The composition of the mobile fast automatic water quality monitoring system is shown in Figure 1. The whole system can be divided into three parts:
 I sampling part: it is composed of self-priming pump 01 and water tank, 02 is the water outlet valve of the water tank; the sampling part is used to obtain stable water samples of the measured surface;
 II Monitoring part: It is composed of water quality detector and GPS receiver 03 to obtain water quality and geographic location data;
 III Terminal processing part: Contains data acquisition card, industrial computer 04, the data monitored by the water quality detector and the geographic location information received by the GPS receiver 03 are collected by the data acquisition unit, and then input into the computer for signal processing and storage, and the data will be recorded The data is transmitted to the remote management center 06 through the GPRS wireless communication network 05.
 When sampling in the sampling part, the water intake port of the water pump is fixed 1m or more below the water surface with steel pipes, and the measured surface water is pumped into the water tank by the suction pump 01. When the ship carrying the monitoring system travels too fast, the negative pressure of the flowing water body will be too large, which will cause difficulty in absorbing water in the water intake pipeline. For this reason, a rigid plastic pipe (water intake part) with a metal wire in it can be preferentially used, as well as a high suction range of 8m and a rated flow rate of 2m. 3 /h suction pump, this can ensure normal water intake when the speed is less than 15km/h (when the suction range is 9m, the maximum speed can reach 20km/h).
 As shown in Figure 2, after the water sample enters the water tank through the inlet pipe 21, it passes through the baffle 22. The baffle is a solid baffle, which can reduce the water flow speed and make the sediment settle quickly, so that the water quality detector faces the outlet pipe 23. The outflow of a relatively stable water sample is tested. When the water tank needs to be cleaned, the drain pipe 24 can be opened to quickly drain the water for cleaning. Due to the constant changes of the speed and the measured water velocity, the surface water flow of the suction tank is unstable. Adjustable valves are set at the outlet pipe 23 and the drain pipe 24 to keep the water level in the water tank stable by controlling the displacement. The setting of the baffle avoids the hydraulic disturbance of the incoming and outgoing water, and stabilizes the water quality of the measured water body to a certain extent. On the other hand, the two baffles allow sediment to settle in the water tank and protect the water quality monitor. The sediment deposited during system maintenance can be flushed through the drain pipe. The baffle is removable, and the water tank can be loaded with a water quality monitor after being removed. The pulley at the bottom of the tank is convenient for transportation.
 In the monitoring part, one or more water quality detectors can be set up as needed, such as various detectors for detecting water temperature, pH, conductivity, COD, TOC, ammonia nitrogen, nitrate nitrogen, phosphate, chlorophyll and many other water quality indicators. The test result enters the data acquisition card.
 In order to meet the needs of different water quality, all or part of the indicators can be selected for monitoring, or other online water quality testing instruments can be added on the basis of the integrated system. For some automatic water quality monitors that are mainly applicable to sewage treatment plants, they can also be used in this system through software revision of the monitoring results.
 The GPS receiver receives the latitude and longitude information of the sampling location in real time and enters it into the data acquisition card. The geographic information and water quality test data are processed in the industrial computer, and the information is sent to the remote management center.
 In the terminal processing part, the data acquisition card transmits the water quality detection information and geographic information data to the industrial computer, and transmits it to the remote management center through the GPRS network.
 A specific implementation scheme is provided below.
 The water tank is shown in Figure 2. The suction pump adopts the New Territories QB70 type micro clean water electric pump, the maximum suction length is 8m, the pipe diameter is 25mm, and the flow rate is about 2m during normal operation. 3 /h.
 Four types of water quality detectors are used:
 STIP-SCAN all-in-one water quality online monitor (multi-parameter water quality online monitor)
The measuring device is a spectrum analyzer, which is a kind of multi-parameter water quality on-line monitor. The range of the analysis spectrum is between 190-720nm. The sensor directly sucks the water sample to be tested into the measurement chamber without any sample pretreatment device. Stip-scan all-in-one water quality online monitor can simultaneously monitor sewage water quality parameters including: nitrate nitrogen, SAC254, COD, TOC, total solids, sludge sedimentation ratio, sludge index, etc.
 ISCO/STIP buoy type ammonia nitrogen analyzer
 The detection principle of the analyzer is an ammonia gas sensor. In alkaline medium, ammonium ion (NH 4 + ) Convert to ammonia gas. Ammonia molecules can selectively permeate the membrane through the gas and produce a pH change. The change in pH can reflect the concentration of ammonia ions. The ammonia nitrogen analyzer measures the ammonia nitrogen online by putting it directly into the aeration tank or the final drain. The filling and emptying of the measuring instrument is realized by the static pressure and air pressure of the water, saving the sewage pump. All valves only contact air, reagents and calibration standards, thus ensuring high reliability of measurement. The front end of the ammonia nitrogen meter is equipped with a purification unit to separate sewage from sludge and other solid substances before entering the reaction unit. When measuring ammonia nitrogen, control the required pH value to ensure the measurement accuracy when the reagent consumption is low. The measuring instrument is automatically calibrated by the standard addition method every day, while compensating for changes in sewage conditions.
 ISCO/STIP Buoy Phosphate Analyzer
 The analyzer is a quasi-continuous analyzer for measuring the phosphate content in sewage. The phosphate in the sample reacts with the added special reagent to produce a bright yellow substance with a concentration absorption wavelength of 380-480nm. The analyzer is equipped with a diode array spectrophotometer, and its measuring wavelength range is 380-780nm. The analyzer is automatically calibrated with two standard samples every day. The peristaltic pump of the SPECTRON analyzer bypasses the sample into the measurement unit. The sample and the reagent are mixed in the measurement unit and form a yellow substance, the absorption wavelength of this substance is 380-480nm.
 Cyclops-7 Fluorometer
 Cyclops-7 underwater fluorometer is a kind of chlorophyll online analyzer. The fluorometer is designed to be integrated with parameter settings for use. It has the characteristics of high precision, low price and small size, making it suitable for use in ocean, fresh water and dyes. Tracer has a wide range of application value. Despite its small size, its sensitivity and dynamic monitoring range have not been affected. It can avoid the interference of turbidity and ensure a good monitoring effect under a variety of environmental conditions. Cyclops-7 Fluorometer can measure a variety of fluorescent substances, including chlorophyll a, rhodamine WT, fluorescein, phycocyanin and phycoerythrin. Cyclops-7 needs an external power supply, which can output 0~5V standard to external display recorder. Three setting functions provide a wide measurement range.
 The GPS receiver should be a GPS receiver that has a positioning error of less than or equal to 30m and can transmit positioning data in real time. This embodiment adopts the UniStrong DGPS2000 positioning system, which is a single-frequency GPS measurement system with 12 satellite signal channels. Using PDA as the data collection terminal, there are multiple GIS data collection modes such as static measurement, fast static, stop-and-go (quasi-dynamic), and dynamic measurement.
 The data acquisition card should have multi-channel digital input and output ports. In this embodiment, the HY110 data controller is used. This product has multiple A/I, A/O, D/I, D/O; it can be remotely awakened and can be connected to the site Equipment communication; support RS485 network, MODBUS protocol, support real-time clock, support data power-down protection, large-capacity storage.
 The upper control computer should integrate multiple serial ports and network ports. Considering the requirements of system stability and portability, this embodiment adopts an industrial computer that integrates multiple serial ports, USB ports, and network ports, and uses a touch screen that can work at 0-60 degrees. . Through the setting and debugging of the serial port, the GPRS module, GPS satellite positioning system module, and data acquisition module respectively use three serial ports.
 The controller, industrial computer, power supply and data acquisition card equipped with each water quality testing instrument are integrated into the control box, which realizes the appearance integration of the system and is convenient for use and transportation.
 The system operation flowchart is shown in Figure 3. The software included in the system includes: industrial control configuration software IES5000, GPRS communication working software HY-GMSVR and GPRS communication master station software qinghuawater_SVR. Three modules of HY110, HY201GM, and HY201GP are installed in the industrial computer, and working software such as 1ES-5000 and HY-GMSVR to support their work, and the Qinghuawater_SVR communication software is installed in the monitoring center computer as the GPRS communication master station. The remote management center sends a monitoring task to the mobile monitoring ship loaded with this system. After receiving the task, the monitoring personnel activate the corresponding water quality monitor and GPS receiver for real-time water quality monitoring. The industrial computer will receive the water quality information and GPS geographic location. After the information is recorded and stored, it is sent to the remote management center through the GPRS network, where it is analyzed in the remote management center, and then the monitoring task is updated to the monitoring ship based on the analysis results. The upper computer communication setting is the software setting used to start the signal receiving task of the remote management center.
 In summary, this mobile rapid water quality automatic monitoring system is based on the integration of multiple water quality automatic monitoring instruments, data acquisition and processing systems, GPS satellite positioning systems, and GPRS wireless communication systems. It can achieve rapid water quality in a wide range of water environments. Mobile monitoring (the analysis frequency of 6 water samples per hour can give the water quality index of the sampled water body in real time). The system satisfies the requirements for rapid automatic water quality monitoring under sailing conditions.