What are the methods of sewage environmental monitoring?

What are the methods of sewage environmental monitoring?
Physical detection method: mainly used to detect the physical properties of sewage, such as temperature, turbidity, suspended solids, conductivity, etc. Commonly used physical inspection methods include specific gravity method, titration method and photometric method.
Chemical detection method: mainly used to detect chemical pollutants in sewage, such as PH value, dissolved oxygen, chemical oxygen demand, biochemical oxygen demand, ammonia nitrogen, total phosphorus, heavy metals, etc. Commonly used chemical detection methods include titration, spectrophotometry, atomic absorption spectrometry, ion chromatography and so on.
Biological detection method: mainly used to detect biological pollutants in sewage, such as pathogenic microorganisms, algae, etc. Commonly used biological detection methods include microscope detection method, culture counting method, microplate reader method and so on.
Toxicity detection method: mainly used to evaluate the toxic effects of pollutants in sewage on organisms, such as acute poisoning, chronic poisoning, etc. Commonly used toxicity testing methods include biological toxicity test method, microbial toxicity test method and so on.
Comprehensive evaluation method: through the comprehensive analysis of various indicators in the sewage, evaluate the overall environmental quality of the sewage. Commonly used comprehensive evaluation methods include pollution index method, fuzzy comprehensive evaluation method, principal component analysis method and so on.
There are many methods for wastewater detection, but the essence is still based on the results of water quality characteristics and wastewater treatment technology. Taking industrial wastewater as the object, the following are two types of wastewater detection for measuring the content of organic matter in wastewater. First, simple oxidation of organic matter in water is used characteristics, and then gradually identify and quantify the organic compounds with complex components in water.
Environmental test
(1) BOD detection, that is, biochemical oxygen demand detection. Biochemical oxygen demand is the target to measure the content of aerobic pollutants such as organic matter in water. The higher the target, the more organic pollutants in water, and the more serious the pollution. Organic pollutants in sugar, food, paper, fiber and other industrial wastewater can be distinguished by the biochemical action of aerobic bacteria, because oxygen is consumed in the process of differentiation, so it is also called aerobic pollutants, if such pollutants Excessive discharge into the water body will cause insufficient dissolved oxygen in the water. At the same time, the organic matter will be decomposed by anaerobic bacteria in the water, causing corruption, and producing foul-smelling gases such as methane, hydrogen sulfide, mercaptans, and ammonia, which will cause the water body to deteriorate and stink.
(2) COD detection, that is, chemical oxygen demand detection, uses chemical oxidants to distinguish oxidizable substances in water through chemical reaction oxidation, and then calculates oxygen consumption through the amount of remaining oxidants. Chemical oxygen demand (COD) is often used as a measure of water The index of organic matter content, the greater the value, the more serious the water pollution. The determination of chemical oxygen demand varies with the determination and determination methods of reducing substances in water samples. At present, the widely used methods are acidic potassium permanganate oxidation method and Potassium dichromate oxidation method.
The two complement each other, but they are different. COD detection can accurately grasp the content of organic matter in wastewater, and it takes less time to measure on time. Compared with it, it is difficult to reflect the organic matter oxidized by microorganisms. From the perspective of hygiene, it can directly explain the degree of pollution. In addition, waste water also contains some reducing inorganic substances, which also need to consume oxygen during the oxidation process, so COD still has errors.
There is a connection between the two, the value of BOD5 is less than COD, the difference between the two is roughly equal to the amount of refractory organic matter, the greater the difference, the more refractory organic matter, in this case, should not use biological Therefore, the ratio of BOD5/COD can be used to judge whether the wastewater is suitable for biological treatment. Generally, the ratio of BOD5/COD is called a biochemical index. The smaller the ratio, the less suitable for biological treatment. The BOD5/COD ratio of wastewater suitable for biological treatment Usually considered greater than 0.3.