Simultaneous organic carbon and nitrogen removal in an SBR controlled at low dissolved oxygen concentration

2001 ◽  
Vol 76 (6) ◽  
pp. 553-558 ◽  
Author(s):  
Peng Dangcong ◽  
Nicolas Bernet ◽  
Jean-Phillipe Delgenes ◽  
Rene Moletta
Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 516 ◽  
Author(s):  
Rauno Lust ◽  
Jaak Nerut ◽  
Kuno Kasak ◽  
Ülo Mander

Assessments of groundwater aquifers made around the world show that in many cases, nitrate concentrations exceed the safe drinking water threshold. This study assessed how bioelectrochemical systems could be used to enhance nitrate removal from waters with low organic carbon concentrations. A two-chamber microbial electrosynthesis cell (MES) was constructed and operated for 45 days with inoculum that was taken from a municipal wastewater treatment plant. A study showed that MES can be used to enhance nitrate removal efficiency from 3.66% day−1 in a control reactor to 8.54% day−1 in the MES reactor, if a cathode is able to act as an electron donor for autotrophic denitrifying bacteria or there is reducing oxygen in a cathodic chamber to favor denitrification. In the MES, greenhouse gas emissions were also lower compared to the control. Nitrous oxide average fluxes were −639.59 and −9.15 µg N m−2 h−1 for the MES and control, respectively, and the average carbon dioxide fluxes were −5.28 and 43.80 mg C m−2 h−1, respectively. The current density correlated significantly with the dissolved oxygen concentration, indicating that it is essential to keep the dissolved oxygen concentration in the cathode chamber as low as possible, not only to suppress oxygen’s inhibiting effect on denitrification but also to achieve better power efficiency.


2019 ◽  
Vol 02 (03n04) ◽  
pp. 1940001
Author(s):  
H. K. Ramaraju ◽  
D. A. Kiran

Mangaluru coast belt spreads about 22 Kms with Arabian Sea in the West and the Western Ghats in the East. Coastal anthropogenic activities such as disposal of untreated or partially treated sewage and industrial effluents and their possible impacts hinder the coastal environment. Huge amount of pollution load from the major industries located nearby are discharged into the sea directly or through the west flowing rivers of the area i.e. Gurupura and Nethravathi. Due to this, the soil properties also get affected. The preliminary study was carried out at the study area by considering surface water samples, i.e. stream water, river water, sea water and also soil samples to study the physicochemical characteristics. The study reveals that most of the surface water samples have low dissolved oxygen concentration and are high in BOD, COD, TDS, Electrical Conductivity (EC) and Chlorides Concentration. Very low dissolved oxygen concentration was observed in the Gurupura–Nethravathi Estuary point. With respect to fertility of the soil, most of the soil samples were below the normal range for the various parameters.


Radiocarbon ◽  
1997 ◽  
Vol 40 (2) ◽  
pp. 915-920 ◽  
Author(s):  
E. Boaretto ◽  
L. Thorling ◽  
Á. E. Sveinbjörnsdóttir ◽  
Y. Yechieli ◽  
J. Heinemeier

The carbonate hydrochemistry of groundwater from the Hvinningdal aquifer (Denmark) was studied by radiocarbon (accelerator mass spectrometry (AMS)) and δ13C measurements as a preliminary step towards 14C groundwater dating. The 14C concentrations varied between 30 and 100 percent modern carbon (pMC) in apparent contradiction with tritium (3H) data, which in most cases indicate a post-bomb date. The dilution of 14C can be explained as being due to the combined effect of dissolution of old soil carbonate and oxidation of old organic carbon. The last effect proved to be essential. To calculate this correction the dissolved oxygen concentration was used together with the δ13C values. The combined corrections bring the 14C concentrations up to post-bomb levels in better agreement with the 3H data.


1992 ◽  
Vol 26 (7-8) ◽  
pp. 1707-1716 ◽  
Author(s):  
K. Baskaran ◽  
P. H. Scott ◽  
M. A. Connor

A pilot study of sewage treatment lagoons near Melbourne indicated that the best way to enhance nitrogen removal in such lagoons was to promote nitrification. Combined algal/bacterial biofilms grown on surfaces immersed in the lagoons showed potential for greatly increasing the extent of nitrification. A laboratory study was undertaken to determine the effect of pH, dissolved oxygen concentration, temperature and other factors on the nitrifying capabilities of such biofilms; effective nitrification was observed at temperatures down to 10°C, at pH's down to 5.5 and at dissolved oxygen levels down to 2.5 mg/L. Tanks containing biofilm-coated plates nitrified much more effectively than tanks containing only suspended microbial growths. At dissolved oxygen levels of 2-3 mg/L, up to 30% of the ammonia-nitrogen fed to tanks containing biofilm-coated plates was removed by denitrification. Photosynthetic activity in the biofilm greatly enhanced nitrification efficiencies at low dissolved oxygen levels.


1992 ◽  
Vol 20 (5) ◽  
pp. 505-516 ◽  
Author(s):  
Masafumi Morita ◽  
Tadashi Sasada ◽  
Isao Nomura ◽  
Yu Qing Wei ◽  
Yukio Tsukamoto

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