Water and wastewater monitoring
1. Water self purification
After pollutants enter the water, they are first diluted, and then undergo a series of complex physical and chemical changes and biological transformations such as volatilization, condensation, hydrolysis, complexation, redox, and microbial degradation to reduce the concentration of pollutants. Used for self purification of water Water pollution: When the discharge of pollutants exceeds the self purification capacity of the water body, it will cause the accumulation of pollutants, continuously deteriorate the water quality, and cause water pollution
2. Chemical Oxygen Demand (COD)
The amount of oxygen consumed by redox substances in 1 liter of water sample, expressed in mg/L oxygen. The reducing substances in water include organic and inorganic substances such as nitrites, sulfides, and ferrous salts
(1) Potassium dichromate method
(2) Potassium permanganate index method
3. Biochemical oxygen demand (BOD)
refers to the amount of dissolved oxygen consumed by aerobic microorganisms in the biochemical oxidation process of decomposing organic matter in water under dissolved oxygen conditions 4. In order to meet the requirements of surface water utilization function and ecological environment quality, how many types of monitoring projects are classified in the "Surface Water Environmental Quality Standards"
(1) Basic projects
(2) Supplementary engineering for centralized drinking water source areas
(3) Special engineering for centralized drinking water source areas
5. Forms of pollutants
The chemical, valence, and isomeric states of pollutants in the environment.
6. Principles for Setting up Monitoring Sections
Monitoring sections should be set up in functional areas with different water quality, water volume changes, and water usage.
(1) A large amount of wastewater is discharged into residential and industrial areas upstream and downstream of rivers (2) The main entrances and exits of lakes and reservoirs (3) Functional areas such as drinking water source areas and water resource areas (4) At the mouth of the estuary, where larger tributaries converge upstream and then merge with the main stream (5) The entrances and exits of international rivers entering and exiting international lines(6) Try to overlap with the hydrological survey section as much as possible
Monitoring section settings:
In order to evaluate the water quality of a complete river system, it is necessary to set up background sections, control sections, control sections, and reduced sections.
. For a certain river section, only three river sections need to be set up for control, control, and reduction (or transit) 7. What type of water sampleRandomly collect instantaneous water samples at specific times and locations
Mixed water samples. Instantaneous water samples collected at the same sampling point at different times.
Comprehensive water samples. Instantaneous water samples collected at different sampling points are mixed with water samples.
8. What are the methods for preserving water samples
Freeze or refrigerate water samples by adding chemical reagents. Filter or centrifuge method
9. The digestion of water samples is divided into wet digestion and dry digestion
Wet digestion is divided into
(1) HNO3: water sample
(2) HNO3 HClO4: refractory organic matter
(3) HNO3 H2SO4: (5:2)
(4) HNO3 H3PO4: elimination of Fe3+interference
(5) Determination of HNO3 KMnO4: Hg
(6) Multiple digestion:(7) Alkali decomposition method
10 What are the enrichment and separation methods for water samples
(1) Stripping, headspace, and distillation methods: volatile components
(2) extraction methods
(3) adsorption method
(4) ion exchange method
(5) co precipitation method:
11. Determination of water sample chromaticity
(1) Platinum cobalt standard colorimetric method
This method is applicable to the colorimetric determination of pure water, natural water, and drinking water with a yellow hue.
(2) Dilution coefficient method
This method is applicable to the determination of color in surface water and industrial wastewater polluted by industrial wastewater
12. Determination methods for water samples
Font method, Saxon disk method (on-site),
13. The color of water can be divided into natural and surface colors
The chromaticity of water generally refers to the true color.
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