New water treatment process: gravity three valve automatic filter filtration

Improved filter, expanding the bottom of the porous plate and the distance between the floor, easy to install and maintain. Filter procedures procedures shown in Table 1. Abstract: In order to overcome the shortcomings of gravity-free valve-less filter pool in traditional waterworks. This paper proposed the use of gravity-type three-valve automatic filter for filtration method, briefly describes the advantages of its operation for the major waterworks or industrial enterprises to adopt. Keywords: Filter media; Adsorption; Three-valve; Improvements One of the most important processes in modern water treatment is filtration, whereas in most towns today the filtration structure of a water plant is a gravity valveless filter cell. Gravity valveless filter tank operation can be carried out automatically, but when the filter backwash, the filter is still stopped in the water, and discharged directly through the siphon, resulting in water loss. Although most water treatment plants adopt such measures as recovery of drainage water or infiltration of water during backwashing, they still cause irreparable economic losses. 1 particle filter principle filter is the raw water through the porous material filter to remove suspended solids in the water process. Filtration can be divided into ordinary filtration and precision filtration. Common filter with fast filter, built-granular filter. Precision filter forming filter or additives used, can also be used granular filter. Ground water filtration must be added to the raw water coagulant to the initial water turbidity. Quick filter to the initial turbidity is not by screening but by contact aggregation. The so-called contact coagulation after coagulation, colloidal particles of the electric double layer is compressed, the particles are adsorbed on the filter surface. Raw water added to the coagulant, the formation of colloids and water-soluble electrolytes, compressed natural water colloidal double layer, reducing the zeta potential, and thus easy to flocculation between particles. Natural colloidal water and coagulant gel generated between the charge neutralization. When these particles flow through the filter layer, the water flow in the pores of the sand during filtration is laminar, and the velocity gradient of the laminar flow causes the particles to rotate and easily flows to the surface of the filter material to be adsorbed on the filter material. Natural water clay and macromolecule particles negatively charged, it is difficult to be negatively charged filter media adsorption, after adding coagulant to compress the electric double layer to strengthen the van der Waals forces between the particles to create the conditions. The coagulant produced by the positively charged aluminum hydroxide or iron hydroxide colloid, it is easy to be charged negatively charged filter media and clay on the adsorption. Precision filter forming filter, the main use of filter pore porosity for different precision mechanical filtration. 2 gravity type three-valve automatic filter Gravity three-valve automatic filter is the application of hydraulic principles of a fast flow rate filter, referred to as the three-valve filter. It is a new type of filter based on gravity valveless filter. Its entire operation, backwashing, scrubbing and other processes can be carried out automatically, and the operation and management are convenient. The air scrubbing device is added in the filter to improve the cleaning effect that the stratified sludge holding ball of the filter layer is not easy to be thoroughly cleaned; At the same time as the bottom of the water tank filter room to increase the drain valve, so in addition to the normal operation of the water, the initial turbidity can not meet the requirements of the water when the valve also serves as a positive wash drain valve to exclude the initial turbidity of the water , Thus improving the water quality. Water turbidity can generally be guaranteed at 1 ~ 2JTU. Three-valve filter diagram shown in Figure 1. Figure 1 3 three-valve filter operation 3.1 Filtering water from the clarifier to the first air through the air separator to discharge air, so as not to affect the normal operation of the filter. The air separator is a steel cylinder with a diameter of 1100mm, a height of 800mm and a volume of 0.23m3. A baffle plate is installed in the air separator, and the flow direction changes after the water flow enters, and the gas in the water is easy to escape. Exhaust at the same time as some water out to help drain lead to the clarifier outlet. Into the water filter room, through the cross-shaped water distributor, so that water evenly leached in the upper filter. Water flow through the filter layer into the lower header, sent to the flushing water tank by the communication pipe. Rinse tank level gradually increased, and finally overflow from the outlet into the underground water tank. 3.2 Anti-wash the filter just put into operation, the water level inside the siphon rise and flush the water tank head is small, about 20mm or so. With the filter, head loss increases, the inflow of water unchanged, to ensure that a certain amount of water, siphon riser water level continues to increase. When the siphon rising tube water level gradually increased to the upper end of the siphon assist, water flow to the electrode tank, electrode tank water level to a certain value, the electrode will send a signal, backwash automatically. Rinse tank volume of 45.6m3, stored filtered water for backwash filter, the water volume calculated according to a flush. Backwash began, the Department of washing water tank gradually decreased, when dropped siphon destroyer, the water was quickly sucked dry, leaving the siphon exposed water, siphon air suction, siphon was destroyed, recoil stopped. Into the water into the filter, siphon water level back to normal, the filter to start again. In order to completely improve the efficiency of backwashing, the lower part of the filter is equipped with an air scrubbing device, which requires the top of the filter layer to maintain a water level of 160mm during air scrubbing to ensure that the filter is thoroughly scrubbed and prevented from being disrupted. Intake air pressure is controlled at 2kg / cm2, intake air volume is 18m3 / min. The backwashing strength of the filter can be adjusted by the inverse baffle of the water regulator. Its flow does not rush out of the filter when the maximum flow rate for effective flow. Backwash intensity adjustment is generally adjusted to the initial backwash intensity of 12L / (m2 · s), the end of the intensity of 8L / (m2.s), the average intensity of not far away 10L / (m2 · s). Filter expansion rate of 30% to 50%, flushing time of 3.5 ~ 5min, backwash intensity were 10 ~ 14.3L / (m2 · s). Backwash intensity should be adjusted at any time according to the seasons. High water temperature, the filter is not easy to disturb, you need to increase the backwash intensity; low water temperature, the filter is easy to disturb, the backwash intensity can be reduced. When the water turbidity is very small, or influent less than 50% of the rated flow and automatic control failure, no backwash in more than 2 days, in order to ensure the normal operation of the filter, the need to force the anti-washing ears to listen. Available 8kg / cm2, 9m3 / h pressure water start mandatory backwash jets, siphon out of the air, you can form a siphon, backwash start. Backwash filter, due to the continuous operation of the clarifier pool, water can drain into the trench through the water inlet. 4 filter to improve the filter to improve the map shown in Figure 2. Figure 2 5 Conclusion From this article we can see that gravity-based three-valve automatic filter gravity valveless automatic filter on the sewage treatment process superiority is beyond doubt. It does not cause loss of water and reduces economic losses, but it has six valves and initially has a higher total investment than a gravity valveless automatic filter. Today's global water pollution is extremely serious, the lack of freshwater resources, sewage treatment to the more depth to deal with the conversion, so to reduce freshwater losses, is not simply to reduce economic losses, the significance of saving has become even more far-reaching significance. Figure 3 More Keywords Search: Valve