1. 1. 2. 3. 4. 5. 6. © Chromium(VI) Inhibition In Multi-Substrate Carbon Oxidation And Nitrification Process In An Upflow Packed Bed Biofilm Reactor Beg, SA; Hassan, MM; Chaudhry, MAS ELSEVIER SCIENCE SA, BIOCHEMICAL ENGINEERING JOURNAL; pp: 143-152; Vol: 1 King Fahd University of Petroleum & Minerals http://www.kfupm.edu.sa Summary The performance of an upflow packed bed biofilm reactor has been analyzed mathematically under multi-substrate limitation of carbon oxidation and nitrification reactions while subjected to inhibition of a continuous dose of Cr(VI). For a fixed inlet concentration of 150 mg 1(-1) of NH4+-N and 250 mg 1(-1) of acetate and varying the inlet concentrations of Cr(VI), the results show that the toxicity of Cr(VI) to both organic oxidation and nitrification processes increases rapidly with increase in its inlet concentration. The toxicity of Cr(VI) has been found to be much pronounced when nitrification alone is considered to take place in the reactor. The concentration profiles within the biofilm show that oxygen is a limiting component near the inlet and at the middle of the reactor. This necessitates the need for ample supply of oxygen at these locations within the reactor as major portion of oxidation of both acetate and NH4+-N takes place there. The model predictions show a close agreement with the available experimental data for a variety of operating conditions. (C) 1998 Elsevier Science S.A. References: *US EPA, 1979, EPA440179003 ADAMS CE, 1975, HEAVY METALS AQUATIC, P277 ATIQULLAH M, 1990, CHEM ENG J, V44, B57 BAGBY MM, 1981, J WAT POLLUT CONTROL, V53, P1609 BARTH EF, 1963, P 18 IND WAST C, P616 BARTH EF, 1965, J WATER POLLUT CONTR, V37, P86 Copyright: King Fahd University of Petroleum & Minerals; http://www.kfupm.edu.sa

2. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. © BEG SA, 1982, J WATER POLLUT CONTR, V54, P482 BEG SA, 1983, J WATER POLLUT CON F, V55, P1080 BEG SA, 1985, CHEM ENG J BIOCH ENG, V30, B1 BEG SA, 1985, J ENV SCI HLTH A, V20, P315 BEG SA, 1987, WATER RES, V21, P191 BEG SA, 1995, CHEM ENG TECH, V19, P43 BEG SA, 1995, INT J ENVIRON STUD, V49, P31 BEG SA, 1997, CHEM ENG TECHNOL, V20, P10 BESZEDITS S, 1988, CHROMIUM NATURAL HUM, P231 CHANG SY, 1986, J ENVIRON ENG-ASCE, V112, P94 GARCIA MT, 1994, TOXICOL ENVIRON CHEM, V44, P225 GOLLA PS, 1990, J ENVIRON ENG-ASCE, V116, P829 GRADY CPL, 1980, BIOL WASTEWATER TREA, P542 HASSAN MM, 1987, CHEM ENG J, V36, B15 HAUG RT, 1972, J WATER P C, V44, P2086 HEATH MS, 1990, RES J WATER POLLUT C, V62, P185 IMAI A, 1993, J ENVIRON ENG-ASCE, V119, P137 JAMES BR, 1984, SOIL BIOL BIOCHEM, V16, P293 KIM BR, 1989, WATER RES, V23, P1491 LANDNER L, 1977, PROG WATER TECHNOL, V8, P55 LEWANDOWSKI Z, 1985, WATER RES, V19, P847 LEWANDOWSKI Z, 1986, WATER RES, V20, P589 LEWANDOWSKI Z, 1987, WATER RES, V21, P147 LIN CY, 1993, WATER RES, V27, P147 MCDERMOTT GN, 1965, J WATER POLLUT CONTR, V37, P163 MCHARNESS DD, 1975, J WAT POLLUT CONTROL, V47, P291 MERTZ W, 1979, CHROMIUM NUTR METABO MOORE WA, 1961, J WAT POLLUT CONTROL, V33, P54 NEUFELD RD, 1975, J WAT POLLUT CONTROL, V47, P310 PERRY RH, 1973, CHEM ENG HDB PETRILLI FL, 1977, APPL ENVIRON MICROB, V33, P805 POON CPC, 1971, J SAN ENG DIV P ASCE, P161 REID GW, 1968, WATER SEWAGE WORKS, V115, P320 RICHARD FC, 1991, WATER RES, V25, P807 ROSS DS, 1981, J ENVIRON QUAL, V10, P145 SAEZ PB, 1988, BIOTECHNOL BIOENG, V32, P379 SAEZ PB, 1992, BIOTECHNOL BIOENG, V39, P790 SHERWOOD TK, 1975, MASS TRANSFER STUMM W, 1980, AQUATIC CHEM SUIDAN MT, 1985, J ENVIRON ENG-ASCE, V111, P634 SUIDAN MT, 1989, WATER RES, V23, P837 SUJARITTANONTA S, 1981, J WAT POLLUT CONTROL, V53, P1314 SUNDSTROM DW, 1979, WASTEWATER TREATMENT, P173 TRAMA FB, 1960, J WAT POLLUT CONTROL, V32, P868 VENITT S, 1974, NATURE, V250, P493 Copyright: King Fahd University of Petroleum & Minerals; http://www.kfupm.edu.sa

3. 52. 53. 54. 55. © WANNER O, 1986, BIOTECHNOL BIOENG, V28, P314 WILLIAMSON K, 1976, J WATER POLLUTION CO, V48, P9 WILSON EJ, 1966, IND ENG CHEM FUND, V5, P9 YOUNG JC, 1969, J WATER POLLUT CONTR, V41, P160 For pre-prints please write to: sabeg@dpc.kfupm.edu.sa Copyright: King Fahd University of Petroleum & Minerals; http://www.kfupm.edu.sa