The hottest water quality and water quality analys

At present, there are three forms of water quality analysis instruments: laboratory analysis instruments, portable analysis instruments and water quality analysis instruments

water quality analysis instruments appeared the latest, but they have grown rapidly. Especially in recent years, they have attracted much attention, and their exposure rate is far higher than the other two, becoming a hot red - the legendary "late mover advantage"

let's take a look: Recently, in traditional and non-traditional media such as television, newspapers, Internet, Weibo, etc., almost all the words "automatic monitoring" and "monitoring" will appear on occasions involving environmental protection and water safety. Some time ago, the Ministry of environmental protection held a meeting on the national environmental quality monitoring of surface water, which also clearly put forward that "we should speed up the construction of automatic water quality stations. Gradually establish a monitoring mode dominated by automatic monitoring and supplemented by manual monitoring?" (it is said that one of the outcomes of this meeting is that in 2018, the government will invest in the construction of 1200 automatic surface water quality monitoring stations nationwide. Is it surprising?)

the "environmental protection tax law of the people's Republic of China", which will be officially implemented on January 1, 2018, The provisions of Article 10 clearly stipulates:

"the emissions of taxable air pollutants, water pollutants, solid waste and the decibels of noise shall be calculated according to the following methods and sequences:

(I) taxpayers who install and use automatic pollution monitoring equipment that meets national regulations and monitoring norms shall be calculated according to the automatic monitoring data of pollutants;

(II) If the taxpayer fails to install and use automatic monitoring equipment for pollutants, it shall be calculated according to the monitoring data issued by the monitoring institution that conforms to the relevant national regulations and monitoring norms; "

explain: at present, the automatic monitoring equipment of water pollutants in China is divided into flow monitoring equipment and concentration monitoring equipment (the product of concentration and flow is the total amount of pollutants). Concentration monitoring equipment is commonly referred to as water quality analysis instruments

more importantly, according to this law, the data of Environmental Tax Taxable pollutant emissions are obtained first by using the data of automatic monitoring equipment, and then by "the data issued by the monitoring institution" - at present, the analytical instruments used by the monitoring institution are mostly laboratories or a few portable analytical instruments (for individual indicators that must be tested on site)

it can be said that this environmental tax law formally established the status of analytical instruments in the form of legal provisions

so, what is the sanctity of such a "high-end atmospheric and high-grade" water quality analysis instrument? Why is it so popular

the authoritative definition is: according to the definition in the international organization for Standardization (ISO) code iso15839 "water quality - Specifications and performance testing of sensors/analytical equipment": analytical sensor/equipment is an automatic measuring device that can continuously (or at a given frequency) output signals proportional to the value of one or more measured substances in the solution

it sounds very profound (does authority always do this?), Is there a popular saying

if you have a problem, go to Baidu

unexpectedly, this time, Du Niang actually let me down. After searching for a long time, I didn't find a more convincing statement

"can't wait, toss and turn". think it over and over again, It seems that the non authoritative statement I made in my speech at the 2007 "Second International Forum on the application and development of analytical instruments" ten years ago is relatively easy to understand:

"water quality analytical instruments are a kind of special automatic analytical instruments, which can collect (water quality indicators) from water samples through real-time and on-site operation Rapid analysis of data output; Water quality analysis instruments generally have the functions of automatic diagnosis, automatic calibration, automatic cleaning, fault alarm, etc., which can realize unattended automatic operation while ensuring the accuracy of analysis results. "

combining authoritative and non authoritative statements, it can be found that the most important characteristics of water quality analysis instruments are three: automatic, continuous and real-time

means serve the purpose. As a tool to obtain the data of water quality indicators, compare the four purposes of obtaining water quality indicators mentioned above: to understand the concentration of impurities; Predict water quality changes; Control and optimize water treatment process; Assess water quality safety; And six categories of water quality indicators: physical indicators, component indicators, evaluation comprehensive indicators, water quality transformation potential indicators, process indicators, and alternative indicators; Let's take a look at the water quality analysis instrument as a new technology. Where was the first breakthrough point of application in that year

undoubtedly, in terms of "controlling and optimizing water treatment process", with the characteristics of "real-time and continuous", water quality analysis instruments play an irreplaceable role. First, important process indicators such as pH, turbidity, dissolved oxygen and ORP are measured; Faced with the challenge that some process index analysis methods are complex or the measurement cycle is long, which can not meet the requirements of automatic control in the process industry, it is the turn of the replacement index to appear brightly

(at present, it is difficult to verify the specific age and occasion of the first water quality analysis instrument. My personal guess is that the first instrument is likely to be a pH meter, which is used for the process control of acid-base regulation)

from a global perspective, the most widely used subdivision of water quality analysis instruments is water treatment process control

the "automatic, continuous and real-time" characteristics of water quality analysis instruments, in addition to being used to control and optimize the water treatment process, also have great advantages over laboratories and portable analysis instruments in understanding the concentration of specific pollutants and evaluating water quality safety

it is self-evident that automation has the advantage of reducing the human labor of analysts. More importantly, since the instrument analysis process does not need human intervention, human errors are also reduced. (over the years, the Chinese government and environmental management departments have been working hard to eliminate the interference of various human factors on pollutant emission data (see the "measures for the determination and treatment of environmental monitoring data fraud" and other regulatory documents, as well as various kinds of environmental data fraud into punishment). At present, China is the most common market in the world to use water quality analysis instruments to automatically monitor sewage discharge, and water quality analysis instruments will become one of the tax tools for the discharge of pollutants (mainly ammonia nitrogen, heavy metals, total phosphorus/total nitrogen and other component indicators, COD and other comprehensive evaluation indicators) stipulated in the environmental protection tax law,

it is estimated that a big reason is that the water quality analysis instrument as an automatic instrument does not need manual intervention in the analysis process)

at the same time, the "continuous and real-time" feature also makes the water quality analysis instrument not only continuously provide real-time data of water quality indicators, but also often serve as an alarm device. Once the water quality indicators exceed a given safety value, The instrument will output an alarm signal (the role of real-time alarm is very important in evaluating water quality safety)

the advantages are more than that. Two more words about the health and safety benefits of operators:

some water samples, such as containing more toxic and volatile chemicals, may endanger the health of analysts during manual analysis; In some workplaces, analysts cannot enter the site to take water samples when the production unit is running. The most extreme example is: in the primary circuit of a nuclear power plant, even operators wearing heavy protective equipment can only stay for a short time due to strong radiation; However, some important water quality index data (such as dissolved oxygen, dissolved hydrogen, conductivity, etc.) must be obtained in time during the operation of nuclear power plants

at this time, the advantages of water quality analysis instruments as automatic equipment can be better reflected

however, although it has so many advantages, whether from the perspective of technological progress or market development, water quality analysis instruments, like any other new technology, are not plain sailing

at the initial stage, due to the relatively low water resource fee, water price and the cost of wastewater discharge, the investment and operation cost of analytical instruments were relatively high at that time; And at that time, the stability and reliability of water quality analysis instruments may not fully meet the requirements of practical work; There are not many water quality indicators that can be analyzed

these two factors caused the operation managers and water treatment engineers in the water industry at that time to have a cautious attitude towards the use of water quality analysis instruments, which seriously restricted the development and application of water quality analysis instruments. (in 1973, at the first ICA (instrumentation, control, automation) expert meeting of the water treatment industry held in London, England, the first consensus reached by the experts at that time was that the insufficient number of instruments was the main obstacle to automatic control. It is believed that according to the development of the instrument at that time, only the measurement of turbidity, dissolved oxygen and conductivity are more reliable)

"I am born to be useful". As people attach importance to water quality safety, environmental protection regulations become more stringent, and water resource fees continue to rise, especially the development of water quality analysis technology and computer information technology, Water quality analysis instruments have gradually shown cost performance advantages (for example, compared with the original analog circuit, the use of digital circuit technology in the unloading device of water quality analyzer has greatly improved the reliability of the instrument, and the cost of instrument design and mass production has been greatly reduced). They have been more and more widely used in many fields, such as water environment monitoring, water treatment process control, drinking water quality safety early warning, etc, It has also been rapidly applied in the field of concentration monitoring and over standard alarm of wastewater pollutant discharge

having talked about the market and application, let's return to water quality analysis instruments. The development and challenges of this technology:

according to the definition of the ISO standard above, there are two forms of water quality analysis instruments: analysis sensors and more complex automatic analysis equipment or devices

let's talk about water quality analysis sensor first:

the national standard gb/t7665 "general terms of sensors" defines the sensor as "a device or device that can sense the specified measured parts and convert them into usable signals according to a certain law (mathematical function law), which is usually composed of sensing elements and conversion elements". The structure of water quality analysis sensor is usually relatively simple, and the data of water quality indicators are obtained through direct contact with the measured water sample

the water quality indicators that can be measured initially by the analysis sensor are mainly some simple physical indicators and component indicators, such as conductivity, pH, ORP, dissolved oxygen, etc; Then there are sensors based on optical principles such as turbidity and suspended solids concentration; Later, sensors with alternative indicators such as UV254 appeared; In recent years, with the improvement of the calculation ability of the instrument and the application of new materials, the ion selective electrode method (measuring ammonia nitrogen, nitrate nitrogen and other important process indicators in sewage) has been used in the assembly of leaf springs in Jinan times Ultraviolet fluorescence (measuring oil in water, etc.) and the principle of full-spectrum scanning (the sensor can indirectly measure cod, BOD, TOC and other organic indicators, turbidity, nitrate nitrogen, nitrite nitrogen and other water quality indicators) have been widely used

the water quality analysis sensor mainly faces two challenges in practical use:

the sensor is in direct contact with water samples, lacking experiments