CN-117092189-B - Method for quickly detecting BDOC in water supply pipe network by using biological film sensing based on electrochemical impedance spectrum

CN117092189BCN 117092189 BCN117092189 BCN 117092189BCN-117092189-B

Abstract

A method for quickly detecting BDOC in a water supply pipe network by using biological membrane sensing based on electrochemical impedance spectrum relates to the field of BDOC detection of water quality biostability indexes. The invention aims to realize effective detection of BDOC in water under the conditions of rapidness, in-situ and no damage, thereby reacting the biostability of the water quality of the pipeline. According to the scheme, the ratio of Ct and the BDOC concentration of the biodegradable organic matters in water have a linear relation, a curve fitting equation can be drawn by utilizing the relation, the capacitance of a biological film growing in an actual water sample is measured according to the same measuring process, and the BDOC concentration of the water sample is obtained by taking the equation of curve fitting. The method can realize rapid BDOC detection, reflect BDOC and water quality biostability more comprehensively by using the biomembrane capacitance, and can be used in a water supply network to realize in-situ and nondestructive on-line BDOC monitoring in the water supply network by using an electrochemical impedance technology.

Inventors

ZHENG CHENGZHI
ZHONG DAN
YIN XIAOMING
ZHAO QIJIA
SUN GUOSHENG
DENG YUHAI
MA WENCHENG

Assignees

哈尔滨工业大学水资源国家工程研究中心有限公司
哈尔滨工业大学
广东粤海水务投资有限公司

Dates

Publication Date: 20260505
Application Date: 20230829

Claims (10)

1. The method for quickly detecting BDOC in a water supply pipe network by using the biological film sensing based on electrochemical impedance spectrum is characterized by comprising the following steps of: s1, preparing a sensing electrode, and placing the sensing electrode in drinking water with BDOC concentration to be detected to form a biological film on the surface of the sensing electrode; S2, measuring electrochemical impedance spectrum of an electrode attached with a biological film on the surface in fixed culture time; S3, carrying out parameter identification on each device in the equivalent circuit model according to the electrochemical impedance spectrum of the electrode with the surface attached with the biological film to obtain an electrochemical parameter capacitance value; S4, detecting microorganisms on the electrode attached with the biological film on the surface in a fixed culture time; S5, collecting a biomembrane on the surface of the electrode, preparing a cell suspension, and counting by using a flow cytometer to obtain a microorganism parameter cell density; s6, detecting BDOC concentration of the standard solution with the sensing electrode in fixed culture time to obtain BDOC concentration; S7, drawing a curve according to a relation formula of the microbial parameter cell density and BDOC concentration, and fitting an equation; The relation formula of the microbial parameter cell density and BDOC concentration is as follows: Wherein tK 1 is a constant under conditions of fixed reaction time, S is a single limiting substrate concentration, N t is on the electrode Cell number attached at time t, N 0 is the cell number attached at the initial time of the electrode; and the drawing curve is fitted with an equation formula: Wherein K is a half-saturation constant, S is a single limiting substrate concentration, the double-layer capacitance ratio of C t , b is a constant, and C 0 is an initial double-layer capacitance value; The calculation formula of the C t is as follows: Wherein K 2 is a half-saturation constant, N t is the number of cells attached to the electrode at time t, and b is a constant; s8, measuring the capacitance of the biological film growing in the actual water sample, carrying out a curve fitting equation, and solving the concentration of the water sample BDOC.
2. The method for quickly detecting BDOC in a water supply pipe network by using biological film sensing based on electrochemical impedance spectroscopy according to claim 1, wherein the sensing electrode is made of stainless steel, and the geometric dimension of the stainless steel electrode is 100mm in length and 5mm in diameter.
3. The method for quickly detecting BDOC in a water supply pipe network based on biological film sensing of electrochemical impedance spectroscopy according to claim 1 or 2, wherein the sensing electrode is pretreated and placed in the drinking water with BDOC concentration to be detected, the pretreatment is that the electrode is immersed in sodium hypochlorite solution for 1 hour, then the electrode is immersed in fresh ultrapure water for 30 minutes three times continuously, and the electrode is placed in an oven at 75 ℃ for 48 hours to remove any residual chlorine, and the total chlorine concentration of the sodium hypochlorite solution is 20mg/L.
4. The method for rapidly detecting BDOC in a water supply network by using biological membrane sensing based on electrochemical impedance spectroscopy according to claim 1, wherein the fixed incubation time in step S2 is measured once every 1d interval, and the specific interval is 0d, 1d, 2d, 3d, 4d, 5d, 6d and 7d.
5. The method for quickly detecting BDOC in a water supply pipe network by using the biomembrane sensing based on electrochemical impedance spectroscopy according to claim 1, wherein in the step S3, parameter identification is performed on each device in an equivalent circuit model according to the electrochemical impedance spectroscopy of an electrode with a biomembrane attached on the surface under an alternating voltage of 10 mV and an alternating voltage of 10 mHz-100 KHz.
6. The method for rapidly detecting BDOC in a water supply pipe network by using biological film sensing based on electrochemical impedance spectroscopy according to claim 1, wherein the equivalent circuit model in the step S3 comprises a solution resistor Rs, a double-layer capacitor C and a charge transfer resistor Rct which are connected in parallel and then connected in series with a diffusion electrochemical element W.
7. The method for rapid detection of BDOC in a water supply network by electrochemical impedance spectroscopy-based biological membrane sensing of claim 1, wherein the fixed incubation time in step S4 is measured once every 1d interval, specifically at 0d, 1d, 2d, 3d, 4d, 5d, 6d and 7d intervals.
8. A method for rapid detection of BDOC in a water supply line by bio-film sensing based on electrochemical impedance spectroscopy according to claim 1, wherein the temperature of the microorganism detection in step S4 is 25 ℃.
9. The method for rapidly detecting BDOC in a water supply pipe network based on biological membrane sensing of electrochemical impedance spectroscopy according to claim 1, wherein the calculation formula of K 1 S is as follows Wherein μ is Rate.
10. The method for rapidly detecting BDOC in a water supply network based on electrochemical impedance spectroscopy of claim 9, wherein said method comprises the steps of The rate mu formula is Wherein mu max The rate, K s , is defined as the half-saturation constant.

Description

Method for quickly detecting BDOC in water supply pipe network by using biological film sensing based on electrochemical impedance spectrum Technical Field The invention belongs to the field of BDOC detection of water quality biostability indexes, and particularly relates to a method for quickly detecting BDOC in a water supply pipe network by using biomembrane sensing based on electrochemical impedance spectroscopy. Background The biological stability of water quality is related to the safety of drinking water quality. Biofilms contain pathogens in drinking water distribution systems, and infectious diseases caused by pathogens such as bacteria, viruses, protozoa, etc. are the most common and widespread health risks associated with drinking water, which can be minimized by controlling the nutrient matrix in the drinking water. Biodegradable soluble organic carbon BDOC is an important index for evaluating the biostability of drinking water. Currently, there are various methods for measuring BDOC, including a suspension culture method, a bioreactor method, a dynamic circulation method, and an active bio-sand method, which are all based on the principle of measuring the change of soluble organic carbon DOC before and after inoculating microorganisms to calculate BDOC, which require a long measurement time, lack timeliness, and limit detection limited by TOC analyzers. In addition to this these methods, since they are batch processes utilizing non-primary bacteria either singly cultivated or highly domesticated bacteria, are not representative of the dynamic local bacterial communities found in most water and distribution systems. Electrochemical Impedance Spectroscopy (EIS) is widely used in the fields of metal corrosion, battery performance research, etc., by applying a small amplitude potential or current to an electrode system to produce an approximately linear relationship response, and analyzing electrode process kinetic information and electrode interface structure information according to the impedance spectrum of the electrode system obtained over a wide frequency range. The use of EIS has been widely studied for microbial attachment and biofilm development, and the non-destructive nature of this technique makes it very advantageous for real-time monitoring of biofilm development. Disclosure of Invention The invention aims to realize effective detection of BDOC in water under the conditions of rapidness, in-situ and no damage, so as to reflect the biostability of water quality of a pipeline, and provides a method for rapidly detecting BDOC in a water supply pipeline network by using a biomembrane sensing method based on electrochemical impedance spectroscopy. The invention discloses a method for quickly detecting BDOC in a water supply pipe network by using biological film sensing based on electrochemical impedance spectrum, which comprises the following steps: s1, preparing a sensing electrode, and placing the sensing electrode in drinking water with BDOC concentration to be detected to form a biological film on the surface of the sensing electrode; S2, measuring electrochemical impedance spectrum of an electrode attached with a biological film on the surface in fixed culture time; S3, carrying out parameter identification on each device in the equivalent circuit model according to the electrochemical impedance spectrum of the electrode with the surface attached with the biological film to obtain an electrochemical parameter capacitance value; S4, detecting microorganisms on the electrode attached with the biological film on the surface in a fixed culture time; S5, collecting a biomembrane on the surface of the electrode, preparing a cell suspension, and counting by using a flow cytometer to obtain a microorganism parameter cell density; s6, detecting BDOC concentration of the standard solution with the sensing electrode in fixed culture time to obtain BDOC concentration; S7, drawing a curve according to a relation formula of the microbial parameter cell density and BDOC concentration, and fitting an equation; The relation formula of the microbial parameter cell density and BDOC concentration is as follows: Where tK 1 is a constant under conditions of fixed reaction time, S is a single limiting substrate concentration, N t is the number of cells attached to the electrode at time t, N 0 is the number of cells attached to the electrode at initial time; and the drawing curve is fitted with an equation formula: wherein K is a half-saturation constant, S is a single limiting substrate concentration, the double-layer capacitance ratio of C t and b is a constant, and the calculation formula of C t is as follows: Ct＝K2Nt+b. Wherein K 2 is a half-saturation constant, N t is the number of cells attached to the electrode at time t, and b is a constant; s8, measuring the capacitance of the biological film growing in the actual water sample, carrying out a curve fitting equation, and solving the concentration of