CN109160596B

CN109160596B - Quick starting method of bioelectrochemical process for deoxidizing oil field wastewater

Info

Publication number: CN109160596B
Application number: CN201811202428.9A
Authority: CN
Inventors: 吴伟林; 杨帆; 林晶晶; 孟章进; 袁玉峰; 李兴
Original assignee: China Petroleum and Chemical Corp; Sinopec Jiangsu Oilfield Co
Current assignee: China Petroleum and Chemical Corp; Sinopec Jiangsu Oilfield Co
Priority date: 2018-10-16
Filing date: 2018-10-16
Publication date: 2021-07-27
Anticipated expiration: 2038-10-16
Also published as: CN109160596A

Abstract

The invention discloses a quick starting method of a bioelectrochemical process for deoxidizing oil field wastewater, which can realize effective, quick and efficient enrichment of electrogenesis microorganisms and quick start of a bioelectrochemical reactor by controlling conditions such as culture medium proportion, inoculation source, line connection, DO control and the like in the starting period. The control condition adjustment starting substrate is the most suitable substrate of the common dominant anode microorganism, simultaneously, the biological diversity of the inoculum is improved by adopting the activated sludge, the control circuit is connected to form high-pressure screening on the functional microorganism, the DO control well matches the demand of facultative microorganisms in the target functional microorganism on oxygen, and simultaneously, the demand of the cathode on oxygen is balanced.

Description

Quick starting method of bioelectrochemical process for deoxidizing oil field wastewater

Technical Field

The invention belongs to the technical field of microbial prevention and control of oxygen electrochemical corrosion, and relates to a quick starting method of a bioelectrochemical deoxidization process.

Background

The injection water containing dissolved oxygen can cause serious corrosion to water injection pipeline equipment and a sleeve, and based on the necessity of removing oxygen from the injection water of an oil field, a novel bioelectrochemical deoxidization reactor is designed and developed, the main working core of the reactor is electrogenesis microorganisms capable of being enriched on an anode, and microorganisms (Escherichia coli) which can be oxidized and fermented on the electrode can be firstly discovered in 1910Since the efficiency of electron transfer is very low, the interest in the study of electron transfer in vitro of microorganisms has not been brought about for a long time since the beginning of the process and the obtaining of current output, and the electrochemical ability of microorganisms has not been mentioned and reported until the sixty years. In the 80 s of the 20 th century, researchers began to try to add some chemical conductive mediators, on one hand, the chemical conductive mediators help and improve the conduction of electrons out of cells by microorganisms, on the other hand, the chemical conductive mediators promote the connection and electron transfer between the microorganisms and electrodes, the electron transfer capacity is improved to a considerable extent by adding electron mediators to promote the electron transfer between the microorganisms and the electrodes until about 2000 years, and the energy output is less than 0.01 mW.m reported earlier^-2Increased to 100 mW.m^-2The above. At the same time, a mediator-assisted electron transfer, a mode of electron transfer mechanism, has also been proposed and is continuously recognized and perfected. The problems associated with mediator addition are the disadvantages of insufficient stability and certain toxicity of the chemical properties of the mediator itself, and the increase in development cost, which limits the development limitations of Microbial Fuel Cells (MFCs) with additional mediators.

It was first discovered by Kim et al in 1999 that mediator-less MFC could also operate and achieve power production capability that was not particularly low. From this point on, the development of MFC has gradually turned to the research and development of special functional microorganisms, and the search for highly efficient electron-transporting bacteria has gradually become the mainstream of development. Rabaey et al found in their studies that in MFC systems without mediator addition, pyocin (pyocyanin) acts as a mediator to help the microorganism transfer electrons. The substance is produced by Pseudomonas aeruginosa, and the secretion can not only help the electron transfer between the cells of the bacterium, but also be utilized by other microorganisms to improve the electron transfer capability. In fact, Pseudomonas aeruginosa is a functional bacterium having an ability of transferring electrons outside the cell, but the ability of MFC to generate electricity by operation is low. Subsequently, functional bacteria having a direct electron transfer function were discovered and developed, and some of them had high electron transfer ability, including Shewanella (Shewanella), Geobactrum (Geobactrum), Clostridium (Clostridium), Pseudomonas (Pseudomonas), Desulfuromicron (Desulfovibrio), and the like. In the research of the bacteria, the research mechanism of the microorganism direct contact type electron transfer is further provided, and the research mechanism comprises a nano-wire electron transfer model represented by Geobacter and Shewanella oneidensis MR-1 and a cell membrane direct electron transfer function mechanism based on cytochrome C. The direct electron transfer mechanism of cell membrane has been studied very deeply, and Shewanella and Geobacter are taken as model strains at present, and the role of various functional structures including cytochrome in the electron transfer process from inside to outside of the cell is clearly explained. It can be seen that there are four structures for electron transfer from inside the cell through the outer cell membrane, and besides the cytochrome linked to the cytoplasm, there are membrane-associated β -barrel structural proteins, which can directly contact with the outside of the cell and realize electron transfer, to which Geobacter belongs. Other functional proteins (such as ferritin and iron-sulfur protein) or extracellular cytochrome structures are generally arranged on the structure to assist in realizing direct transfer of electrons.

Therefore, a simple and quick starting mode is developed, the starting process of the bioelectrochemical reactor can be effectively accelerated, and the method has important practical significance for improving the oxygen removing capability of the bioelectrochemical reactor in the later period.

Disclosure of Invention

In order to solve the problem of quick start of the conventional bioelectrochemical deoxygenation device, the invention provides a quick start method of a bioelectrochemical process for deoxygenating oil field wastewater, which can effectively enrich functional microorganisms of an anode of a bioelectrochemical reactor in a short time and accelerate the start process of the reactor.

A quick starting method of a bioelectrochemical process for deoxidizing oil field wastewater comprises the following steps:

(1) preparing an oil field wastewater inlet solution, wherein the oil field wastewater is prepared by mixing oil field ground sewage and sludge at the bottom of a sewage biochemical treatment pool according to the weight ratio of (10-100) to 1, and the oil field wastewater is also added with the following components to prepare the inlet solution:

the concentration of the acetate is 0.8-1.5g/L, the concentration of the vitamin solution is 0.8-1.2ml/L, the concentration of the trace element solution is 0.8-1.8ml/L, and the pH value of the water inlet solution is adjusted to 7.0 by adopting 45-65mM phosphoric acid buffer solution;

(2) line connection and voltage setting

Respectively connecting a power supply with two anodes and one cathode, and controlling the voltage between the anode and the cathode to be stabilized at 0.9-1.1V;

(3) controlling operating conditions

Taking the 0 th day as the starting point of operation, controlling the dissolved oxygen of the inlet water to be between 1.5 and 3.2mg/L, controlling the dissolved oxygen of the inlet water to be between 3.8 and 5.3mg/L every day on the 1 st to 3 rd days, and controlling the dissolved oxygen of the inlet water to be between 5.5 and 7.5mg/L every day on the 4 th to 5 th days;

controlling water conservancy residence time: the residence time is controlled to be 2-3 days from day 0 to 4, and then 6-8h from day 5.

Further, the concentration of the main components of the vitamin solution is as follows: 0.15-0.35g/L of vitamin H, 0.15-0.35g/L of folic acid, 1-1.3g/L of vitamin B6, 0.45-0.65g/L of riboflavin, 0.45-0.65g/L of vitamin B1, 0.45-0.65g/L of nicotinic acid, 0.45-0.65g/L of pantothenic acid, 0.01-0.04g/L of B-12, 0.45-0.65g/L of P-aminobenzoic acid and 0.45-0.65g/L of lipoic acid.

Further, the concentration of the main components of the trace element liquid is as follows: MgSO (MgSO)₄ 2.5-4g/L，MnSO₄·H₂O0.45-0.65g/L，NaCl 0.8-1.5g/L，FeSO₄·7H₂O 0.1-0.3g/L，CaCl₂·2H₂O0.1-0.3g/L，CoCl₂·6H₂O 0.1-0.3g/L，ZnCl₂ 0.1-0.3g/L，CuSO₄·5H₂O0.01-0.028g/L，AlK(SO₄)₂·12H₂O 0.01-0.03g/L，H₃BO₃ 0.01-0.03g/L，Na₂MoO₄ 0.02-0.038g/L，NiCl₂·6H₂O 0.02-0.035g/L，Na₂WO₄·2H₂O0.02-0.035g/L。

Further, the phosphate buffer solution had the following composition: 11 to 12.5g/L of disodium hydrogen phosphate dodecahydrate, 2.5 to 3.0g/L of sodium dihydrogen phosphate dihydrate, 0.3 to 0.55g/L of ammonium chloride and 0.1 to 0.3g/L of potassium chloride.

Further, the effective volume of the reactor used was 1.8L, the height to diameter ratio was 15: 1.

further, the temperature during the operation was 30 ℃.

According to the invention, by controlling the culture medium proportion, inoculation source, line connection, running conditions and the like in the starting period, the efficient electricity-generating microorganisms can be effectively and rapidly enriched, and the rapid starting of the bioelectrochemical reactor can be realized. The control condition adjustment starting substrate is the most suitable substrate of the common dominant anode microorganism, simultaneously, the biological diversity of the inoculum is improved by adopting the activated sludge, the control circuit is connected to form high-pressure screening of the functional microorganism, the control of the operation condition is well matched with the requirement of facultative microorganisms in the target functional microorganism on oxygen, and the requirement of the cathode on the oxygen is balanced.

The main substrate adopts acetate, and the pH value of inlet water is controlled by adopting a phosphoric acid buffer solution with the concentration of 50mM, and the added microorganisms and trace elements ensure the growth and synthesis requirements of the microorganisms. The mixed solution adopted by the inoculation source comprises sludge at the bottom of the sewage biochemical treatment tank and oil field ground sewage, the sludge at the bottom of the sewage biochemical treatment tank can improve the diversity of inoculants, and the effluent of the microbial electrolysis tank ensures the existence of a large amount of anode functional flora in the inoculation source. Two anodes corresponding to a single cathode are adopted on the circuit connection, and the voltage is higher than the operating voltage and reaches more than 1.0V, so that the selective pressure on functional microorganisms is improved. The operation condition control process adopts a gradually-improved strategy, the initial lower dissolved oxygen concentration of 2mg/L can ensure the requirement of the cathode on an electron acceptor, the anode is basically in an anoxic state at the moment and is beneficial to the growth of anaerobic microorganisms and the culture of facultative microorganisms, along with the enrichment of the anode microorganisms, the requirement of the cathode on the electron acceptor is improved, so the DO concentration is properly improved at the moment, the requirement of the cathode is further met, the DO concentration at the moment is improved to 4mg/L, the requirement of the cathode is not only met, meanwhile, the micro-aerobic environment is brought to the anode and is beneficial to the growth of the facultative microorganisms, the current starts to be obviously improved in 4 th and 5 th days, at the moment, the dissolved oxygen concentration of inlet water can be improved to 5.5mg/L, and the requirement of the electron acceptor of the cathode can be further met.

The invention can enrich the functional microorganisms of the anode of the bioelectrochemical reactor in a short time, accelerate the starting process of the reactor, remove dissolved oxygen, reduce oxygen corrosion and improve water quality.

Drawings

FIG. 1 is a schematic diagram of the circuit connection of the present invention.

Fig. 2 is a graph of the current change during start-up of the present invention.

Fig. 3 is a graph of the change in potential during start-up of the present invention.

FIG. 4 is a schematic diagram showing the COD change of inlet and outlet water during the start-up period.

Fig. 5 is a schematic diagram of the change in dissolved oxygen during the start-up period.

FIG. 6 is a schematic diagram of the dissolved oxygen removal rate during the start-up period.

Detailed Description

The present invention will be described in detail below with reference to the drawings and examples, but the practice of the invention is not limited thereto.

Example 1

(1) The effective volume of the reactor is 1.8L, and the height-diameter ratio is 15: 1.

(2) the water intake formula is as follows:

the concentration of acetate is 1.0 g/L; 1ml/L vitamin solution and 1ml/L microelement solution, 50mM phosphoric acid buffer solution (pH 7.0): concentration of main component of phosphoric acid buffer solution: 11.55g/L disodium hydrogen phosphate dodecahydrate, 2.77g/L sodium dihydrogen phosphate dihydrate, 0.31g/L ammonium chloride and 0.13g/L potassium chloride; the concentration of the main components of the vitamin liquid is as follows: 0.2g/L of vitamin H, 0.2g/L of folic acid, 0.2g/L of vitamin B6, 1g/L of riboflavin, 0.5g/L of vitamin B1, 0.5g/L of nicotinic acid, 0.5g/L of pantothenic acid, 0.12 g/L of B-12, 0.01g/L of P-aminobenzoic acid, 0.5g/L of lipoic acid and 0.5g/L of lipoic acid.

The concentration of the main components of the trace element liquid is as follows: MgSO (MgSO)₄ 3g/L，MnSO₄·H₂O 0.5g/L，NaCl 1g/L，FeSO₄·7H₂O 0.1g/L，CaCl₂·2H₂O 0.1g/L，CoCl₂·6H₂O 0.1g/L，ZnCl₂

0.13g/L，CuSO₄·5H₂O 0.01g/L，AlK(SO₄)₂·12H₂O 0.01g/L，H₃BO₃ 0.01g/L，Na₂MoO₄ 0.025g/L，NiCl₂·6H₂O 0.024g/L，Na₂WO₄·2H₂O 0.025g/L。

(3) Line connection and voltage setting

The line connection is as shown in fig. 1, and the voltage between the cathode 1 and the

anodes

2 and 3 is controlled to be stabilized at 1.0V.

(4) Operating condition control

And (4) DO control: the dissolved oxygen of the water inflow is controlled to be 2mg/L at the 0 th day, 4mg/L at the 1 st, 2 nd and 3 rd days, and 5.5mg/L at the 4 th and 5 th days.

Controlling the hydraulic retention time: the residence time was controlled to 2 days from day 0 to 4 and then to 6 hours from day 5.

Wherein, the hydraulic retention time refers to the average retention time of the sewage to be treated in the reactor, namely the average reaction time of the sewage and the microorganism action in the bioreactor, and the hydraulic retention time is equal to the ratio of the volume of the reactor to the inflow water.

Temperature control: the temperature during start-up was controlled to 30 degrees celsius.

And (3) pH control: the pH during start-up was controlled to 7.

Example 2

(2) the water intake formula is as follows:

the concentration of acetate is 1.2 g/L; 1ml/L vitamin solution and 1.5ml/L microelement solution, 60mM phosphoric acid buffer solution (pH 7.0): concentration of main component of phosphoric acid buffer solution: 12.3g/L disodium hydrogen phosphate dodecahydrate, 2.95g/L sodium dihydrogen phosphate dihydrate, 0.5g/L ammonium chloride and 0.25g/L potassium chloride; the main components of the vitamin solution are vitamin H, 0.3g/L, folic acid, 0.3g/L, vitamin B6, 1.2g/L, riboflavin, 0.6g/L, vitamin B1, 0.6g/L, nicotinic acid, 0.6g/L, pantothenic acid, 0.6g/L, B-12, 0.03g/L, P-aminobenzoic acid, 0.6g/L and lipoic acid, and 0.6 g/L.

The concentration of the main component of the microelement liquid comprises MgSO₄ 3.5g/L，MnSO₄·H₂O 0.6g/L，NaCl

1.2g/L，FeSO₄·7H₂O 0.2g/L，CaCl₂·2H₂O 0.2g/L，CoCl₂·6H₂O 0.2g/L，ZnCl₂0.25g/L，CuSO₄·5H₂O 0.02g/L，AlK(SO₄)₂·12H₂O 0.02g/L，H₃BO₃0.02g/L，Na₂MoO₄0.035g/L，NiCl₂·6H₂O 0.03g/L，Na₂WO₄·2H₂O0.032g/L。

(3) Line connection and voltage setting

anodes

2 and 3 is controlled to be stabilized at 1.1V.

(4) Operating condition control

And (4) DO control: the dissolved oxygen of the water inflow is controlled to be 3mg/L at the 0 th day, 5mg/L at the 1 st, 2 nd and 3 rd days, and 7mg/L at the 4 th and 5 th days.

Controlling water conservancy residence time: the residence time was controlled to 3 days from day 0 to 4 and then to 7 hours from day 5.

And (3) pH control: the pH during start-up was controlled to 7.

Example 3

For the test of the start-up effect of example 2:

(1) as shown in FIG. 2, the current fluctuates at the beginning of water feeding and then levels off, the current fluctuates when the dissolved oxygen of the fed water is increased from 2mg/L to 4mg/L on the next day, then levels off, and the increase is stable and slow, the current rapidly increases from the next day, reaches the maximum at day 6, 6.4mA, then begins to level off, and the current is basically maintained at the level of 6mA after day 5.

(2) As can be seen from FIG. 3, the potentials of both anodes rapidly dropped during the start-up period, and dropped from 0mV to-0.5 mV (vs Ag/AgCl) during the start-up period, respectively.

(3) As can be seen from FIG. 4, after the start-up was stabilized, the COD concentration of the influent water was 1000mg/L and the effluent water was about 600mg/L, with a removal rate of 40%. Tests show that the coulombic efficiency of the anode is 4% after stable operation.

(4) Referring to fig. 5-6, the acclimatization stage is started, the anode potential is continuously maintained at < -400mV, the hydraulic retention time is 6h, 80% of dissolved oxygen is removed, the metal cathode is arranged below the anode, 50% of dissolved oxygen can be removed firstly through reduction reaction, and the dissolved oxygen can be further consumed by the subsequent anode through microbial respiration.

While the preferred embodiments of the present invention have been described in detail, it will be understood by those skilled in the art that the invention is not limited thereto, and that various changes and modifications may be made without departing from the spirit of the invention, and the scope of the appended claims is to be accorded the full range of equivalents.

Claims

1. A quick starting method of a bioelectrochemical process for deoxidizing oil field wastewater is characterized by comprising the following steps:

(2) line connection and voltage setting

(3) controlling operating conditions

controlling the hydraulic retention time: controlling the retention time from day 0 to day 4 to be 2-3 days, and then controlling the retention time from day 5 to be 6-8 h;

the vitamin liquid comprises the following main components in concentration: 0.15-0.35g/L vitamin H, 0.15-0.35g/L folic acid, 1-1.3g/L vitamin B6, 0.45-0.65g/L riboflavin, 0.45-0.65g/L vitamin B1, 0.45-0.65g/L nicotinic acid, 0.45-0.65g/L pantothenic acid, 0.01-0.04g/L B-12, 0.45-0.65g/L P-aminobenzoic acid, 0.45-0.65g/L lipoic acid;

the concentration of the main components of the trace element liquid is as follows: MgSO (MgSO)₄ 2.5-4g/L，MnSO₄·H₂O 0.45-0.65g/L，NaCl 0.8-1.5g/L，FeSO₄·7H₂O 0.1-0.3g/L，CaCl₂·2H₂O 0.1-0.3g/L，CoCl₂·6H₂O 0.1-0.3g/L，ZnCl₂ 0.1-0.3g/L，CuSO₄·5H₂O 0.01-0.028g/L，AlK(SO₄)₂·12H₂O 0.01-0.03g/L，H₃BO₃0.01-0.03g/L，Na₂MoO₄ 0.02-0.038g/L，NiCl₂·6H₂O 0.02-0.035g/L，Na₂WO₄·2H₂O 0.02-0.035g/L。

2. The rapid start-up method according to claim 1, wherein the phosphate buffer solution is composed of: 11 to 12.5g/L of disodium hydrogen phosphate dodecahydrate, 2.5 to 3.0g/L of sodium dihydrogen phosphate dihydrate, 0.3 to 0.55g/L of ammonium chloride and 0.1 to 0.3g/L of potassium chloride.

3. The rapid start-up method according to claim 1, wherein the reactor used has an effective volume of 1.8L, an aspect ratio of 15: 1.

4. the rapid start-up method according to claim 1, characterized in that the temperature during operation is 30 ℃.