Urban Pollution Treatment

Primary treatment:

　　The primary treatment system is also called the physical treatment system, which mainly removes the suspended solid pollutants in the sewage. Most of the physical treatment methods can only meet the requirements of the primary treatment.After primary treatment, BOD can generally be removed by about 30%, which does not meet the discharge standard.Primary treatment belongs to the pretreatment of secondary treatment.

　　Coarse grid:

　　The purpose of the coarse grid is to remove the coarser suspended solids that may block the pump unit and pipeline valves, and to ensure the normal operation of the follow-up treatment facilities.Coarse grille is composed of a group (or groups) of parallel metal grid bars and frames, installed obliquely on the water inlet channel, or at the inlet of the water collection well of the water inlet pumping station, to intercept coarse suspended matter and Impurities.

　Grit chamber:

　　Sewage will inevitably be mixed with mud and sand in the process of migration, flow and collection.If the sand in the sewage is not pre-sedimented and separated, it will affect the operation of the subsequent treatment equipment.The grit chamber is mainly used to remove sand particles with a particle size greater than 0.2mm and a density greater than 2.65t/m3 in sewage, so as to protect pipelines, valves and other facilities from wear and blockage.Its working principle is based on gravity separation, so the water flow rate of the grit chamber should be controlled so that the inorganic particles with large specific gravity sink, while the organic suspended particles can be taken away with the water flow.In general grit chambers, ultrasonic liquid level gauges or drop-in liquid level gauges (need to add a filter) are used to detect the height of the liquid level.

　　Lift pump:

　　The main function of the sewage lift pump is to pump sewage from one pool to another, or from one sewage treatment link to another, to realize the transmission of sewage, and it is used more in the sewage treatment process.

　　The sewage lifting pump is placed at the water inlet of the sewage treatment plant. The sewage transported by the sewage pipe network has a low water level. A sewage lifting pump is required to pump the sewage with a low water level to the subsequent treatment process equipment.Many sewage treatment facilities are set up according to the elevation, and through the water level difference, the sewage can flow by itself and automatically flow to the follow-up facilities, thereby reducing energy consumption.Another function is to pump the treated sewage from the previous pool to the next pool for a different sewage treatment process.Electromagnetic flowmeters are needed in the lifting pump station. Due to the many impurities in the sewage, the medium composition is complex and corrosive, the use of electromagnetic flowmeters can effectively overcome these problems, and the price of electromagnetic flowmeters is also relatively affordable. , cost-effective.In the current sewage treatment industry, most of the flow measurement is realized by electromagnetic flowmeter.

　　Primary sedimentation pool:

　　The primary sedimentation tank can remove sinkable and floating matter in wastewater.After primary settling of wastewater, it can remove about 50% of sinkables, grease and floating matter, and 20% of BOD. Calculated by removing unit mass of BOD or solids, the primary settling tank is the most economical purification step. For Both domestic sewage and industrial sewage with high suspended solids are easily pretreated by primary sedimentation tanks.The primary settling tank will also involve an ultrasonic level gauge or an input level gauge (need to add a filter) to detect the height of the liquid level.

　　The sludge interface meter is also involved in the primary settling tank. The ultrasonic sludge interface meter is specially designed for continuous on-line monitoring of the sludge interface in the sewage treatment process.The instrument uses the reliable ultrasonic echo detection principle to realize the real-time detection of sludge thickness, and provides reliable data for the process control of related processes, thereby optimizing the process control processes such as sludge discharge and dosing.

　　In the primary sedimentation tank, dosing control is required to adjust the pH in the tank, so the online PH will also be used.