Distributed On-Line Water Environment Monitoring System

Rivers and lakes provide human with required water resources and rich aquatic products, at the same time, rivers and lakes can coordinate regional precipitation and improve the climate and environment. With the improvement of productivity and accretion of population, the hydrological ecological was continuously damaged. Water environment monitoring not only can control water quality situation in real time and implement water pollution early warning, but also can provide reliable data for the study and protection of the hydrologic environment.Because of remote geographical location, vast water area and inconvinient energy supply of rivers and lakes, traditional water quality monitoring was mostly artificial acquisition of parameters, with low execution efficiency and high cost. Aimed at such issues, this system combined wireless sensor network technology (ZigBee module) of 3G (WCDMA) technology with sensors and solar energy power supply system, designed distributed on-line water environment monitoring system, solved the problem of energy supply in the field water environment monitoring, distributed parameter acquisition and remote wireless transmission.The main research contents are as follows:First, considering remote location and large area of water spaces, this paper presented a systematic solution of wireless sensor network for water environment online monitoring, which consists of sensor acquisition node,3G gateway node and server. Due to the lack of available power supply circuit at monitoring position, the system used solar panels and Lithium battery to build up a green energy system, in order to make sure for energy supply of the field monitoring system. Sensor acquisition nodes and 3G gateway nodes (coordinate nodes) are used in independent sensor network for short distance data transmission, and 3G gateway nodes use WCDMA network and data server for remote wireless communication.Second, this paper designed the data acquisition nodes and 3G gateway nodes. The hardware design includes multiple water quality sensor detection circuit, acquisition node CC2430 processor and RF front-end CC2591 circuit; 3G gateway processor MSP430 peripheral circuit,3G (WCDMA) module EM770W circuit and solar energy power supply system circuit. The software design includes wireless sensor network node in the network and data transmission, sensor driver software design and the design of the 3G gateway communication.Finally, the test analyses on the monitoring system are discussed. Its various monitoring resualt of water quality meet the standard of national water quality monitoring precision and the paper analyses the monitored area water conditions combined with water quality standards. Using the standard Dissolved Oxygen meter, we calibrate the DO sensor data of the system. Network of the sensor nodes connect quickly and stability, communication distance up to 250m and node packet loss rate lower than 4% per month. It has stable and reliable operation, realizing distributed remote monitoring of water environment. The system has the advantages of regional distribution monitoring, remote transmission, energy conservation and low cost, so that can be generallized to other occasions such as atmospheric data monitoring, greenhouse cultivation monitoring and aquaculture monitoring.