Wastewater treatment methods
1. Mechanical treatment method
Including preliminary treatment, sedimentation, and filtration processes. This method is often used in the pre-treatment stage to separate large floating objects, separate sedimented impurities from wastewater to ensure that pumps and pipes operate effectively without clogging and at the same time reduce pollution load. Works applying mechanical treatment methods such as: Trash racks, sand settling tanks, settling tanks, grease traps, and filter tanks
2. Chemical treatment method
Chemical methods used in wastewater treatment include: neutralization, oxidation and reduction. All of these methods use chemical agents and are therefore expensive. Chemical methods are used to remove dissolved substances and in closed water supply systems. Sometimes these methods are used as a preliminary treatment before biological treatment or after this stage as a final treatment method for wastewater discharged into the source.
3. Biological treatment method
Biological treatment method is to use the ability of microorganisms to live and work to decompose organic pollutants in wastewater. Microorganisms use organic compounds and some minerals as a source of nutrition and energy. During the nutritional process, they receive nutrients to build cells, grow and reproduce, so their biomass is increased. The process of decomposing organic substances by microorganisms is called biochemical oxidation. Biological treatment method can be carried out in aerobic conditions (in the presence of oxygen) or in anaerobic conditions (without oxygen).
Biological treatment method can be applied to completely clean wastewater containing dissolved or small dispersed organic substances. Therefore, this method is often applied after removing coarse impurities from wastewater with high organic content.
Biological treatment process includes the following steps
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Converts carbonaceous compounds in colloidal and soluble form into gaseous form and into microbial cell walls
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Creates biological flocs consisting of microbial cells and inorganic colloids in wastewater
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Removes flocs from wastewater by sedimentation.
3.1. Anaerobic biological treatment method
Anaerobic treatment is a method that uses microorganisms to decompose organic substances in wastewater. The product of completely decomposing organic compounds of the anaerobic treatment process is biogas, mainly CH4 and CO2, which can be used as fuel. Normally, this method is only applied to wastewater with high pollution content (BOD > 1800mg/l; SS ≥ 3000mg/l).
Anaerobic treatment works such as: UASB, EGSB, UAF, Cigar Lake...
3.2. Aerobic biological treatment method
Aerobic method is a method that uses microorganisms to oxidize organic compounds in wastewater. Normally, this method is only applied to wastewater with low BOD content (BOD < 1500mg/l)
Aerobic treatment works such as: Biofilter, SBR, Oxidation ditch, Aeroten, aerobic pond, ...
