CN112125470A

CN112125470A - Biochemical system and biochemical method for short-cut nitrification and denitrification sewage

Info

Publication number: CN112125470A
Application number: CN202010966355.1A
Authority: CN
Inventors: 姜成坤; 邱银锋; 范晔晖; 邓娟; 邓东林
Original assignee: Huadian Water Engineering Co ltd
Current assignee: Huadian Water Engineering Co ltd
Priority date: 2020-09-15
Filing date: 2020-09-15
Publication date: 2020-12-25

Abstract

The invention discloses a short-range nitrification and denitrification sewage biochemical system which comprises a raw water tank, an anoxic tank, an aerobic tank, a facultative tank and a membrane element, wherein a first pipeline is arranged between the raw water tank and the anoxic tank, the raw water tank is connected with the anoxic tank through the first pipeline, the bottoms of the anoxic tank, the aerobic tank and the facultative tank are sequentially communicated, the membrane element is arranged in the facultative tank, a second pipeline is arranged at the upper part of the membrane element, and a water production pump is arranged on a pipe section of the second pipeline, which protrudes out of the facultative tank. The invention also discloses a biochemical method. The invention effectively shortens the reaction process and improves the nitrification and denitrification rates; the hydraulic retention time is shortened; the oxygen demand of the short-cut nitrification is reduced by 25 percent, and the energy consumption is reduced; effectively saving 40% of carbon source as hydrogen donor; the discharge amount of the residual sludge is reduced.

Description

Biochemical system and biochemical method for short-cut nitrification and denitrification sewage

Technical Field

The invention relates to a biochemical system and a biochemical method for shortcut nitrification and denitrification sewage, belonging to the technical field of biological sewage treatment.

Background

The traditional anoxic/aerobic (AN/O) process is a complete biological denitrification process, and comprises three processes of ammoniation, nitrification and denitrification. An ammoniation stage: the organic nitrogen compound is decomposed and converted into ammoniacal nitrogen under the action of ammoniating bacteria. A nitration stage: the ammonia nitrogen is further decomposed and oxidized under the action of nitrite bacteria, firstly, the ammonia is converted into nitrite nitrogen, and then the nitrite nitrogen is further converted into nitrate nitrogen under the action of nitrobacteria. A denitrification stage: under the action of denitrifying bacteria, nitrite nitrogen and nitrate nitrogen are reduced into gaseous nitrogen. Traditional biological denitrification requires the oxidation of all ammonia nitrogen to nitrate nitrogen.

The basic principle of biological denitrification by short-cut nitrification and denitrification is to control the nitrification process at the nitrite stage, prevent further nitrification of NO2 < - >, and then directly perform denitrification. The reaction process has long reaction course, low nitrification and denitrification rate, long hydraulic retention time, high energy consumption and large residual sludge discharge.

Disclosure of Invention

The invention aims to provide a biochemical system for short-cut nitrification and denitrification sewage, and also provides a biochemical system for short-cut nitrification and denitrification sewage and a biochemical method thereof, so that the reaction process is effectively shortened, and the nitrification and denitrification rates are improved; the hydraulic retention time is shortened; the oxygen demand of the short-cut nitrification is reduced by 25 percent, and the energy consumption is reduced; effectively saving 40% of carbon source as hydrogen donor; the discharge amount of the residual sludge is reduced.

In order to solve the technical problems, the invention adopts the following technical scheme: a biochemical system for sewage by short-cut nitrification and denitrification comprises a raw water tank, an anoxic tank, an aerobic tank, a facultative tank and a membrane element, wherein a first pipeline is arranged between the raw water tank and the anoxic tank, the raw water tank is connected with the anoxic tank through the first pipeline, the bottoms of the anoxic tank, the aerobic tank and the facultative tank are sequentially communicated, the membrane element is arranged in the facultative tank, a second pipeline is arranged at the upper part of the membrane element, and a water production pump is arranged on a pipe section of the second pipeline, which protrudes out of the facultative tank; the reaction process is effectively shortened, and the nitrification and denitrification rates are improved; the hydraulic retention time is shortened; the oxygen demand of the short-cut nitrification is reduced by 25 percent, and the energy consumption is reduced; effectively saving 40% of carbon source as hydrogen donor; the discharge amount of the residual sludge is reduced.

In the biochemical system for short-cut nitrification and denitrification of sewage, the raw water tank is internally provided with the temperature transmitter and the heating coil; the heating coil heats the raw water, and the temperature transmitter accurately controls the temperature of the raw water on line, thereby effectively shortening the reaction process and improving the nitrification and denitrification rates.

In the biochemical system for short-cut nitrification and denitrification of sewage, the filler is arranged in the anoxic tank, and the filler is in a honeycomb shape or a corrugated plate shape; so that the anoxic tank has enough concentration of suspended matters in the mixed solution to facilitate denitrification.

In the biochemical system for short-cut nitrification and denitrification of sewage, a microporous air diffuser and an oxygen dissolving instrument are arranged in the aerobic tank, a third pipeline is arranged at one end of the microporous air diffuser, one end of the third pipeline is connected with the microporous air diffuser, a fan is arranged at the other end of the third pipeline, which protrudes out of the aerobic tank, a first regulating valve is arranged on a pipe section, which protrudes out of the aerobic tank, between the microporous air diffuser and the fan, and a first flowmeter is arranged on a pipe section, which is between the first regulating valve and the fan; the fan supplies air to the aerobic tank through the microporous air diffuser for aeration to provide dissolved oxygen, the ammonifying bacteria oxidize organic matters in an aerobic environment, and the first regulating valve, the first flow meter and the dissolved oxygen meter are linked to control the aeration flow in an online manner.

In the biochemical system for short-cut nitrification and denitrification of sewage, an online ammonia nitrogen instrument and an online PH instrument are arranged in the facultative tank, a fourth pipeline is also arranged in the facultative tank, one end of the fourth pipeline is arranged in the facultative tank, the other end of the fourth pipeline, which protrudes out of the facultative tank, is provided with an alkali metering pump, the pipe section of the fourth pipeline, which protrudes out of the facultative tank, is provided with an alkali metering pump, the bottom of the facultative tank is provided with a second regulating valve, and the second regulating valve is connected with a bottom pipeline of the facultative tank; alkali liquor in the alkali metering box is conveyed to the facultative tank through the alkali metering pump, the nitrification effect of the facultative tank is monitored by the online ammonia nitrogen instrument, and the PH in the facultative tank is controlled online through the linkage of the online PH instrument and the alkali metering pump.

In the biochemical system for short-cut nitrification and denitrification of sewage, the first pipeline is provided with the raw water pump, a pipe section between the raw water pump and the anoxic tank is provided with the third regulating valve, and a pipe section between the third regulating valve and the raw water pump is provided with the second flowmeter; the third regulating valve and the second flowmeter are interlocked to control the raw water pump on line, so that the outlet flow of the raw water flowing into the anoxic pond is controlled.

In the biochemical sewage treatment system adopting short-cut nitrification and denitrification, the side wall of the facultative tank is provided with the fifth pipeline, one end of the fifth pipeline is connected with the side wall of the facultative tank, the other end of the fifth pipeline is connected to the pipe section between the third regulating valve and the anoxic tank, the fifth pipeline is provided with the fourth regulating valve, the pipe section between the fourth regulating valve and the facultative tank is provided with the reflux pump, and the pipe section between the reflux pump and the fourth regulating valve is provided with the third flow meter; the reflux pump reflows the sewage in the facultative tank to the anoxic tank to provide nitrified liquid, and the fourth regulating valve and the third flow meter are linked to control the water outlet flow on line.

A biochemical method of a short-cut nitrification and denitrification sewage biochemical system comprises the following steps:

s1, storing raw water in a raw water tank, homogenizing and homogenizing, heating the raw water to 30-35 ℃ by a heating coil, and accurately controlling the temperature of the raw water on line by a temperature transmitter;

s2, conveying the raw water in the raw water tank to an anoxic tank through a raw water pump, and fully mixing the raw water with the filler to form a mixed solution of the raw water and the nitrified liquid;

s3, enabling a mixed solution of raw water and a nitrifying liquid in the anoxic tank to flow into the aerobic tank, supplying air into the aerobic tank through a microporous air diffuser by a fan, carrying out an aeration reaction on the mixed solution of the raw water and the nitrifying liquid to provide dissolved oxygen, controlling the aeration amount on line by an oxygen dissolving instrument, controlling the dissolved oxygen in the aerobic tank to be 1-3mg/L, and oxidizing ammonia nitrogen in the mixed solution of the raw water and the nitrifying liquid into nitrite nitrogen and nitrate nitrogen under aerobic conditions to form a nitrite nitrogen and nitrate nitrogen mixed solution;

s4, enabling mixed liquid of nitrite nitrogen and nitrate nitrogen to flow into a facultative tank, conveying alkali liquor in an alkali metering box to the facultative tank through an alkali metering pump, interlocking an online PH meter and the alkali metering pump, controlling the PH value of the mixed liquid of nitrite nitrogen and nitrate nitrogen in the facultative tank on line, controlling the PH value to be 7.9-8.2, monitoring the nitrification effect of the mixed liquid of nitrite nitrogen and nitrate nitrogen in the facultative tank by the online ammonia nitrogen meter, wherein the mixed liquid contains nitrite nitrogen and nitrate nitrogen, and the ratio of nitrite nitrogen is higher than that of nitrate nitrogen by controlling the measures of PH, temperature, dissolved oxygen and the like to form mixed liquid of high nitrite nitrogen and low nitrate nitrogen;

s5, enabling the mixed liquid with high nitrite nitrogen and low nitrate nitrogen to flow back to the anoxic pond through the reflux pump, controlling the water outlet flow on line through a fourth regulating valve and a third flow meter, and repeating the steps of S3 and S4 to form nitrified mixed liquid, providing nitrite nitrogen and nitrate nitrogen for the anoxic pond, so that the nitrified mixed liquid is reduced into gaseous nitrogen by denitrifying bacteria under the anoxic condition to form denitrifying mixed liquid;

and S6, making the denitrification mixed liquid permeate the membrane element to discharge water under the action of negative pressure suction of the water production pump, and forming regenerated water.

Compared with the prior art, the invention has the advantages that the raw water tank, the anoxic tank, the aerobic tank, the facultative tank and the membrane element are arranged between the raw water tank and the anoxic tank, the raw water tank is connected with the anoxic tank through the first pipeline, the bottom parts of the anoxic tank, the aerobic tank and the facultative tank are sequentially communicated, the membrane element is arranged in the facultative tank, the upper part of the membrane element is provided with the second pipeline, the second pipeline protrudes out of the facultative tank, the pipe section is provided with a water production pump, and meanwhile, the invention also provides a biochemical method of the short-distance nitrification and denitrification sewage biochemical system; the hydraulic retention time is shortened; the oxygen demand of the short-cut nitrification is reduced by 25 percent, and the energy consumption is reduced; effectively saving 40% of carbon source as hydrogen donor; the discharge amount of the residual sludge is reduced.

Drawings

Fig. 1 is a schematic structural view of the present invention.

Reference numerals: 1-raw water tank, 2-anoxic tank, 3-aerobic tank, 4-facultative tank, 5-membrane element, 6-first pipeline, 7-second pipeline, 8-water producing pump, 9-temperature transmitter, 10-heating coil, 11-filler, 12-microporous air diffuser, 13-dissolved oxygen meter, 14-third pipeline, 15-blower, 16-first regulating valve, 17-first flow meter, 18-online ammonia nitrogen meter, 19-online PH meter, 20-fourth pipeline, 21-alkali metering tank, 22-alkali metering pump, 23-second regulating valve, 24-raw water pump, 25-third regulating valve, 26-second flow meter, 27-fifth pipeline, 28-fourth regulating valve, 29-reflux pump, 30-third flow meter.

The invention is further described with reference to the following figures and detailed description.

Detailed Description

Example 1 of the invention: a biochemical system for sewage by short-cut nitrification and denitrification comprises a raw water tank 1, an anoxic tank 2, an aerobic tank 3, a facultative tank 4 and a membrane element 5, wherein a first pipeline 6 is arranged between the raw water tank 1 and the anoxic tank 2, the raw water tank 1 is connected with the anoxic tank 2 through the first pipeline 6, the bottoms of the anoxic tank 2, the aerobic tank 3 and the facultative tank 4 are sequentially communicated, the membrane element 5 is arranged in the facultative tank 4, a second pipeline 7 is arranged at the upper part of the membrane element 5, and a water production pump 8 is arranged on a pipe section of the second pipeline 7 protruding out of the facultative tank 4; the reaction process is effectively shortened, and the nitrification and denitrification rates are improved; the hydraulic retention time is shortened; the oxygen demand of the short-cut nitrification is reduced by 25 percent, and the energy consumption is reduced; effectively saving 40% of carbon source as hydrogen donor; the discharge amount of the residual sludge is reduced.

Example 2 of the invention: a biochemical system for sewage by short-cut nitrification and denitrification comprises a raw water tank 1, an anoxic tank 2, an aerobic tank 3, a facultative tank 4 and a membrane element 5, wherein a first pipeline 6 is arranged between the raw water tank 1 and the anoxic tank 2, the raw water tank 1 is connected with the anoxic tank 2 through the first pipeline 6, the bottoms of the anoxic tank 2, the aerobic tank 3 and the facultative tank 4 are sequentially communicated, the membrane element 5 is arranged in the facultative tank 4, a second pipeline 7 is arranged at the upper part of the membrane element 5, and a water production pump 8 is arranged on a pipe section of the second pipeline 7 protruding out of the facultative tank 4; the reaction process is effectively shortened, and the nitrification and denitrification rates are improved; the hydraulic retention time is shortened; the oxygen demand of the short-cut nitrification is reduced by 25 percent, and the energy consumption is reduced; effectively saving 40% of carbon source as hydrogen donor; the discharge amount of the residual sludge is reduced; a temperature transmitter 9 and a heating coil 10 are arranged in the raw water tank 1; the heating coil 10 heats the raw water, and the temperature transmitter 9 accurately controls the temperature of the raw water on line, thereby effectively shortening the reaction process and improving the nitrification and denitrification rates.

Example 3 of the invention: a biochemical system for sewage by short-cut nitrification and denitrification comprises a raw water tank 1, an anoxic tank 2, an aerobic tank 3, a facultative tank 4 and a membrane element 5, wherein a first pipeline 6 is arranged between the raw water tank 1 and the anoxic tank 2, the raw water tank 1 is connected with the anoxic tank 2 through the first pipeline 6, the bottoms of the anoxic tank 2, the aerobic tank 3 and the facultative tank 4 are sequentially communicated, the membrane element 5 is arranged in the facultative tank 4, a second pipeline 7 is arranged at the upper part of the membrane element 5, and a water production pump 8 is arranged on a pipe section of the second pipeline 7 protruding out of the facultative tank 4; the reaction process is effectively shortened, and the nitrification and denitrification rates are improved; the hydraulic retention time is shortened; the oxygen demand of the short-cut nitrification is reduced by 25 percent, and the energy consumption is reduced; effectively saving 40% of carbon source as hydrogen donor; the discharge amount of the residual sludge is reduced; a temperature transmitter 9 and a heating coil 10 are arranged in the raw water tank 1; the heating coil 10 heats the raw water, and the temperature transmitter 9 accurately controls the temperature of the raw water on line, so that the reaction process is effectively shortened, and the nitrification and denitrification rates are improved; a filler 11 is arranged in the anoxic tank 2, and the filler 11 is in a honeycomb shape or a corrugated plate shape; so that the anoxic tank 2 has enough concentration of mixed liquid suspended matters to facilitate denitrification.

Example 4 of the invention: a biochemical system for sewage by short-cut nitrification and denitrification comprises a raw water tank 1, an anoxic tank 2, an aerobic tank 3, a facultative tank 4 and a membrane element 5, wherein a first pipeline 6 is arranged between the raw water tank 1 and the anoxic tank 2, the raw water tank 1 is connected with the anoxic tank 2 through the first pipeline 6, the bottoms of the anoxic tank 2, the aerobic tank 3 and the facultative tank 4 are sequentially communicated, the membrane element 5 is arranged in the facultative tank 4, a second pipeline 7 is arranged at the upper part of the membrane element 5, and a water production pump 8 is arranged on a pipe section of the second pipeline 7 protruding out of the facultative tank 4; the reaction process is effectively shortened, and the nitrification and denitrification rates are improved; the hydraulic retention time is shortened; the oxygen demand of the short-cut nitrification is reduced by 25 percent, and the energy consumption is reduced; effectively saving 40% of carbon source as hydrogen donor; the discharge amount of the residual sludge is reduced; a temperature transmitter 9 and a heating coil 10 are arranged in the raw water tank 1; the heating coil 10 heats the raw water, and the temperature transmitter 9 accurately controls the temperature of the raw water on line, so that the reaction process is effectively shortened, and the nitrification and denitrification rates are improved; a filler 11 is arranged in the anoxic tank 2, and the filler 11 is in a honeycomb shape or a corrugated plate shape; the oxygen-poor pool 2 has enough concentration of mixed liquid suspended matters to facilitate denitrification; a microporous air diffuser 12 and an oxygen dissolving instrument 13 are arranged in the aerobic tank 3, a third pipeline 14 is arranged at one end of the microporous air diffuser 12, one end of the third pipeline 14 is connected with the microporous air diffuser 12, a fan 15 is arranged at the other end of the third pipeline 14 protruding out of the aerobic tank 3, a first regulating valve 16 is arranged on a pipe section between the microporous air diffuser 12 and the fan 15 protruding out of the aerobic tank 3, and a first flowmeter 17 is arranged on a pipe section between the first regulating valve 16 and the fan 15; the fan 15 supplies air to the aerobic tank 3 through the microporous air diffuser 12 for aeration, dissolved oxygen is provided, ammoniated bacteria oxidize organic matters in an aerobic environment, and the aeration flow is controlled by the first adjusting valve 16, the first flow meter 17 and the dissolved oxygen meter 13 in a linkage and on-line mode.

Example 5 of the invention: a biochemical system for sewage by short-cut nitrification and denitrification comprises a raw water tank 1, an anoxic tank 2, an aerobic tank 3, a facultative tank 4 and a membrane element 5, wherein a first pipeline 6 is arranged between the raw water tank 1 and the anoxic tank 2, the raw water tank 1 is connected with the anoxic tank 2 through the first pipeline 6, the bottoms of the anoxic tank 2, the aerobic tank 3 and the facultative tank 4 are sequentially communicated, the membrane element 5 is arranged in the facultative tank 4, a second pipeline 7 is arranged at the upper part of the membrane element 5, and a water production pump 8 is arranged on a pipe section of the second pipeline 7 protruding out of the facultative tank 4; the reaction process is effectively shortened, and the nitrification and denitrification rates are improved; the hydraulic retention time is shortened; the oxygen demand of the short-cut nitrification is reduced by 25 percent, and the energy consumption is reduced; effectively saving 40% of carbon source as hydrogen donor; the discharge amount of the residual sludge is reduced; a temperature transmitter 9 and a heating coil 10 are arranged in the raw water tank 1; the heating coil 10 heats the raw water, and the temperature transmitter 9 accurately controls the temperature of the raw water on line, so that the reaction process is effectively shortened, and the nitrification and denitrification rates are improved; a filler 11 is arranged in the anoxic tank 2, and the filler 11 is in a honeycomb shape or a corrugated plate shape; the oxygen-poor pool 2 has enough concentration of mixed liquid suspended matters to facilitate denitrification; a microporous air diffuser 12 and an oxygen dissolving instrument 13 are arranged in the aerobic tank 3, a third pipeline 14 is arranged at one end of the microporous air diffuser 12, one end of the third pipeline 14 is connected with the microporous air diffuser 12, a fan 15 is arranged at the other end of the third pipeline 14 protruding out of the aerobic tank 3, a first regulating valve 16 is arranged on a pipe section between the microporous air diffuser 12 and the fan 15 protruding out of the aerobic tank 3, and a first flowmeter 17 is arranged on a pipe section between the first regulating valve 16 and the fan 15; the fan 15 supplies air to the aerobic tank 3 through the microporous air diffuser 12 for aeration to provide dissolved oxygen, the ammonifying bacteria oxidize organic matters in an aerobic environment, and the first regulating valve 16, the first flow meter 17 and the dissolved oxygen meter 13 are linked to control the aeration flow on line; an online ammonia nitrogen instrument 18 and an online PH instrument 19 are arranged in the facultative tank 4, a fourth pipeline 20 is also arranged in the facultative tank 4, one end of the fourth pipeline 20 is arranged in the facultative tank 4, the other end of the fourth pipeline 20 protruding out of the facultative tank 4 is provided with an alkali metering tank 21, a pipe section of the fourth pipeline 20 protruding out of the facultative tank 4 is provided with an alkali metering pump 22, the bottom of the facultative tank 4 is provided with a second regulating valve 23, and the second regulating valve 23 is connected with a bottom pipeline of the facultative tank 4; alkali liquor in the alkali metering box 21 is conveyed to the facultative tank 4 through the alkali metering pump 22, the nitrification effect of the facultative tank is monitored by the online ammonia nitrogen instrument 18, and the PH in the facultative tank 4 is controlled online through the linkage of the online PH instrument 19 and the alkali metering pump 22.

Example 6 of the invention: a biochemical system for sewage by short-cut nitrification and denitrification comprises a raw water tank 1, an anoxic tank 2, an aerobic tank 3, a facultative tank 4 and a membrane element 5, wherein a first pipeline 6 is arranged between the raw water tank 1 and the anoxic tank 2, the raw water tank 1 is connected with the anoxic tank 2 through the first pipeline 6, the bottoms of the anoxic tank 2, the aerobic tank 3 and the facultative tank 4 are sequentially communicated, the membrane element 5 is arranged in the facultative tank 4, a second pipeline 7 is arranged at the upper part of the membrane element 5, and a water production pump 8 is arranged on a pipe section of the second pipeline 7 protruding out of the facultative tank 4; the reaction process is effectively shortened, and the nitrification and denitrification rates are improved; the hydraulic retention time is shortened; the oxygen demand of the short-cut nitrification is reduced by 25 percent, and the energy consumption is reduced; effectively saving 40% of carbon source as hydrogen donor; the discharge amount of the residual sludge is reduced; a temperature transmitter 9 and a heating coil 10 are arranged in the raw water tank 1; the heating coil 10 heats the raw water, and the temperature transmitter 9 accurately controls the temperature of the raw water on line, so that the reaction process is effectively shortened, and the nitrification and denitrification rates are improved; a filler 11 is arranged in the anoxic tank 2, and the filler 11 is in a honeycomb shape or a corrugated plate shape; the oxygen-poor pool 2 has enough concentration of mixed liquid suspended matters to facilitate denitrification; a microporous air diffuser 12 and an oxygen dissolving instrument 13 are arranged in the aerobic tank 3, a third pipeline 14 is arranged at one end of the microporous air diffuser 12, one end of the third pipeline 14 is connected with the microporous air diffuser 12, a fan 15 is arranged at the other end of the third pipeline 14 protruding out of the aerobic tank 3, a first regulating valve 16 is arranged on a pipe section between the microporous air diffuser 12 and the fan 15 protruding out of the aerobic tank 3, and a first flowmeter 17 is arranged on a pipe section between the first regulating valve 16 and the fan 15; the fan 15 supplies air to the aerobic tank 3 through the microporous air diffuser 12 for aeration to provide dissolved oxygen, the ammonifying bacteria oxidize organic matters in an aerobic environment, and the first regulating valve 16, the first flow meter 17 and the dissolved oxygen meter 13 are linked to control the aeration flow on line; an online ammonia nitrogen instrument 18 and an online PH instrument 19 are arranged in the facultative tank 4, a fourth pipeline 20 is also arranged in the facultative tank 4, one end of the fourth pipeline 20 is arranged in the facultative tank 4, the other end of the fourth pipeline 20 protruding out of the facultative tank 4 is provided with an alkali metering tank 21, a pipe section of the fourth pipeline 20 protruding out of the facultative tank 4 is provided with an alkali metering pump 22, the bottom of the facultative tank 4 is provided with a second regulating valve 23, and the second regulating valve 23 is connected with a bottom pipeline of the facultative tank 4; conveying alkali liquor in an alkali metering box 21 to the facultative tank 4 through an alkali metering pump 22, monitoring the nitrification effect of the facultative tank through an online ammonia nitrogen instrument 18, and controlling the PH in the facultative tank 4 on line through linkage of an online PH instrument 19 and the alkali metering pump 22; a raw water pump 24 is arranged on the first pipeline 6, a third regulating valve 25 is arranged on a pipe section between the raw water pump 24 and the anoxic pond 2, and a second flowmeter 26 is arranged on a pipe section between the third regulating valve 25 and the raw water pump 24; the third regulating valve 25 and the second flowmeter 26 are interlocked to control the raw water pump 24 on line, thereby controlling the outlet flow of the raw water flowing into the anoxic tank 2.

Example 7 of the invention: a biochemical system for sewage by short-cut nitrification and denitrification comprises a raw water tank 1, an anoxic tank 2, an aerobic tank 3, a facultative tank 4 and a membrane element 5, wherein a first pipeline 6 is arranged between the raw water tank 1 and the anoxic tank 2, the raw water tank 1 is connected with the anoxic tank 2 through the first pipeline 6, the bottoms of the anoxic tank 2, the aerobic tank 3 and the facultative tank 4 are sequentially communicated, the membrane element 5 is arranged in the facultative tank 4, a second pipeline 7 is arranged at the upper part of the membrane element 5, and a water production pump 8 is arranged on a pipe section of the second pipeline 7 protruding out of the facultative tank 4; the reaction process is effectively shortened, and the nitrification and denitrification rates are improved; the hydraulic retention time is shortened; the oxygen demand of the short-cut nitrification is reduced by 25 percent, and the energy consumption is reduced; effectively saving 40% of carbon source as hydrogen donor; the discharge amount of the residual sludge is reduced; a temperature transmitter 9 and a heating coil 10 are arranged in the raw water tank 1; the heating coil 10 heats the raw water, and the temperature transmitter 9 accurately controls the temperature of the raw water on line, so that the reaction process is effectively shortened, and the nitrification and denitrification rates are improved; a filler 11 is arranged in the anoxic tank 2, and the filler 11 is in a honeycomb shape or a corrugated plate shape; the oxygen-poor pool 2 has enough concentration of mixed liquid suspended matters to facilitate denitrification; a microporous air diffuser 12 and an oxygen dissolving instrument 13 are arranged in the aerobic tank 3, a third pipeline 14 is arranged at one end of the microporous air diffuser 12, one end of the third pipeline 14 is connected with the microporous air diffuser 12, a fan 15 is arranged at the other end of the third pipeline 14 protruding out of the aerobic tank 3, a first regulating valve 16 is arranged on a pipe section between the microporous air diffuser 12 and the fan 15 protruding out of the aerobic tank 3, and a first flowmeter 17 is arranged on a pipe section between the first regulating valve 16 and the fan 15; the fan 15 supplies air to the aerobic tank 3 through the microporous air diffuser 12 for aeration to provide dissolved oxygen, the ammonifying bacteria oxidize organic matters in an aerobic environment, and the first regulating valve 16, the first flow meter 17 and the dissolved oxygen meter 13 are linked to control the aeration flow on line; an online ammonia nitrogen instrument 18 and an online PH instrument 19 are arranged in the facultative tank 4, a fourth pipeline 20 is also arranged in the facultative tank 4, one end of the fourth pipeline 20 is arranged in the facultative tank 4, the other end of the fourth pipeline 20 protruding out of the facultative tank 4 is provided with an alkali metering tank 21, a pipe section of the fourth pipeline 20 protruding out of the facultative tank 4 is provided with an alkali metering pump 22, the bottom of the facultative tank 4 is provided with a second regulating valve 23, and the second regulating valve 23 is connected with a bottom pipeline of the facultative tank 4; conveying alkali liquor in an alkali metering box 21 to the facultative tank 4 through an alkali metering pump 22, monitoring the nitrification effect of the facultative tank through an online ammonia nitrogen instrument 18, and controlling the PH in the facultative tank 4 on line through linkage of an online PH instrument 19 and the alkali metering pump 22; a raw water pump 24 is arranged on the first pipeline 6, a third regulating valve 25 is arranged on a pipe section between the raw water pump 24 and the anoxic pond 2, and a second flowmeter 26 is arranged on a pipe section between the third regulating valve 25 and the raw water pump 24; the third regulating valve 25 and the second flowmeter 26 are interlocked to control the raw water pump 24 on line, so as to control the water outlet flow of the raw water flowing into the anoxic pond 2; a fifth pipeline 27 is arranged on the side wall of the facultative tank 4, one end of the fifth pipeline 27 is connected with the side wall of the facultative tank 4, the other end of the fifth pipeline 27 is connected to a pipe section between the third regulating valve 25 and the anoxic tank 2, a fourth regulating valve 28 is arranged on the fifth pipeline 27, a reflux pump 29 is arranged on the pipe section between the fourth regulating valve 28 and the facultative tank 4, and a third flow meter 30 is arranged on the pipe section between the reflux pump 29 and the fourth regulating valve 28; the reflux pump 29 refluxes the sewage in the facultative tank 4 to the anoxic tank 2 to provide nitrified liquid, and the fourth regulating valve 28 and the third flow meter 30 are interlocked to control the effluent flow on line.

Example 8 of the invention: a biochemical system for sewage by short-cut nitrification and denitrification comprises a raw water tank 1, an anoxic tank 2, an aerobic tank 3, a facultative tank 4 and a membrane element 5, wherein a first pipeline 6 is arranged between the raw water tank 1 and the anoxic tank 2, the raw water tank 1 is connected with the anoxic tank 2 through the first pipeline 6, the bottoms of the anoxic tank 2, the aerobic tank 3 and the facultative tank 4 are sequentially communicated, the membrane element 5 is arranged in the facultative tank 4, a second pipeline 7 is arranged at the upper part of the membrane element 5, and a water production pump 8 is arranged on a pipe section of the second pipeline 7 protruding out of the facultative tank 4; the reaction process is effectively shortened, and the nitrification and denitrification rates are improved; the hydraulic retention time is shortened; the oxygen demand of the short-cut nitrification is reduced by 25 percent, and the energy consumption is reduced; effectively saving 40% of carbon source as hydrogen donor; the discharge amount of the residual sludge is reduced; a temperature transmitter 9 and a heating coil 10 are arranged in the raw water tank 1; the heating coil 10 heats the raw water, and the temperature transmitter 9 accurately controls the temperature of the raw water on line, so that the reaction process is effectively shortened, and the nitrification and denitrification rates are improved; a filler 11 is arranged in the anoxic tank 2, and the filler 11 is honeycomb-shaped; the oxygen-poor pool 2 has enough concentration of mixed liquid suspended matters to facilitate denitrification; a microporous air diffuser 12 and an oxygen dissolving instrument 13 are arranged in the aerobic tank 3, a third pipeline 14 is arranged at one end of the microporous air diffuser 12, one end of the third pipeline 14 is connected with the microporous air diffuser 12, a fan 15 is arranged at the other end of the third pipeline 14 protruding out of the aerobic tank 3, a first regulating valve 16 is arranged on a pipe section between the microporous air diffuser 12 and the fan 15 protruding out of the aerobic tank 3, and a first flowmeter 17 is arranged on a pipe section between the first regulating valve 16 and the fan 15; the fan 15 supplies air to the aerobic tank 3 through the microporous air diffuser 12 for aeration to provide dissolved oxygen, the ammonifying bacteria oxidize organic matters in an aerobic environment, and the first regulating valve 16, the first flow meter 17 and the dissolved oxygen meter 13 are linked to control the aeration flow on line; an online ammonia nitrogen instrument 18 and an online PH instrument 19 are arranged in the facultative tank 4, a fourth pipeline 20 is also arranged in the facultative tank 4, one end of the fourth pipeline 20 is arranged in the facultative tank 4, the other end of the fourth pipeline 20 protruding out of the facultative tank 4 is provided with an alkali metering tank 21, a pipe section of the fourth pipeline 20 protruding out of the facultative tank 4 is provided with an alkali metering pump 22, the bottom of the facultative tank 4 is provided with a second regulating valve 23, and the second regulating valve 23 is connected with a bottom pipeline of the facultative tank 4; conveying alkali liquor in an alkali metering box 21 to the facultative tank 4 through an alkali metering pump 22, monitoring the nitrification effect of the facultative tank through an online ammonia nitrogen instrument 18, and controlling the PH in the facultative tank 4 on line through linkage of an online PH instrument 19 and the alkali metering pump 22; a raw water pump 24 is arranged on the first pipeline 6, a third regulating valve 25 is arranged on a pipe section between the raw water pump 24 and the anoxic pond 2, and a second flowmeter 26 is arranged on a pipe section between the third regulating valve 25 and the raw water pump 24; the third regulating valve 25 and the second flowmeter 26 are interlocked to control the raw water pump 24 on line, so as to control the water outlet flow of the raw water flowing into the anoxic pond 2; a fifth pipeline 27 is arranged on the side wall of the facultative tank 4, one end of the fifth pipeline 27 is connected with the side wall of the facultative tank 4, the other end of the fifth pipeline 27 is connected to a pipe section between the third regulating valve 25 and the anoxic tank 2, a fourth regulating valve 28 is arranged on the fifth pipeline 27, a reflux pump 29 is arranged on the pipe section between the fourth regulating valve 28 and the facultative tank 4, and a third flow meter 30 is arranged on the pipe section between the reflux pump 29 and the fourth regulating valve 28; the reflux pump 29 refluxes the sewage in the facultative tank 4 to the anoxic tank 2 to provide nitrified liquid, and the fourth regulating valve 28 and the third flow meter 30 are interlocked to control the effluent flow on line.

Example 9 of the invention: a biochemical system for sewage by short-cut nitrification and denitrification comprises a raw water tank 1, an anoxic tank 2, an aerobic tank 3, a facultative tank 4 and a membrane element 5, wherein a first pipeline 6 is arranged between the raw water tank 1 and the anoxic tank 2, the raw water tank 1 is connected with the anoxic tank 2 through the first pipeline 6, the bottoms of the anoxic tank 2, the aerobic tank 3 and the facultative tank 4 are sequentially communicated, the membrane element 5 is arranged in the facultative tank 4, a second pipeline 7 is arranged at the upper part of the membrane element 5, and a water production pump 8 is arranged on a pipe section of the second pipeline 7 protruding out of the facultative tank 4; the reaction process is effectively shortened, and the nitrification and denitrification rates are improved; the hydraulic retention time is shortened; the oxygen demand of the short-cut nitrification is reduced by 25 percent, and the energy consumption is reduced; effectively saving 40% of carbon source as hydrogen donor; the discharge amount of the residual sludge is reduced; a temperature transmitter 9 and a heating coil 10 are arranged in the raw water tank 1; the heating coil 10 heats the raw water, and the temperature transmitter 9 accurately controls the temperature of the raw water on line, so that the reaction process is effectively shortened, and the nitrification and denitrification rates are improved; a filler 11 is arranged in the anoxic tank 2, and the filler 11 is corrugated; the oxygen-poor pool 2 has enough concentration of mixed liquid suspended matters to facilitate denitrification; a microporous air diffuser 12 and an oxygen dissolving instrument 13 are arranged in the aerobic tank 3, a third pipeline 14 is arranged at one end of the microporous air diffuser 12, one end of the third pipeline 14 is connected with the microporous air diffuser 12, a fan 15 is arranged at the other end of the third pipeline 14 protruding out of the aerobic tank 3, a first regulating valve 16 is arranged on a pipe section between the microporous air diffuser 12 and the fan 15 protruding out of the aerobic tank 3, and a first flowmeter 17 is arranged on a pipe section between the first regulating valve 16 and the fan 15; the fan 15 supplies air to the aerobic tank 3 through the microporous air diffuser 12 for aeration to provide dissolved oxygen, the ammonifying bacteria oxidize organic matters in an aerobic environment, and the first regulating valve 16, the first flow meter 17 and the dissolved oxygen meter 13 are linked to control the aeration flow on line; an online ammonia nitrogen instrument 18 and an online PH instrument 19 are arranged in the facultative tank 4, a fourth pipeline 20 is also arranged in the facultative tank 4, one end of the fourth pipeline 20 is arranged in the facultative tank 4, the other end of the fourth pipeline 20 protruding out of the facultative tank 4 is provided with an alkali metering tank 21, a pipe section of the fourth pipeline 20 protruding out of the facultative tank 4 is provided with an alkali metering pump 22, the bottom of the facultative tank 4 is provided with a second regulating valve 23, and the second regulating valve 23 is connected with a bottom pipeline of the facultative tank 4; conveying alkali liquor in an alkali metering box 21 to the facultative tank 4 through an alkali metering pump 22, monitoring the nitrification effect of the facultative tank through an online ammonia nitrogen instrument 18, and controlling the PH in the facultative tank 4 on line through linkage of an online PH instrument 19 and the alkali metering pump 22; a raw water pump 24 is arranged on the first pipeline 6, a third regulating valve 25 is arranged on a pipe section between the raw water pump 24 and the anoxic pond 2, and a second flowmeter 26 is arranged on a pipe section between the third regulating valve 25 and the raw water pump 24; the third regulating valve 25 and the second flowmeter 26 are interlocked to control the raw water pump 24 on line, so as to control the water outlet flow of the raw water flowing into the anoxic pond 2; a fifth pipeline 27 is arranged on the side wall of the facultative tank 4, one end of the fifth pipeline 27 is connected with the side wall of the facultative tank 4, the other end of the fifth pipeline 27 is connected to a pipe section between the third regulating valve 25 and the anoxic tank 2, a fourth regulating valve 28 is arranged on the fifth pipeline 27, a reflux pump 29 is arranged on the pipe section between the fourth regulating valve 28 and the facultative tank 4, and a third flow meter 30 is arranged on the pipe section between the reflux pump 29 and the fourth regulating valve 28; the reflux pump 29 refluxes the sewage in the facultative tank 4 to the anoxic tank 2 to provide nitrified liquid, and the fourth regulating valve 28 and the third flow meter 30 are interlocked to control the effluent flow on line.

s1, storing raw water in a raw water tank (1), homogenizing and homogenizing, heating the raw water to 30-35 ℃ by a heating coil (10), and accurately controlling the temperature of the raw water on line by a temperature transmitter (9);

s2, conveying the raw water in the raw water tank (1) to the anoxic tank (2) through the raw water pump (24), and fully mixing the raw water with the filler (11) to form a mixed solution of the raw water and the nitrified liquid;

s3, enabling a mixed solution of raw water and nitrifying liquid in the anoxic pond (2) to flow into the aerobic pond (3), supplying air into the aerobic pond (3) through a microporous air diffuser (12) by a fan (15), carrying out an aeration reaction on the mixed solution of the raw water and the nitrifying liquid to provide dissolved oxygen, controlling the aeration amount on line by an oxygen dissolving instrument (13), controlling the dissolved oxygen in the aerobic pond (3) to be 1-3mg/L, and oxidizing ammonia nitrogen in the mixed solution of the raw water and the nitrifying liquid into nitrite nitrogen and nitrate nitrogen under aerobic conditions to form a mixed solution of the nitrite nitrogen and the nitrate nitrogen;

s4, enabling a nitrite-nitrogen and nitrate-nitrogen mixed solution to flow into a facultative tank (4), conveying alkali liquor in an alkali metering box (21) to the facultative tank (4) through an alkali metering pump (22), interlocking an online pH instrument (19) with the alkali metering pump (22), controlling the pH value of the nitrite-nitrogen and nitrate-nitrogen mixed solution in the facultative tank (4) on line, controlling the pH value to be 7.9-8.2, monitoring the nitrification effect of the nitrite-nitrogen and nitrate-nitrogen mixed solution in the facultative tank (4) through the online ammonia-nitrogen instrument (18), containing nitrite nitrogen and nitrate nitrogen, and enabling the proportion of nitrite nitrogen to be higher than that of nitrate nitrogen through measures of controlling pH, temperature, dissolved oxygen and the like to form a high nitrite-nitrogen and low-nitrogen mixed solution;

s5, enabling the mixed liquid with high nitrite nitrogen and low nitrate nitrogen to flow back the mixed liquid in the facultative tank (4) to the anoxic tank (2) through the reflux pump (29), controlling the water outlet flow rate on line through the fourth regulating valve (28) and the third flow meter (30), and repeating the steps of S3 and S4 to form a nitrified mixed liquid, providing nitrite nitrogen and nitrate nitrogen for the anoxic tank (2), so that the nitrified mixed liquid is reduced into gaseous nitrogen by denitrifying bacteria under an anoxic condition to form a denitrifying mixed liquid;

s6, the denitrification mixed liquid passes through the membrane element (5) to discharge water under the action of negative pressure suction of the water producing pump (8) to form regenerated water.

Example 10 of the present invention: a biochemical system for sewage by short-cut nitrification and denitrification comprises a raw water tank 1, an anoxic tank 2, an aerobic tank 3, a facultative tank 4 and a membrane element 5, wherein a first pipeline 6 is arranged between the raw water tank 1 and the anoxic tank 2, the raw water tank 1 is connected with the anoxic tank 2 through the first pipeline 6, the bottoms of the anoxic tank 2, the aerobic tank 3 and the facultative tank 4 are sequentially communicated, the membrane element 5 is arranged in the facultative tank 4, a second pipeline 7 is arranged at the upper part of the membrane element 5, and a water production pump 8 is arranged on a pipe section of the second pipeline 7 protruding out of the facultative tank 4; the reaction process is effectively shortened, and the nitrification and denitrification rates are improved; the hydraulic retention time is shortened; the oxygen demand of the short-cut nitrification is reduced by 25 percent, and the energy consumption is reduced; effectively saving 40% of carbon source as hydrogen donor; the discharge amount of the residual sludge is reduced; a temperature transmitter 9 and a heating coil 10 are arranged in the raw water tank 1; the heating coil 10 heats the raw water, and the temperature transmitter 9 accurately controls the temperature of the raw water on line, so that the reaction process is effectively shortened, and the nitrification and denitrification rates are improved; a filler 11 is arranged in the anoxic tank 2, and the filler 11 is in a honeycomb shape or a corrugated plate shape; the oxygen-poor pool 2 has enough concentration of mixed liquid suspended matters to facilitate denitrification; a microporous air diffuser 12 and an oxygen dissolving instrument 13 are arranged in the aerobic tank 3, a third pipeline 14 is arranged at one end of the microporous air diffuser 12, one end of the third pipeline 14 is connected with the microporous air diffuser 12, a fan 15 is arranged at the other end of the third pipeline 14 protruding out of the aerobic tank 3, a first regulating valve 16 is arranged on a pipe section between the microporous air diffuser 12 and the fan 15 protruding out of the aerobic tank 3, and a first flowmeter 17 is arranged on a pipe section between the first regulating valve 16 and the fan 15; the fan 15 supplies air to the aerobic tank 3 through the microporous air diffuser 12 for aeration to provide dissolved oxygen, the ammonifying bacteria oxidize organic matters in an aerobic environment, and the first regulating valve 16, the first flow meter 17 and the dissolved oxygen meter 13 are linked to control the aeration flow on line; an online ammonia nitrogen instrument 18 and an online PH instrument 19 are arranged in the facultative tank 4, a fourth pipeline 20 is also arranged in the facultative tank 4, one end of the fourth pipeline 20 is arranged in the facultative tank 4, the other end of the fourth pipeline 20 protruding out of the facultative tank 4 is provided with an alkali metering tank 21, a pipe section of the fourth pipeline 20 protruding out of the facultative tank 4 is provided with an alkali metering pump 22, the bottom of the facultative tank 4 is provided with a second regulating valve 23, and the second regulating valve 23 is connected with a bottom pipeline of the facultative tank 4; conveying alkali liquor in an alkali metering box 21 to the facultative tank 4 through an alkali metering pump 22, monitoring the nitrification effect of the facultative tank through an online ammonia nitrogen instrument 18, and controlling the PH in the facultative tank 4 on line through linkage of an online PH instrument 19 and the alkali metering pump 22; a raw water pump 24 is arranged on the first pipeline 6, a third regulating valve 25 is arranged on a pipe section between the raw water pump 24 and the anoxic pond 2, and a second flowmeter 26 is arranged on a pipe section between the third regulating valve 25 and the raw water pump 24; the third regulating valve 25 and the second flowmeter 26 are interlocked to control the raw water pump 24 on line, so as to control the water outlet flow of the raw water flowing into the anoxic pond 2; a fifth pipeline 27 is arranged on the side wall of the facultative tank 4, one end of the fifth pipeline 27 is connected with the side wall of the facultative tank 4, the other end of the fifth pipeline 27 is connected to a pipe section between the third regulating valve 25 and the anoxic tank 2, a fourth regulating valve 28 is arranged on the fifth pipeline 27, a reflux pump 29 is arranged on the pipe section between the fourth regulating valve 28 and the facultative tank 4, and a third flow meter 30 is arranged on the pipe section between the reflux pump 29 and the fourth regulating valve 28; the reflux pump 29 refluxes the sewage in the facultative tank 4 to the anoxic tank 2 to provide nitrified liquid, and the fourth regulating valve 28 and the third flow meter 30 are interlocked to control the effluent flow on line.

s1, storing raw water in a raw water tank (1), homogenizing and homogenizing, heating the raw water to 30 ℃ by a heating coil (10), and accurately controlling the temperature of the raw water on line by a temperature transmitter (9);

s3, enabling a mixed solution of raw water and nitrifying liquid in the anoxic pond (2) to flow into the aerobic pond (3), supplying air into the aerobic pond (3) through the microporous air diffuser (12) by the fan (15), carrying out aeration reaction on the mixed solution of the raw water and the nitrifying liquid to provide dissolved oxygen, controlling the aeration amount on line by the dissolved oxygen meter (13), controlling the dissolved oxygen in the aerobic pond (3) to be 3mg/L, and oxidizing ammonia nitrogen in the mixed solution of the raw water and the nitrifying liquid into nitrite nitrogen and nitrate nitrogen under aerobic conditions to form a mixed solution of the nitrite nitrogen and the nitrate nitrogen;

s4, enabling a nitrite-nitrogen-nitrate mixed solution to flow into a facultative tank (4), conveying alkali liquor in an alkali metering box (21) to the facultative tank (4) through an alkali metering pump (22), interlocking an online pH instrument (19) with the alkali metering pump (22), controlling the pH value of the nitrite-nitrogen-nitrate mixed solution in the facultative tank (4) on line, controlling the pH value to be 8.2, monitoring the nitrification effect of the nitrite-nitrogen-nitrate mixed solution in the facultative tank (4) through an online ammonia-nitrogen instrument (18), wherein the nitrite-nitrogen-nitrate mixed solution contains nitrite nitrogen and nitrate nitrogen, and the ratio of nitrite nitrogen is higher than that of nitrate nitrogen through controlling the pH, temperature, dissolved oxygen and other measures to form a high nitrite-nitrogen-low-nitrate mixed solution;

Example 11 of the invention: a biochemical system for sewage by short-cut nitrification and denitrification comprises a raw water tank 1, an anoxic tank 2, an aerobic tank 3, a facultative tank 4 and a membrane element 5, wherein a first pipeline 6 is arranged between the raw water tank 1 and the anoxic tank 2, the raw water tank 1 is connected with the anoxic tank 2 through the first pipeline 6, the bottoms of the anoxic tank 2, the aerobic tank 3 and the facultative tank 4 are sequentially communicated, the membrane element 5 is arranged in the facultative tank 4, a second pipeline 7 is arranged at the upper part of the membrane element 5, and a water production pump 8 is arranged on a pipe section of the second pipeline 7 protruding out of the facultative tank 4; the reaction process is effectively shortened, and the nitrification and denitrification rates are improved; the hydraulic retention time is shortened; the oxygen demand of the short-cut nitrification is reduced by 25 percent, and the energy consumption is reduced; effectively saving 40% of carbon source as hydrogen donor; the discharge amount of the residual sludge is reduced; a temperature transmitter 9 and a heating coil 10 are arranged in the raw water tank 1; the heating coil 10 heats the raw water, and the temperature transmitter 9 accurately controls the temperature of the raw water on line, so that the reaction process is effectively shortened, and the nitrification and denitrification rates are improved; a filler 11 is arranged in the anoxic tank 2, and the filler 11 is in a honeycomb shape or a corrugated plate shape; the oxygen-poor pool 2 has enough concentration of mixed liquid suspended matters to facilitate denitrification; a microporous air diffuser 12 and an oxygen dissolving instrument 13 are arranged in the aerobic tank 3, a third pipeline 14 is arranged at one end of the microporous air diffuser 12, one end of the third pipeline 14 is connected with the microporous air diffuser 12, a fan 15 is arranged at the other end of the third pipeline 14 protruding out of the aerobic tank 3, a first regulating valve 16 is arranged on a pipe section between the microporous air diffuser 12 and the fan 15 protruding out of the aerobic tank 3, and a first flowmeter 17 is arranged on a pipe section between the first regulating valve 16 and the fan 15; the fan 15 supplies air to the aerobic tank 3 through the microporous air diffuser 12 for aeration to provide dissolved oxygen, the ammonifying bacteria oxidize organic matters in an aerobic environment, and the first regulating valve 16, the first flow meter 17 and the dissolved oxygen meter 13 are linked to control the aeration flow on line; an online ammonia nitrogen instrument 18 and an online PH instrument 19 are arranged in the facultative tank 4, a fourth pipeline 20 is also arranged in the facultative tank 4, one end of the fourth pipeline 20 is arranged in the facultative tank 4, the other end of the fourth pipeline 20 protruding out of the facultative tank 4 is provided with an alkali metering tank 21, a pipe section of the fourth pipeline 20 protruding out of the facultative tank 4 is provided with an alkali metering pump 22, the bottom of the facultative tank 4 is provided with a second regulating valve 23, and the second regulating valve 23 is connected with a bottom pipeline of the facultative tank 4; conveying alkali liquor in an alkali metering box 21 to the facultative tank 4 through an alkali metering pump 22, monitoring the nitrification effect of the facultative tank through an online ammonia nitrogen instrument 18, and controlling the PH in the facultative tank 4 on line through linkage of an online PH instrument 19 and the alkali metering pump 22; a raw water pump 24 is arranged on the first pipeline 6, a third regulating valve 25 is arranged on a pipe section between the raw water pump 24 and the anoxic pond 2, and a second flowmeter 26 is arranged on a pipe section between the third regulating valve 25 and the raw water pump 24; the third regulating valve 25 and the second flowmeter 26 are interlocked to control the raw water pump 24 on line, so as to control the water outlet flow of the raw water flowing into the anoxic pond 2; a fifth pipeline 27 is arranged on the side wall of the facultative tank 4, one end of the fifth pipeline 27 is connected with the side wall of the facultative tank 4, the other end of the fifth pipeline 27 is connected to a pipe section between the third regulating valve 25 and the anoxic tank 2, a fourth regulating valve 28 is arranged on the fifth pipeline 27, a reflux pump 29 is arranged on the pipe section between the fourth regulating valve 28 and the facultative tank 4, and a third flow meter 30 is arranged on the pipe section between the reflux pump 29 and the fourth regulating valve 28; the reflux pump 29 refluxes the sewage in the facultative tank 4 to the anoxic tank 2 to provide nitrified liquid, and the fourth regulating valve 28 and the third flow meter 30 are interlocked to control the effluent flow on line.

s1, storing raw water in a raw water tank (1), homogenizing and homogenizing, heating the raw water to 33 ℃ by a heating coil (10), and accurately controlling the temperature of the raw water on line by a temperature transmitter (9);

s3, enabling a mixed solution of raw water and nitrifying liquid in the anoxic pond (2) to flow into the aerobic pond (3), supplying air into the aerobic pond (3) through a microporous air diffuser (12) by a fan (15), carrying out aeration reaction on the mixed solution of the raw water and the nitrifying liquid to provide dissolved oxygen, controlling the aeration quantity on line by an oxygen dissolving instrument (13), controlling the dissolved oxygen in the aerobic pond (3) to be 2mg/L, and oxidizing ammonia nitrogen in the mixed solution of the raw water and the nitrifying liquid into nitrite nitrogen and nitrate nitrogen under aerobic conditions to form a mixed solution of the nitrite nitrogen and the nitrate nitrogen;

s4, enabling a nitrite-nitrogen-nitrate mixed solution to flow into a facultative tank (4), conveying alkali liquor in an alkali metering box (21) to the facultative tank (4) through an alkali metering pump (22), interlocking an online pH instrument (19) with the alkali metering pump (22), controlling the pH value of the nitrite-nitrogen-nitrate mixed solution in the facultative tank (4) on line, controlling the pH value to be 8.1, monitoring the nitrification effect of the nitrite-nitrogen-nitrate mixed solution in the facultative tank (4) through an online ammonia-nitrogen instrument (18), wherein the nitrite-nitrogen-nitrate mixed solution contains nitrite nitrogen and nitrate nitrogen, and the ratio of nitrite nitrogen is higher than that of nitrate nitrogen through controlling the pH, temperature, dissolved oxygen and other measures to form a high nitrite-nitrogen-low-nitrate mixed solution;

Example 12 of the present invention: a biochemical system for sewage by short-cut nitrification and denitrification comprises a raw water tank 1, an anoxic tank 2, an aerobic tank 3, a facultative tank 4 and a membrane element 5, wherein a first pipeline 6 is arranged between the raw water tank 1 and the anoxic tank 2, the raw water tank 1 is connected with the anoxic tank 2 through the first pipeline 6, the bottoms of the anoxic tank 2, the aerobic tank 3 and the facultative tank 4 are sequentially communicated, the membrane element 5 is arranged in the facultative tank 4, a second pipeline 7 is arranged at the upper part of the membrane element 5, and a water production pump 8 is arranged on a pipe section of the second pipeline 7 protruding out of the facultative tank 4; the reaction process is effectively shortened, and the nitrification and denitrification rates are improved; the hydraulic retention time is shortened; the oxygen demand of the short-cut nitrification is reduced by 25 percent, and the energy consumption is reduced; effectively saving 40% of carbon source as hydrogen donor; the discharge amount of the residual sludge is reduced; a temperature transmitter 9 and a heating coil 10 are arranged in the raw water tank 1; the heating coil 10 heats the raw water, and the temperature transmitter 9 accurately controls the temperature of the raw water on line, so that the reaction process is effectively shortened, and the nitrification and denitrification rates are improved; a filler 11 is arranged in the anoxic tank 2, and the filler 11 is in a honeycomb shape or a corrugated plate shape; the oxygen-poor pool 2 has enough concentration of mixed liquid suspended matters to facilitate denitrification; a microporous air diffuser 12 and an oxygen dissolving instrument 13 are arranged in the aerobic tank 3, a third pipeline 14 is arranged at one end of the microporous air diffuser 12, one end of the third pipeline 14 is connected with the microporous air diffuser 12, a fan 15 is arranged at the other end of the third pipeline 14 protruding out of the aerobic tank 3, a first regulating valve 16 is arranged on a pipe section between the microporous air diffuser 12 and the fan 15 protruding out of the aerobic tank 3, and a first flowmeter 17 is arranged on a pipe section between the first regulating valve 16 and the fan 15; the fan 15 supplies air to the aerobic tank 3 through the microporous air diffuser 12 for aeration to provide dissolved oxygen, the ammonifying bacteria oxidize organic matters in an aerobic environment, and the first regulating valve 16, the first flow meter 17 and the dissolved oxygen meter 13 are linked to control the aeration flow on line; an online ammonia nitrogen instrument 18 and an online PH instrument 19 are arranged in the facultative tank 4, a fourth pipeline 20 is also arranged in the facultative tank 4, one end of the fourth pipeline 20 is arranged in the facultative tank 4, the other end of the fourth pipeline 20 protruding out of the facultative tank 4 is provided with an alkali metering tank 21, a pipe section of the fourth pipeline 20 protruding out of the facultative tank 4 is provided with an alkali metering pump 22, the bottom of the facultative tank 4 is provided with a second regulating valve 23, and the second regulating valve 23 is connected with a bottom pipeline of the facultative tank 4; conveying alkali liquor in an alkali metering box 21 to the facultative tank 4 through an alkali metering pump 22, monitoring the nitrification effect of the facultative tank through an online ammonia nitrogen instrument 18, and controlling the PH in the facultative tank 4 on line through linkage of an online PH instrument 19 and the alkali metering pump 22; a raw water pump 24 is arranged on the first pipeline 6, a third regulating valve 25 is arranged on a pipe section between the raw water pump 24 and the anoxic pond 2, and a second flowmeter 26 is arranged on a pipe section between the third regulating valve 25 and the raw water pump 24; the third regulating valve 25 and the second flowmeter 26 are interlocked to control the raw water pump 24 on line, so as to control the water outlet flow of the raw water flowing into the anoxic pond 2; a fifth pipeline 27 is arranged on the side wall of the facultative tank 4, one end of the fifth pipeline 27 is connected with the side wall of the facultative tank 4, the other end of the fifth pipeline 27 is connected to a pipe section between the third regulating valve 25 and the anoxic tank 2, a fourth regulating valve 28 is arranged on the fifth pipeline 27, a reflux pump 29 is arranged on the pipe section between the fourth regulating valve 28 and the facultative tank 4, and a third flow meter 30 is arranged on the pipe section between the reflux pump 29 and the fourth regulating valve 28; the reflux pump 29 refluxes the sewage in the facultative tank 4 to the anoxic tank 2 to provide nitrified liquid, and the fourth regulating valve 28 and the third flow meter 30 are interlocked to control the effluent flow on line.

s1, storing raw water in a raw water tank (1), homogenizing and homogenizing, heating the raw water to 35 ℃ by a heating coil (10), and accurately controlling the temperature of the raw water on line by a temperature transmitter (9);

s3, enabling a mixed solution of raw water and nitrifying liquid in the anoxic pond (2) to flow into the aerobic pond (3), supplying air into the aerobic pond (3) through a microporous air diffuser (12) by a fan (15), carrying out aeration reaction on the mixed solution of the raw water and the nitrifying liquid to provide dissolved oxygen, controlling the aeration quantity on line by an oxygen dissolving instrument (13), controlling the dissolved oxygen in the aerobic pond (3) to be 1mg/L, and oxidizing ammonia nitrogen in the mixed solution of the raw water and the nitrifying liquid into nitrite nitrogen and nitrate nitrogen under aerobic conditions to form a mixed solution of the nitrite nitrogen and the nitrate nitrogen;

s4, enabling a nitrite-nitrogen-nitrate mixed solution to flow into a facultative tank (4), conveying alkali liquor in an alkali metering box (21) to the facultative tank (4) through an alkali metering pump (22), interlocking an online pH instrument (19) with the alkali metering pump (22), controlling the pH value of the nitrite-nitrogen-nitrate mixed solution in the facultative tank (4) on line, controlling the pH value to be 7.9, monitoring the nitrification effect of the nitrite-nitrogen-nitrate mixed solution in the facultative tank (4) through an online ammonia-nitrogen instrument (18), wherein the nitrite-nitrogen-nitrate mixed solution contains nitrite nitrogen and nitrate nitrogen, and the ratio of nitrite nitrogen is higher than that of nitrate nitrogen through controlling the pH, temperature, dissolved oxygen and other measures to form a high nitrite-nitrogen-low-nitrate mixed solution;

The working principle of one embodiment of the invention is as follows: the method comprises the steps of firstly enabling sewage to enter an anoxic tank 2, arranging a filler 11 in the anoxic tank 2, and reducing nitrite nitrogen in nitrifying liquid flowing back from a facultative tank 4 into nitrogen by denitrifying bacteria attached to the filler 11 in the form of a biological membrane; then the sewage enters an aerobic pool 3, ammoniation bacteria oxidize ammonia nitrogen in the sewage into ammonia nitrogen, nitrite bacteria oxidize the ammonia nitrogen into nitrite nitrogen, and meanwhile nitrifying bacteria oxidize the ammonia nitrogen into nitrate nitrogen; finally, sewage flows into a facultative tank 4, the facultative tank 4 is a biological selector, nitrite bacteria become dominant strains relative to nitrifying bacteria by controlling the measures of PH, dissolved oxygen, residual sludge discharge and the like, a membrane element 5 is arranged in the facultative tank 4 to intercept activated sludge so as to improve the concentration of microorganisms in the mixed liquid, so that the activated sludge can achieve a better nitrification effect in a shorter time, and meanwhile, the quality of the effluent of the sewage can basically meet the requirement of deep treatment; the nitrified liquid is conveyed to the anoxic tank 2 through the return pump 29, denitrifying bacteria in the anoxic tank 2 reduce nitrite nitrogen in the nitrified liquid into nitrogen by taking biological oxygen demand of sewage as a carbon source, and the return water passes through the membrane element 5 under the action of negative pressure suction of the water producing pump 8 to be discharged to form regenerated water.

Claims

1. The utility model provides a biochemical system of denitrification sewage is nitrified to short distance, its characterized in that, includes former water tank (1), oxygen deficiency pond (2), good oxygen pond (3), facultative tank (4) and film element (5), be provided with first pipeline (6) between former water tank (1) and oxygen deficiency pond (2), former water tank (1) is connected with oxygen deficiency pond (2) through first pipeline (6), oxygen deficiency pond (2), good oxygen pond (3) and facultative tank (4) bottom communicate in proper order, film element (5) set up in facultative tank (4), and the upper portion of film element (5) is provided with second pipeline (7), second pipeline (7) protrusion is provided with product water pump (8) on the pipeline section in facultative tank (4).

2. The biochemical system for short-cut nitrification and denitrification of sewage according to claim 1, wherein a temperature transmitter (9) and a heating coil (10) are arranged in the raw water tank (1).

3. The biochemical system for short-cut nitrification and denitrification of sewage according to claim 1, wherein the anoxic tank (2) is internally provided with a filler (11), and the filler (11) is in a honeycomb shape or a corrugated plate shape.

4. The biochemical system for short-cut nitrification and denitrification of sewage according to claim 1, wherein a microporous air diffuser (12) and an oxygen dissolving instrument (13) are arranged in the aerobic tank (3), one end of the microporous air diffuser (12) is provided with a third pipeline (14), one end of the third pipeline (14) is connected with the microporous air diffuser (12), the other end of the third pipeline (14) protruding out of the aerobic tank (3) is provided with a fan (15), a first regulating valve (16) is arranged on a pipe section protruding out of the aerobic tank (3) between the microporous air diffuser (12) and the fan (15), and a first flowmeter (17) is arranged on a pipe section between the first regulating valve (16) and the fan (15).

5. The biochemical system for the short-cut nitrification and denitrification of the sewage according to claim 1, wherein an online ammonia nitrogen instrument (18) and an online pH instrument (19) are arranged in the facultative tank (4), a fourth pipeline (20) is further arranged in the facultative tank (4), one end of the fourth pipeline (20) is arranged in the facultative tank (4), the other end of the fourth pipeline (20) protruding out of the facultative tank (4) is provided with an alkali metering tank (21), an alkali metering pump (22) is arranged on a pipe section of the fourth pipeline (20) protruding out of the facultative tank (4), the bottom of the facultative tank (4) is provided with a second regulating valve (23), and the second regulating valve (23) is connected with a bottom pipe of the facultative tank (4).

6. The biochemical system for short-cut nitrification and denitrification of sewage according to claim 1, wherein the first pipeline (6) is provided with a raw water pump (24), a pipe section between the raw water pump (24) and the anoxic tank (2) is provided with a third regulating valve (25), and a pipe section between the third regulating valve (25) and the raw water pump (24) is provided with a second flowmeter (26).

7. The biochemical system for short-cut nitrification and denitrification of sewage according to claim 6, wherein a fifth pipeline (27) is arranged on the side wall of the facultative tank (4), one end of the fifth pipeline (27) is connected with the side wall of the facultative tank (4), the other end of the fifth pipeline (27) is connected to the pipe section between the third regulating valve (25) and the anoxic tank (2), a fourth regulating valve (28) is arranged on the fifth pipeline (27), a reflux pump (29) is arranged on the pipe section between the fourth regulating valve (28) and the facultative tank (4), and a third flow meter (30) is arranged on the pipe section between the reflux pump (29) and the fourth regulating valve (28).

8. A biochemical method of a short-cut nitrification and denitrification sewage biochemical system is characterized by comprising the following steps: