CN-121999917-A - Method for evaluating generation of byproduct NDMA of precursor substance in chloramine disinfection

CN121999917ACN 121999917 ACN121999917 ACN 121999917ACN-121999917-A

Abstract

The invention discloses an evaluation method for the generation of a byproduct NDMA of a precursor substance in chloramine disinfection, which comprises the steps of collecting data of NDMA generated by a drug precursor and a flocculant precursor in the chloramine disinfection process, converting an original independent variable and a dependent variable into a secondary power and logarithmic form by using SPSS, carrying out regression analysis by adopting a stepping method, removing a variable with a parameter significance P of more than 0.1, inputting the rest variable into the SPSS again to obtain a regression model, measuring or calculating the concentration of the precursor substance, the concentration of chloramine, pH, temperature and reaction time in a designated environment, and substituting the obtained product into the regression model to calculate the NDMA generated quantity of the designated precursor substance under a certain condition. The invention can accurately calculate the generation condition of the NDMA in the monochloramine disinfection process, and can feed back the generation amount of the NDMA in the water plant in real time according to different water qualities, thereby not only avoiding the condition that the concentration is too low to be detected, but also dynamically guiding the generation of the NDMA, and being efficient, convenient and practical.

Inventors

JI MIAO
GUO RUSHENG
ZHANG ZHAOWEI
ZHANG YU
LU XULONG
LI KAN
SHI WENTAO
FENG ZHUO
LIU YANG
GUO ZHE

Assignees

中核第七研究设计院有限公司

Dates

Publication Date: 20260508
Application Date: 20260120

Claims (4)

1. A method for evaluating the production of NDMA, a byproduct of chloramine sterilization, as a precursor material, comprising: S1, collecting data of NDMA generated by a drug precursor and a flocculant precursor in a chloramine disinfection process, converting original independent variables and dependent variables into a second power and logarithmic form by using SPSS, and carrying out regression analysis on all the original variables and the converted variables by adopting a stepping method; S2, eliminating a variable with the parameter significance P >0.1 in the regression analysis formula, and inputting the rest variable into the SPSS again to obtain a regression model; S3, measuring or calculating the concentration of the precursor substances, the concentration of chloramine, the pH, the temperature and the reaction time in the appointed environment, substituting the measured or calculated data into a regression model, and calculating the NDMA generation amount of the appointed precursor substances under a certain condition, wherein the model parameters are adjusted to minimize the NDMA generation amount.
2. The method for evaluating the production of NDMA, a by-product of which is produced during chloramine sterilization, as claimed in claim 1, wherein said prodrug comprises at least ranitidine and nizatidine, and said flocculant comprises at least polyamine and polydimethyldiallylammonium chloride.
3. The method for evaluating the generation of NDMA, a byproduct of chloramine sterilization, as claimed in claim 2, wherein after the parameter significance P in S2 is removed, a regression model equation is established for the drug precursor in the regression analysis process: ranitidine: Nizatidine: Wherein, the For the amount of NDMA produced, Is the concentration of the precursor species in the body of water, Is the concentration of monochloramine in the water body, For the reaction time of the precursor material with monochloramine, Is the pH value in the water body, 、、、、、 Is the regression equation coefficient of ranitidine, 、、、、、 Is the regression equation coefficient of nizatidine.
4. The method for evaluating the generation of NDMA, a byproduct of chloramine sterilization, as claimed in claim 2, wherein after the parameter significance P in S2 is removed, a regression model equation is established for the drug precursor in the regression analysis process: Polydimethyldiallylammonium chloride: Polyamine: Wherein, the For the amount of NDMA produced, Is the concentration of the precursor species in the body of water, Is the concentration of monochloramine in the water body, For the reaction time of the precursor material with monochloramine, Is the pH value in the water body, 、、、、、、 Is the regression equation coefficient of polydimethyl diallyl ammonium chloride, 、、、、、、 Is the regression equation coefficient of polyamine.

Description

Method for evaluating generation of byproduct NDMA of precursor substance in chloramine disinfection Technical Field The invention relates to the technical field of industrial wastewater treatment, in particular to an evaluation method for the generation of a byproduct NDMA in chloramine disinfection. Background Chlorination has become the most common water disinfection method because of simple application and low cost, however, chlorine disinfection can generate disinfection byproducts harmful to the environment and people while improving water quality, and meanwhile, research shows that chloramine disinfection can reduce the generation of disinfection byproducts, but can generate nitrogen-containing disinfection byproducts which are more harmful to human bodies, such as novel water disinfection byproduct nitrosodimethylamine NDMA with a 'three-effect', which is used as one of carcinogens and can cause irreversible damage to human bodies, and drug precursor substances are also often detected in water bodies and the disinfection byproducts NDMA are easy to generate when chloramine is disinfected. In the existing chloramine disinfection, the chloramine is used, the disinfection mechanism of the chloramine is that the chloramine is hydrolyzed in water to generate hypochlorous acid HClO with strong bactericidal effect, the hypochlorous acid can not only act on cell walls and virus shells in the process of sterilizing and killing viruses, but also permeate into the virus bodies due to small hypochlorous acid molecules to perform oxidation reaction with virosome organic polymers so as to kill pathogenic microorganisms, and the existing researches prove that the chlorine disinfection can generate halogenated disinfection byproducts with great harm, so that the chlorine disinfection is replaced by the chloramine in order to reduce the generation of the hypochlorous acid. And the monochloramine disinfection has the advantages of low cost, high efficiency and the like. However, in the actual water disinfection process, when the concentration of NDMA in water is too low, the NDMA is difficult to detect, so that a mathematical model is required to be built for generating the NDMA, but the existing mathematical model does not carry out subdivision evaluation on precursor substances, the difference characteristics of different water qualities and precursors with different structures cannot be accurately matched, the prediction error is too large, the generation amount of the NDMA in the water cannot be accurately calculated, and most of the NDMA is subjected to end point evaluation, so that the generation trend of the NDMA in the disinfection process cannot be dynamically guided. Therefore, the application provides a method for evaluating the generation of a byproduct NDMA of a precursor substance in chloramine disinfection, and the technical problems are solved by correspondingly correlating the generation of the NDMA with strong correlation of pH and reaction time. Disclosure of Invention The invention aims to provide an evaluation method for the generation of a byproduct NDMA of a precursor substance in chloramine disinfection, which is characterized in that the generation amount of the NDMA is dynamically guided by quantitatively calculating the generation amount of the NDMA of a drug precursor substance and a flocculating agent precursor substance in the chloramine disinfection process by controlling main variables influencing the generation of the NDMA, namely the concentration of the precursor substance, the concentration of chloramine, the pH, the reaction temperature and the reaction time, so as to accurately predict the generation amount of the NDMA and solve the technical problems in the background technology. The invention adopts the following technical scheme to solve the technical problems: The method for evaluating the generation of the byproduct NDMA of the precursor substances in chloramine disinfection selects the common precursors of two industrial waste water, namely a drug precursor and a flocculating agent precursor, wherein the drug precursor comprises ranitidine and nizatidine, the flocculating agent precursor comprises Polyamine (PA) and polydimethyldiallyl ammonium chloride (PDMDAAC), the generation amount of the NDMA of the drug precursor substances and the flocculating agent precursor in the chloramine disinfection process is quantitatively calculated by a method of establishing a mathematical model by using SPSS data analysis software through a computer, and the generation of the drug precursor substances and the flocculating agent precursor is controlled from the process, and the method comprises the following steps of: S1, collecting data of NDMA generated by a drug precursor and a flocculant precursor in a chloramine disinfection process, converting original independent variables and dependent variables into a second power and logarithmic form by using SPSS, and carrying out regression an