Monitoring of pollution factors of solidified body leachate in a drilling well site and its influence on the surface water environment

Aiming at the pollution of the leaching solution of the solidified body in the wellbore, a water eutrophication level evaluation algorithm based on the optimized analytic hierarchy process is proposed from the current situation of many factors affecting the eutrophication of the water body and the difficulty of evaluation. Based on this, the user-oriented PC software monitoring system was developed, which mainly includes three major modules: surface water environment monitoring, water eutrophication evaluation, water bloom prediction and warning, and system assistance. The surface water environment monitoring module can receive and display the surface water environment parameter information in real time, and has the functions of data comparison analysis and historical data search, and the eutrophication assessment and water bloom prediction and warning module can analyze the eutrophication status of water bodies in real time and provide short-term and mediumterm warnings for water blooms. This research can promote the control of the leachate pollution of the wellbore in the wellbore and the optimization of the surface water environment.


INTRODUCTION
In recent years, the problem of contamination of the solidified body leachate in surface water environment drilling wells, especially the eutrophication of water bodies, has seriously affected or even threatened industrial and agricultural production and people's lives. Drilling well field solidified body leaching solutions will cause huge pollution of the well site by solidified body leaching of solution in the surface water environment, and monitoring the contamination of the well body solidified body leaching liquid is very important (Wang et al. ). Compared with the general surface water pollution, the solidified exudate has the characteristics of high salinity, heavy metal content and chemical additives. In surface water pollution monitoring, it is necessary to pay attention to the real-time changes of water salinity, organic matter and other indicators. Therefore, a buoy-type multifunctional surface water environment monitoring system was designed and implemented, and by monitoring the surface water environment information of rivers and lakes, at the same time, the evaluation of water eutrophication and the prediction of water blooms are of great significance to the protection and treatment of the surface water environment (Furukawa et al. ).
Based on the overall structural framework of the buoytype multifunctional surface water environment monitoring system, the hardware and software parts of the system have been designed in detail (Kusaiynov et al. ). In terms of hardware design, the rigid float ball is used as the main body, and the sensing device such as the main controller, water quality sensor, small weather station, and pan/tilt network camera is equipped to obtain water quality parameter information, meteorological parameter information and water surface real-time image (Liu et al. ). The ARM (Advanced RISC Machines) processor is a low-power microprocessor designed by Acorn Ltd. Among them, based on ARM embedded technology development, the main controller of monitoring, integrating information collection, processing and remote transmission is the focus of hardware design (Sazonov & Mokhov ). The program for the main controller in C language, and is a large control system integrating the water quality data collection and processing system, the meteorological data collection and processing system, the GPS (Global Positioning System) geographic information collection and processing system, the SMS alarm sending system and the ARM control system, and it has the characteristics of being able to quickly process a large amount of surface water environment monitoring data, and quickly analyze and process data and transmit data, which is innovative (Li et al. ). The research is divided into three parts. The first part is the literature review. The second part is the hardware and software development of the pollution factor monitoring of the solidified body leaching solution in the well site, and the software and hardware design. The third part is testing of the system and the proposed method verification.

RELATED WORK
According to Keller and colleagues, there are currently three methods commonly used in water quality information monitoring methods in China: the first is that people collect water samples and then go to the laboratory for analysis, but the monitoring process is cumbersome, and the cycle from the initial collection of water samples to the results is too long (Keller et al. ). The second is a large-scale fixed water quality automatic monitoring station, Alam and colleagues proposed, its large size, difficult to move, high cost of construction and maintenance (Alam et al. ). The third is to use a conventional ship to monitor the water body using a portable instrument for the carrier. Xia and colleagues applied it, who and believes that the water quality information obtained is too simple and cannot be transmitted online (Xia et al. ). Alves and colleagues believe that these three types of monitoring methods have their own shortcomings, and it is impossible to monitor the waters in real time, dynamically and extensively, and it is not effective to carry out water eutrophication evaluation and water bloom prediction and warning (Alves et al. ).
Therefore, Pavlidis & Tsihrintzis applied a buoy-type multipurpose surface water environment monitoring system for rivers and lakes with large water area, which carries out the real-time dynamic monitoring of water bodies. The monitored surface water environment parameters are transmitted to the upper computer software monitoring system, which can monitor the surface water environment parameter information in real time, which has great ecological and social value for protecting surface water environment resources (Pavlidis & Tsihrintzis ). Li and co-workers evaluated the eutrophication of water bodies and believes that because of its many influencing fac- Unit) uses a powerful ARM9 series processor with low power consumption, small size and low cost. In addition, compared to the previous series, the ARM9 series selects the Harvard architecture, and its increased pipeline architecture enhances its parallel processing skills; it improved the instruction cycle, which greatly improves the performance of the processor, which can increase performance by about 30%; the main controller developed by this system is shown in Figure 1. In terms of hardware, the main controller mainly includes a central processing unit, a 2-way serial interface, a GPS module, a memory, and a GPRS general packet wireless service module, multiple output voltage, two analog inputs, Ethernet interface, program programming interface, eight dry contact switch inputs and four dry contact switch outputs. Figure 1 shows the main structure of the main controller.
In the main controller of the buoy system, the central processor is connected to eight circuits to control the working process of all functional modules, including data acquisition, analysis, format integration and transmission.
As the core of the entire buoy-type multi-purpose surface water environment monitoring system, the central processor controls other functional modules to complete their respective work. In addition to the central processor, the remaining modules in the controller complete their respective functions at the appropriate time. The ferroelectric memory and the FLASH module complement each other and are used to store water quality data information, weather parameter information, and other information. After the RS232 serial port is connected to the RS232-RS485 function chip, it is connected to each sensor, which is used to obtain water quality information and meteorological information of the monitored water body. The GPS module is used for dynamic positioning in monitoring the buoy system, and collects position information of the buoy at various time points.
Using the 3G wireless network router, the water quality parameter information collected by the water quality sensor, the meteorological parameter information collected by the small weather station and the geographical location information collected by the GPS are transmitted to the upper computer software by using the 3G wireless network; the GPRS module is used to push the surface water environment information or alarm SMS to the user's mobile phone through the mobile phone network at an appropriate time. In addition to this, the master also has a watchdog circuit and a reset button. The watchdog circuit is used to protect various hardware devices to work properly. The reset button is related to two reset modes. When the reset button is pressed shortly, the hardware device is reset.
When the reset button is pressed, the hardware restores the initial value. The network interface circuit is mainly embodied in the transformer circuit and is mainly used to transmit Ethernet signals. In order to ensure the quality of the network signal, the circuit also has anti-interference  Table 1.

Software function development
The lower part of the buoy system selects the fourth generation version of Code Composer Studio as the lower platform for development. The software is slightly different from other software in that it has a single user interface that can be used to complete every step of the R&D design process. As a powerful software tool that can be   Figure 3.
Once the buoy-type multifunctional surface water environment monitor is powered on, the system configuration is first initialized, and the corresponding parameters of the GPRS module are configured in the form of an AT command. After that, it is connected with the address and port number of the upper remote monitoring system, and establishes a TCP transmission control protocol connection with it to prepare for transmitting the surface water environment information to the upper system. After the system initialization process ends, the water quality information, weather information, and geographic location information are collected, processed, and transmitted as the timer expires. In the water quality information collection, processing and transmission module, one of the two RS232 interfaces is used to connect with the water quality sensor, and the water quality information is transmitted to the upper monitoring system by using the 3G wireless network.
The flow chart of water quality information collection, processing and transmission module is shown in Figure 4.
When the timing of the timer design arrives, the water quality sensor sends the water quality information collected by the water quality sensor to the main controller, that is, the original water quality parameter data. After that, the original data and the recombined data format are parsed in order according to the program in the controller, and the data packet is prepared according to the communication protocol of the upper system. Finally, there is a wait for it to be transmitted to the upper software monitoring system through the 3G wireless network, and complete a cycle, and repeat the process. In this module, another pathway of two RS232 interfaces is connected with a small weather station (wind speed and direction sensor, rain sensor, and illuminance sensor), and the 3G wireless network is used to complete the weather monitoring information sent to the upper monitoring system. The flow chart of the meteorological information acquisition, processing and transmission module is shown in Figure 5.
When the timing of the timer design arrives, the small weather station (wind speed direction sensor, rainfall sensor, illuminance sensor) sends its own collected meteorological information, i.e., the original weather parameter data, to the main controller. After that, the original data and the recombined data format are parsed in order according to the program in the controller, and the data packet is prepared according to the communication protocol of the     Otherwise, the application cannot be made. When the connection confirmation is confirmed, when the upper server responds to the lower application, it will send the description of its SOCKET to the lower computer through the thread, and the lower digit confirms that the two are connected. After that, the upper server replies to the initial server listening state, waiting for other lower computers to issue an application. of drilling well site, the organic matter content in the surface water will increase, and the corresponding water quality indexes such as cod will reflect obvious abnormality. In case of surface water pollution, when the pollution exceeds a certain range, water eutrophication will occur. Table 2 shows the monitoring results of surface water environment in the software system. According to the monitoring results in Table 2   water environment monitoring functions. In addition, the application software can also implement system-assisted functions such as user login, report printing, and network status viewing. The study provides a theoretical reference for the monitoring of the pollution factor of the solidified body leachate in the well site and its impact on the surface water environment. In the next step, the networking mode can be increased, and other networking methods can be tried, such as receiving data using the mobile app, to further improve work efficiency.

DATA AVAILABILITY STATEMENT
All relevant data are included in the paper or its Supplementary Information.