...
The lime feeded by lime feeder will help to increase the Alkalinity in raw water during coagulation process, help the original carbonate system to build the buffer to cancel the impact to neutralize the Acidity from adding Aluminum Sulfate, thus improve the quality of treated effluent water, our team want to find the relationship between flow rate of lime feeder and the pH and Alkalinity in raw water.
...
Since the effluent pH should be constant based on our assumption, the way we can change the lime concentration in raw water is depend on the flow rate of lime feeder, it also create convenience for the operator to use the apparetus changing pH and AlK in raw water. The flow rate should be in certain range which could provide the pH environment in the tank between 6.5 to 7.5, it is the range coagulation could coagulation will be most efficient. . <Water Quality and Treatment by Letter 1999>
Our next step is to build the model between flow rate of lime feeder and the possible change in pH, Alkalinity in plant Marcala and Cuatro Comunidades based on their data from Honduras report spanish version translated by our team member Ximena.
The lime dosage dos\age we want should be able to increase the pH of water to the degree we want, while neutralizing the effect of the alum that will be shortly added to it. By calculating the alkalinity under the orginial pH we can find the total carbonate e.g.CT in the system, and then we can find the relationship between the target ANC and the desired pH we want(see figure 1). The total lime dose required in tank is the sum of the amount using to neutralize the alum and to raise the raw water to the desired pH(see equation 2).
...