title: Removal of highly elevated nitrate from drinking water by pH-heterogenized heterotrophic denitrification facilitated with ferrous sulfide-based autotrophic denitrification.
abstract: The performance of acetic acid-supported pH-heterogenized heterotrophic denitrification (HD) facilitated with ferrous sulfide-based autotrophic denitrification (AD) was investigated in upflow activated carbon-packed column reactors for reliable removal of highly elevated nitrate (42 mg NO(3)-Nl(-1)) in drinking water. The use of acetic acid as substrate provided sufficient internal carbon dioxide to completely eliminate the need of external pH adjustment for HD, but simultaneously created vertically heterogenized pH varying from 4.8 to 7.8 in the HD reactor. After 5-week acclimation, the HD reactor developed a moderate nitrate removal capacity with about one third of nitrate removal occurring in the acidic zone (pH 4.8-6.2). To increase the treatment reliability, acetic acid-supported HD was operated under 10% carbon limitation to remove >85% of nitrate, and ferrous sulfide-based AD was supplementally operated to remove residual nitrate and formed nitrite without excess of soluble organic carbon, nitrite or sulfate in the final effluent.
authors: Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Science, Shenyang 110016, People's Republic of China. huangbin@iae.ac.cn
authors: Bin
authors: B
authors: Huang
authors: Guangyu
authors: G
authors: Chi
authors: Xin
authors: X
authors: Chen
authors: Yi
authors: Y
authors: Shi
mesh_terms: D000064:Acclimatization / Q000187:drug effects; D000085:Acetates / Q000032:analysis; D052818:Autotrophic Processes / Q000187:drug effects; D001673:Biodegradation, Environmental / Q000187:drug effects; D019149:Bioreactors / Q000382:microbiology; D002244:Carbon / Q000494:pharmacology; D058440:Denitrification / Q000187:drug effects; D060766:Drinking Water / Q000737:chemistry*; D005296:Ferrous Compounds / Q000737:chemistry*; D052836:Heterotrophic Processes / Q000187:drug effects; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D009566:Nitrates / Q000302:isolation & purification*; D009573:Nitrites / Q000032:analysis; D013431:Sulfates / Q000032:analysis; D013997:Time Factors; D014865:Waste Disposal, Fluid; D014876:Water Pollution / Q000032:analysis; D018508:Water Purification / Q000379:methods*
chemical_list: D000085:Acetates; D060766:Drinking Water; D005296:Ferrous Compounds; D009566:Nitrates; D009573:Nitrites; D013431:Sulfates; D002244:Carbon; C022597:ferrous sulfide