Design of municipal diatomite filters for iron removal

Abstract

A-Filter or septum area 2. C-Constant 3. C D-Concentration of diatomite (body feed rate) mg/l 4. CHP-Constant head permeameter 5. conc.-Concentration 6. C s-Concentration of suspended solids (iron) mg/l 7. Cu-copper 8. dg-weight of suspended matter per unit volume as trapped in the filter 9. Eff-Effluent 10. Exp-Experiment 11. Fe-iron, ferrous or ferric state 12. ft-feet 13. gal-gallons 14. gpm/sq ft-gallons per minute per square foot 15. h-head loss 16. H-Hydrogen 17. Inf-Influent 18. K-Coefficient of permeability or permeability of porous media 19. Ki-a given constant 20. L-Thickness of porous media 21. lb-pound 22. lb/cu ft-pounds per cubic foot X ABBREVIATIONS AND SYMBOLS (Continued) 23. mg/l-milligrams per liter, often referred to as ppm (parts per million) 24. min-minutes 25. ml-milliliters 26. no.-Number 27. 0-0xygen 28. P-The ratio of void space to the volume occupied by the filter cake 29. PP-Pilot plant 30. Q-Rate of filtration, volume per area per time 31. Sptrn-Slope of straight line from a CHP run CHP (in rate/gal) 32. Sypp-Slope of straight line from a VHP run 1 (a head loss/gal) 33. T-time 34. THL-Terminal head loss 35. u-micron = l/lOOO millimeter 36. V-volume 37. VHP-Variable head permeameter 12 CHP throughout this study. 8. Iron The terra iron, as used througnout tnis study, refers to the ferric or ferrous ions in solution or in suspension in water regardless of their combined state.

Effect of ions in solution on the permeability of filter aids

“…The outstanding features of diatomite include its high porosity and high permeability, low apparent density, relative chemical inertness, and a high melting point, about 1500°C. It has been calculated that 1 ln J of diatomite consists of the skeletons of 40-70 million diatoms (15)• Approximately 10,000 distinct species of diatoms have been reported with sizes varying from 0.1 to 0.005 mm. Diatomite weighs approximately 7 lbs/ft^ dry and loose, approximately 16 lbs/ft^ when packed by wetting and up to 20 lbs/ft^ in a filter cake (15).…”

“…It has been calculated that 1 ln J of diatomite consists of the skeletons of 40-70 million diatoms (15)• Approximately 10,000 distinct species of diatoms have been reported with sizes varying from 0.1 to 0.005 mm. Diatomite weighs approximately 7 lbs/ft^ dry and loose, approximately 16 lbs/ft^ when packed by wetting and up to 20 lbs/ft^ in a filter cake (15). It has a specific gravity of approximately 2.35 and a filter cake porosity of 88 to 90 per cent (15).…”

“…Diatomite weighs approximately 7 lbs/ft^ dry and loose, approximately 16 lbs/ft^ when packed by wetting and up to 20 lbs/ft^ in a filter cake (15). It has a specific gravity of approximately 2.35 and a filter cake porosity of 88 to 90 per cent (15). water for field troops in 1944.…”

Effect of coagulation of clay on filter cake resistance

“…was described in detail by Mi ley(24), LaFrenz(13) andHawley (9). A few major changes were made in the pilot plant to facilitate coagulant addition and to simplify the operation of the plant.…”