RU2051134C1 - Device for biochemical treatment of sewage and removal of nitrogen compounds - Google Patents

Abstract

FIELD: biochemical sewage treatment; can be used for biochemical treatment of domestic and similar sewage with a high content of reduced and oxidized forms of nitrogen. SUBSTANCE: device is comprised of a denitrifier, mixing chamber, biofilter with a sprinkling system and guide tray, settling air tank, aerating columns, circulating pump, and auxiliary pipes. Efficiency of nitrification and denitrification processes is ensured by arranging the denitrifier before the mixing chamber and connecting the denitrifier inlet pipes to source sewage pipe and to pressure pipe which feeds the nontreated sewage from the mixing chamber into the biofilter. EFFECT: improved design. 1 dwg

Description

 The invention relates to biochemical treatment of wastewater under anaerobic and aerobic conditions, in particular to biochemical treatment of water from organic and nitrogen-containing substances, and can be used for biochemical treatment of domestic and similar wastewater with a high content of reduced and oxidized forms nitrogen.

 A device for biochemical wastewater treatment containing a biofilter, aeration tank-settler, an irrigation system, aeration columns, mixing chambers, a circulation pump and process piping.

NO $\genfrac{}{}{0ex}{}{\text{-}}{\text{2}}$

NO $\genfrac{}{}{0ex}{}{\text{-}}{\text{3}}$

N

Так, в этом устройстве при очистке хозяйственно-бытовых стоков концентрации нитритов и нитратов (по азоту) в процессе очистки повышаются соответственно с 0,01 мг/дм³ до 0,3-0,5 мг/дм³ и с 0,8-1,0 мг/дм³ до 9-12 мг/дм³, а содержанием аммонийного азота снижается с 12 мг/дм³ только до 3-5 мг/дм³, что является недостаточным по санитарным требованиям.However, this device does not provide the proper degree of purification of water from nitrogen-containing substances. The device creates the conditions for the process of aerobic oxidation of organic substances, but does not provide the efficiency of the nitrification and denitrification process. As a result of the operation of the device in the system, a shift in the dynamic equilibrium of redox forms of nitrogen is established towards ammonium, which leads to the accumulation of the latter
NH $\genfrac{}{}{0ex}{}{\text{+}}{\text{4}}$

NO $\genfrac{}{}{0ex}{}{\text{-}}{\text{2}}$

NO $\genfrac{}{}{0ex}{}{\text{-}}{\text{3}}$

N

So, in this device, when cleaning domestic wastewater, the concentrations of nitrites and nitrates (by nitrogen) during the cleaning process increase, respectively, from 0.01 mg / dm ³ to 0.3-0.5 mg / dm ³ and from 0.8- 1.0 mg / dm ³ to 9-12 mg / dm ³ , and the ammonium nitrogen content decreases from 12 mg / dm ³ only to 3-5 mg / dm ³ , which is insufficient for sanitary requirements.

 The objective of the invention is to increase the efficiency of nitrification and denitrification processes during biochemical wastewater treatment.

 For this, a device for biochemical wastewater treatment and removal of nitrogen compounds, containing a biofilter with an irrigation system and a guiding tray, to which feed pipes (aeration columns), an aeration tank, a mixing chamber, a circulation pump, pressure and gravity pipelines are connected, are equipped with a denitrifier, installed in front of the mixing chamber and connected to the supply pipelines with control valves to the source sewage pipe and the pressure pipe from the circulation pump, and The denitrification pipeline is connected to the mixing chamber.

 The introduction of a denitrifier into the device and its connection with the mixing chamber in this way allows creating conditions in the mixing chamber for the subsequent formation of a specific biocenosis in the biofilter and aeration tank-settler due to the addition of a denitrifying silt liquid containing new ones from the denitrifier to the mixing chamber (as compared with the known device) microorganisms optional anaerobes. The latter intensify the processes of nitrification and denitrification in a biofilter and aeration tank settler.

The supply of sludge liquid from the aeration tank with oxidized forms of nitrogen (NO ₂ ^- , NO ₃ ^- ) to the denitrifier through the mixing chamber, the reduction of NO ₂ ^- and NO ₃ ^- in it to gaseous forms (N ₂ , N ₂ O) and subsequent removal them into the atmosphere through the irrigation system in the biofilter allows you to shift the dynamic equilibrium of the redox forms of nitrogen in the direction of the formation of final products and thereby increase the speed of the process of removal of nitrogen-containing substances.

 In addition, the introduction of a denitrifier into a known device makes it possible to reduce the rate of circulation of the sludge mixture in a known device due to the oxidation of a part of organic substances under anaerobic conditions in a denitrifier.

 The drawing shows a diagram of a device for biochemical wastewater treatment and removal of nitrogen compounds.

 A device for biochemical wastewater treatment and removal of nitrogen compounds contains a denitrifier 1, a mixing chamber 2, a biofilter 3 with an irrigation system and a guide pan, aeration tank 4, aeration columns, a circulation pump 5 and pressure pipelines 6 and 7, gravity 8-10 connecting the elements of the device with each other.

 The device operates as follows.

 The source wastewater enters through the pipeline 10 into the denitrifier 1 and into the mixing chamber 2. The flow control is carried out using shutoff valves. In the denitrifier, the initial wastewater is mixed with a sludge mixture supplied through a pipe 6 connected to a pressure pipe 7 of the circulation pump 5.

 In the denitrifier, organic substances are oxidized under anaerobic conditions and the oxidized forms of nitrogen are completely reduced to molecular nitrogen.

The denitrification process is carried out at a certain ratio of the concentrations of organic pollutants and oxidized nitrogen compounds.
qx BOD ₅ q ₁ x 3.65 m, where q is the amount of source wastewater in the denitrifier, m ³ ;
BOD _{5 is the} concentration of organic substances expressed through the biochemical oxygen demand, mg O ₂ / dm ³ ;
q _{1 the} amount of sludge mixture, m ³ ;
3.65 calculated coefficient;
m the concentration of nitrogen in oxidized form in the mixing chamber, mg / DM ³ .

 The denitrifying liquid is discharged from the denitrifier through pipeline 9 to the mixing chamber 2, in which it is mixed with the initial wastewater and sludge mixture, their sediment aeration tank 4 is fed through pipeline 8, and then the sludge mixture is fed to the denitrifier and to the biofilter irrigation system 3 In the biofilter, the sludge mixture is distributed by the irrigation system along the loading surface, while the molecular nitrogen formed during the denitrification process is removed into the atmosphere due to contact with air.

 Organic and nitrogen-containing substances contained in the silt mixture undergo biochemical decomposition under the influence of aerobic and anaerobic microorganisms located in the biocenosis of fouling. In the biofilter, facultative anaerobes, partially removed from the denitrifier, are switched from anaerobic respiration to aerobic and are included in the nitrification process.

 From the biofilter, the sludge mixture and the spent microflora of the biofilter passes through aeration columns to the aeration tank settler 4. The dissolved oxygen coming in with the sludge mixture stimulates the growth of nitrifying microflora. In the sump aeration tank, the rest of the organic contaminants (not oxidized in the biofilter) are oxidized, the spent microflora of the biofilter is mineralized, and the nitrification process is intensive. In this case, the aeration tank-settler mainly performs the role of a nitrifier.

The use of the invention allows to flexibly vary the organic carbon content of wastewater in biochemical oxidation and denitrification processes and to eliminate or reduce the amount of added methanol, the need of which for ordinary wastewater is about 60 mg / dm ³ .

Claims (1)

 DEVICE FOR BIOCHEMICAL WASTE WATER TREATMENT AND REMOVAL OF NITROGEN COMPOUNDS, containing a biofilter with an irrigation system, a drain pan and feed pipes with aeration columns, an aeration tank, a mixing chamber, a circulation pump with a pressure pipe and a source sewage pipe, which is installed in front of which a denitrifier mixing chamber with supply pipelines having control valves connected to the source effluent pipeline and the pressure piping pump, and with a discharge pipe connected to the mixing chamber.

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