Detection and prevention of eutrophication of water by chlorophyll analyzer
First, the concept of water eutrophication
Eutrophication (eutrophication) is under the impact of human activities, the desired biological nitrogen and phosphorus and other nutrients poured into lakes, estuaries, bays and other slow water body, causing plankton algae and other rapidly, the amount of dissolved oxygen Decline, water quality deteriorates, and fish and other organisms die in large numbers. Under natural conditions, lakes also transition from oligotrophic to eutrophic, but this natural process is very slow. The eutrophication of water caused by artificial discharge of industrial wastewater containing nutrients and domestic sewage can occur in a short period of time. When the water body is eutrophic, the planktonic algae multiply and form water blooms. Due to the different colors of the dominant phytoplankton, the water surface is often blue, red, brown, milky white and so on. This phenomenon is called red tide or red tide in the ocean.
Second, the main indicators of water eutrophication
1) The nitrogen content in the water is greater than 0.2~0.3mg/L , and the phosphorus content is greater than 0.01mg/L .
2) Biochemical oxygen demand is greater than 10mg/L ,
3) the total amount of bacteria in the fresh water to 104 / ml,
4) Growth of algae flag chlorophyll a (chlorophyll meter) concentration of greater than 10 μ g / L.
Third, the source of water eutrophication
Excessive amounts of nitrogen, phosphorus and other nutrients in water mainly come from untreated or incompletely treated industrial and domestic sewage, organic waste and livestock and poultry manure, as well as agricultural fertilizers. The largest source of this is the large amount of fertilizer applied on farmland.
4. Water eutrophication hazards
Eutrophication affects the water quality of the water body, which causes the transparency of the water to decrease, making it difficult for sunlight to penetrate the water layer, thereby affecting the photosynthesis of plants in the water, which may cause supersaturation of dissolved oxygen. Supersaturation of dissolved oxygen and less dissolved oxygen in water are harmful to aquatic animals, causing a large number of fish to die. At the same time, because of the eutrophication of water bodies, a large number of algae, which are dominated by cyanobacteria and green algae, grow on the surface of the water, forming a layer of “green scumâ€, causing harmful gases and some harmful substances generated by the decomposition of organic matter under the anaerobic conditions. Biotoxins produced by plankton also harm fish. Because eutrophicated water contains nitrates and nitrites, humans and animals who drink water with a certain content exceeding a certain standard for a long time may also be poisoned.
After the formation of "green scum", underwater algae will breathe oxygen in the water due to lack of sunlight, and photosynthesis cannot be performed. Oxygen in the water will gradually decrease, and organisms in the water will die due to insufficient oxygen. The dead algae and organisms will oxidize in the water, and the water will become stinky, and the water will be polluted and cannot be reused.
This article published by the shadow finishing Ltd. Connaught Instrument (Shanghai)
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