1、 (1/3) Combining of membrane and fluidized bed reactor to remove hardness NSC 89-2211-E-032-019 89 8 1 90 7 31 UF UF 160mg/L as CaCO 3 5mm HIOP pH pH Abstract In this work, combination of UF membrane and fluidized bed pellet reactor is used to remove hardness from drinking water sources. The idea is
2、 to use merit of membrane and fluidized bed pellet reactor to overcome the shortcomings of using these two processes alone for water softening.The results show that UF alone is not an effective process to remove hardness, due to the slow kinetic of calcium carbonate precipitation without presenting
3、of pellet. Addition of three different kinds of pellets can lower hardness from 300 to less than 160 mg/L as CaCO 3 , depending on the surface area provided by the pellets and pH. Removal efficiency increases with increasing pH and surface area of pellets in the reactor. HIOP pellet with particle si
4、ze of about 5mm is most attractive due to its small size and high specific surface area. 92 500 150 mg/L as CaCO 3 (1) (suspended solid) (2, 3) ( ) ( ) pH 1. 2. 3. pH 1 ( ) 1. 0.4 0.04 m 30 15 92 1% 1000mg/L 300 mg/L pH 9 9.5 pH NaOH 2. CaCO 3 0.6mm 0.3mm 25 m HIOP (Heated-iron-oxide particles) pH=9
5、 (Cake layer) 3. pH p H pH pH ( ) pH 9.0 9.5 CaCO 3 (saturation index) 98 282 CaCO 3 2 250- 300(mg/L as CaCO 3 ) pH 9.0 9.5 3 pH pH=9.5 pH=9.0 ( ) 2 pH 3 p H ( ) 1 4 10 pH 10 110 160 HIOP 0.01% 5 HIOP HIOP HIOP HIOP 5m 2 /L 40mg/L as CaCO 3 85% 1: HIOP (mm) 0.6 0.297 0.005 (g/cm 3 ) 2.69 1.86 2.76 (
6、g/L) 498 187 0.33 (%) 43 23 0.01 (m 2 /L) 2.2 2.4 0.07 4 pH 9.0 5 (HIOP) ( ) pH 2 HIOP pH pH pH 2 pH 8.5 9.0 9.5 35% 58% 67% HIOP 44% 58% 73% 5mm HIOP 85% 1. “ “ EPA-82-E3-J1-09-03 (1998). 2. , (1999). 3. W. D. Harms, Jr., R. B. Robinson, Softening by fluidized bed crystallizers., Journal of Environmental Engineering 118(4), 513-29 (1992).
