Basic concepts of sewage treatment

It is also possible to borrow the concept of unit operation and unit process in chemical engineering to divide various treatment processes into two categories: unit operation (which does not produce chemical reactions, such as liquid transport, precipitation, filtration, reverse osmosis, etc.) and unit process (which produces chemical reactions, such as coagulation, disinfection, chemical precipitation, biological oxidation, etc.).

Typical process

The process of making finished water from ordinary river water. ② The process of making finished water from heavily polluted river water. (3) The process of producing high purity water from urban water supply. ④ Also remove iron, manganese well water treatment process. (5) Biological wastewater treatment process. The process of physical and chemical treatment of wastewater.

Water treatment technology

Sewage treatment generally includes the following three levels of treatment:

Primary treatment is to remove the stones, sand and fats, iron ions, manganese ions, fats and so on contained in the sewage through mechanical treatment, such as grille, precipitation or air flotation.

Secondary treatment is biological treatment, where pollutants in sewage are degraded and converted into sludge under the action of microorganisms.

Tertiary treatment is the advanced treatment of sewage, which includes the removal of nutrients and the disinfection of sewage by chlorination, ultraviolet radiation or ozone technology. Depending on the target of the treatment and the quality of the water, some sewage treatment processes do not include all of the above processes.

Treatment method

water treatment is the process of using physical, chemical, biological and other methods to improve the water quality of source water or water that does not meet the water quality requirements. Water treatment can be summarized in three ways:

① The most commonly used is to obtain the required water quality by removing part or all of the impurities in the raw water;

② By adding new ingredients in the raw water to obtain the required water quality;

The processing of raw water does not involve the removal of impurities or the addition of new ingredients.

Softened water treatment:

Treated with a chemical "resin", such as hard water to soften. Common wastewater treatment technology Biological chemical method, such as Activated Sludge Process (Activated Sludge Process), biological stratification method (Fixed Biofilm Processes), mixed biological Processes (Combined Biological Processes) and so on; Physicochemical methods, such as Granular Media Filtration, Activated Carbon Adsorption, Chemical Precipitation, Membrane Processes etc.; Natural treatment methods, such as Stabilization Ponds method, Aeratedor Facultative Lagoons method, Constructed Wetlands method, chemical color Coxex resin treatment method.

Water treatment method

Water treatment process:

Sewage treatment generally includes the following three levels of treatment:

Primary treatment is to remove the stones, sand and fat and grease contained in the sewage through mechanical treatment, such as grille, precipitation or air flotation.

Secondary treatment is biological treatment, where pollutants in sewage are degraded and converted into sludge under the action of microorganisms.

Tertiary treatment is the advanced treatment of sewage, which includes the removal of nutrients and the disinfection of sewage by chlorination, ultraviolet radiation or ozone technology. Depending on the target of the treatment and the quality of the water, some sewage treatment processes do not include all of the above processes.

Mechanical handling section

The mechanical (first-level) treatment section includes structures such as grilles, sand settling ponds, and initial settling ponds to remove coarse particles and suspended matter for the purpose of treatment. The principle of treatment is to achieve solid-liquid separation by physical method and separate pollutants from sewage, which is a commonly used sewage treatment method.

Mechanical (primary) treatment is essential for all wastewater treatment processes (although some processes sometimes omit the primary sedimentation tank), and the typical removal rates of BOD5 and SS for municipal wastewater primary treatment are 25% and 50%, respectively. In biological phosphorus and nitrogen removal wastewater treatment plants, aerated sand sedimentation tanks are generally not recommended to avoid the removal of rapidly degrading organic matter. In the case that the water quality characteristics of the original sewage are not conducive to phosphorus and nitrogen removal, the setting of the initial sedimentation and the setting method should be carefully analyzed and considered according to the subsequent process of the water quality special injection, so as to ensure and improve the influent water quality of the subsequent process such as phosphorus and nitrogen removal.

Biochemical treatment of sewage

Sewage biochemical treatment is A secondary treatment, to remove non-sinkable suspended matter and soluble biodegradable organic matter as the main purpose, its process composition is diverse, can be divided into activated sludge method, AB method, A/O method, A2 /O method, SBR method, oxidation ditch method, stabilization pond method, land treatment method and other treatment methods.