CN109534489B

CN109534489B - Culture method of efficient nitrifying bacteria

Info

Publication number: CN109534489B
Application number: CN201811522809.5A
Authority: CN
Inventors: 李海松; 许子聪; 建峥嵘; 邓军磊; 骆圣达; 张金涛
Original assignee: Zhihe Environmental Protection Technology Co ltd
Current assignee: Zhihe Environmental Protection Technology Co ltd
Priority date: 2018-12-13
Filing date: 2018-12-13
Publication date: 2020-10-02
Anticipated expiration: 2038-12-13
Also published as: CN109534489A

Abstract

The invention relates to a culture method of efficient nitrifying bacteria, which screens and enriches strains with efficient nitrifying capacity by adjusting the operation of a reactor. The invention is characterized in that under the condition of not changing the quality of inlet water, a large amount of nitrobacteria are quickly enriched by a method of shortening the aeration time, the problem of low proliferation content of the nitrobacteria is solved, and the load of a reactor and the load of sludge are improved. Compared with the culture method of improving the water inlet concentration by fixing the aeration time, the method can achieve higher volume load and sludge load, can reduce the volume of the reactor under the condition of the same water quality and water quantity, and saves the capital cost. The conventional activated sludge is cultured by using the actual wastewater, additional addition of nutrient substances and trace elements is not needed, the operation cost is saved, and the popularization and the use are facilitated. The automatic control device is adopted to control the operation of the reactor, thereby saving labor and reducing the idle time of the reactor. The enriched nitrobacteria have good treatment effect on high ammonia nitrogen and low ammonia nitrogen wastewater.

Description

Culture method of efficient nitrifying bacteria

Technical Field

The invention belongs to the field of water treatment application, and particularly relates to a culture method of efficient nitrifying bacteria, which is mainly used for rapidly enriching nitrifying bacteria with high-efficiency nitrifying capability and removing ammonia nitrogen in water by adjusting the operating parameters of a reactor, and is suitable for treating various industrial wastewater containing ammonia nitrogen and producing domestic sewage.

Background

With the development of socioeconomic and science, pesticides, fertilizers, industrial raw materials and the like are used in large quantities in production activities, and the water ecological environment gradually deteriorates. The nitrogen pollutants are one of the main reasons for water body pollution and eutrophication, so the removal of the nitrogen in the water body is of great significance for cleaning the water body.

It is generally considered that biological denitrification is performed by 2 processes of nitrification and denitrification, and nitrification is mainly performed by nitrifying bacteria. Nitrifying bacteria are chemoautotrophic bacteria with a nitrifying effect and comprise two physiological floras of nitrosobacteria and nitrifying bacteria. The main characteristics are as follows: autotrophic property, low growth rate, aerobic property, adhesiveness, acidity generation and the like. Due to the above characteristics of nitrifying bacteria, the content of nitrifying bacteria is low in a general sewage treatment system. The nitrifying bacteria are the microorganisms playing the most important role in biological nitrification, and the content of the nitrifying bacteria in the sewage is in direct proportion to the nitrification speed, so that the enrichment culture technology of the nitrifying bacteria is developed, the yield of the nitrifying bacteria is improved, and the method has important significance in the aspects of sewage treatment, environmental protection and the like. CN101240253A discloses a method for enriching nitrobacteria by gradually increasing the concentration of inlet water, but the degradation of high-concentration ammonia nitrogen needs to consume a large amount of alkalinity, which is not beneficial to the culture with actual waste water.

The invention aims to provide a method for culturing high-efficiency nitrifying bacteria, which can enrich a large amount of high-efficiency nitrifying bacteria in a short time by utilizing actual wastewater, and the cultured strains have high sludge load and high ammonia nitrogen degradation rate and can be applied to various industrial wastewater containing ammonia nitrogen and production domestic sewage.

Disclosure of Invention

Aiming at the problems of low content of nitrifying bacteria, slow nitrification rate and the like in a conventional sewage treatment system, the invention provides a new idea by combining the background technology, and the main contents are as follows: a method for culturing high-efficiency nitrifying bacteria.

The technical scheme of the invention is as follows:

and culturing the inoculated sludge by adopting a sequencing batch method, and screening and enriching the sludge by gradually shortening the aeration time. Culturing the strain in an adaptive reactor, wherein the inoculated sludge is flocculent sludge from a sewage treatment plant, and the sludge concentration is 3000-10000 mg/L; the operation of the reactor is accurately controlled by a Programmable Logic Controller (PLC), and the program of the PLC is edited to control the output of different signals so as to control the operation time of each operation stage; one cycle of operation includes: water feeding, aeration, sedimentation and water discharging, wherein the volume exchange ratio is 1/10-1/2; the aeration time is 12 h-1.5 h, and when the aeration time is shortest, the maximum volume load and the sludge load are reached; the aeration time is properly shortened under the conditions that the ammonia nitrogen in the effluent is not more than 5mg/L and the volume load improvement amount is not more than 40 percent according to the operating condition of the reactor; adopting high ammonia nitrogen wastewater to domesticate sludge, wherein the wastewater quality is as follows: ammonia nitrogen 100-400 mg/L, COD 100-800 mg/L; the reaction control conditions were: the pH value is 6.0-9.0, the dissolved oxygen is 3-8 mg/L, and the water temperature is 25-30 ℃. According to the sludge proliferation condition, sludge is discharged every 7-15 days, the reactor operates for about 30 days, and the discharged sludge has high-efficiency nitrification performance.

The invention is further improved as follows: under the condition of not changing the quality of inlet water, the aeration time is gradually shortened, the load of the reactor and the load of sludge are increased, the sludge is greatly proliferated under the condition of ensuring dissolved oxygen and sufficient nitrogen source, and a large amount of high-efficiency nitrobacteria are quickly cultured. Compared with the culture method of improving the water inlet concentration by fixing the aeration time, the method can achieve higher volume load and sludge load, can reduce the volume of the reactor under the condition of the same water quality and water quantity, and saves the capital cost. The low carbon-nitrogen ratio ensures the activity of heterotrophic bacteria symbiotic with nitrobacteria on one hand and provides a good growth environment for autotrophic nitrobacteria on the other hand. The requirement on the inoculated sludge is not high, and the flocculent sludge of various sewage treatment plants can be used as the inoculated sludge for culture.

The invention is characterized in that: a large amount of nitrobacteria can be rapidly enriched by the method for shortening the aeration time, and the problem of low proliferation rate and low content of the nitrobacteria is solved. When the cultured efficient nitrobacteria is used for wastewater treatment, the volume of the reactor can be greatly reduced, and the cost is saved. The conventional activated sludge is cultured by using the actual wastewater, additional addition of nutrient substances and trace elements is not needed, the operation cost is saved, and the popularization and the use are facilitated. The automatic control device is adopted to control the operation of the reactor, thereby saving labor and reducing the idle time of the reactor. The enriched nitrobacteria have good treatment effect on high ammonia nitrogen and low ammonia nitrogen wastewater.

Drawings

FIG. 1 is a schematic diagram of a reactor for culturing high-efficiency nitrifying bacteria

Reference numerals

1-a water inlet barrel; 2-a water inlet pump; 3-a water inlet; 4-an aeration head; 5-an aeration pump; 6-water outlet; 7-water outlet pump; 8-water outlet; 9-a reactor body; 10-a circuit; 11-PLC.

Detailed Description

The invention is further illustrated by way of example in the following figures:

FIG. 1 is a schematic diagram of a reactor for culturing nitrifying bacteria with high efficiency.

The reactor set-up is shown in FIG. 1, and the reactor operating scheme is described as follows:

the operation of the reactor was controlled by PLC 11: the water inlet pump 2 starts to operate through a power-on signal output by the PLC11, raw water enters the reactor main body 9 from the water inlet barrel 1, after water inlet is finished, the PLC11 controls the water inlet pump 3 to be disconnected, the aeration pump 5 starts to work, after the set aeration time length is reached, the PLC11 controls the aeration pump 5 to be disconnected, the water outlet pump 6 is started, water is discharged from the reactor, water discharging is finished, one period is finished, the PLC11 enters a circulation program, and the reactor enters the operation of the next period. The setting parameters of the PLC11 can be adjusted according to the requirements, and then the water inlet, aeration and drainage time can be controlled.

Example 1

The culture method is adopted to culture the sludge of a certain municipal sewage treatment plant. Establishing a square organic glass reactor with the volume of 12cm multiplied by 35cm and the effective volume of 4L, inoculating the sludge with the concentration of 4500mg/L, and regularly discharging the sludge according to the change of the sludge concentration in the reactor, wherein the minimum sludge concentration in the reactor is not less than 3000 mg/L; feeding water for 1min, aerating for 8-3h, precipitating for 10min, draining for 1min, and performing volume exchange at 1/2; the aeration time is 8h at the initial operating stage and is 3h at the final operating stage; the sewage used for culturing is the production wastewater of a certain fertilizer plant, and the water quality index is as follows: COD: 340mg/L, ammonia nitrogen 198mg/L and pH value 7.32. The reactor was run for 60 days, and after 30 days, the reactor had a steady high volumetric load, at which time the sludge load was also high, as detailed data in table 1.

Table 1 monitoring data for example 1

Example 2

The sludge of a sewage treatment plant in a certain industrial park is cultured by adopting the culture method. Establishing a square organic glass reactor with the effective volume of 100L and the sludge concentration of 8000mg/L, and regularly discharging sludge according to the change of the sludge concentration in the reactor, wherein the sludge concentration in the reactor is not less than 4000 mg/L; water is fed for 10min, aeration is carried out for 12-2h, sedimentation is carried out for 30min, water is discharged for 10min, and the volume exchange ratio is 1/4; the aeration time is 12h at the initial operating stage and 2h at the final operating stage; the sewage used for culturing is the production wastewater of a certain chemical plant, and the water quality index is as follows: COD: 530mg/L, ammonia nitrogen 298mg/L, and pH value 8.37. The reactor was run for a total of 80 days, and after 40 days, the reactor had a steady high volumetric load, at which time the sludge load was also high, as detailed data in table 2.

Table 2 monitoring data for example 2

Comparative example

A square organic glass reactor with the effective volume of 4L and the volume of 12cm multiplied by 35cm is established, nitrobacteria are cultured in a mode of fixing aeration time and increasing the ammonia nitrogen load of inlet water, and experimental water is simulated waste water prepared by tap water. The concentration of inoculated sludge is 4500mg/L, sludge is discharged periodically according to the change of the concentration of sludge in the reactor, and the lowest concentration of sludge in the reactor is not less than 3000 mg/L; feeding water for 1min, aerating for 8h, precipitating for 10min, draining for 1min, and fixing the aeration time according to the volume exchange ratio of 1/4; the ammonia nitrogen concentration of the inlet water at the initial stage of operation is 100mg/L, the ammonia nitrogen concentration of the inlet water at the end of operation is 700mg/L (at the moment, the reactor is inhibited by free ammonia toxicity, and the nitrification performance is obviously deteriorated), and the carbon source (methanol) is added according to the COD/N of 1.7 in the example 1. The reactor is operated for 60 days, the final volume load and the sludge load of the reactor are lower than those of the reactor in example 1, and the high-efficiency nitrobacteria culture method provided by the invention has obvious advantages, and the detailed data are shown in Table 3.

TABLE 3 monitoring data for comparative examples

Examples 1 and 2 used the same reactor as the comparative example, and examples 1 and 2 used the culture method of the present invention in which the aeration time was gradually shortened; the comparative example uses the culture method of fixing aeration time and increasing the water inlet concentration in the prior art. In example 1, the volumetric load reached 0.79 kgN/(m) on day 60³D), the sludge load reaches 0.26gN/(gMLSS d); however, in the comparative example, the highest volume loading was only 0.45 kgN/(m)³D), the sludge load is only 0.11gN/(gMLSS d), much less than in example 1. Therefore, the culture method of the invention can be used for culturing the high-efficiency nitrifying bacteria with higher sludge load and volume load.

Claims

1. A method for culturing efficient nitrifying bacteria is characterized by comprising the following steps: cultivating the inoculated sludge by adopting a sequencing batch method, and screening and enriching the sludge by gradually shortening the aeration time; the culture method is carried out in a matched reactor, and the operation of the reactor is controlled by a PLC (11);

the method for gradually shortening the aeration time comprises the following steps: the aeration time is gradually shortened according to a certain gradient, the ammonia nitrogen in effluent is ensured not to exceed 5mg/L after the aeration time is shortened, and the volume load increase is not more than 40%;

the inoculation sludge source of the reactor is flocculent sludge of a sewage treatment plant, and the sludge concentration is 3000-10000 mg/L; the water quality of the waste water used for culturing the strains is as follows: ammonia nitrogen 100-400 mg/L, COD 100-800 mg/L.

2. The culture method according to claim 1, wherein: one operating cycle of the reactor comprises: water inlet, aeration, precipitation and drainage; the volume exchange ratio of the reactor is 1/10-1/2; the reaction control conditions were: the pH value is 6.0-9.0, the dissolved oxygen is 3-8 mg/L, and the water temperature is 25-30 ℃.

3. The culture method according to claim 1, wherein: the aeration time is 12-1.5 h.