High nitrification rate with upflow biofiltration

Abstract

In order to investigate the upper limit of aerated biofilm processes, a series of experiments has been carried out on a pilot scale with a synthetic effluent containing only ammonium nitrogen and inorganic carbon as substrates. The influence of water velocity, air velocity and media height has been studied without the interaction of organic carbon and suspended solids. Under these conditions, the increase of the hydraulic load has a positive effect on the maximum nitrified load, despite the shortening of contact time. The pilot plant was able to nitrify 2.7 kg NH4+-N/m3.d at 14° C with an empty bed hydraulic retention time as short as 6 minutes - under a 30 m3/m2.h hydraulic load. It was also demonstrated that a cubic meter of granular bed presents the same nitrification capacity in a 3 m or in a 4 m media high biofilter, only if placed under the same conditions of air and water velocities. The results confirmed that water velocity significantly improves substrate bulk/biofilm transfer, and demonstrated that neither a contact time - based on the pore volume - as short as 2 minutes nor a media height of 4 m limit the nitrification rate.

Tertiary treatment of textile wastewater with combined media biological aerated filter (CMBAF) at different hydraulic loadings and dissolved oxygen concentrations

“…Higher hydraulic loadings coincide with higher organic loadings, which may accelerate microbial development on the top of the CMBAF. In addition, the increase of hydraulic loading may improve substrate transfer into the biofilm [29] and remove internal diffusion limitations by controlling the biofilm thickness [30]. Fig.…”

Ammonium nitrogen removal characteristics of zeolite media in a Biological Aerated Filter (BAF) for the treatment of textile wastewater

“…The primary purposes of BAF technology were to simultaneously accomplish the biological oxidation of organics and physical filtration of suspended solids. Nowadays, several treatment processes based on BAF were extensively developed to combine carbon and nitrogen removal [6,7]. The BAF process normally is known as having lots of advantages as compared with conventional activated sludge process.…”

Studies in nitrification of municipal sewage in an upflow biofilter

“…Later on, the population of nitri®ers was increased by pumping enrichment culture medium of a speci®ed composition [7] as given in Table 1 for about three weeks at the rate of 1.89 l/h in batch mode. When enough biomass concentration was observed visibly, and in conform with the literature of 30 days of acclimation [8], the acclimation was stopped after ®ve weeks and the continuous experiments were started with the wastewaters to be studied. The pH of the in¯uent wastewater was adjusted to 8.0 with sodium bicarbonate.…”