title: Particulate-biofilm, expanded-bed technology for high-rate, low-cost wastewater treatment: nitrification.
abstract: The performance of a particulate-biofilm, expanded-bed process for nitrification of activated sludge final effluent (ASFE) is reported for a plant receiving mixed industrial and domestic wastewater. The support material for the particulate-biofilms was glassy coke, to which the nitrifying bacteria attached and formed a highly active biofilm. An average nitrification rate of 1.7+/-0.6 kg m(expanded bed)(-3)d(-1) was recorded during operation of the bioreactor, which had a hydraulic residence time of 15 min. On average, the ASFE contained 12.6+/-3.7 g m(-3) NH3-N, which was reduced to 2.6+/-3.3 g m(-3) NH3-N. Furthermore, transfer of 10-12% of the oxygen in air was achieved using counter-current aeration. This investigation has demonstrated that a high rate of nitrification can be achieved with a particulate-biofilm, expanded-bed process. It has also demonstrated that the process can operate without backwashing and still remove particulate material from the ASFE feed.
authors.affiliation: Department of Biological Sciences, Faculty of Science and Engineering, Manchester Metropolitan University, Chester Street, Manchester M1 5GD, UK. mdempsey@mmu.ac.uk
authors.forename: M J
authors.initials: MJ
authors.lastname: Dempsey
authors.forename: K C
authors.initials: KC
authors.lastname: Lannigan
authors.forename: R J
authors.initials: RJ
authors.lastname: Minall
mesh_terms: D000388:Air; D000641:Ammonia / Q000378:metabolism; D018441:Biofilms; D018533:Biomass; D019149:Bioreactors; D005160:Facility Design and Construction; D005374:Filtration; D009573:Nitrites / Q000737:chemistry / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000191:economics / Q000379:methods*
chemical_list: D009573:Nitrites; D000641:Ammonia; D010100:Oxygen