| Water resources are the source of human life.With the development of society and economy,the water environment pollution is becoming more and more serious,and the quality of water resources continues to decline.Because of the problems and accidents caused by water pollution,water pollution has seriously affected people’s health and the sustainable development of society.How to strengthen water quality monitoring and scientific management,in the global scope of experts and scholars have aroused high attention,the rapid and accurate monitoring of water quality change is imperative.With the rapid progress of photoelectric technology and optical communication technology,optical fiber sensing technology has developed rapidly.Optical fiber sensor has unique advantages in national major engineering safety monitoring due to its advantages of no electricity,light weight,small volume,strong electromagnetic interference resistance,explosion-proof,fire-proof,corrosion resistance,high sensitivity,suitable for harsh environment,long-term real-time online continuous monitoring,etc.It is widely used in the monitoring of Bridges,mines,pipelines,chemicals,offshore oil and gas Wells and other frequently polluted environments.Especially,optical fiber water pollution sensing technology can not only meet the needs of high accuracy and real-time online detection in the field of water quality detection,but also avoid secondary pollution,which has broad application prospects.Aiming at the technical requirements of water quality monitoring,this thesis studies a water quality monitoring system which combines optical fiber sensing technology with organisms,and realizes the on-line monitoring of water pollutants by organisms as media.In this thesis,mussels were selected as sample organisms to design a new online monitoring system for shellfish vital signs.Biological strain sensor based on fiber Bragg grating was designed to monitor the physiological characteristics of mussels and obtain their living rules in water,so as to indirectly obtain information reflecting the change of water quality.The system can not only monitor water quality online in real time,but also help to solve the current problems such as complicated operation of water quality monitoring equipment,high cost and failure to detect pollution in time.This study provides an efficient,stable and real-time online monitoring method for water quality monitoring such as drinking water safety,aquaculture and pollution discharge.The main contents of this thesis are as follows:1.This thesis summarizes the research background,research purpose and significance,briefly introduces the research status of water quality monitoring technology and optical fiber sensing technology at home and abroad,and summarizes different water quality monitoring methods.2.The sensing principle of fiber Bragg grating is studied.Theoretical analysis and experimental study are carried out on the characteristics of reflection and transmission spectrum of fiber Bragg grating,and the characteristics of bandwidth and reflectivity of reflection spectrum of fiber Bragg grating are analyzed.Several common FBG demodulation techniques are briefly compared and analyzed.3.The living characteristics of bivalves were studied and selected as sample organisms for water quality monitoring.Combining the fiber optic sensing technology with bivalve shellfish,the fiber optic biosensing probe was designed,and the fiber optic demodulation instrument was analyzed and studied.A new water quality monitoring system based on fiber optic sensing technology was built.4.The experimental research on the water quality monitoring system based on fiber grating sensing technology was carried out.By monitoring the physiological characteristics of the mussels in the water body,the life rules of the mussels in the water body were obtained to achieve the purpose of water quality monitoring;The solution was tested,and the experimental results were analyzed and discussed in detail. |
