Volume of polymer required, gal 



_ 192,000 cu yd x 764.4 l/cu yd * 15 mg/£ 

 8.5 lb/gal x 454,000 mg/lb 



= 685 gal (with a 1.2 safety factor) 



60. Concentrated polymer pumping. The concentrated polymer should be 

 dispensed using a positive displacement pump. The pump should be capable of 

 discharging between the range of 0.002 to 0.08 gpm to handle the possible 

 range of required polymer dosages and flow rates of water to be treated. The 

 average polymer feed rate is based on the average flow rate, the polymer opti- 

 mum dosage, and the specific weight of polymer (see calculations below). 



Average feed rate, gpm 



= 3 cfs x 15 mg/JL x 28.31 £/ft x 60 sec/min 

 8.5 lb/gal x 454,000 mg/lb 



= 0.02 gpm 



The polymer pump flow capabilities should range between 0.1 and 4 times the 

 average feed rate. The pump range is 0.002 to 0.08 gpm. 



61. Polymer dilution. The polymer must be diluted with water to reach 

 a polymer concentration of 0.5 percent. Therefore, the water pump must be 

 able to discharge at a rate of 8.1 gpm (see calculations below). The polymer 

 and dilution water will be mixed using an in-line static mixer. 



62. The polymer dilution pump rate is based on the specific weight of 

 the polymer, the average polymer feed rate, and the final polymer concentra- 

 tion of 0.5 percent (or 5 g/£). The dilution factor must be 204. At the 

 average polymer flow rate, the required dilution water flow rate would be 



4.1 gpm. The dilution water pump capacity should be twice this rate to dilute 

 higher polymer flows adequately. Therefore, the dilution water flow rate 

 should be 



Polymer dilution rate, gpm 



i.5 lb/gal x 2 x Q.02 gpm 



5 g/4 x 1 lb/454 g x 3.785 ft/gal 

 =8.1 gpm 



39 



