Design On Microalgae Detection System In Ship’s Ballast Water

With the continuous advancement of the process of globalization,the economic and transportation exchanges between countries are becoming more and more frequent.Among them,shipping,as an important mode of transportation,plays a key role in the process of globalization.The phytoplankton in the ship’s ballast water is transferred in various sea areas with the ship,which can easily lead to the invasion of alien organisms.The Ballast Water Convention proposed by the International Maritime Organization limits the specific requirements for ballast water discharge performance standards: the minimum size is less than50μm but greater than or equal to 10μm.The viable organisms are less than 10/m L,and the main ones within this size range are microalgae cells.This thesis proposes a microalgae detection system design based on quartz capillary and FDA fluorescence detection technology.Using quartz capillary as the detection platform and using FDA dyeing laser-induced fluorescence technology as the detection principle,the detection system of active microalgae cells’ concentration in ship’s ballast water is realized.The system design mainly includes hardware and software.The hardware part mainly includes detection area design,circuit design,data acquisition design,ARM main control design,sample channel design,power supply design and external structure design.The detection area design includes the comparative and selection of the optical path structure and the design of the mechanical structure;the key parts of the circuit design are the signal processing circuit and the driving circuit,the signal processing circuit completes the filtering and amplifying processing of the optical-to-electrical signal,and the driving circuit is responsible for receiving the instructions of the ARM board to control the elements in this system;the data acquisition design realizes the conversion of analog-to-digital signals;the ARM main control design includes the control of each part of the system and the promotion of the entire detection process;the sample channel design is mainly divided into the overall pipeline design and the dyeing area design;the power supply design is responsible for powering the whole system;the external structure design includes the design of external accessories and the mechanical structure design of the whole system.The software part mainly includes logic program design,interface program design and auxiliary function design.The logic program design includes the average filtering processing of the signal and the effective peak judgment processing,the interface program realizes the software interface that can be used for human-computer interaction,and finally added the functions of data export,data viewing and data printing.After completed the overall integration of the system,dyeing experiments,concentration experiments,salinity experiments and turbidity experiments were carried out with different algae species,which proved the accuracy and stability of the system.The system has the advantages of convenient operation,short detection time,high accuracy and easy portability,and is suitable for real ship ballast water detection in the maritime sector.