How much do you know about sewage treatment?-6

41. What is resin density?

Resin density: generally refers to two representation methods of wet true density and wet apparent density. The wet true density is related to the backwash strength of the resin layer, the expansion rate and the resin stratification of the mixed bed and double bed, and the wet apparent density is used to calculate the amount of wet resin that the ion exchanger needs to fill.

42. What is the function of water spray filler?

The function of the water spray filler: it is to make the water droplets splashed by the water distribution system become tiny water droplets or water films after repeated splashes, increase the contact area between water and air, and prolong the contact time, so as to ensure good heat and quality of air and water exchange effect.

43. What is mixed liquor volatile suspended solids?

Mixed liquid volatile suspended solids (MLVSS) refers to the weight of volatile substances in the dry sludge contained in the mixed liquid of the biochemical tank per unit volume, and the unit is also mg/L. Since it does not include the inorganic substances in the activated sludge, it can More accurately represent the number of microorganisms in activated sludge.

44. Why is there surplus sludge?

During the biochemical treatment, the microorganisms in the activated sludge continuously consume the organic matter in the wastewater.

Among the consumed organic matter, a part of the organic matter is oxidized to provide the energy required for the life activities of the microorganisms, and the other part of the organic matter is used by the microorganisms to synthesize new cytoplasm, thereby enabling the reproduction of the microorganisms. While the microorganisms are metabolizing, there are A part of the old microorganisms dies, so excess sludge is produced.

45. What is Acupuncture Charcoal Technology?

Iron-carbon treatment method, also known as iron-carbon micro-electrolysis method or iron-carbon internal electrolysis method, is an application form of metal iron wastewater treatment technology. Using iron-carbon method as a pretreatment technology to treat toxic, harmful, and high-concentration COD wastewater has certain advantages. unique effect.

46. Why should the pH of the effluent of the neutralization sedimentation tank be adjusted to above 9?

The effluent of iron charcoal contains a large amount of ferrous sulfate. If it is not removed, it will affect the growth and reproduction of microorganisms in the subsequent biochemical tank.

Therefore, we must use lime to increase the pH value of the wastewater from 5-6 to above 9, so that the water-soluble ferrous sulfate is converted into insoluble ferrous hydroxide and calcium sulfate, and then they are made by coagulation and sedimentation. Precipitate, to ensure that the wastewater entering the biochemical tank does not contain ferrous sulfate.

47. What are the types of air flotation?

Air flotation is divided into: dissolved air flotation (divided into vacuum dissolved air flotation and pressurized dissolved air flotation), diffuse air flotation, electrolytic air flotation.

48. What is flocculation?

Flocculation is to add polymer coagulation agents to wastewater, and after the polymer coagulation agents are dissolved, polymers will be formed. The structure of this polymer is a linear structure, one end of the line pulls a tiny particle, and the other end pulls another tiny particle, which plays a role of bonding and bridging between the two particles far apart, making the particle Gradually become larger, and finally form large-particle flocs (commonly known as alum flowers), which accelerate particle settlement.

49. Why should polyferric be used for flocculation and adsorption treatment of wastewater?

The iron hydroxide floc formed by polyferric during the coagulation process has a good ability to adsorb organic substances in wastewater. Experimental data show that after wastewater is flocculated and adsorbed with polyferric, it can remove about 10%-20% of COD in wastewater. This can greatly reduce the operating burden of the biochemical pool, and is conducive to the discharge of treated wastewater up to the standard.

In addition, coagulation pretreatment with polyiron can remove trace substances that are toxic to microorganisms and have inhibitory effects in wastewater, so as to ensure the normal operation of microorganisms in biochemical pools. Among many coagulants, the price of polyferron is relatively cheap (25-300 yuan/ton), so the treatment cost is relatively low, and it is more suitable for the pretreatment of process wastewater.

50. Why are the colloidal particles in wastewater not easy to settle naturally?

Many impurity suspended solids, large particles, and easily settled suspended solids in wastewater with specific gravity greater than 1 can be removed by natural sedimentation, centrifugation and other methods.

However, the suspended solid particles with a specific gravity less than 1, which are tiny or even invisible to the naked eye, are difficult to settle naturally. For example, colloidal particles are particles with a size of 10-4-10-6mm, which are very stable in water, and their settling speed is extremely slow. It takes 200 years to plow for 1m of subsidence.