CN111362522A

CN111362522A - High-nitrogen wastewater treatment method and system

Info

Publication number: CN111362522A
Application number: CN202010288860.5A
Authority: CN
Inventors: 桂琪; 骆政; 梁朋
Original assignee: Guangzhou Environmental Protection Technology Co ltd Ebizal Source
Current assignee: Guangzhou Environmental Protection Technology Co ltd Ebizal Source
Priority date: 2020-04-14
Filing date: 2020-04-14
Publication date: 2020-07-03

Abstract

The invention discloses a high-nitrogen wastewater treatment method and system. The high-nitrogen wastewater treatment method comprises the following steps: introducing the waste water into a water collecting tank after removing slag; lifting the wastewater and the resin concentrated solution to a regulating tank and homogenizing and equalizing the wastewater and the resin concentrated solution; uniformly distributing the water quantity to a subsequent multi-section A/O system for treatment after the water is homogenized and uniformly distributed in the regulating tank; effluent of the multi-section A/O system automatically flows into an MBR membrane system for purification treatment; and lifting the effluent of the MBR membrane system to a deep denitrification system for enhanced denitrification. The high-nitrogen wastewater treatment system can be used for realizing the high-nitrogen wastewater treatment method and comprises a water collecting tank, a regulating tank, a multi-section A/O system, an MBR (membrane bioreactor) system and a deep denitrification system which are sequentially connected. The method comprises the steps of slag removal, adjusting tank adjustment, A/O system denitrification, MBR membrane system purification, deep denitrification system enhanced denitrification and the like, and the wastewater is treated in steps, so that the wastewater is purified, the total nitrogen content in the wastewater is reduced, and the effluent quality meets the V-type water quality requirement.

Description

High-nitrogen wastewater treatment method and system

Technical Field

The invention relates to the technical field of wastewater treatment, in particular to a high-nitrogen wastewater treatment method and system.

Background

The sewage of the wastewater treatment station comprises production sewage, domestic sewage and accident sewage (accident pool and wastewater)The processing stations are adjacent). The nitric acid device district is equipped with the neutralization pond during normal production, and ammonium nitrate device district is equipped with technology steam condensate recovery unit (electrodialysis method), and the high concentration sewage that has the short time during abnormal production discharges to the waste water treatment station. And returning the recycled water to the regulating reservoir when the recycled water monitoring is unqualified. The main sewage is coke oven gas condensate, conversion condensate, gas compression separation water, analysis and test water, circulating water sewage, domestic sewage and the like, and the above waste water is treated by a waste water treatment station. The sewage station is required to have the treatment capacity of 120m³H is 2880m³And d, the COD of the effluent water quality is less than or equal to 30mg/L, and other indexes meet the V-type water quality requirement of the environmental quality Standard of surface water (GB 3838-2002).

After the wastewater is treated by the system, except that COD is less than or equal to 30mg/L, other indexes execute the V-type water quality requirements (unit: mg/L, except temperature and pH) of the environmental quality Standard of surface Water (GB3838-2002), and the following table is shown:

item

COD

SS

Cyanide compounds

Sulfide compound

TN

NH₃-N

TP

Oils, their preparation and their use

Volatile phenols

pH

Index (I)

≤30

≤20

≤0.2

≤1

≤2

≤0.4

≤1

≤0.1

6.0-9.0

TABLE 1

The denitrification resin adsorption system in the prior art lacks the regeneration function against the current, can only suitably prolong resin life, need take out the denitrification resin in the jar body and carry out backwash and forward wash, complex operation, influence waste water treatment efficiency, the waste water after whole waste water treatment system handles moreover hardly satisfies above-mentioned index requirement, especially total nitrogen content exceeds standard, and quality of water can not reach V class quality of water requirement, causes environmental pollution.

Disclosure of Invention

Based on the above, the invention aims to provide a high-nitrogen wastewater treatment method and system.

The high-nitrogen wastewater treatment method comprises the following steps:

introducing the waste water into a water collecting tank after removing slag;

lifting the wastewater and the resin concentrated solution to a regulating tank and homogenizing and equalizing the wastewater and the resin concentrated solution;

uniformly distributing the water quantity to a subsequent multi-section A/O system for treatment after the water is homogenized and uniformly distributed in the regulating tank;

effluent of the multi-section A/O system automatically flows into an MBR membrane system for purification treatment;

and lifting the effluent of the MBR membrane system to a deep denitrification system for enhanced denitrification.

The high-nitrogen wastewater treatment method comprises the steps of slag removal, regulation of a regulating tank, denitrification of an A/O system, purification of an MBR (membrane bioreactor) membrane system, enhanced denitrification of a deep denitrification system and the like, and the wastewater is treated in steps, so that the wastewater is purified, the total nitrogen content in the wastewater is reduced, and the quality of effluent water meets the V-type water quality requirement.

In some embodiments, the introducing the waste water into the collecting tank after removing the slag includes: removing residues of the wastewater through a grid, and performing oil removal and cooling in a pretreatment section flowing into a water collecting tank to ensure that the oil content of the wastewater is less than or equal to 3mg/L and the temperature is less than or equal to 40 ℃. Before the wastewater is introduced into the water collecting tank, slag is removed, so that large-particle waste in the wastewater is prevented from being introduced into a high-nitrogen wastewater treatment system, and the safety of equipment is ensured; oil removal and temperature reduction treatment, so that the wastewater is easier to be subjected to subsequent treatment.

In some embodiments, the following processing in the multi-stage a/O system includes: and a carbon source in water is supplemented before each section of A pool of the multi-section A/O system, a mixed liquid reflux pump is arranged at the tail end of a final-stage O pool of the multi-section A/O system, and the nitrified mixed liquid is returned to the front of the first-stage A pool, so that the completion of denitrification is ensured. Because the carbon source in the raw water is less, the completion of the reverse digestion can be ensured by supplementing the carbon source in the water.

In some embodiments, the MBR membrane system is subjected to a purification treatment, comprising: and filtering by the MBR membrane system for 8min, intermittently performing for 2min, and continuously aerating in the tank. The MBR membrane system can fully purify the wastewater by filtering and intermittent treatment and continuous aeration.

In some embodiments of the technical scheme, the MBR membrane system is subjected to online water backwashing once a day, is subjected to online chemical cleaning once in 2-4 weeks, and is subjected to offline chemical cleaning once in 3-12 months. Through online backwash, online chemical backwash and off-line chemical backwash, wash the maintenance to MBR membrane system, avoid it to appear blockking up and reduce purifying effect.

In some embodiments of the above technical solution, sludge obtained after the MBR membrane system is subjected to purification treatment is conveyed to a sludge dewatering system through a pump, sludge cake is formed after dewatering treatment and is transported to an outside, and filtrate generated by dewatering treatment is led to a regulating tank. The sludge is dewatered, the sludge is convenient to transport, and the environmental pollution can be avoided.

In some embodiments, the raising of the effluent of the MBR membrane system to a deep denitrification system for enhanced denitrification includes: the wastewater enters a resin bed layer for adsorption to remove nitrate nitrogen;

regenerating with sodium chloride of 1.5-2.5 times of the volume of the single-column resin at a flow rate of 3-4Bv/h, and eluting nitrate nitrogen from the resin;

washing the resin with water of 2-4 times of the volume of the single-column resin at a flow rate of 3-4 Bv/h;

the resin is washed by water with the volume of 1-2 times of the volume of the single-column resin, and the flow rate is the same as the inflow water flow rate.

Nitrate nitrogen is removed through resin adsorption, and the resin is regenerated, leached slowly and washed quickly, so that the nitrate nitrogen is eluted from the resin, and the adsorption effect of the resin is recovered.

In some embodiments, the raising of the effluent of the MBR membrane system to a deep denitrification system for enhanced denitrification includes: if the total nitrogen concentration of the effluent is higher than 12mg/L, the effluent enters a denitrification filter;

if the total nitrogen concentration of the effluent is lower than 12mg/L, the effluent is directly adsorbed by resin, and the total nitrogen is treated to reach the standard of surface V-type water and then can be discharged after reaching the standard.

The wastewater with the total nitrogen concentration higher or lower than 12mg/L is respectively treated, so that the denitrification effect can be improved.

The invention further provides a high-nitrogen wastewater treatment system which can be used for realizing any one of the high-nitrogen wastewater treatment methods, and the high-nitrogen wastewater treatment system comprises a water collecting tank, a regulating tank, a multi-section A/O system, an MBR (membrane bioreactor) system and a deep denitrification system which are connected in sequence, wherein,

the water collecting tank is used for introducing the waste water after slag removal;

the adjusting tank is used for lifting the wastewater and the resin concentrated solution into a homogenizing and equalizing amount;

the multi-section A/O system is used for uniformly distributing water quantity to the water after the water is homogenized and uniformly distributed by the regulating tank for post-treatment;

the MBR membrane system is used for automatically flowing the effluent of the multi-section A/O system into the MBR membrane system and performing purification treatment;

and the deep denitrification system is used for enhancing denitrification after lifting the effluent of the MBR membrane system.

The high-nitrogen wastewater treatment method and the high-nitrogen wastewater treatment system respectively carry out the steps of slag removal, regulation of the regulating tank, denitrification of the A/O system, purification of the MBR membrane system, enhanced denitrification of the deep denitrification system and the like by arranging the water collecting tank, the regulating tank, the multi-section A/O system, the MBR membrane system and the deep denitrification system, and treat the wastewater in steps, so that the wastewater is purified, the total nitrogen content in the wastewater is reduced, and the quality of the effluent reaches the V-type water quality requirement.

For a better understanding and practice, the invention is described in detail below with reference to the accompanying drawings.

Drawings

FIG. 1 is a block flow diagram of a high nitrogen wastewater treatment process of the present invention.

FIG. 2 is an exemplary flow diagram of a multi-segment A/O system.

Fig. 3 is an exemplary flow diagram of an MBR membrane system.

FIG. 4 is an exemplary flow diagram of a deep denitrification system.

Detailed Description

The terms of orientation of up, down, left, right, front, back, top, bottom, and the like, referred to or may be referred to in this specification, are defined relative to their configuration, and are relative concepts. Therefore, it may be changed according to different positions and different use states. Therefore, these and other directional terms should not be construed as limiting terms.

The implementations described in the exemplary embodiments below are not intended to represent all implementations consistent with the present disclosure. Rather, they are merely examples of methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.

The terminology used in the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used in this disclosure and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

Referring to FIG. 1, FIG. 1 is a block diagram of a process for treating high-nitrogen wastewater according to the present invention.

The high-nitrogen wastewater treatment method comprises the following steps:

step 101, introducing the waste water into a water collecting tank after removing slag;

step 102, lifting the wastewater and the resin concentrated solution to a regulating tank and homogenizing;

step 103, uniformly distributing the water quantity to a subsequent multi-section A/O system for treatment after the water is homogenized and uniformly distributed by the regulating reservoir;

104, enabling effluent of the multi-section A/O system to automatically flow into an MBR (membrane bioreactor) membrane system for purification treatment;

and 105, lifting the effluent of the MBR membrane system to a deep denitrification system for enhanced denitrification.

The high-nitrogen wastewater treatment system can be used for realizing the high-nitrogen wastewater treatment method, and comprises a water collecting tank, a regulating tank, a multi-section A/O system, an MBR membrane system and a deep denitrification system which are connected in sequence, wherein,

The method comprises the steps of slag removal, regulation of a regulating tank, denitrification of an A/O system, purification of an MBR membrane system, enhanced denitrification of an advanced denitrification system and the like, and the wastewater is treated in steps, so that the wastewater is purified, the total nitrogen content in the wastewater is reduced, and the quality of the effluent reaches the V-type water quality requirement.

Specifically, in step 101, the step of introducing the waste water into the water collecting tank after removing the slag includes: removing residues of the wastewater through a grid, and performing oil removal and cooling in a pretreatment section flowing into a water collecting tank to ensure that the oil content of the wastewater is less than or equal to 3mg/L and the temperature is less than or equal to 40 ℃. Before the wastewater is introduced into the water collecting tank, slag is removed, so that large-particle waste in the wastewater is prevented from being introduced into a high-nitrogen wastewater treatment system, and the safety of equipment is ensured; oil removal and temperature reduction treatment, so that the wastewater is easier to be subjected to subsequent treatment.

For example, 120m may be used³And h, carrying out slag removal treatment on workshop wastewater through a grating.

In the step 102, there may be one regulating reservoir, and of course, a plurality of regulating reservoirs may be preferably arranged by modification and addition, for example, a 1# regulating reservoir and a 2# regulating reservoir are arranged to perform uniform water quality and water quantity.

In the step 103, the processing in the subsequent multi-stage a/O system includes: and a carbon source in water is supplemented before each section of A pool of the multi-section A/O system, a mixed liquid reflux pump is arranged at the tail end of a final-stage O pool of the multi-section A/O system, and the nitrified mixed liquid is returned to the front of the first-stage A pool, so that the completion of denitrification is ensured. Because the carbon source in the raw water is less, the completion of the reverse digestion can be ensured by supplementing the carbon source in the water.

The carbon source can adopt sodium acetate, glucose, flour, methanol and the like, the former two carbon sources are used more, and the purity is high, the cod value is stable, and the biodegradability is good. The flour has large cod fluctuation and the adding amount is not well determined due to different batches. Methanol is a dangerous article, has high use and storage requirements, and is gradually replaced and not used unless the methanol is produced in the factory.

Referring further to FIG. 2, FIG. 2 is an exemplary flow diagram of a multi-stage A/O system.

In the figure, a pool A is an anoxic pool and is used for carrying out denitrification reaction to reduce nitrogen in nitrate into gaseous nitrogen for denitrification and COD reduction; the O tank is an aerobic tank and performs nitration reaction to convert the ammonia salt into nitrite and nitrate; and sewage in the O tank flows back to the A tank, a mixed liquid reflux pump is arranged at the tail end of the second-level O2 tank, and the nitrified mixed liquid is returned to the front of the first-level A tank to ensure the completion of denitrification.

Under aerobic conditions, nitrogenous organic matters are decomposed into ammonia by bacteria, are further converted into nitrite under the action of nitrosobacteria, and are converted into nitrate under the action of nitrobacteria, so that the nitration reaction is completed;

under the anoxic condition, the facultative heterotrophic bacteria utilize the organic carbon source in water as electron donor and nitrate as electron acceptor to replace molecular oxygen for anaerobic respiration to decompose organic matter and reduce nitrogen in nitrate into gaseous nitrogen, so as to complete denitrification and reduce chemical oxygen demand.

The multi-section A/O system can realize the conversion of the A, O pool and adjust the reaction scale of nitrification and denitrification according to the characteristics of water inlet indexes.

When the system normally operates, the system is an AOOAOO process, F1, F2, F3, F4, F5, F7 and F8 are opened, F6 and F9 are closed, primary O2 flows back to a primary A pool, and a secondary O2 pool flows back to the primary A pool and a secondary A pool; f1 is closed, the primary O1 pool is converted into an anoxic pool, the system is an AAOAOO process, F2, F3, F4, F5, F6, F7 and F8 are opened, F1 and F9 are closed, the primary O2 flows back to the primary A pool and the primary O1 pool, and the secondary O2 pool flows back to the primary A pool, the primary O1 pool and the secondary A pool; f1 and F3 are closed, a primary O1 pool and a secondary O1 pool are converted into anoxic pools, the system is an AAOAAO process, F2, F4, F5, F6, F7, F8 and F9 are opened, F1 and F3 are closed, primary O2 flows back to a primary A pool and a primary O1 pool, and a secondary O2 pool flows back to a primary A pool, a primary O1 pool, a secondary A pool and a secondary O1 pool.

Referring further to fig. 3, fig. 3 is an exemplary flow diagram of an MBR membrane system.

In step 104, the MBR membrane system is subjected to a purification treatment, including: and filtering by the MBR membrane system for 8min, intermittently performing for 2min, and continuously aerating in the tank. The MBR membrane system can fully purify the wastewater by filtering and intermittent treatment and continuous aeration.

Preferably, the MBR membrane system is subjected to online water backwashing once a day, is subjected to online chemical cleaning once in 2-4 weeks and is subjected to offline chemical cleaning once in 3-12 months. The cleaning period can be adjusted by combining the water quality of the inlet water. Through online backwash, online chemical backwash and off-line chemical backwash, wash the maintenance to MBR membrane system, avoid it to appear blockking up and reduce purifying effect.

Under the filtering action of the MBR membrane system, most pollutants are intercepted in the membrane tank, the sludge concentration in the tank is higher, and the pollutants in water can be more easily degraded.

Preferably, the sludge obtained after the MBR membrane system is purified is conveyed to a sludge dewatering system through a pump, sludge cakes are formed after dewatering treatment and are transported to the outside, and filtrate generated by dewatering treatment is led to a regulating reservoir. The sludge is dewatered, the sludge is convenient to transport, and the environmental pollution can be avoided.

In the step 105, the effluent of the MBR membrane system is lifted to a deep denitrification system for enhanced denitrification, which includes:

a. adsorption: the wastewater enters a resin bed layer for adsorption to remove nitrate nitrogen;

b. regeneration: regenerating with sodium chloride of 1.5-2.5 times of the volume of the single-column resin, preferably 2 times of the volume of the single-column resin, wherein the concentration of the sodium chloride is 10-15%, and the flow rate is 3-4Bv/h, and eluting nitrate nitrogen from the resin;

c. slow leaching: washing the resin with water of 2-4 times the volume of the single-column resin, preferably 3 times the volume of the single-column resin, at a flow rate of 3-4 Bv/h;

d. quick washing: the resin is washed by water with 1-2 times of the volume of the single-column resin, preferably 1.5 times of the volume of the single-column resin, and the flow rate is the same as the water inlet flow rate.

The resin type is macroporous adsorption resin, polystyrene, polyacrylate or polyacrylamide, and the resin exists in the form of particles.

The regeneration is a countercurrent regeneration process, the countercurrent regeneration of the denitrification resin can be carried out during normal denitrification, the purposes of dual-purpose regeneration and cyclic alternate use are realized, the vertical taking-out in the tank body is not required for backwashing and forward washing, the operation is reduced, and the wastewater treatment efficiency is greatly improved.

Both slow rinsing and fast rinsing are processes in the forward washing process. Through slow leaching and quick rinsing, the liquid nitrogen and the residual saline solution on the resin can be further eluted, and the resin regeneration is realized.

Referring further to FIG. 4, FIG. 4 is an exemplary flow diagram of a deep denitrification system. The exemplary deep denitrification system comprises tanks No. 1, 2 and 3, and pipelines, valves and the like which are connected, each set of the exemplary deep denitrification system has the treatment capacity of 60 square/hour, the operation mode of a single set of devices is 2-stage series connection, and 1 set of devices is standby. The working principle is as follows:

the tank 1 and the tank 2 are connected in series for operation, and the tank 3 is reserved or regenerated; or 2 and 3 tanks are connected in series for operation, and the 1 tank is standby or regenerated; alternatively, tank No. 3 is run in series with tank No. 1 and tank No. 2 is either on standby or regenerated.

When 1 and 2 tanks are operated in series: f4, F8 and F11 are opened, the No. 3 tank is regenerated, salt is absorbed by backwashing, F15 and F3 are opened, then washing is carried out, F18 and F21 are opened, and other valves are in a closed state; 2 and 3 tanks in series: f5, F9 and F12 are opened, salt is absorbed by backwashing, F13 and F1 are opened, then washing is carried out, F16 and F19 are opened, and other valves are closed; and 3, when the tank is connected with the tank No. 1 in series: f6, F7 and F10 are opened, backwash salt absorption F14 and F2 are opened, then forward washing is carried out, F17 and F20 are opened, and other valves are closed.

Further, MBR membrane system goes out water and promotes to degree of depth denitrogenation system and carry out intensive denitrogenation, include: if the total nitrogen concentration of the effluent is higher than 12mg/L, the effluent enters a denitrification filter;

The water quality index (unit: mg/L, except temperature and pH) of the wastewater treated by the technical scheme of the invention is as follows:

TABLE 2

The effluent quality requirements (unit: mg/L) of each treatment stage are as follows:

index (mg/L)	COD	TN	NH₃-N	TP
					Multi-section A/O system and MBR membrane system effluent	≤30.00	≤20.00	≤2.00	≤0.40
Effluent of deep denitrification system	≤30.00	≤2.00	≤2.00	≤0.40

TABLE 3

The actual effluent quality (unit: mg/L) of each treatment stage is as follows:

TABLE 4

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.

Claims

1. A high-nitrogen wastewater treatment method is characterized by comprising the following steps:

introducing the waste water into a water collecting tank after removing slag;

2. The method for treating high-nitrogen wastewater according to claim 1, comprising: the water collecting tank is introduced after the wastewater is cleared, and the method comprises the following steps: removing residues of the wastewater through a grid, and performing oil removal and cooling in a pretreatment section flowing into a water collecting tank to ensure that the oil content of the wastewater is less than or equal to 3mg/L and the temperature is less than or equal to 40 ℃.

3. The method for treating high-nitrogen wastewater according to claim 1, comprising: the subsequent multi-segment A/O system processing comprises: and a carbon source in water is supplemented before each section of A pool of the multi-section A/O system, a mixed liquid reflux pump is arranged at the tail end of a final-stage O pool of the multi-section A/O system, and the nitrified mixed liquid is returned to the front of the first-stage A pool, so that the completion of denitrification is ensured.

4. The method for treating high-nitrogen wastewater according to claim 1, comprising: the MBR membrane system carries out purification treatment, including: and filtering by the MBR membrane system for 8min, intermittently performing for 2min, and continuously aerating in the tank.

5. The method for treating high-nitrogen wastewater according to claim 4, comprising: and carrying out online water backwashing on the MBR membrane system once a day, carrying out online chemical cleaning for 2-4 weeks, and carrying out offline chemical cleaning for 3-12 months.

6. The method for treating high-nitrogen wastewater according to claim 5, comprising: and conveying the sludge obtained after the MBR membrane system is subjected to purification treatment to a sludge dewatering system through a pump, carrying out dewatering treatment to form a sludge cake, and introducing filtrate generated by the dewatering treatment to a regulating tank.

7. The high-nitrogen wastewater treatment method according to any one of claims 1 to 6, characterized in that: the MBR membrane system goes out water and promotes to degree of depth denitrogenation system and carries out the intensive denitrogenation, includes: the wastewater enters a resin bed layer for adsorption to remove nitrate nitrogen;

8. The method for treating high-nitrogen wastewater according to claim 7, comprising: the MBR membrane system goes out water and promotes to degree of depth denitrogenation system and carries out the intensive denitrogenation, includes: if the total nitrogen concentration of the effluent is higher than 12mg/L, the effluent enters a denitrification filter;

9. A high-nitrogen wastewater treatment system for implementing the high-nitrogen wastewater treatment method according to any one of claims 1 to 8, comprising a collecting tank, a regulating tank, a multi-stage A/O system, an MBR membrane system and a deep denitrification system connected in sequence, wherein,