, food processing wastewater, papermaking black liquor, slaughterhouse wastewater, etc. Advantages: high treatment efficiency, low energy consumption, large biogas production.
The combination of the two realizes "nitrogen removal" from sewage, solving the eutrophication problem caused by nitrogen pollution.
Utilizes the metabolic characteristics of phosphorus-accumulating organisms (PAOs): 1. Anaerobic phase: PAOs release phosphorus stored in their bodies and absorb organic matter in sewage. 2. Aerobic phase: PAOs multiply in large quantities and excessively absorb phosphorus from sewage (3-7 times that of ordinary bacteria). Phosphorus removal from sewage is achieved by discharging excess sludge rich in phosphorus (removal rate up to 70%-90%).
Further treatment after secondary treatment, aiming to improve water quality to meet reuse standards or strict discharge standards. It includes processes such as filtration (sand filtration, ultrafiltration), activated carbon adsorption, reverse osmosis, advanced oxidation (ozone oxidation, Fenton oxidation), nitrogen and phosphorus removal (chemical method), disinfection, etc., which need to be combined according to reuse requirements.
Industrial wastewater has a complex composition (such as containing heavy metals, toxic organic matter, strong acids and alkalis). Some substances (such as heavy metals, antibiotics) can inhibit or kill microorganisms in municipal sewage treatment plants, leading to the collapse of the biological treatment system. Pre-treatment can remove toxic substances, adjust pH value, and reduce pollutant concentration, making the water quality meet the acceptance standards of municipal pipe networks and avoiding affecting subsequent treatment.
Main pollutants: oil (animal and vegetable oil), suspended solids, high-concentration organic matter (COD up to 2000-5000mg/L), detergents. Treatment process: oil separator (removes floating oil) → DAF tank (removes emulsified oil and fine suspended solids) → equalization tank (adjusts water quality) → biological treatment (such as biological contact oxidation, SBR, decomposes organic matter) → disinfection and discharge.
Characteristics: large water volume, high chroma (caused by dyes), high organic matter concentration (COD 1000-5000mg/L), complex composition (containing dyes, auxiliaries, heavy metals, salts), poor biodegradability (BOD₅/COD < 0.3). Treatment difficulties: decolorization and removal of refractory organic matter (such as azo dyes, anthraquinone dyes). Combined processes such as chemical oxidation (ozone, Fenton), adsorption (activated carbon), and biological treatment (acclimated salt-tolerant microorganisms) are required.
The key focus is disinfection and sterilization to kill pathogenic microorganisms (bacteria, viruses, parasite eggs) and harmful microorganisms in sewage, preventing disease transmission. At the same time, it is necessary to remove organic matter, suspended solids, and drug residues. Treatment process: grille → equalization tank → biological treatment (such as activated sludge process) → sedimentation → disinfection (chlorine disinfection, ultraviolet disinfection) → discharge. A separate treatment system must be built, and direct discharge without disinfection is strictly prohibited.
If you need filter elements, please feel free to contact us! We provide 24/7 uninterrupted technical support to further help you optimize the selection plan. For customized filter elements tailored to your working conditions, please contact: +86 15936809132.
