1. Sedimentation pond sand-water separationApplianceIntroduction
The sedimentation pond's function is to remove inorganic particles with higher relative density (such as silt, coal slag, etc.). It is typically installed before pump stations or siphon pipes to reduce wear on pumps and pipelines by these particles. It can also be placed before a sedimentation pond to alleviate the pond's load and eliminate the impact of particles on anaerobic digestion of sludge. Sedimentation basins come in four types: horizontal flow, vertical flow, aeration, and vortex flow. The horizontal flow sedimentation basin boasts a simple structure and good treatment effectiveness; however, the drawback is that the sediment contains...15%Organic matter increases the difficulty of subsequent treatment for settled sand. In a vertical flow sand settling tank, wastewater enters from the bottom through a central pipe, and inorganic particles settle at the bottom of the tank by gravity, generally resulting in poor treatment effectiveness. The aeration sand settling tank...Please provide the Chinese content to be translated into American English.The major advantage is that it allows sand particles to rub against each other under aeration, effectively removing organic pollutants attached to the sand particles. Additionally, due to the flotation effect of aeration, oils and fats in the wastewater rise to the surface and form scum, which is then removed. For wastewater treatment plants designed for biological phosphorus removal, aeration sand sedimentation tanks are generally not used to ensure phosphorus removal efficiency. In recent years, the increasingly widely used vortex sand sedimentation tank utilizes mechanical force to control flow state and velocity, with the main advantages being a small land area, minimal impact of water volume changes on sedimentation efficiency, good sand-water separation, low moisture content in the separated sand, low organic matter content, and ease of transportation. Given the relatively small water volume in this design, the flow fluctuations have a significant impact on the horizontal flow sedimentation tank, thus it is not adopted, yet it is not sufficient to meet the requirements of the aeration sedimentation tank.Please provide the Chinese content to be translated.Low water depth requirements necessitate the use of a vortex sedimentation tank. However, it should be noted that the spacing of the fine格栅 should be as small as possible to prevent the entry of objects like rags, which could affect the impeller and sand lifting pump among other equipment.
A vortex grit chamber, which is a type of vortex grit chamber, consists of an inlet, outlet, grit separation zone, grit collection area, grit lifting pipe, grit discharge pipe, electric motor, and transmission box, etc. Wastewater enters the grit chamber along the tangent direction from the inflow, and is rotated by the turntable and inclined blade with the electric motor and transmission device, driven by the centrifugal force. The dense sand particles in the wastewater are ejected towards the pool wall and fall into the grit hopper, while organic matter remains in the non-swelling area. By adjusting the rotation speed, the desired grit removal efficiency can be achieved.ReasonableSedimentation effect. Sediment is removed by compressed air through the riser and sand discharge pipe after cleaning. The cleaning water returns to the sedimentation area. 1.2Process Design
Sedimentation Basin: Wastewater is pre-treated by a fine格栅 before entering the sedimentation basin. Two basins are installed, one in use and one as a backup. The sand removed during the sedimentation process is transported to the sand-water separator using a sand pump (with two pumps serving as backups). The dehydrated sand is then stored in a sand storage bin.
2.In the design of the sand settling pond, the following principles must be adhered to:
（1City sewage plants should be equipped with sedimentation basins, with the number of basins or compartments not less than2Seated(Please provide the Chinese content to be translated.)Considered in parallel operation principle.
（2Design flow considering phased construction:a) As wastewater flows in, it should be handled according to each batch.Please provide the Chinese content you would like translated into American English.Large-scale design flow calculation b)When wastewater is pumped in, it should be according to the capacity of each working pump cycle.Please provide the Chinese content to be translated.Large combination traffic calculation c) In a combined flow treatment system, the design flow should be calculated based on the rainfall event.
（3Sedimentation pond-removed sand particles contain impurities with a specific gravity of2.65ton/Cubic meters, particle size0.2mmThe above particles are primarily the focus.
（4The sedimentation volume of urban wastewater can be measured by per...10The sand settlement volume of the wastewater is ten million cubic meters.30Calculated in cubic meters, with a moisture content of60%, Capacity:1500kg/cubic meters.
（5The capacity of the sand storage bucket hoist should be2Calculation of daily sediment volume, the inclination angle of the storage sand pit wall from the horizontal plane should not be less than55The diameter of the sand removal pipe should not be less than0.3m。
（6Sedimentation pond's super elevation should not be less than0.3m 。
（7Mechanical methods are generally preferred for sand removal. When gravity sand separation is used, the sedimentation pond and sand drying facility should be as close as possible to minimize the length of the sand discharge pipe.3.Turbulent sedimentation tank design3.1 Design Key Points
（1Hydraulic surface load approximatelyqPlease provide the Chinese content to be translated.150~200m3/（m2·h）
（2）Please provide the Chinese content you would like translated into American English.Long停留时间 for large design traffic is no less than30s
（3Effective Water Depth1~2mThe pool diameter to depth ratio2.0~2.5
（4Inlet channel flow rate: At the flow rate of40%~80%In the case of0.6~0.9m/s, atCompareAt low flow rates, greater than0.15m/s, atPlease provide the Chinese content to be translated.Not greater than during high flow conditions1.2m/s
（5The straight section length of the water intake channel should be equal to the channel width.7Not less than4.5m
（6The angle between the outlet channel and the inlet channel is greater than270°, please provide the Chinese content for translation.Please provide the Chinese content to be translated into American English.Maximize the retention time of water flow in the sand sedimentation pond to achieve the purpose of sand removal.
3.2 Design Parameters
（1Number of settling tanks:2Seating
（2Design Flow Rate:Q = 5000m3/d = 0.058 m3/S Qmax=0.10092 m3/s ≈0.101 m3/s （3Flow Rate of Inflowv1 = 0.7 m/s （4Surface Load:q=200 m3/（m2·h） （5Hydraulic Retention Time:t=35s （6Screening intervalT=2d （7City Sewage Sand Content:X=30 m3 / 106 m3 3.3Design Calculations3.3.1 Sedimentation pond diameter
D = p qQ3600 max4In the formula:D ——Sedimentation pond diameter, m Qmax DesignPlease provide the Chinese content you would like translated into American English.High water flowm3/s q Hydraulic surface loadm3/（m2·h) )
D= p ´´´2003600 101.04= 1.52m Please provide the Chinese content to be translated.2.14m 3.3.2 Sedimentation Pond Effective Depthh2
= p 2maxD4t Q In the formula:h2 —— Effective settling pond depthm t Hydraulic retention times Thenh2
= p ´´´2 14.235 101.04=0.98 m 3.3.3 Sedimentation chamber sediment volume
V = 6 10 XT Q Equation:V —— Sediment contentm3
Q Design traffic flowm3 /d
X —— Sand content in urban wastewaterm3 T Sand separation intervald ThenV = 6 102500030´´= 0.3 m 3 3.3.4 Sediment sump capacity
V`=()2225412 1 41rdrdhhd---pp Equation:V` Slurry Sump Volume, m3 h3 Sedimentation basin buffer layer height0.33m h4 —— Sump sump cylinder height,1.2 m h5 —— Sump sump circular platform height,0.50 m d —— Sand separator upper diameter,1.0m r —— Underflow hopper diameter, 0.3m Amongst them,h
3= ()°-30tand21 D= 0.5（2.14-1.0）°30tan = 0.33m h
5=()°-55tanr21 d= 0.5（1.0-0.3）°55tan =0.50m Then
V=() 23.0-3.01-15.012 1 -2.1141´´´´´´pp=0.86 m3 > 0.6 m3 Over two days of dust content, hence, qualifies.3.3.5 Total Sand Sump HeightH = h1 + h2 + h3 + h4 + h5 In the formula:H —— Total sand settling tank heightm h1 —— Extra high, generally used0.3~0.5m , Take0.3m ThenH = 0.3+0.98+ 0.33+1.2+0.5=3.31m 3.3.6 Inlet Channels - The inlet channels feed into the vortex sand separator at a tangent to provide the initial velocity of the vortex. Channel Width:B1
= h vQ 1 In the formula:B1 Channel Widthm h —— Depth of the water channel0.6m Effective Water Depth, Channel Depth0.8） v1 Flow rate of incoming water0.7m/s
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Jiangsu Du'an Environmental ProtectionOrder Requirements for Spiral Sand and Water Separator
1Write the full name according to the model representation method.
2Application Environment (indoor, outdoor, and others)
3If a reinforced concrete water tank is used, provide engineering design documents for the relevant sections.
