Biological treatment process

UASB – UPFLOW ANAEROBIC SLUDGE BLANKET

Microbial populations (mostly bacteria) will decompose into the organic matter in anaerobic condition (absence of oxygen) with the end product is a gas mixture consists of CH₄,CO₂, female₂, H₂S, CO, etc., in which methane CH4 is the main component.₄.

UASB includes 2 main zones: digestion zone and three-phase separation zone. Wastewater distributed from the tank bottom will flow through this anaerobic sludge layer in digestion zone, at which organic substances will be degraded by the anaerobic microorganisms. To keep the sludge layer in suspension and to create a favorable condition for granular sludge forming, up-flow velocity in UASB will be maintained in the range between 0.6 – 0.9m/h. UASB is often applied in industrial wastewater treatment with high COD concentration.

Structure of UASB tank in wastewater treatment

CONTINUOUS MIXING Anaerobic Biotreatment Technology (CSTR)

The CSTR technology includes a continuously stirred anaerobic digester followed by a degassing tank to remove excess biogas and a settling tank to separate the treated water and biomass. This technology is a good choice for anaerobic digestion of wastewater with high concentrations of suspended solids and COD, which can create flocs between biomass and suspended solids in influent wastewater through agitation. evenly throughout the tank. Thanks to this floc formation mechanism, the biomass and undissolved suspended solids will be collected at the bottom of the clarifier and then recirculated back to the CSTR tank to maintain the necessary microbial density and compost. further destroy this residue. With a large amount of biogas generated from the CSTR tank, usually a gas storage unit will be provided with this tank to store gas and fuel, serving the use of boilers or generators, helping to save energy. consumption for investors.

ANOXIC BIOGRAPHIC TREATMENT TECHNOLOGY

Microorganisms in anoxic tanks are capable of denitrifying from nitrate conversion into free nitrogen gas. This amount of nitrate is supplied from the aeration tank (placed before or after the anoxic tank) through the internal circulation pump system (if the anoxic tank is located before the aeration tank). Wastewater after denitrification at the anoxic tank will continue to be treated in the aerobic tank by oxidizing organic substances combined with nitrification.

Anoxic tank completed construction

TRADITIONAL Aerobic Activated Ball Technology (AEROTANK)

Under the condition of continuous aeration, while the aerobic heterotrophic microbial population will use organic compounds as a source of energy and carbon to synthesize new cells and produce inorganic compounds. as simple as CO₂ and THEY₂O, then the autotrophic microbial population will use CO₂ as a source of carbon and oxidize inorganic compounds for energy synthesis. The aerotank tank is the most popular biological treatment tank in the world, very suitable for the treatment of wastewater contaminated with biodegradable organic matter.

Aerotank tank has completed the construction (not installed the blower disc)

OXYGEN DOCK TECHNOLOGY (OD)

Oxidation ditch operation process diagram (Source: Greenerso)

Oxidation raceway is developed based on prolonged aeration technology. Low speed surface aerators or brush aerators are used both to provide the oxygen needed to support the biodegradation process and to keep the activated sludge in suspension by keeping the activated sludge in suspension. transport the mixed biomass running around the ditch. Thanks to the closed-loop raceway shape, the wastewater is recirculated around the ditch with a very high coefficient (> 20 times) without the use of any internal recirculation pump, the activated sludge microorganisms also decompose efficiently. results in organic matter and nitrogenous compounds through successive anaerobic and aerobic zones. This advantage of the oxidation raceway will help control the quality of COD and nitrogen outflow with very low operating costs.

Oxidation ditch completed construction

CODE ACTIVE BIOTECHNOLOGY (SBR)

SBR batch biotechnology is a suspended growth activated sludge technology in which the main treatment steps all occur in the same tank in alternate sequence without the need for a sludge settling tank. This advantage of the SBR tank can make the project investment cost more competitive than other technologies when applied to large capacity projects.

Operation process of SBR . tank

Reaction process Sedimentation process Water collection process

Reaction process: Wastewater is put into the reaction tank and mixed with biomass for biological reaction.

– Aerobic: Oxygen is introduced by aeration to meet oxygen demand to remove BOD and Nitrification.

– Aeration: Stop aeration and turn on the mixer to create anoxic conditions for denitrification.

Settlement Process: The Aerator and Mixer are turned off while the wastewater continues to react. A static condition is created in the main reactor zone for efficient sludge settling.
Water collection process: Treated wastewater is lowered to collect the final wastewater. A decanter will be used to remove the supernatant sludge from the tank. The system will then have a period called waiting time to refill the water in preparation for the next batch.

375m . capacity SBR treatment tank³/day in operation

SBR tanks can be designed and operated to enhance Nitrogen, Phosphorus and Ammonia treatment along with SS and BOD removal by optimizing anaerobic, anaerobic, aerobic and settling phases in the same cycle. .

With the flexibility in changing the time of the reaction cycle and the number of operating tanks, SBR technology is commonly applied in industrial wastewater treatment systems with a flow rate of up to 5,000m.³/day.

INTEGRATED TECHNOLOGY OF ACTIVE FLOORS AND MICROBIOTES ON CARDS (IFAS)

IFAS is a technology that combines suspended growth microorganisms and growth microorganisms attached to the substrate in the same reaction tank. Thanks to the addition of these substrates to the activated sludge system (for both anaerobic and aerobic tanks), the tank has a large number of microorganisms that adhere to the surface of the substrate, increasing the duration of the process. sludge retention time in the tank. The sludge layer on the substrate includes anaerobic microorganisms in the inner layer and aerobic microorganisms in the outer layer, which will help the process to effectively treat COD and nitrogen pollutants at the same time. With a higher density of microorganisms than traditional activated sludge systems, IFAS technology is very suitable for applications in:

New treatment station design with small area
Increase the capacity of the existing processing station
Improve the processing performance of the existing station

TECHNOLOGY OF MICRO-BIOLOGICAL TREATMENT WITH MOBILE BACK (MBBR)

Basically, the MBBR technology has the same structure as the IFAS technology mentioned above, which means it will also include an (anoxic tank, and) an aerobic tank followed by a sludge settling tank. However, the main treatment principle of the MBBR tank is developed based on biological filtration technology with decomposition based on the activity of adherent microorganisms while the IFAS tank includes both suspended growth microorganisms and sticky growth. Therefore, the settling tank in MBBR technology is only used for separating old sludge and residual sludge from the system without being recirculated back to the MBBR tank.

This advanced technology is designed with a special hydraulic regime to ensure that the movement of the media is evenly distributed in the reaction tank.

Along with the advantages of IFAS technology, MBBR has the following additional advantages:

Very compact system
Can withstand large load fluctuations
Very low sludge production
High and stable processing performance

Membrane Bioremoval (MBR)

MBR is a reactor that combines activated sludge technology and ultrafiltration membrane technology to produce high quality treated water. With this technology, the MLSS in the MBR tank can be maintained up to 15,000mg/l. MBR technology, which can be designed for both domestic and industrial wastewater treatment, has many operational and economic advantages when compared to traditional activated sludge technology, such as:

No need for secondary clarifier and higher treatment
Increased processing efficiency with small use area
The treated water can be reused for many purposes: irrigation, flushing toilets, washing cars, washing roads...

MBR tank is in the process of being installed