Foreword:
The per capita occupancy of water resources in China is small and the spatial distribution is uneven. With the acceleration of urbanization and industrialization in China, the demand gap for water resources is also increasing. Therefore, protecting limited water resources and increasing the recycling of water resources has received more and more attention from companies and society. In this context, the sewage treatment industry has become an emerging industry and is currently in an equally important position with the tap water production, water supply, drainage, and water reuse industries. Sewage consists of two parts, one is production wastewater and the other is domestic sewage. The production wastewater mainly comes from large-scale water industrial plants such as electric furnace steelmaking, silicon steel, and chemical plants.
At present, of the 661 municipal cities in China, 792 sewage treatment plants have been built in 383 cities. Of these, 135 cities have achieved or have reached a sewage treatment rate of 70%, and the single plant treatment capacity has reached 1 million cubic meters per day. Although the national and all levels of government are paying more attention to environmental protection, China's sewage treatment industry is growing rapidly, and the urban sewage treatment rate continues to increase. However, at present, China's sewage treatment industry is still in the initial stage of development.
The sensor becomes the eye of industrial wastewater treatment:
The monitoring and control system of the sewage treatment process consists of four parts: model, sensor, local regulator and superior monitoring strategy. Among them, the sensor is the most important and basic link in the sewage treatment plant monitoring system. Increasingly stringent effluent discharge standards have led to complications in wastewater treatment process and equipment. At the same time, this also puts forward higher requirements for the performance of sensors used for monitoring and controlling the sewage treatment process, and promotes the development of sensor technology in the field of sewage treatment. As a result, some new types of sensors that are suitable for the sewage treatment process have come out one after another. There are many kinds of instruments involved in the sewage treatment process. Most of the sensors are unique to the sewage treatment process and can be applied to different occasions separately because the signals collected by these special sensors will reflect the status information changes of one or more specific variables. . Objectively speaking, sensors will become the eyes of industrial wastewater treatment.
Industrial water treatment plant issues:
Because sensors play a decisive role in industrial wastewater treatment, the layout of sensors is very important. The scale of industrial water treatment is quite large, and generally it takes several steps. If the crude fraction can be divided into: pretreatment process, hydrolysis acidification process, SBR process, contact oxidation process, sludge dehydration process, subdivision can be further divided into: crude Grid and sewage lifting pumps, fine grids, aerated grit chambers, biochemical pools, pooled wells, final sinks, filters, disinfection channels, etc. A medium-sized water treatment plant must occupy a pool of tens of acres to several hundred acres. In such a large area, in order to collect analog data for sensors placed in sewage, a long data line needs to be laid out. To the stability of the signal, sometimes also need to use the shielded cable. The cost of trenching wiring and the use of high-performance wires will occupy a large part of the project budget, greatly limiting the development of water treatment plants.
The DX70 wireless network system becomes the eye-sight nerve of industrial wastewater treatment:
In response, Bonner's DX70 wireless network system is well positioned to meet the needs of applications in the water treatment industry.
Banner DX70 Wireless Network System
When sewage enters the corresponding treatment tank through a process, first, various monitoring instruments (including sensors for temperature, pressure, liquid level, flow, pH, conductivity, suspended solids, etc.) collect the relevant values ​​of the sewage. These monitoring instruments will be connected to the node of the Bonner DX70 wireless network system, and then the DX70 wireless network system node will send the collected analog data to the gateway through radio waves, and then the gateway will transmit the data to the main control PLC or computer system to achieve Full monitoring and control of the sewage treatment process.
Bonner wireless sensor technology enables remote signal acquisition and multi-point monitoring and measurement, which greatly facilitates the implementation of sewage treatment process monitoring. Wireless sensor technology has great potential compared with traditional wired systems. Water treatment plants have become a very difficult problem because of geographical restrictions and restrictions on sewage. At certain towers, it is impossible to realize wiring to collect data. At this time, the wireless system can play a key role. effect. Bonner's DX70 wireless network system gives users both cost savings and implementation time convenience.
DX70 wireless network system wiring diagram
The DX70 wireless network system can transmit on-site discrete sensor signals through the nodes to the control room's gateway. Can support a variety of sensor input, such as the switch, analog, thermocouple and other signals. Using frequency hopping spread spectrum technology (FHSS), good anti-interference performance. SureCross node can connect various analog signals such as liquid level, PH value, conductivity, and flow, and these analog signals are distributed in different places of the water treatment plant. The nodes send data to the central control center through the gateway, and the DX70 wirelessly. The network system has solved the environmental obstacles of the sewage treatment plant, the influence of the resources and other factors, and it has become a visual neural network system that connects the sensors in all aspects of the sewage treatment.
DX70 wireless network field use map
Bonner wireless network system topology:
As the main equipment, the wireless network system gateway bears the mapping relationship and control between the input and output of each node, and communicates with the upper system to realize data exchange. The node is responsible for the collection of field data and sends it to the gateway. The number of nodes can be flexibly configured.
Illustration: Using a star network topology technology, such as a gateway and 15 nodes, the gateway implements two-way communication with each node.
Explanation: The gateway acts as a master device and bears the mapping relationship and control between the input and output of each node, and communicates with the upper system at the same time to realize data exchange.
The supported communication protocols are:
1. RS-485 Modbus RTU
2. Modbus TCP
3. Ethernet IP
The node is responsible for the collection of field data and sends it to the gateway. The number of nodes can be flexibly configured.
Technical parameters of Bonner wireless network system:
n Frequency Hopping Spread Spectrum (FHSS) The combination of radio frequency hopping spread spectrum and Time Division Multiple Access (TDMA) time division multiple access control architecture provides strong interference immunity.
n Wireless Industrial I/O System, 4 Channel Switch I/O, 2 Channels Analog I/O, Loss of Link Signal Output
n The gateway and the node are bidirectional data transmissions, including data transmission response
n Robust housing with IP67 protection rating
n Plug and play
n 2.4 GHz frequency
n Built-in signal strength indication
n Built-in or external antenna optional, a wide range of antennas
n Super long distance 3.2 Km
to sum up:
The Bonner DX70 wireless network system is applicable to various existing sensor installations in practical applications, reducing the cost of increasing wiring distances, eliminating obstacles to on-site wiring (overhead bridges, bridges, rivers...) and production interruptions or Restrictions on outdoor work, and solve the need for time-consuming and laborious wiring and on-site environment such as dust and other issues. This product can be applied to many kinds of signal inputs and outputs of industry and automation without wiring. The emergence of the DX70 wireless network system will bring more extensive and efficient product applications to the domestic sensor market.
According to statistics from relevant agencies, when using wireless sensors and using wired sensors, the overall application cost will be three times that of the former when the application conditions and output are the same. Because wired lines inevitably lead to routine operations such as wiring and slotting, wireless sensors will be used more freely and conveniently. It is believed that with the improvement of application concepts, more cost-effective and practical wireless sensors will be accepted by more and more domestic enterprises.
Attached:
1. FHSS-Frequency Hopping Spread Spectrum Technology: The carrier frequency is controlled by a pseudo-random code. Within its effective operating bandwidth, it changes continuously according to the random laws of the PN code to achieve spectrum expansion. At the same time, at the receiving end, the frequency synthesizer of the receiver is controlled by the same pseudo-random code, and through synchronization measures, it is consistent with the transition order of the transmitting end, and finally achieves two-way communication. The advantage of frequency hopping is strong anti-interference performance. Compared with other single frequency communication methods (such as digital radio), once the communication is interfered by external noise at a certain time, it can actively jump to other channels to continue communication.
2. Common instruments for the wastewater treatment process include sensors for temperature, pressure, level, flow, pH, conductivity, and suspended solids.
1 Anaerobic Digestion Temperature sensors are even more important because they are often temperature controlled. A typical temperature measurement element is a thermal resistance.
2 Pressure measurements are often used as alarm parameters for aeration and anaerobic digestion processes.
3 level measurement for water level monitoring, usually using buoys, differential pressure transmitter, capacity measurement, ultrasonic water level detection and other methods.
4 flow monitoring instruments are mainly plate, rotor flowmeter, turbine flowmeter, target metering tank, electromagnetic flowmeter, ultrasonic flowmeter and so on.
5 The pH value is an important variable in the biochemical process, and it is also the key value of the anaerobic digestion and nitrification process. Usually, the pH electrode immersed in the sewage sludge is installed in the sewage treatment plant. Through different cleaning strategies, long-term maintenance-free can be achieved. For highly buffered wastewater, pH measurements may not be sensitive to process variations and therefore are not suitable for process monitoring and control. This can be replaced with carbonate measurement systems.
6 Conductivity sensors are used to monitor changes in the composition of incoming water and are also the basis for chemical phosphorus removal control strategies.
7 Traditional biomass measurements are based on the scattering and absorbance of incident light by suspended particles.