Water pollution source online monitoring system solution

I. Overview

Water is an indispensable resource for human survival, life and production. With the rapid development of modern industry and the continuous increase of population, the problem of water environment in China has reached an urgent level. In the early days of reform and opening up, China's economic growth mode was extensive. Many enterprises simply pursued economic benefits, neglected environmental and ecological benefits, and the environmental damage caused by waste materials generated in industrialization projects and the resulting negative impact became more and more apparent. Come out, it is a serious threat to people's survival and safety. The increasingly serious water problem has also become one of the important constraints to achieving the strategic goals of development in the new era. In this regard, China has continuously increased environmental protection efforts, taking environmental industry as one of the basic industries for priority development, and has formulated a series of policy documents: In February 2015, the Standing Committee of the Political Bureau of the Central Committee deliberated and approved the "Water Ten Articles". It aims to supervise and start strict accountability in many aspects such as sewage treatment, industrial wastewater, and comprehensive control of pollutant discharge, and turn iron-handed pollution into a normal state. In December 2015, the Beijing-Tianjin-Hebei Environmental Protection Bureau officially signed The Beijing-Tianjin-Hebei regional environmental protection is the first to break through the cooperation framework agreement, clearly requiring the three places to unify the atmosphere, water and soil management; in June 2017, the Twenty-eighth meeting of the Standing Committee of the 12th National People's Congress amended the "Chinese Law of the People's Republic of China on the Prevention and Control of Water Pollution, to amend the law to protect and improve the environment, prevent and control water pollution...

With the attention of the people and the introduction of policies, China's water pollution collection and monitoring process has matured, but traditional methods such as manual collection, analysis of data, manual processing of data, manual summary of tabulations, etc. are not only costly, time-consuming and laborious, but also long-term, data The analysis is slow and the delivery is not timely, and it is difficult to grasp the current situation of the environment in real time and accurately. In view of the current situation, Zhiyi Times has launched a set of automatic water pollution monitoring system for continuous automatic sampling, measurement, transmission and data processing of wastewater discharged from pollution sources, providing real-time data analysis and diagnosis. The system can monitor COD, BOD, ammonia nitrogen, total phosphorus, total nitrogen and other pollution parameters online, 24-hour online data collection and upload communication, and has real-time alarm function and statistical analysis report.

Second, the system introduction

The online monitoring system for water pollution sources consists of water quality analyzers, integrated control transmission systems, pumps, pretreatment devices and other related ancillary facilities. The main function is to monitor the field devices, analyze and detect the water quality, and transmit the monitored related data to the remote server through the network.

Instrument introduction

3.1 CODcr water quality online analyzer

1) Product Overview

This product is a new COD online monitoring instrument based on the magnetic conductivity measurement technology platform and combined with constant temperature fiber, digestion and colorimetric integration technology.

The working principle of this product is in line with "HI/T 399-2007 Determination of Chemical Oxygen Demand in Water Quality - Rapid Digestion Spectrophotometry", which has the characteristics of high reliability, low quantitative limit, good stability and strong resistance to chloride ion interference. In the fields of pollution sources, industrial production processes, municipal sewage, etc.

2) Basic principles

The instrument uses the potassium dichromate rapid digestion spectrophotometric method to measure the organic matter content in the water sample. The water sample, potassium dichromate and sulfuric acid-silver sulfate mixture are digested at 165 ° C, and the solution is digested to convert chromium (VI) to chromium (III). The amount of chromium (III) corresponds to the amount of organic matter in the water sample. The instrument obtained the COD value of the water sample by colorimetric measurement.

Inorganic ions such as nitrite and ferrous ions in the water sample make the test value high, but are acceptable as part of the COD.

Interference of chloride ions in the water sample is masked by the addition of mercury sulfate.

Some volatile organic compounds, pyrimidines, and materials that are more difficult to oxidize require sufficient contact with the oxidant for a period of time to be more fully oxidized.

3.2 Ammonia nitrogen water quality online automatic analyzer

1) Product Overview

This product is based on a magnetic permeability metering platform, combined with constant temperature fiber, digestion and colorimetric integration technology to achieve high-precision, low detection limit, high stability and low maintenance of ammonia nitrogen automatic online monitoring.

The working principle of this product is in line with the "HJ 536-2009 water quality ammonia nitrogen determination - salicylic acid spectrophotometry", fully meet the application of pollution sources, industrial production processes, municipal sewage and other fields.

2) Basic principles

The instrument uses salicylic acid spectrophotometry to measure the ammonia nitrogen content of the water sample. In the presence of an alkaline medium (pH = 11.7) and sodium nitroferricyanide, ammonia and ammonium ions in water react with salicylate and hypochlorous acid ions to form a blue compound, and the absorbance is measured at 697 nm.

Severe interference from aniline and ethanolamine is rare, and interference is usually produced by primary amines. Chloramines, excessive acidity, alkalinity, and substances that cause the reduction of hypochlorite ions can also cause interference.

Pre-distillation is required if the water sample is too dark and too salty, and the potassium tartrate masking ability of the metal ions in the water sample is insufficient, or when high concentrations of calcium, magnesium and chloride are present in the water sample.

3.3 total nitrogen water quality online analyzer

1) Product Overview

This product is based on a magnetic conductivity metering platform, combined with constant temperature fiber, digestion and colorimetric color integration technology to achieve high-precision, low detection limit, high stability and low maintenance of total nitrogen automatic online monitoring.

The working principle of this product is in line with the "GB1189-89 determination of total nitrogen in water - alkaline potassium persulfate digestion ultraviolet spectrophotometry", fully meet the application of pollution sources, industrial production processes, municipal sewage and other fields.

2) Basic principles

In an aqueous solution above 60 ° C, potassium persulfate can be decomposed to produce potassium hydrogen sulfate and atomic oxygen, and potassium hydrogen sulfate dissociates in solution to generate hydrogen ions, so the decomposition process tends to be promoted in an alkaline medium of sodium hydroxide. complete.

The decomposed atomic oxygen can convert the nitrogen element of the nitrogen-containing oxide into nitrate in the condition of 120 ° C ~ 124 ° C, and in the process, the organic matter is simultaneously oxidized and decomposed. The absorbances A220 and A275 were measured by ultraviolet spectrophotometry at wavelengths of 220 nm and 275 nm, respectively, and the corrected absorbance A was calculated according to the formula A=A220-2A275.

3.4 Total Phosphorus Water Quality Online Analyzer

1) Product Overview

This product is based on magnetic permeability measurement platform, combined with constant temperature fiber, digestion and colorimetric integration technology to achieve high precision, low detection limit, high stability and low maintenance of total phosphorus automatic online monitoring.

The working principle of this product is in line with the "GB11893-1989 determination of total phosphorus in water - ammonium molybdate spectrophotometry", fully meet the application of pollution sources, industrial production processes, municipal sewage and other fields.

2) Basic principles

The instrument uses the potassium persulfate digestion and oxidation under neutral conditions to oxidize all the phosphorus-containing substances in the sample to orthophosphate. In the acidic medium, the orthophosphate reacts with ammonium molybdate to form phosphorus molybdenum in the presence of cerium salt. Immediately after the polyacid, it was reduced by ascorbic acid to form a blue complex, which was measured by spectrophotometry.

Interference of ferric ions in the water sample is masked by the addition of phosphoric acid.

3.5 BOD water quality online analyzer

1) Product Overview

The working principle of this product is in line with "HI/T 399-2007 Determination of Chemical Oxygen Demand in Water Quality - Rapid Digestion Spectrophotometry", which has the characteristics of high reliability, low quantitative limit, good stability and strong resistance to chloride ion interference. In the fields of pollution sources, industrial production processes, municipal sewage, etc.

2) Basic principles

The instrument uses the potassium dichromate rapid digestion spectrophotometric method to measure the organic matter content in the water sample. The water sample, potassium dichromate and sulfuric acid-silver sulfate mixture are digested and sealed at 165 ° C to convert chromium (VI) to chromium (III), and the amount of chromium (III) corresponds to the amount of organic matter in the water sample. The instrument obtained the COD value of the water sample by colorimetric measurement. According to the constant conversion relationship between BOD and COD, the BOD value of the water sample is obtained.