h1. Alum Stock Tank Design Program
The purpose of the alum stock tank design program is to calculate the dimensions of the stock tank. The stock tank is placed on a platform close to the entrance tank so that the alum coagulant can be added to the raw water during rapid mix. The calculations for the alum stock tank can be found in the "ChemStorageTanks" MathCAD file, which is in the "Final Designs" folder on the AguaClara sourceforge. The design drawing can be found in the "AlumStock" AutoCAD file.
h2. Alum Stock Tank Drawing
[Stock Tank AutoCAD Drawing|AutoCAD ChemicalAlum Stock Tank Program]
h3. Alum Stock Tank Design Algorithm
The maximum flow rate through the alum stock tank is calculated based on the plant flow rate, and concentration of alum. These values are found in the [User Inputs|User Inputs Design Program] program.
{latex}
\large
$$
Q_{AlumStockMax} = {{Q_{Plant} \cdot C_{FcmDoseMax} } \over {C_{FcmAlum} }}
$$
{latex}
The volume of the Alum stock tank can then be calculated based on the [User Inputs|User Inputs Design Program].
{latex}
\large
$$
V_{AlumTank} = Q_{AlumStockMax} \cdot Ti_{StockMin}
$$
{latex}
The height necessary to overcome head loss from the Alum stock tank is calculated using the orifice flow equation.
{latex}
\large
$$
H_{MinAlumTank} = ({{Q_{AlumStockMax} } \over {Kvc \cdot (0.5 \cdot D_{FcmValveOrifice} )^2 \cdot \pi }})^2 {1 \over {2 \cdot g}} + .1m
$$
{latex}
Using a height to diameter ratio of 1.5 we calculate the stock tank radius.
{latex}
\large
$$
R_{AlumTank} = ({{V_{AlumTank} } \over {2\pi \cdot Ratio_{HeightToDiameterStockTank} }})^{1/3}
$$
{latex}
With the calculated radius we know the height of the stock tank.
{latex}
\large
$$
H_{AlumTank} = Ratio_{HeightToDiameterStockTank} \cdot 2\pi \cdot R_{AlumTank}
$$
{latex}
If H.AlumTank is greater than or equal to H.MinAlumTank then we have achieved the goal and we stop here. However, if the H.AlumTank is less than H.MinTank we set the height of the tank equal to H.MinAlumTank. Then we recalculate the radius based off the height diameter ratio. | 