Swine wastewater treatment technology to reduce nitrous oxide emission by using an aerobic bioreactor packed with carbon fibres

2016 ◽  
Vol 56 (3) ◽  
pp. 330 ◽  
Author(s):  
Takahiro Yamashita ◽  
Makoto Shiraishi ◽  
Ryoko Yamamoto-Ikemoto ◽  
Hiroshi Yokoyama ◽  
Akifumi Ogino ◽  
...  

From a global warming perspective it is important to control emissions of methane (CH4) and nitrous oxide (N2O) from excreta and manure management. To mitigate emissions of N2O during swine wastewater treatment, we examined aerobic treatment technologies that use carbon fibre carriers as an alternative to conventional activated sludge treatment. We used scaled-up experiment equipment (water volume, 700 L) to evaluate the treatment performance. The N2O emission factor was 0.008 g N2O-N/g total N load in an aerobic bioreactor packed with carbon fibres (CF reactor), compared with 0.021 gN2O-N/g total N load in an activated sludge reactor (AS reactor). The CF treatment reduced N2O emissions by more than 60% compared with the AS treatment. Combined CH4 and N2O emissions from the CF reactor were 504 g-CO2 eq/m3.day, whereas those from the AS reactor were 1333 g-CO2 eq/m3.day. Interestingly, N2O emissions from the CF reactor were reduced even when nitrate and nitrite accumulated.

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1013 ◽  
Author(s):  
Takahiro Yamashita ◽  
Makoto Shiraishi ◽  
Hiroshi Yokoyama ◽  
Akifumi Ogino ◽  
Ryoko Yamamoto-Ikemoto ◽  
...  

Nitrous oxide (N2O) is a potent greenhouse gas that is emitted from wastewater treatment plants. To reduce emissions of N2O from swine wastewater treatment plants, we constructed an experimental aerobic bioreactor packed with carbon fibres (ca. 1 m3 bioreactor) as an alternative to conventional activated sludge treatment. The N2O emission factor for the aerobic bioreactor packed with carbon fibres (CF) was 0.002 g N2O-N/g TN-load and the value for the typical activated sludge (AS) reactor was 0.013 g N2O-N/g TN-load. The CF treatment method achieved more than 80% reduction of N2O emissions, compared with the AS treatment method. The experimental introduction of a CF carrier into an actual wastewater treatment plant also resulted in a large reduction in N2O generation. Specifically, the N2O emission factors decreased from 0.040 to 0.005 g N2O-N/g TN-load following application of the carrier. This shows that it is possible to reduce N2O generation by more than 80% by using a CF carrier during the operation of an actual wastewater treatment plant. Some bacteria from the phylum Chloroflexi, which are capable of reducing N2O emissions, were detected at a higher frequency in the biofilm on the CF carrier than in the biofilm formed on the AS reactor.


2004 ◽  
Vol 49 (5-6) ◽  
pp. 359-371 ◽  
Author(s):  
N. Kishida ◽  
J.H. Kim ◽  
Y. Kimochi ◽  
O. Nishimura ◽  
H. Sasaki ◽  
...  

To evaluate control parameters for nitrous oxide (N2O) emissions in the swine wastewater treatment process, the N2O emission was compared in the activated sludge from SBRs acclimated in different carbon/nitrogen (C/N) ratios. N2O emission from a denitrification phase was very strongly dependent on C/N ratio of swine wastewater, and the total N2O emission in the operating condition of BOD5/TN ratio of 2.6 was approximately 270 times greater than that in BOD5/TN ratio of 4.5. However, the effect of C/N ratio on N2O emission amount from nitrification was not significant in an oxic phase study. It is considered that stabilization of the C/N ratio through optimal solid-liquid separation of slurry or use of an external carbon source is indispensable for effective N2O emission control from nitrogen removal process of swine wastewater.


2017 ◽  
Vol 76 (9) ◽  
pp. 2337-2349 ◽  
Author(s):  
Renato P. Ribeiro ◽  
Rodrigo F. Bueno ◽  
Roque P. Piveli ◽  
Débora C. Kligerman ◽  
William Z. de Mello ◽  
...  

Abstract The continuous measurements of N2O emissions from the aeration tanks of three activated sludge wastewater treatment plants (WWTPs) operated with biological nitrogen removal (BNR) and non-BNR were performed during the different operating conditions of several parameters, such as aeration, dissolved oxygen (DO) profiling and organic shock loading (with landfill leachate). The nitrification process is the main driving force behind N2O emission peaks. There are indications that the variation of the air flow rate influenced N2O emissions; high N2O emissions denote over-aeration conditions or incomplete nitrification, with accumulation of NO2− concentrations. Thus, continuous measurements of N2O emissions can provide information on aeration adequacy and the efficiency of complete nitrification, with major focus on DO control, in order to reduce N2O emissions. An additional concern is the observed propensity of WWTPs in developing countries to receive landfill leachates in their wastewater systems. This practice could have adverse effects on climate change, since wastewater treatment during periods of organic shock loading emitted significantly higher amounts of N2O than without organic shock loading. In short, non-BNR WWTPs are subject to high N2O emissions, in contrast to BNR WWTP with controlled nitrification and denitrification processes.


Author(s):  
A. Kuokkanen ◽  
K. Blomberg ◽  
A. Mikola ◽  
M. Heinonen

Abstract Nitrous oxide emissions can contribute significantly to the carbon footprint of municipal wastewater treatment plants even though emissions from conventional nitrogen removal processes are assumed to be moderate. An increased risk for high emissions can occur in connection with process disturbances and nitrite (NO2−) accumulation. This work describes the findings at a large municipal wastewater treatment plant where the levels of NO2− in the activated sludge process effluent were spontaneously and strongly increased on several activated sludge lines which was suspected to be due to shortcut nitrogen removal that stabilized for several months. The high NO2− levels were linked to a dramatic increase in nitrous oxide (N2O) emissions. As much as over 20% of the daily influent nitrogen load was emitted as N2O. These observations indicate that highly increased NO2− levels can occur in conventional activated sludge processes and result in high nitrous oxide emissions. They also raise questions concerning the risk of increased greenhouse gas (GHG) emissions of the nitritation-denitritation processes – although the uncontrolled nature of the event described here must be taken into consideration – and underline the importance of continuous monitoring and control of N2O emissions.


2004 ◽  
Vol 48 (11-12) ◽  
pp. 363-370 ◽  
Author(s):  
N. Noda ◽  
N. Kaneko ◽  
M. Mikami ◽  
Y. Kimochi ◽  
S. Tsuneda ◽  
...  

Nitrous oxide (N2O) is emitted from wastewater treatment processes, and is known to be a green house gas contributing to global warming. It is thus important to develop technology that can suppress N2O emission. The effects of sludge retention time (SRT) and dissolved oxygen (DO) on N2O emission in an anoxic-oxic activated sludge system were estimated. Moreover, the microbial community structure in the sludge, which plays an important role in N2O suppression, was clarified based on nitrous oxide reductase (nosZ) gene analysis by molecular biological techniques. The results showed that under low SRT conditions, nitrification efficiency was reduced and the N2O emission rate in the oxic reactors was increased. It was also observed that N2O emission was enhanced under low DO conditions, where the available oxygen is insufficient for nitrification. Moreover, molecular analysis revealed that the clones identified in this study were closely related to Ralstonia eutropha and Paracoccus denitrificans. The fact that the identified sequences are not closely related to known culturable denitrifier nosZ sequences indicates a substantial in situ diversity of denitrifiers contributing to N2O suppression, which are not reflected in the cultivatable fraction of the population. The further application of these new molecular techniques should serve to enhance our knowledge of the microbial community of denitrifying bacteria contributing to N2O suppression in wastewater treatment systems.


2014 ◽  
Vol 86 (3) ◽  
pp. 358-368 ◽  
Author(s):  
Takahiro Yamashita ◽  
Ryoko Yamamoto-Ikemoto ◽  
Hiroshi Yokoyama ◽  
Hirofumi Kawahara ◽  
Akifumi Ogino ◽  
...  

Engevista ◽  
2015 ◽  
Vol 17 (3) ◽  
pp. 375 ◽  
Author(s):  
Renato Pereira Ribeiro ◽  
Jaime Lopes da Mota Oliveira ◽  
Débora Cynamon Kligerman ◽  
Renata Barbosa Alvim ◽  
Samara Almeida Andrade ◽  
...  

Nitrous oxide emissions were determined in three campaigns in the aeration tank of a full scale conventional activated sludge wastewater treatment plant. During these experiments, the carbonaceous organic matter (BOD and COD) removal was high and rather constant (97-98% and 93-96%). The results indicate that the concentration of total nitrogen in the influent wastewater, especially NH4+, and the aeration flow rate are key controlling factor of N2O emissions from the aeration tank. Nitrification was the major source of N2O, suggested by the behavior of DO concentrations, NO3-/NH4+ ratio and pH values along the six interlinked zones of the aeration tank. Excessive air flow intensified N2O transfer from the liquor to the atmosphere by air stripping.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Khadim Dawar ◽  
Shah Fahad ◽  
M. M. R. Jahangir ◽  
Iqbal Munir ◽  
Syed Sartaj Alam ◽  
...  

AbstractIn this study, we explored the role of biochar (BC) and/or urease inhibitor (UI) in mitigating ammonia (NH3) and nitrous oxide (N2O) discharge from urea fertilized wheat cultivated fields in Pakistan (34.01°N, 71.71°E). The experiment included five treatments [control, urea (150 kg N ha−1), BC (10 Mg ha−1), urea + BC and urea + BC + UI (1 L ton−1)], which were all repeated four times and were carried out in a randomized complete block design. Urea supplementation along with BC and BC + UI reduced soil NH3 emissions by 27% and 69%, respectively, compared to sole urea application. Nitrous oxide emissions from urea fertilized plots were also reduced by 24% and 53% applying BC and BC + UI, respectively, compared to urea alone. Application of BC with urea improved the grain yield, shoot biomass, and total N uptake of wheat by 13%, 24%, and 12%, respectively, compared to urea alone. Moreover, UI further promoted biomass and grain yield, and N assimilation in wheat by 38%, 22% and 27%, respectively, over sole urea application. In conclusion, application of BC and/or UI can mitigate NH3 and N2O emissions from urea fertilized soil, improve N use efficiency (NUE) and overall crop productivity.


2021 ◽  
Vol 13 (9) ◽  
pp. 4928
Author(s):  
Alicia Vanessa Jeffary ◽  
Osumanu Haruna Ahmed ◽  
Roland Kueh Jui Heng ◽  
Liza Nuriati Lim Kim Choo ◽  
Latifah Omar ◽  
...  

Farming systems on peat soils are novel, considering the complexities of these organic soil. Since peat soils effectively capture greenhouse gases in their natural state, cultivating peat soils with annual or perennial crops such as pineapples necessitates the monitoring of nitrous oxide (N2O) emissions, especially from cultivated peat lands, due to a lack of data on N2O emissions. An on-farm experiment was carried out to determine the movement of N2O in pineapple production on peat soil. Additionally, the experiment was carried out to determine if the peat soil temperature and the N2O emissions were related. The chamber method was used to capture the N2O fluxes daily (for dry and wet seasons) after which gas chromatography was used to determine N2O followed by expressing the emission of this gas in t ha−1 yr−1. The movement of N2O horizontally (832 t N2O ha−1 yr−1) during the dry period was higher than in the wet period (599 t N2O ha−1 yr−1) because of C and N substrate in the peat soil, in addition to the fertilizer used in fertilizing the pineapple plants. The vertical movement of N2O (44 t N2O ha−1 yr−1) was higher in the dry season relative to N2O emission (38 t N2O ha−1 yr−1) during the wet season because of nitrification and denitrification of N fertilizer. The peat soil temperature did not affect the direction (horizontal and vertical) of the N2O emission, suggesting that these factors are not related. Therefore, it can be concluded that N2O movement in peat soils under pineapple cultivation on peat lands occurs horizontally and vertically, regardless of season, and there is a need to ensure minimum tilling of the cultivated peat soils to prevent them from being an N2O source instead of an N2O sink.


Soil Research ◽  
2016 ◽  
Vol 54 (5) ◽  
pp. 604 ◽  
Author(s):  
G. D. Schwenke ◽  
B. M. Haigh

Summer crop production on slow-draining Vertosols in a sub-tropical climate has the potential for large emissions of soil nitrous oxide (N2O) from denitrification of applied nitrogen (N) fertiliser. While it is well established that applying N fertiliser will increase N2O emissions above background levels, previous research in temperate climates has shown that increasing N fertiliser rates can increase N2O emissions linearly, exponentially or not at all. Little such data exists for summer cropping in sub-tropical regions. In four field experiments at two locations across two summers, we assessed the impact of increasing N fertiliser rate on both soil N2O emissions and crop yield of grain sorghum (Sorghum bicolor L.) or sunflower (Helianthus annuus L.) in Vertosols of sub-tropical Australia. Rates of N fertiliser, applied as urea at sowing, included a nil application, an optimum N rate and a double-optimum rate. Daily N2O fluxes ranged from –3.8 to 2734g N2O-Nha–1day–1 and cumulative N2O emissions ranged from 96 to 6659g N2O-Nha–1 during crop growth. Emissions of N2O increased with increased N fertiliser rates at all experimental sites, but the rate of N loss was five times greater in wetter-than-average seasons than in drier conditions. For two of the four experiments, periods of intense rainfall resulted in N2O emission factors (EF, percent of applied N emitted) in the range of 1.2–3.2%. In contrast, the EFs for the two drier experiments were 0.41–0.56% with no effect of N fertiliser rate. Additional 15N mini-plots aimed to determine whether N fertiliser rate affected total N lost from the soil–plant system between sowing and harvest. Total 15N unaccounted was in the range of 28–45% of applied N and was presumed to be emitted as N2O+N2. At the drier site, the ratio of N2 (estimated by difference)to N2O (measured) lost was a constant 43%, whereas the ratio declined from 29% to 12% with increased N fertiliser rate for the wetter experiment. Choosing an N fertiliser rate aimed at optimum crop production mitigates potentially high environmental (N2O) and agronomic (N2+N2O) gaseous N losses from over-application, particularly in seasons with high intensity rainfall occurring soon after fertiliser application.


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