scholarly journals Impacts of willow and miscanthus bioenergy buffers on biogeochemical N removal processes along the soil-groundwater continuum

GCB Bioenergy ◽  
2016 ◽  
Vol 9 (1) ◽  
pp. 246-261 ◽  
Author(s):  
Andrea Ferrarini ◽  
Flavio Fornasier ◽  
Paolo Serra ◽  
Federico Ferrari ◽  
Marco Trevisan ◽  
...  
Keyword(s):  
N Removal ◽  
Removal Processes

scholarly journals Nitrogen removal processes in lakes of different trophic states from on-site measurements and historic data

2021 ◽  
Vol 83 (2) ◽  
Author(s):  
Beat Müller ◽  
Raoul Thoma ◽  
Kathrin B. L. Baumann ◽  
Cameron M. Callbeck ◽  
Carsten J. Schubert
Keyword(s):  
Eutrophic Lake ◽  
Oligotrophic Lake ◽  
Removal Rates ◽  
N Removal ◽  
Central Switzerland ◽  
Denitrification Activity ◽  
Historic Data ◽  
Anthropogenic Nitrogen ◽  
Removal Processes ◽  
Sediment Interface

AbstractFreshwater lakes are essential hotspots for the removal of excessive anthropogenic nitrogen (N) loads transported from the land to coastal oceans. The biogeochemical processes responsible for N removal, the corresponding transformation rates and overall removal efficiencies differ between lakes, however, it is unclear what the main controlling factors are. Here, we investigated the factors that moderate the rates of N removal under contrasting trophic states in two lakes located in central Switzerland. In the eutrophic Lake Baldegg and the oligotrophic Lake Sarnen, we specifically examined seasonal sediment porewater chemistry, organic matter sedimentation rates, as well as 33-year of historic water column data. We find that the eutrophic Lake Baldegg, which contributed to the removal of 20 ± 6.6 gN m−2 year−1, effectively removed two-thirds of the total areal N load. In stark contrast, the more oligotrophic Lake Sarnen contributed to 3.2 ± 4.2 gN m−2 year−1, and had removed only one-third of the areal N load. The historic dataset of the eutrophic lake revealed a close linkage between annual loads of dissolved N (DN) and removal rates (NRR = 0.63 × DN load) and a significant correlation of the concentration of bottom water nitrate and removal rates. We further show that the seasonal increase in N removal rates of the eutrophic lake correlated significantly with seasonal oxygen fluxes measured across the water–sediment interface (R2 = 0.75). We suggest that increasing oxygen enhances sediment mineralization and stimulates nitrification, indirectly enhancing denitrification activity.

Ammonium and nitrate removal in vegetated and unvegetated gravel bed microcosm wetlands

1995 ◽  
Vol 32 (3) ◽  
pp. 219-228 ◽  
Author(s):  
Zhu Tong ◽  
F. J. Sikora
Keyword(s):  
Root Biomass ◽  
Plant Biomass ◽  
N Uptake ◽  
Nitrate Removal ◽  
Solution Chemistry ◽  
Batch Mode ◽  
Organic C ◽  
N Removal ◽  
Removal Processes ◽  
Nutrient Solutions

A greenhouse experiment was conducted at Tennessee Valley Authority, Alabama, USA, in the summer of 1993 to investigate ammonium and nitrate removal processes in constructed wetlands. Microcosm wetlands cells were used in the study and consisted of plastic containers with 0.4 × 0.35 m2 surface area and 0.5 m depth. Two separate experiments were conducted. One experiment analyzed NH4-N removal and the other analyzed NO3-N removal. Nutrient solutions containing approximately 48 mg/l NH4-N or NO3-N were added in a batch mode to the wetland microcosms and the solution chemistry was analyzed with time. Treatments consisted of unplanted cells or cells planted with canarygrass (Phalaris arundinacea), reed (Phragmites communis), bulrush (Scirpus atrovirens georgianus) or typha (Typha latifolia). Another treatment consisted of added nutrient solutions containing or not containing C at 112 mg/l. In the NH4-N removal experiment, the rate of NH4-N removal occurred in the order: reed > canarygrass = bulrush > typha ≫ unplanted in wetland cells with and without C. The order of NH4-N removal was believed to be associated with the density of root biomass in the gravel. The greater the root biomass, the greater the chance for plant N uptake or nitrification mediated by O2 transport to the rhizosphere. In the NO3-N experiment, the rate of NO3-N removal occurred in the order: reed = canarygrass > typha = bulrush > unplanted cells. Labelled K15NO3 was used to trace the NO3-N removal process. By measuring the 15N in the plant biomass, the quantity of NO3-N removed via plant uptake was delineated from combined removal processes of denitrification and immobilization. In the treatments with C, 55 to 70% of the NO3-N was removed via denitrification and immobilzation. For bulrush, reed and typha, the quantity of NO3-N removed via denitrification and immobilization without added C was reduced to 14 to 30%. However, NO3-N removal via denitrification and immobilization remained high at 72% of added NO3-N in canarygrass cells due to high concentrations of organic C released from the canarygrass roots (15-20 mg/l C) that apparently did not limit denitrification or immobilization.

Towards energy neutral wastewater treatment: methodology and state of the art

2014 ◽  
Vol 16 (6) ◽  
pp. 1223-1246 ◽  
Author(s):  
Han Gao ◽  
Yaniv D. Scherson ◽  
George F. Wells
Keyword(s):  
Wastewater Treatment ◽  
Energy Recovery ◽  
State Of The Art ◽  
N Removal ◽  
Removal Processes

An optimal way to maximize energy recovery from wastewater treatment is to separate carbon and nutrient (particular N) removal processes.

Heavy metal pollution from Russian landfill leachates and its elimination together with other contaminants

2004 ◽  
Vol 50 (5) ◽  
pp. 51-58 ◽  
Author(s):  
S. Kalyuzhnyi ◽  
M. Gladchenko
Keyword(s):  
National Standards ◽  
Treated Wastewater ◽  
Inorganic N ◽  
Landfill Leachates ◽  
Total N ◽  
N Removal ◽  
Removal Processes ◽  
Direct Discharge ◽  
Uasb Reactors ◽  
Final Effluent

Systematic monitoring of raw leachates (RL) from the operating landfill “Khmet'yevo7rdquo; during December, 2001-June, 2002 with regard to heavy metals (HM) revealed that these RL were moderately contaminated with Fe, Zn, Pb and Cd (Cu is present in non-dangerous concentrations). This contamination depends on season - the winter leachates are less polluted compared to the summer ones. For removal of HM together with removal of bulk COD, the UASB reactors were applied where, besides elimination of the major part of organic matter, concomitant precipitation of HM in the form of insoluble sulphides inside the sludge bed occurred due to development of the process of biological sulphate reduction. Both removal processes were quite efficient even during operation under submesophilic and psychrophilic conditions (20-10°C). The subsequent submesophilic aerobic-anoxic treatment of submesophilic anaerobic effluents led to only 75% of total inorganic N removal due to COD deficiency for denitrification created by a too efficient anaerobic step. On the contrary, psychrophilic anaerobic effluents (richer in COD compared to the submesophilic ones) were more suitable for subsequent aerobic-anoxic treatment giving the total N removal of 95 and 92% at 20 and 10°C, respectively. The final effluent is approaching the current national standards for direct discharge of treated wastewater.

How short should the SRT be? – Investigation of parallel vs series C- and N-removal processes at the Blue Plains AWTP

2015 ◽  
Vol 2015 (16) ◽  
pp. 6188-6195 ◽  
Author(s):  
B Wett ◽  
A Al-Omari ◽  
G Bowden ◽  
B Stinson ◽  
N Szilágyi ◽  
...  
Keyword(s):  
N Removal ◽  
C And N ◽  
Removal Processes

Nitrogen and Phosphorus Removal Performance and Characteristics of a Sequencing Batch Moving Bed Biofilm Reactor

2011 ◽  
Vol 71-78 ◽  
pp. 2844-2847
Author(s):  
Hai Yan Guo ◽  
Teng Teng Feng ◽  
Zhi Gang Liu ◽  
Zhen Guo
Keyword(s):  
Phosphorus Removal ◽  
Operating Mode ◽  
Biofilm Reactor ◽  
Moving Bed Biofilm Reactor ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Moving Bed ◽  
N Removal ◽  
Removal Processes ◽  
P Removal

Laboratory scale experiments were conducted to study the performance and characteristics of nitrogen (N) and phosphorus (P) removal of a sequencing batch moving bed biofilm reactor (SBMBBR) with simple anaerobic/aerobic operating mode. Experimental results indicated that, under the operating condition of influent N concentration of 114 mg/L and P concentration of 12 mg/L, N and P removal efficiency reached 95% and 94% respectively under the conditions of influent COD/N (C/N) ratio of 2.8 to 4.0. Track studies of N, P and other operating parameters demonstrated that N removal was accomplished by anoxic denitrification during the filling and mixing stage and simultaneous nitrification and denitrification (SND) process in aerobic stage, while removal of P was realized through conventional phosphorus removal and denitrifying phosphorus removal processes.

Impact of Nitrogen Management Practices on Total Nitrogen in the Fruits of High Productive Hamlin Orange Trees

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 498e-498
Author(s):  
S. Paramasivam ◽  
A.K. Alva
Keyword(s):  
Crop Production ◽  
Management Practices ◽  
Fine Sand ◽  
Fruit Production ◽  
Perennial Crop ◽  
Total N ◽  
N Removal ◽  
Leaf N Concentration ◽  
N Rates ◽  
Orange Trees

For perennial crop production conditions, major portion of nutrient removal from the soil-tree system is that in harvested fruits. Nitrogen in the fruits was calculated for 22-year-old `Hamlin' orange (Citrus sinensis) trees on Cleopatra mandarin (Citrus reticulata) rootstock, grown in a Tavares fine sand (hyperthermic, uncoated, Typic Quartzipsamments) that received various N rates (112, 168, 224, and 280 kg N/ha per year) as either i) broadcast of dry granular form (DGF; four applications/year), or ii) fertigation (FRT; 15 applications/year). Total N in the fruits (mean across 4 years) varied from 82 to 110 and 89 to 111 kg N/ha per year for the DGF and FRT sources, respectively. Proportion of N in the fruits in relation to N applied decreased from 74% to 39% for the DGF and from 80% to 40% for the FRT treatments. High percentage of N removal in the fruits in relation to total N applied at low N rates indicate that trees may be depleting the tree reserve for maintaining fruit production. This was evident, to some extent, by the low leaf N concentration at the low N treatments. Furthermore, canopy density was also lower in the low N trees compared to those that received higher N rates.

Arsenic removal by MF membrane with chemical sludge adsorption and NF membrane equipped with vibratory shear enhanced process

2003 ◽  
Vol 3 (5-6) ◽  
pp. 303-310 ◽  
Author(s):  
S.-H. Yi ◽  
S. Ahmed ◽  
Y. Watanabe ◽  
K. Watari
Keyword(s):  
Arsenic Removal ◽  
Membrane Surface ◽  
Membrane Process ◽  
Low Concentrations ◽  
Strong Shear ◽  
Low Levels ◽  
Removal Processes ◽  
Removal Of Arsenic ◽  
Concentration Polarization Layer ◽  
Chemical Sludge

Conventional arsenic removal processes have difficulty removing low concentrations of arsenic ion from water. Therefore, it is very hard to comply with stringent low levels of arsenic, such as below 10 μg/L. So, we have developed two arsenic removal processes which are able to comply with more stringent arsenic regulations. They are the MF membrane process combined with chemical sludge adsorption and NF membrane process equipped with the vibratory shear enhanced process (VSEP). In this paper, we examine the performance of these new processes for the removal of arsenic ion of a low concentration from water. We found that chemical sludge produced in the conventional rapid sand filtration plants can effectively remove As (V) ions of H2AsO4- and HAsO42- through anion exchange reaction. The removal efficiency of MF membrane process combined with chemical sludge adsorption increased to about 36%, compared to MF membrane alone. The strong shear force on the NF membrane surface produced by vibration on the VSEP causes the concentration polarization layer to thin through increased back transport velocity of particles. So, it can remove even dissolved constituents effectively. Therefore, As (V) ions such as H2AsO4- and HAsO42- can be removed. The concentration of As (V) ions decreased from 50 μg/L to below 10 μg/L and condensation factor in recirculating water increased up to 7 times by using NF membrane equipped with VSEP.

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