AU2020104390A4

AU2020104390A4 - A novel biological treatment process and device for mariculture tail water

Info

Publication number: AU2020104390A4
Application number: AU2020104390A
Authority: AU
Inventors: Baoshan Li; Chengqiang WANG
Original assignee: Shandong Marine Resource and Environment Research Institute
Current assignee: Shandong Marine Resource and Environment Research Institute
Priority date: 2020-12-30
Filing date: 2020-12-30
Publication date: 2021-03-18
Anticipated expiration: 2028-12-30

Abstract

The invention relates to a novel biological treatment process and device for mariculture tail water, belonging to that technical field of aquaculture tail water treatment. The process flow is as follows: mechanical filtration system -- protein separation system -- aerobic nitrification conversion system -- anaerobic denitrification conversion system -- COD reduction system -- disinfection and oxygenation system, all of which are communicated with each other by transmission pipelines, with different physical and chemical conditions. Because of the adoption of nitrifying bacteria and denitrifying bacteria screened from the bottom mud of marine aquaculture ponds, it is suitable for the growth of specific microorganisms which can improve the biotransformation rate of aquaculture tail water. Further, the microbial attachment base pressed by renewable materials has variable shape and low cost. The method can greatly improve the treatment efficiency of mariculture tail water, improve the utilization rate of seawater resources, reduce the adverse impact of mariculture on the environment, improve the repeated utilization rate of mariculture tail water by more than 15%, its process is simple and the device is easy to maintain. 1/6 Mechanical MaricultureDisinfection syltai a utilization Protein Aerobic Anaerobic COD separation nitrification denitrification reucio Figure 1. The flow chart of the biological treatment process of mariculture tail water of the present invention 2 Bz F Ce Dr s Figure2.Thechemaicpavewfeoicircd.asorainsse

Description

1/6

Mechanical MaricultureDisinfection

syltai a utilization

Protein Aerobic Anaerobic COD separation nitrification denitrification reucio

Figure 1. The flow chart of the biological treatment process of mariculture tail water

of the present invention

2

Bz

Figure2.Thechemaicpavewfeoicircd.asorainsse

F Ce Dr s

AUSTRALIA

PATENTS ACT 1990

PATENT SPECIFICATION FOR THE INVENTIONENTITLED:

A novel biological treatment process and device for mariculture tail water

The invention is described in the following statement:-

A novel biological treatment process and device for mariculture tail water

TECHNICAL FIELD

The invention relates to a novel biological treatment process for mariculture tail water,

in particular to a process and device for treating mariculture tail water with different kinds

of microorganisms, so as to improve the recycling utilization rate of aquaculture water,

which belongs to the technical field of aquaculture tail water treatment.

BACKGROUND

Coarse discharge is still the main way to use water for seawater ponds and factory

farming in China, and the aquaculture tailwater contains a large amount of feces and

uneaten feed of aquaculture organisms, which endangers the surrounding ecology when

discharged into the environment.

The treatment of aquaculture tail water is mainly applied in the closed recirculating

aquaculture mode. The core of the process is based on the ammonia transformation of

biological contact oxidation method, which uses nitrifying bacteria to convert ammonia

nitrogen and nitrite nitrogen into nitrate nitrogen under aerobic conditions. The efficiency

of water treatment is extremely related to the material and properties of nitrifying bacteria

substrate and the species and density of attached bacteria. In some aquaculture systems

with good tail water treatment technology, the reuse rate of tail water can reach more than

%. The nitrifying bacteria and denitrifying bacteria in the existing aquaculture tail water

treatment process rely on natural selection and natural growth, and it is difficult to make selections in species, bacterial density and growth conditions. Moreover, there is no clear demarcation line between nitrification and denitrification process. The treatment process is not clear, and the efficiency of nitrification and denitrification is low. Therefore, the cost of water treatment is increased.

In addition, with the continuous reuse of aquaculture tail water, nitrogen nitrate and

COD in water will accumulate more and more, which will eventually reduce the service

performance of water and affect the reuse of water. At present, denitrification devices and

COD reduction devices are not involved in all seawater aquaculture tail water treatment.

SUMMARY

The present invention is to solve the shortcomings of the prior art and provide a novel

biological treatment process for the tail water of mariculture, which divides the water

treatment system into an aerobic nitrification zone, an anaerobic denitrification zone and a

COD reduction zone by adjusting the physical and chemical environment of the water

treatment system, and each zone is communicated with each other with different physical

and chemical conditions, which is suitable for the growth of specific microorganisms and

improves their biological conversion rate. At the same time, the microbial attachment base

pressed by renewable materials has variable shape and low cost. In addition, the invention

adopts nitrifying bacteria and denitrifying bacteria screened from the bottom mud of the

mariculture pond, which has strong specificity and high biotransformation rate, and it can

greatly improve the treatment efficiency of the tail water of mariculture as well as the

utilization rate of seawater resources. Also, it can reduce the adverse impact of mariculture on the environment, its process is simple and the device is easy to maintain.

Technical scheme:

The novel biological treatment process for mariculture tail water comprises

mechanical filtration system, protein separation system and disinfection and aeration

system. Especially, it also includes aerobic nitrification conversion system, anaerobic

denitrification conversion system and COD reduction system. The systems are connected

with transmission pipelines. The solid in the tail water is removed by mechanical filtration

system in physical filtration In the aerobic nitrification system, ammonia nitrogen and

nitrite nitrogen are converted into nitrate nitrogen, and enter into the anaerobic

denitrification system. Under anaerobic conditions, nitrate nitrogen is converted into

nitrogen and discharged into the air, and enters into the COD reduction system to reduce

COD in the tail water. Finally, it enters into the disinfection and oxygenation system.

Further, the aerobic nitrification conversion system is a device for converting

ammonia nitrogen and nitrite nitrogen into nitrate nitrogen in the aquaculture tail water.

The system is divided into four independent areas in turn, namely, the preliminary contact

area, the intensive reaction zone, the buffer zone and the pH adjustment zone. Aerated

stones and air pipes are distributed at the bottom of the first three areas, and microbial

attachment bases are piled on the aerated stones and air pipes. The direction of water pipes

in the microbial attachment bases is parallel to the water flow direction. The microbial

attachment bases in the preliminary reaction zone, dense reaction zone and buffer zone are

placed according to the abduction trapezoid, while the microbial attachment bases and

aerated stones are not placed in the pH adjustment zone. The volume capacity of the tail water treatment system accounts for 6/10-7/10 of the total water treatment system.

When the system works, firstly, the cultured nitrifying bacteria (109cfu/ml) are diluted

1000 times with seawater, sprinkled on the microbial attachment, with the initial amount

of the diluent with 2/1000 of the treated water volume per unit time. Then, the culture tail

water is filled, during which the water temperature is kept above 15°C, and the aeration is

maintained for more than 5 days. Then, the pH is adjusted by NaOH at 8.55pH10 in the

pH adjustment area.

Furthermore, the anaerobic denitrification conversion system is a device for

converting nitrate nitrogen into nitrogen gas in aquaculture tail water, which enables

denitrifying bacteria to convert nitrate nitrogen into nitrogen gas and discharge it into the

air under anaerobic conditions. The system requires that microbial attachment groups be

piled up in the system, and the water pipe direction in the microbial attachment groups is

parallel to the water flow direction. The volume capacity of tail water treatment in the

system accounts for 2/10-3/10 of the total water treatment system volume.

When the system is running, the cultured denitrifying bacteria (109 cfu/ml) are diluted

1000 times with seawater and sprinkled on the microbial attachment base. The initial total

addition amount of the diluent is 2/1000 of the treated water volume per unit time, and the

aquaculture tail water after the previous stage treatment is filled, during which the water

temperature is kept above 15°C, and aeration is strictly prohibited for more than 3 days.

The COD reduction system is a device for reducing COD in aquaculture tail water.

When the system is constructed, the bottom inflatable stone and air pipe are first arranged,

and the microbial attachment groups are piled up. The volume capacity of tail water treatment of the system accounts for 1/10 ~ 2/10 of the total water treatment system volume.

When the system is running, the screened and expanded compound microorganism

(109 cfu/ml) is diluted by 1000 times with seawater, and sprinkled on the microorganism

attachment base. The initial addition amount of the diluent is 5 %o of the treated water

volume per unit time, which is put into the cultured tail water after the last stage of

treatment.

Additionally, the microbial attachment base is a customized microbial attachment

base, which is formed by pressing renewable composite plastic materials, and its shape and

size are customized according to the shape requirements of respective systems. The main

body of the microbial attachment base is honeycomb-shaped, and the inner diameter of the

pipe can be adjusted according to the volume and capacity of the tail water treatment of

each system. The amount of treated tail water per unit time is proportional to the inner

diameter of the pipe, and the water pipe in the microbial attachment base is parallel to the

direction of water flow.

The microbial attachment group is formed by stacking a plurality of unit modules.

The microbial attachment base is customized according to the shape of the system.

The aerobic nitrification conversion system, nitrifying bacteria screened by

inoculation culture are isolated from bottom mud of seawater pond as original strains,

which are subjected to fermentation expansion culture and freeze drying. The separation

method is conventional plate coating and streak culture method, and after separation, they

are identified as corresponding strains by 16SrRNA.

The denitrifying bacteria used in the anaerobic denitrifying conversion system are denitrifying bacteria with high salt resistance, which are separated from the bottom mud of the mariculture pond. The separation method is conventional plate coating and streak culture method, and after separation, they are identified as corresponding strains by 16S rRNA.

The composite microorganism used in the COD reduction system is composed of high

salt resistant Bacillus subtilis and Enterococcusfaecalis,and its ratio of biomass is 1:1.

The microbial attachment bases in the above systems are all customized microbial

attachment bases, which are made by pressing renewable composite plastic materials, and

their shapes and sizes are customized according to the shape requirements of their

respective systems. The microbial attachment bases are honeycomb-shaped, and the inner

diameter of pipes can be adjusted according to the volume and capacity of tail water

treatment in each system, which is generally between 1 and 5 cm. The amount of treated

tail water per unit time is directly proportional to the inner diameter of pipes, and the water

pipes in the attachment bases are parallel to the direction of water flow. The microbial

attachment base can be formed by stacking a plurality of unit modules, or can be

customized integrally according to the shape of the system. The integrated microbial

attachment can reduce the collision and wear among the attachment in water treatment, and

at the same time form afixed water flow channel with smooth water flow and sufficient

contact between bacteria and water, which is beneficial to the biotransformation of

microorganisms.

The capacity volume ratio of aerobic nitrification system, anaerobic denitrification

system and COD reduction system is (6 ~ 7): (2 ~ 3): (1 ~ 2) respectively.

Accord to that marine aquaculture tail water biological treatment device disclosed by

the invention, the treatment efficiency of the aquaculture tail water is directly proportional

to the contact time of microorganism attachment groups and the dosage of the attachment

groups, that is, the more the attachment group is added, the longer the contact time and the

higher the treatment efficiency will be.

Beneficial effects:

1. By controlling dissolved oxygen, pH and dominant microorganisms, the water

treatment system is divided into nitrification reaction zone, denitrification reaction zone

and COD reaction zone with clear boundaries. Each zone is connected with each other and

has different physical and chemical conditions, which is suitable for the growth of specific

microorganisms and improves their biotransformation rate.

2. Taking renewable plastics to press microbial attachment base can greatly reduce

the cost of the system, while it also can customize the size and shape of the attachment base

according to the shape of the water treatment system. The integrated microbial attachment

can reduce the collision and wear among the attachment in water treatment, and form a

fixed water flow channel with smooth water flow and sufficient contact between bacteria

and water, which is beneficial to the biotransformation of microorganisms.

3. Nitrifying bacteria and denitrifying bacteria isolated from the sediment of

mariculture ponds were selected as the initial inoculation strains. On the one hand, it

shortened the time for the corresponding bacteria to form dominant bacteria group, on the

other hand, it improved the biological treatment efficiency of bacteria.

4. When the ratio of aquaculture water volume to treatment water volume is 2:1, the treatment volume of tail water of aerobic nitrification conversion system accounts for 6 ~

7 / 10 of the total water treatment system volume, the tail water treatment volume of

anaerobic denitrification system accounts for 2 ~ 3 / 10 of the total water treatment system

volume, and the tail water treatment volume capacity of COD reduction system accounts

for 1 ~ 2 / 10 of the total water treatment system volume. According to the water treatment

process time, nitrification reaction time accounts for about 7/10 of the total water treatment

time, denitrification reaction accounts for about 2/10 of the water treatment time, and COD

reduction reaction accounts for about 1/10 of the water treatment time.

5. Under certain conditions (water temperature at 10-30°C, pH at 8 in nitrification

reaction zone and COD reduction zone, dissolved oxygen >6mg/L, pH at 8.5 or above in

denitrification reaction zone, dissolved oxygen <2mg/L, salinity >20), the biological

treatment efficiency of tail water is directly proportional to the treatment time and

microbial attachment volume.

The invention adopts nitrifying bacteria and denitrifying bacteria screened from the

bottom mud of mariculture pond, which has strong specificity and high bioconversion rate,

it can greatly improve the treatment efficiency of mariculture tail water and the utilization

rate of sea water resources. In addition ,it can reduce the adverse impact of mariculture on

the environment. The reuse rate of aquaculture tail water can be increased by more than

%, its process is simple and the device is easy to maintain.

BRIEF DESCRIPTION OF THE FIGURES

Fig. 1 is the flow chart of the biological treatment process of mariculture tail water of the present invention;

Fig. 2 is the schematic plan view of aerobic nitrification and transformation system;

Fig. 3 is the schematic cross-sectional view of aerobic nitrification and transformation

system;

Fig. 4 is the schematic plan view of the anaerobic denitrification system;

Fig. 5 is the schematic sectional view of anaerobic denitrification system;

Fig. 6 is the schematic plan view of COD reduction system;

Fig. 7 is the schematic cross-sectional view of COD reduction system;

Fig. 8 is the schematic plan view of biological water treatment for circulating water

culture;

Fig. 9 is the schematic plan view of the reformed biological water treatment for

circulating water culture;

Fig. 10 is the schematic sectional view of aerobic nitrification conversion system,

anaerobic denitrification conversion system and COD reduction system;

Fig. 11 is the schematic diagram of the structure of microbial attachment group.

Components in the figures: 1. microbial attachment base; 2. aerated stone; A.

preliminary contact zone; B. intensive reaction zone; C. buffer zone; D. pH adjustment

zone; a. collecting channel; b. air flotation machine; c. biological water treatment system;

d. temperature controller; e. high level pool; f. aquaculture pool; g. management room; III.

aerobic nitrification conversion system; IV. anaerobic denitrification conversion system;

V. COD reduction system.

DESCRIPTION OF THE INVENTION

With reference to the figures, specific embodiments of the present invention are given

below to further illustrate the constitution of the present invention.

Example 1

As shown in Fig. 1, the biological treatment process of mariculture tail water in this

embodiment includes a mechanical filtration system, a protein separation system and a

disinfection and oxygenation system. Especially, an aerobic nitrification conversion system,

an anaerobic denitrification conversion system and a COD reduction system are also

provided, which are communicated with each other by liquid conveying pipelines. The

aquaculture tail water enters into mechanical filtration system to remove suspended solids

in the tail water, then enters into the protein separation system. With the protein separator,

soluble organic matters in the tail water is removed. Then the aquaculture tail water enters

into the aerobic nitrification transformation system, which converts ammonia nitrogen and

nitrite nitrogen into nitrate nitrogen, and enters into the anaerobic denitrification

transformation system. Under anaerobic conditions, the system converts nitrate nitrogen

into nitrogen and discharges it into the air, and then the tail water enters the COD reduction

system to reduce the COD in the tail water. Finally, the tail water enters into the disinfection

and aeration system to realize the recycling of aquaculture water.

Aerobic nitrification and transformation system is a device for converting ammonia

nitrogen and nitrite nitrogen into nitrate nitrogen in aquaculture tail water. its structural schematic diagram is shown in Figure 2 and Figure 3. The system is divided into four independent areas in turn, namely, preliminary contact area A, dense reaction area B, buffer area C and pH adjustment area D. Inflatable stones 2 and air pipes are distributed at the bottom of the first three areas, and microbial attachment bases 1 are stacked on the inflatable stones and air pipes in turn. The water pipe direction in the microbial attachment bases 1 is parallel to the water flow direction. In the preliminary reaction zone, the dense reaction zone and the buffer zone, the microbial attachment is placed according to the abduction trapezoid, and the pH adjustment zone is not placed with the microbial attachment and aerated stone. The volume capacity of the tail water treatment system accounts for 7/10 of the total water treatment system.

When the system works, the cultured nitrifying bacteria (109 cfu/ml) are diluted 1000

times with seawater, sprinkled on the microbial attachment 1, and the initial total addition

amount of the diluent is 2/1000 of the treated water volume per unit time. Then, the culture

tail water is filled in the system, during which the water temperature is kept above 15°C

and the aeration (air) is kept for 6 days, and the pH is adjusted to 8.5 with NaOH in the pH

adjustment area.

The nitrifying bacteria screened by inoculation culture take the nitrifying bacteria

isolated from the bottom mud of seawater pond as the original strain, and performing

freeze-drying after fermentation expansion culture. The separation method is the

conventional plate coating and lineation culture method. After separation, it is identified as

the corresponding strain by 16SrRNA.

Anaerobic denitrification conversion system is a device for converting nitrate nitrogen into nitrogen gas in aquaculture tail water. The device enables denitrifying bacteria to convert nitrate nitrogen into nitrogen gas and discharge it into the air under anaerobic conditions. The system requires that microbial attachment 1 be stacked in the system, and the water pipe direction in the microbial attachment 1 is parallel to the water flow direction.

The volume capacity of the tail water treatment of the system accounts for 2/10 of the total

water treatment system volume. Its structural schematic diagram is shown in Figure 4 and

Figure 5.

1000 times with seawater and sprinkled on the microbial attachment 1. The initial total

cultured tail water after the previous stage treatment is filled in the system, during which

the water temperature is kept above 15°C, and aeration is strictly prohibited for 3 days.

The denitrifying bacteria are high-salt resistant denitrifying bacteria isolated from the

bottom mud of the mariculture pond, and the separation method is a conventional plate

coating and streaking culture method. After separation, the denitrifying bacteria is

identified as corresponding strains by 16S rRNA.

Anaerobic environment is realized by removing aerated stones from the system and

relying on the oxygen consumption of nitrifying bacteria.

COD reduction system is a device for reducing COD in aquaculture tail water. its

structural schematic diagram is shown in Fig. 6 and Fig. 7. When the system is constructed,

the bottom aeration stone 2 and the air pipe are first arranged accordingly, and the microbial

attachment base 1 is piled up. The volume capacity of tail water treatment of the system accounts for 1/10 of the total water treatment system volume.

When the system is running, the screened and expanded compound microorganism

attachment 1, with the initial addition amount of the diluent being 5 %o of the treated water

volume per unit time, and then put into the cultured tail water after the previous stage of

treatment.

The compound microorganism is composed of Bacillus subtilis and Enterococcus

faecalis with high salt tolerance, and the biomass ratio of the two is 1:1.

diameter of the tubes can be adjusted according to the volume and capacity of the tail water

treatment of each system, which is generally between 1-5cm and 5 cm. The water pipes in

the microbial attachment bases are parallel to the direction of water flow. The microbial

attachment is formed by stacking several unit modules, and the structural schematic

diagram of the microbial attachment is shown in Figure 11.

The volume ratio of aerobic nitrification system, anaerobic denitrification system and

COD reduction system is 7:2:1.

Example 2

In this embodiment, the tail water treatment system of a circulating water aquaculture

workshop in Dongying, Shandong Province is reformed in 2019 according to the process flow of biological treatment of marine aquaculture tail water provided by the present invention. The plane schematic diagram of biological water treatment of circulating water aquaculture before the reform is shown in Figure 8. The aquaculture water body of the workshop is 384m 3 , the tail water treatment capacity is 96m 3 /h, and the daily average water supplement is 320m 3. In this tail water treatment process, nitrification process and denitrification process are mixed together. Because of the severe oxygen consumption in nitrification process, denitrification process is the main process, which seriously limits the efficiency of biological contact oxidation. After multiple cycles of aquaculture water, nitrate nitrogen and COD accumulate a lot in water, which affects the recycling rate of aquaculture water.

The plan schematic diagram of the reformed biological water treatment for circulating

water aquaculture is shown in Figure 9. The aquaculture tail water flows from the

aquaculture pond f through the water collection channel a, enters the air floatation machine

b to filter and remove the suspended solids in the tail water, then enters into the biological

water treatment system. Equipping aerobic nitrification system III, anaerobic

denitrification system IV and COD reduction system V, with the volume ration as follow:

aerobic nitrification system: anaerobic denitrification system: COD reduction system

=7:2:1. After biological treatment, the tail water enters into the temperature control

machine to treat the water body.

Aerobic nitrification conversion system III is divided into four independent regions:

preliminary contact zone, dense reaction zone, buffer zone and pH adjustment zone.

Aerated stones and gas pipes are arranged at the bottom of the first three areas, and then

microbial attachment bases are accumulated on the aerated stones and trachea. The water pipe direction of microbial attachment base is parallel to the water flow direction, and microorganisms are placed in the preliminary reaction zone, dense reaction zone and buffer zone .The volume of tail water treatment of the system accounts for 7 / 10 of the total water treatment system.

When the system works, the cultured nitrifying bacteria (109 The initial dosage of

diluent is 2 / 1000 of the volume of treated water per unit time, and it is filled with

aquaculture tail water. During this period, the water temperature is kept above 15 °C and

aeration (air) is maintained for more than 5 days. Then, taking NaOHto adjust 8.5 < pH <

in the pH adjustment area.

cultured tail water after the previous stage treatment is filled, during which the water

temperature is kept above 15°C, and aeration is strictly prohibited for 3 days.

The denitrifying bacteria used are denitrifying bacteria with high salt resistance, which

are isolated from the bottom mud of mariculture ponds. The separation method is

conventional plate coating and streak culture method, and after separation, they are

identified as corresponding strains by 16S rRNA.

relying on the oxygen consumption of nitrifying bacteria.

COD reduction system V is a device to reduce COD in aquaculture tail water. When

the system is constructed, aerated stone 2 and gas pipe are arranged at the bottom, and microbial attachment base 1 is accumulated. The volume of tail water treatment of the system accounts for 1 / 10 of the total volume of the water treatment system.

When the system is running, the screened and expanded compound microorganism

(109 cfu/ml) is diluted by 1000 times with seawater, which is sprinkled on the

microorganism attachment 1. The initial addition amount of the diluent is five thousandths

of the treated water volume per unit time, and the cultured tail water after the previous

stage of treatment is filled in.

The compound microorganism used is composed of Bacillus subtilis and

Enterococcusfaecaliswith high salt tolerance, and the biomass ratio of the two is 1:1.

The microbial attachment bases used in each system are all customized microbial

attachment bases, which are made by pressing renewable composite plastic materials. The

microbial attachment bases are integrated and customized according to their respective

system shapes, and their main bodies are honeycomb-shaped. The inner diameter of the

pipes can be adjusted according to the volume and capacity of the tail water treatment of

each system. The water pipes in the microbial attachment bases are parallel to the direction

of water flow between 1~5cm and 5 cm. The integrated microbial attachment can reduce

the collision and wear among the attachment in water treatment, and form a fixed water

flow channel with smooth water flow and sufficient contact between bacteria and water,

which is beneficial to the biotransformation of microorganisms.

After the renovation of the tail water treatment system in the aquaculture workshop,

the comprehensive treatment capacity of tail water is still 96m3 /h, and the daily average

water supplement can be reduced to 80 m 3, which greatly reduces the daily average water supplement and the adverse impact of mariculture on the environment, while much water are saved.

The invention is also suitable for centralized treatment of aquaculture tail water in

modern fishery culture areas. After centralized collection of tail water of each aquaculture

unit, two to three aquaculture treatment systems are set according to the tail water quantity,

and each aquaculture system consists of aerobic nitrification, anaerobic denitrification and

COD reduction modules. The water treated by each system will be reused or discharged

after being combined by pipelines.

The section diagram of aerobic nitrification conversion system III, anaerobic

denitrification conversion system IV and COD reduction system V is shown in Fig. 10.

The volume ratio of each device can be adjusted according to the content of nitrate in local

water.

The above-mentioned embodiments are only the better embodiments of the invention,

and the protection scope of the invention is not limited to the above-mentioned

embodiments. All technical solutions that can be realized according to the ideas of the

invention belong to the protection scope of the invention.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. The novel biological treatment process for mariculture tail water includes

system. It is characterized in that aerobic nitrification conversion system, anaerobic

denitrification conversion system and COD reduction system are also set up. The systems

are connected with transmission pipelines. The solid in the tail water is removed by

mechanical filtration system in physical filtration In the aerobic nitrification system,

ammonia nitrogen and nitrite nitrogen are converted into nitrate nitrogen, and enter into

the anaerobic denitrification system. Under anaerobic conditions, nitrate nitrogen is

converted into nitrogen and discharged into the air, and enters into the COD reduction

system to reduce COD in the tail water. Finally, it enters into the disinfection and

oxygenation system.

2. The novel biological treatment process for mariculture tail water according to claim

1, which is characterized in that the aerobic nitrification conversion system is a device for

converting ammonia nitrogen and nitrite nitrogen into nitrate nitrogen in the aquaculture

tail water. The system is divided into four independent areas in turn, namely, the

preliminary contact area, the intensive reaction zone, the buffer zone and the pH adjustment

zone. Aerated stones and air pipes are distributed at the bottom of the first three areas, and

microbial attachment bases are piled on the aerated stones and air pipes. The direction of

water pipes in the microbial attachment bases is parallel to the water flow direction. The

microbial attachment bases in the preliminary reaction zone, dense reaction zone and buffer

zone are placed according to the abduction trapezoid, while the microbial attachment bases

and aerated stones are not placed in the pH adjustment zone. The volume capacity of the tail water treatment system accounts for 6/10-7/10 of the total water treatment system.

pH adjustment area.

3. The novel biological treatment process for mariculture tail water according to claim

1, which is characterized in that the anaerobic denitrification conversion system is a device

for converting nitrate nitrogen into nitrogen gas in aquaculture tail water, which enables

system accounts for 2/10-3/10 of the total water treatment system volume.

When the system is running, the cultured denitrifying bacteria (10 9 cfu/ml) are diluted

4. The novel biological treatment process for mariculture tail water according to claim

1, which is characterized in that the COD reduction system is a device for reducing COD in aquaculture tail water. When the system is constructed, the bottom inflatable stone and air pipe are first arranged, and the microbial attachment groups are piled up. The volume capacity of tail water treatment of the system accounts for 1/10 ~ 2/10 of the total water treatment system volume.

When the system is running, the screened and expanded compound microorganism

treatment.

5. The novel biological treatment process for mariculture tail water according to claim

2, claim 3 or claim 4, which is characterized in that the microbial attachment base is a

customized microbial attachment base, which is formed by pressing renewable composite

plastic materials, and its shape and size are customized according to the shape requirements

of respective systems. The main body of the microbial attachment base is honeycomb

shaped, and the inner diameter of the pipe can be adjusted according to the volume and

capacity of the tail water treatment of each system. The amount of treated tail water per

unit time is proportional to the inner diameter of the pipe, and the water pipe in the

microbial attachment base is parallel to the direction of water flow.

6. The novel biological treatment process for mariculture tail water according to claim

is characterized in that the microbial attachment group is formed by stacking a plurality

of unit modules.

7. The novel biological treatment process for mariculture tail water according to claim is characterized in that the microbial attachment base is customized according to the shape of the system.

8. The novel biological treatment process for mariculture tail water according to claim

2 is characterized in that in the aerobic nitrification conversion system, nitrifying bacteria

screened by inoculation culture are isolated from bottom mud of seawater pond as original

strains, which are subjected to fermentation expansion culture and freeze drying. The

separation method is conventional plate coating and streak culture method, and after

separation, they are identified as corresponding strains by 16SrRNA.

9. The novel biological treatment process for mariculture tail water according to claim

3 is characterize in that the denitrifying bacteria used in the anaerobic denitrifying

conversion system are denitrifying bacteria with high salt resistance, which are separated

from the bottom mud of the mariculture pond. The separation method is conventional plate

coating and streak culture method, and after separation, they are identified as corresponding

strains by 16S rRNA.

10. The novel biological treatment process for mariculture tail water according to

claim 4 is characterized in that the composite microorganism used in the COD reduction

system is composed of high salt resistant Bacillus subtilis and Enterococcusfaecalis,and

its ratio of biomass is 1:1.