Densified Sludge Selector is easily integrated into various activated sludge treatment processes. By continuously screening out sludges, the system can alter the distribution of biological species, enhance biological denitrification and remove phosphorus, stabilize SVI, improve SV30, and effectively resolve sludge expansion issues caused by excessive filamentous bacterial growth in the biological reaction tank.
专精特新
核心技术
Easily installed on return activated sludge or waste activated sludge pipes for new or existing wastewater treatment plant.
Using physical methods to select activated sludge without chemical addition and running automatically.
Suitable for most activated sludge treatment processes, such as oxidation ditches, A2/O, CASS, CAST, MSBR, etc.
Return activated sludge (RAS) or waste activated sludge (WAS) flows into the sludge selector at a controlled speed along the tangent. Inside the selector, the mixed liquor undergoes rotational motion due to centrifugal force and the inner wall of the device. Heavier particles experience stronger centrifugal force, causing them to be propelled towards the wall and spiral downward, forming densified sludge that returns to the biological reaction tank. Lighter sludge particles and filamentous sludge tend to move upward along the axis and are discharged through the overflow port into the sludge concentration tank. Through prolonged selection, loosely bound filamentous bacteria and other lightweight sludge components are continuously removed, allowing denser sludge to accumulate and eventually forming densified or granular sludge.
Densified Sludge Selector removes flocculent sludge, free bacteria, and small bacterial aggregates with particles generally less than 200um, as well as filamentous bacteria. This type of sludge has a loose structure and density close to water, ranging from 1.03 to 1.04g/cm³.
Either the return activated sludge (RAS) or the waste activated sludge (WAS) mixture is allowed.
Densified sludge at the bottom is recirculated back into the biological system, with a density ranging from 1.04 to 1.10 g/cm³.
Aerobic granular sludge forms by microorganisms self-aggregating, resulting in granular-shaped activated sludge. This type of sludge enhances sedimentation performance, settling at over three times the rate of typical flocculent sludge, enabling bioreactors to achieve sludge concentrations of up to 12,000 mg/L. Synergistic interactions among microorganisms greatly boost treatment efficiency.
AGS is a three-dimensional layered microbial community comprising various organisms like polyphosphate-accumulating organisms (PAOs), ammonia-oxidizing bacteria (AOB), nitrite-oxidizing bacteria (NOB), heterotrophic denitrifying bacteria, and even anaerobic ammonia-oxidizing bacteria (Anammox). This system significantly boosts the removal of nitrogen and phosphorus. With its fast settling speed, abundant biomass, and impressive nitrogen and phosphorus removal capabilities, aerobic granular sludge shows remarkable resilience to shocks and toxins.
As time progresses, the morphology and distribution ratio of aerobic granular sludge changes, as illustrated in the figure above. The proportion of small and large granules remains relatively stable during the slow growth phase. However, it notably increases during the granule formation phase, continuing to rise with the overall expansion of the total sludge, and eventually reaching stability.
Particles such as flocculent sludge, free bacteria, small bacterial clusters, and filamentous bacteria typically have sizes smaller than 200 micrometers. They exhibit a loose structure and a density close to that of water, ranging from 1.03 to 1.04 grams per cubic centimeter.
Densified sludge falls between floc sludge and granular sludge in morphology, exhibiting some characteristics of granular sludge but not fully formed into granules.
Aerobic granular sludge is essentially another form of fixed biofilm, appearing as relatively uniform spherical or oval shapes. These granules typically range in size from 0.1 to 3 mm, occasionally reaching 5 mm, with a density of 1.04 to 1.10 g/cm3, slightly heavier than water.
By selecting optimal microbial populations, the sludge selector improves settling, increases microbial concentration, enhances nitrogen and phosphorus removal, improves effluent quality, and boosts treatment capacity.
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