164 ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 3 4 



Belt traveling screen which removes floating sticks and other foreign 

 matter. 



The pump house, adjacent to these concrete wells, contains two 

 30-inch centrifugal pumps. One of these has a capacity of about 

 26,000 gallons per minute, and the other can deliver approximately 

 32,000 gallons per minute. They are operated by 300-horsepower 

 synchronous motors. The intake pipe for the pumps extends 9 feet 

 below the water level at low tide, whereas the screens operate to 

 practically the full depth of the compartment, which is 3 feet lower. 

 In starting the pumps a Nash Hytor vacuum pump is employed to 

 prime them. Three to five minutes are usually required to accom- 

 plish priming by this method. An interior view of the pump house 

 appears in plate 2, figure 1. 



Each of the centrifugal pumps is connected to a separate 42-inch 

 steel pipe line which carries the water under a road into a 72-inch 

 steel pipe. The latter conducts the water up over a concrete dam 

 (pi. 2, fig. 2) into a canal and pond. The purpose of the dam is 

 to prevent the emptying of the canal and pond back into the ocean 

 when the pumps are not in operation. The top of the dam is at a 

 level of 23 feet above mean low tide. 



The canal is about 6 feet deep and extends about 4,000 feet across 

 the peninsula to the plant, which is located close to the shore of the 

 Cape Fear Kiver. Approximately 2,200 feet of the canal are diked 

 off from a pond through which the sea water is bypassed during 

 the summer months. With some 900,000 square feet of exposed 

 surface, the pond permits an increase in temperature during warm 

 weather. This increases the efficiency of the process during several 

 months of the year. After the water has been pumped over the 

 dam and into the canal or pond, it flows to the extraction plant 

 with a loss in head of only about 3 inches. A view of the canal and 

 pond is shown in plate 3, figure 1. The pilot plant is visible near 

 the far left-hand corner of the pond. 



BROMINE EXTRACTION 



The extraction of bromine from sea water takes place in two 

 identical units which are located at the exit of the canal. A dia- 

 gram of one of them is shown in figure 7. Each unit consists 

 chiefly of a blowing-out tower in which a current of air removes 

 the bromine from acidified and oxidized sea water, and an adjacent 

 absorption tower in which the bromine is extracted from the air 

 by means of a soda-ash solution. The towers are built of brick 

 and have concrete floors and foundations. The foundations of each 

 unit cover an area 197 by 84 feet. Wood piles 30 feet long were 

 driven in the ground beneath the foundations to avoid any possibility 

 of their settling;. 



