Soil surface electrochemical properties may have a strong influence on nitrifying microorganisms, Hþ and NH4 þ activities, and therefore on the nitrification process. A gradient of surface electrochemical parameters was obtained by amendment of a subtropical acid pine soil (Oxisol) with 0% (control), 3%, 5%, 8%, 10% and 12% pure Ca-Montmorillonite by weight. The Hþ and NH4þ activities, the abun...

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(expan...

We combine field observations, microcosm, stoichiometry, and molecular and stable isotope techniques to quantify N2O generation processes in an intensively managed low carbon calcareous fluvo-aquic soil. All the evidence points to ammonia oxidation and linked nitrifier denitrification (ND) being the major processes generating N2O. When NH4(+)-based fertilizers are applied the soil will produce ...

Nitrification of ammonia (NH4) is a critical component for improved systems of animal wastewater treatment. One of the most effective processes uses nitrifying microorganisms encapsulated in polymer resins. It is used in Japan in municipal wastewater treatment plants for higher nitrification rates, shorter hydraulic retention times (HRT), and lower aeration treatment cost. We evaluated whether ...

EXTENDED ABSTRACT Nowadays, biological nutrient removal (BNR) processes have been applied widely for wastewater treatment. However, one type of greenhouse gases, nitrous oxide (N2O), can be released from both nitrification and denitrification during BNR. In our previous study, we found that N2O emission during nitrification could be affected by heterotrophic activities significantly in a BNR sy...

In this study, an approach using influent COD/N ratio reduction was employed to improve process performance and nitrification efficiency in a membrane bioreactor (MBR). Besides sludge reduction, membrane fouling alleviation was observed during 330 d operation, which was attributed to the decreased production of soluble microbial products (SMP) and efficient carbon metabolism in the autotrophic ...

Nitrification, denitrification and nitrate reduction rates in the sediments at two stations in Hiroshima Bay were studied seasonally from August 1994 to May 1995. The acetylene (C2H2) inhibition technique was used to evaluate the rate of these processes. The seasonal average of nitrification and denitrification rates ranged from 0.00 to 299 μg atN m–2h–1 and 0.00 to 69.0 μg atN m–2h–1, respecti...

The ability of a recent isolate, Tetraselmis sp. CTP4, for nutrient removal from sewage effluents before and after the nitrification process under batch and continuous cultivation was studied. Biomass productivities in both wastewaters were similar under continuous conditions (0.343±0.053gL-1d-1) and nutrient uptake rates were maximal 31.4±0.4mgNL-1d-1 and 6.66±1.57mgP-PO43-L-1d-1 in WW before ...

Nitrifying activity in the surface water of the Włocławek Dam Reservoir (WDR) was determined by use of a nitrification selective inhibitor (ATU). The highest values of nitrification were observed in the stations nearer the dam, with lower flow velocity, where the activity amounted to up to 120 μg N/dm3/day. Nitrification process [%] involvement in biochemical oxygen demand increased with passin...

This study examines the effects of erythromycin on activated sludge from two French urban wastewater treatment plants (WWTPs). Wastewater spiked with 10 mg/L erythromycin inhibited the specific evolution rate of chemical oxygen demand (COD) by 79% (standard deviation 34%) and the specific N-NH4+ evolution rate by 41% (standard deviation 25%). A temporary increase in COD and tryptophan-like fluo...