Both data whlch we present for Tomales Bay (California, USA) and general geochemical reasoning provide evidence to suggest that nearshore marine env~ronments tend to be net heterotrophic by a small margin, and that these systems oxidize on the order of 1 % of their primary production by denitrification. The rate of denitrification can be interpreted to be a simple stoichiometric function of the...

black tea sample was dried by a vibro-fluidized bed dryer to find its aerodynamic behavior and thermal performance during drying. the drying experiments were conducted at three different inlet air temperatures of 100, 115 and 130°c and fluidization condition at five vibration intensity levels of 0 (no vibration), 0.063, 0.189, 0.395 and 1.184. the results showed that bed channeling and defluidi...

the experiment was conducted to determine the effects of different photoperiods and darkness on the growth and survival of juvenile catla catla in the laboratory for 90 days. fishes were divided into four aquaria (10 fish per aquarium), and subjected to different photoperiod regimes of 8 hours light: 16 hours dark (8l:16d), 16 hours light: 8 hours dark (16l:8d), continuous light (24l:0d) and co...

nitrous oxide (n2o) has significant impact on global warming and leads to the depletion of ozone in the stratosphere. agricultural soil is regarded as a major source of n2o emissions. in recent years, greenhouse grown vegetables have rapidly developed in china. although excessive fertilizer application in greenhouse vegetable production can result in increased n2o emissions, research data on su...

Nitric oxide production was measured during nitrification in a laboratory-scale bioreactor, operated at conditions relevant to municipal nitrifying wastewater treatment plants. This study aims to determine which type of microorganism and which metabolic pathway is responsible for nitric oxide emission during nitrification. Simulation studies were used to identify which pathway is the main sourc...

The advent of molecular techniques has improved our understanding of the microbial communities responsible for denitrification and is beginning to address their role in controlling denitrification processes. There is a large diversity of bacteria, archaea, and fungi capable of denitrification, and their community composition is structured by long-term environmental drivers. The range of tempera...

A fluidized bed bioreactor has been used to carry out biological denitrification in the present work as it offers many advantages over other types of reactors. Plastic beads of low density (1055 kg/m3) were used as fluidizing media with Pseudomonas stuzeri, a denitrifying microorganism immobilized on them. The denitrification rate under different operating conditions was studied. The results of...

The cold-adapted bacterium Pseudomonas putida Y-9 was investigated and exhibited excellent capability for nitrogen removal at 15°C. The strain capable of heterotrophic nitrification and aerobic denitrification could efficiently remove ammonium, nitrate, and nitrite at an average removal rate of 2.85 mg, 1.60 mg, and 1.83 mg NL-1 h-1, respectively. Strain Y-9 performed nitrification in preferenc...

We investigated rice husk as the sole carbon source as well as biofilm carrier in the biological denitrification of wastewater in up-flow laboratory reactors. Fast startup of the reactor and high nitrate removal efficiency was observed. The highest denitrification rate (about 0.096kg/m·d) was achieved when flow rate and nitrate concentration were 41.4L/d and 25.0mg/L, respectively. Flow rate an...

Simultaneous partial nitrification, anammox and denitrification (SNAD) process was developed in a sequential batch reactor (SBR) and the influence of hydraulic retention time (HRT) on the SNAD process was investigated. Around 96% NH(4)(+)-N removal and 87% COD removal were observed at 9 d HRT. Marginal decreases in the removal efficiencies were observed when the HRT was reduced to 3d or the loa...