Nitrogen removal from digested manure in a simple one-stage process

2011 ◽  
Vol 63 (9) ◽  
pp. 1991-1996 ◽  
Author(s):  
J. D. Villegas ◽  
H. Fruteau de Laclos ◽  
J. Dovat ◽  
Y. Membrez ◽  
C. Holliger
Keyword(s):  
Suspended Solids ◽  
Biogas Production ◽  
Gaseous Ammonia ◽  
Ammonia Emissions ◽  
Ammonium Oxidation ◽  
Removal Rates ◽  
Oxidation Activity ◽  
One Stage ◽  
N Removal ◽  
Stage Process

A process based on partial nitrification and recirculation into the anaerobic digester was studied to remove nitrogen from digested manure and thus reduce enhanced gaseous ammonia emissions due to on-farm biogas production. An anaerobic reactor representing an anaerobic manure digester was fed with a nitrite solution and digested manure liquor. Nitrite was efficiently removed from the influent and ammonium formation was observed first. Ammonium was subsequently eliminated up to a maximum of 90% of the influent concentration, indicating anaerobic ammonium oxidation activity. This activity, however, decreased again and was lost at the end of the 4-month operation period. In a 1.5 L aerobic CSTR that was fed with digested manure liquor, ammonium was efficiently removed from the influent. Nitrite and nitrate formation was observed but mass balances indicated significant N-removal. Accumulation of suspended solids was observed at the end of the experiment suggesting presence of oxygen-free environments. In a second test in a 15 L CSTR where suspended solids sedimentation could be avoided, low N-removal rates were observed in the absence of biofilm carrier elements whereas high N-removal rates were achieved in their presence. A simple one-stage process based on immobilized biomass could therefore be installed downstream of agricultural anaerobic digesters in order to mitigate undesirable gaseous ammonia emissions.

Improving nitrogen removal in predenitrification-nitrification biofilters

2004 ◽  
Vol 48 (11-12) ◽  
pp. 419-428 ◽  
Author(s):  
L. Larrea ◽  
A. Abad ◽  
J. Gayarre
Keyword(s):  
Dissolved Oxygen ◽  
Activated Sludge ◽  
Nitrogen Removal ◽  
Suspended Solids ◽  
Complete Removal ◽  
Cod Removal ◽  
Nitrification Rate ◽  
Removal Rates ◽  
N Removal ◽  
Activated Sludge Processes

The effect on NH4-N removal rates in nitrification biofilters of filtered biodegradable COD and particulate COD leaving predenitrification biofilters was studied in a lab scale plant configured with the separated system of biofilters for secondary nitrogen removal from urban wastewaters. Applying a typical COD load of 11 kg/m3.day to the predenitrification biofilter and maximizing its COD removal by adding nitrates or by operating an improved control of the internal recycle, only 60% removal of filtered biodegradable COD was found. This value corresponds to the complete removal of the readily biodegradable substrate (30% of influent filtered COD) and 36% of filtered slowly biodegradable substrate (50% of influent COD). The remaining 64% of the latter entered the nitrification biofilter, causing competition between heterotrophs and nitrifiers for dissolved oxygen in the inner layers of the biofilm. Consequently the nitrification rate had relatively low values (0.5 kgN/m3.d) at 14°C despite using dissolved oxygen levels of 6 mg/l. This behaviour may explain the lower nitrification rates obtained in some cases of nitrification biofilters compared to those in tertiary nitrification after activated sludge processes. The particulate COD entering the nitrification biofilter is associated with the suspended solids leaving the denitrification biofilter which are adsorbed by the external layers of the biofilm, increasing its thickness. The activity of the nitrifiers was affected because of a lack of oxygen when the thickness was left to grow considerably. Therefore no significant particulate COD effect is expected to occur as long as backwashing is carried out with the appropriate frequency.

The Study of Sludge Characteristics for One-Stage Autothermal Thermophilic Aerobic Digestion Process

2011 ◽  
Vol 236-238 ◽  
pp. 437-440 ◽  
Author(s):  
Jie Hong Cheng ◽  
Yan Yan Zhang ◽  
Nan Wen Zhu ◽  
Shu Gen Liu
Keyword(s):  
Fatty Acid ◽  
Retention Time ◽  
Volatile Fatty Acid ◽  
Suspended Solids ◽  
Removal Rates ◽  
Aerobic Digestion ◽  
Digestion Process ◽  
One Stage ◽  
Thermophilic Aerobic Digestion ◽  
Autothermal Thermophilic Aerobic Digestion

One-stage Autothermal Thermophilic Aerobic Digestion was autonomously designed to treat municipal sludges. By the way of batch operation experiment, the influence of removal rates of volatile suspended solids(VSS), total suspended solids(TSS), auto-rise temperature, and COD concentration, volatile fatty acid concentration of sludge, were investigated respectively. The results showed that a large part of reactor temperature was in thermophilic statues at 56°C-60°C during sludge digestion period; Municipal sludges treated have achieved stabilization standard of 503 articles of EPA while removal rates of VSS and TSS at 38.9% and 31% respectively for 360h retention time. Resulting from micro-organisms hydrolysis reaction, total COD concentration of sludge supernatant (SCOD) was increased firstly and then dropped afterward during the process of digestion while total COD concentration of solid phase of sludge(TCOD) still fall down with removal rate of TCOD at 35.6% for 360h retention time. A sum of concentration of volatile fatty acid(VFA) was accumulated gradually in the sludge supernatant at 2745mg/L for 360h retention time because of micro-aerobic situation in the beginning of digestion process, and can be use as the carbon sources for wastewater treatment process.

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.

Anammox brings WWTP closer to energy autarky due to increased biogas production and reduced aeration energy for N-removal

2008 ◽  
Vol 57 (3) ◽  
pp. 383-388 ◽  
Author(s):  
H. Siegrist ◽  
D. Salzgeber ◽  
J. Eugster ◽  
A. Joss
Keyword(s):  
Hydraulic Retention Time ◽  
Biogas Production ◽  
Sludge Treatment ◽  
N Removal ◽  
Secondary Sludge ◽  
Organic Carbon Source ◽  
Anammox Process ◽  
Dry Weather Flow ◽  
Heterotrophic Denitrification ◽  
Bod Removal

Fifty years ago when only BOD was removed at municipal WWTPs primary clarifiers were designed with 2–3 hours hydraulic retention time (HRT). This changed with the introduction of nitrogen removal in activated sludge treatment that needed more BOD for denitrification. The HRT of primary clarification was reduced to less than one hour for dry weather flow with the consequence that secondary sludge had to be separately thickened and biogas production was reduced. Only recently the ammonia rich digester liquid (15–20% of the inlet ammonia load) could be treated with the very economic autotrophic nitritation/anammox process requiring half of the aeration energy and no organic carbon source compared to nitrification and heterotrophic denitrification. With the introduction of this new innovative digester liquid treatment the situation reverts, allowing us to increase HRT of the primary clarifier to improve biogas production and reduce aeration energy for BOD removal and nitrification at similar overall N-removal.

Granular biomass capable of partial nitritation and anammox

2008 ◽  
Vol 58 (5) ◽  
pp. 1113-1120 ◽  
Author(s):  
S. E. Vlaeminck ◽  
L. F. F. Cloetens ◽  
M. Carballa ◽  
N. Boon ◽  
W. Verstraete
Keyword(s):  
Removal Rate ◽  
Batch Reactor ◽  
Ammonium Oxidation ◽  
Autotrophic Nitrification ◽  
Partial Nitritation ◽  
One Stage ◽  
Biomass Retention ◽  
Granular Biomass ◽  
The One

A novel and efficient way of removing nitrogen from wastewater poor in biodegradable organic carbon, is the combination of partial nitritation and anoxic ammonium oxidation (anammox), as in the one-stage oxygen-limited autotrophic nitrification/denitrification (OLAND) process. Since anoxic ammonium-oxidizing bacteria grow very slowly, maximum biomass retention in the reactor is required. In this study, a lab-scale sequencing batch reactor (SBR) was used to develop granular, rapidly settling biomass. With SBR cycles of one hour and a minimum biomass settling velocity of 0.7 m/h, OLAND granules were formed in 1.5 months and the nitrogen removal rate increased from 50 to 450 mg N L−1 d−1 in 2 months. The granules had a mean diameter of 1.8 mm and their aerobic and anoxic ammonium-oxidizing activities were well equilibrated to perform the OLAND reaction. Fluorescent in-situ hybridization (FISH) demonstrated the presence of both β-proteobacterial aerobic ammonium oxidizers and planctomycetes (among which anoxic ammonium oxidizers) in the granules. The presented results show the applicability of rapidly settling granular biomass for one-stage partial nitritation and anammox.

scholarly journals Vertical segregation among pathways mediating nitrogen loss (N<sub>2</sub> and N<sub>2</sub>O production) across the oxygen gradient in a coastal upwelling ecosystem

2017 ◽  
Vol 14 (20) ◽  
pp. 4795-4813 ◽  
Author(s):  
Alexander Galán ◽  
Bo Thamdrup ◽  
Gonzalo S. Saldías ◽  
Laura Farías
Keyword(s):  
Coastal Upwelling ◽  
Nitrite Reduction ◽  
15N Tracer ◽  
Ammonium Oxidation ◽  
N Loss ◽  
N2o Production ◽  
Coastal System ◽  
Central Chile ◽  
N Removal ◽  
Bottom Waters

Abstract. The upwelling system off central Chile (36.5° S) is seasonally subjected to oxygen (O2)-deficient waters, with a strong vertical gradient in O2 (from oxic to anoxic conditions) that spans a few metres (30–50 m interval) over the shelf. This condition inhibits and/or stimulates processes involved in nitrogen (N) removal (e.g. anammox, denitrification, and nitrification). During austral spring (September 2013) and summer (January 2014), the main pathways involved in N loss and its speciation, in the form of N2 and/or N2O, were studied using 15N-tracer incubations, inhibitor assays, and the natural abundance of nitrate isotopes along with hydrographic information. Incubations were developed using water retrieved from the oxycline (25 m depth) and bottom waters (85 m depth) over the continental shelf off Concepción, Chile. Results of 15N-labelled incubations revealed higher N removal activity during the austral summer, with denitrification as the dominant N2-producing pathway, which occurred together with anammox at all times. Interestingly, in both spring and summer maximum potential N removal rates were observed in the oxycline, where a greater availability of oxygen was observed (maximum O2 fluctuation between 270 and 40 µmol L−1) relative to the hypoxic bottom waters ( <  20 µmol O2 L−1). Different pathways were responsible for N2O produced in the oxycline and bottom waters, with ammonium oxidation and dissimilatory nitrite reduction, respectively, as the main source processes. Ammonium produced by dissimilatory nitrite reduction to ammonium (DNiRA) could sustain both anammox and nitrification rates, including the ammonium utilized for N2O production. The temporal and vertical variability of δ15N-NO3− confirms that multiple N-cycling processes are modulating the isotopic nitrate composition over the shelf off central Chile during spring and summer. N removal processes in this coastal system appear to be related to the availability and distribution of oxygen and particles, which are a source of organic matter and the fuel for the production of other electron donors (i.e. ammonium) and acceptors (i.e. nitrate and nitrite) after its remineralization. These results highlight the links between several pathways involved in N loss. They also establish that different mechanisms supported by alternative N substrates are responsible for substantial accumulation of N2O, which are frequently observed as hotspots in the oxycline and bottom waters. Considering the extreme variation in oxygen observed in several coastal upwelling systems, these findings could help to understand the ecological and biogeochemical implications due to global warming where intensification and/or expansion of the oceanic OMZs is projected.

scholarly journals Effect of Corrosive Media on the Chemical and Mechanical Resistance of IPS e.max® CAD Based Li2Si2O5 Glass-Ceramics

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 365
Author(s):  
Anna Švančárková ◽  
Dagmar Galusková ◽  
Aleksandra Ewa Nowicka ◽  
Helena Pálková ◽  
Dušan Galusek
Keyword(s):  
Wear Resistance ◽  
Acetic Acid ◽  
Prolonged Exposure ◽  
Glass Ceramics ◽  
Mechanical Resistance ◽  
Two Stage ◽  
Lithium Metasilicate ◽  
Dynamic Conditions ◽  
One Stage ◽  
Stage Process

The influence of 4% acetic acid (pH~2.4) and an alkaline solution of NaOH (pH~10) on the corrosion resistance and micromechanical properties of disilicate crystals containing glass-ceramics (LS2-GC’s) is studied. Partially crystallized lithium metasilicate crystal containing glass-ceramics (LS-GC’s) are annealed to fully LS2-GC’s using a one stage and a two-stage heating to induce nucleation. Materials with various chemical and wear resistance are prepared. The content of the crystalline phase in the material annealed in the two-stage process A is 60.0% and increases to 72.2% for the material heated in the one-stage process B. The main elements leached in the acidic medium are lithium and phosphorus, while lithium, silicon, and phosphorus leached into the alkaline environment. Material B exhibits better chemical resistance to the corrosive influence of 4% acetic acid under quasi-dynamic conditions. In the alkaline corrosion medium, silicon is leached from material A faster compared to the material B. After prolonged exposure to acidic or basic environments, both materials show evidence of surface structural changes. A decrease of the sliding wear resistance is observed after corrosion in the acidic environment under dynamic conditions. In both materials, the wear rate increases after corrosion.

Research on the Treatment of Coal Chemical Wastewater by Activated Sludge Process with Fixed Biological Media Process and Strains

2012 ◽  
Vol 610-613 ◽  
pp. 2006-2011
Author(s):  
Chun Yan Xu ◽  
Hong Jun Han
Keyword(s):  
Activated Sludge ◽  
Stenotrophomonas Maltophilia ◽  
Coal Gasification ◽  
Total Phenol ◽  
Phenol Removal ◽  
Activated Sludge Process ◽  
Biological Media ◽  
Removal Rates ◽  
Term Operation ◽  
N Removal

Full scale two-stage activated sludge process (ASP) with fixed biological media was used to treat coal gasification wastewater. The ASP has operated for more than one year and COD, total phenol and NH4-N removal effects were illuminated. COD and total phenol removal rates were around 85% and 90% during long term operation. Effluent COD and total phenol of the first stage of the ASP had an abnormal increase and turned to normal after several weeks. Nitrification of the ASP increased slowly and NH4-N removal rates achieved 80% after 15 weeks. Stenotrophomonas maltophilia K279a is isolated from coal chemical industry wastewater. The optimum conditions for PO production are phenol 1000mg/L, temperature 30-34 and pH 7-7.5. The strain resists 980mg/L COD and 805mg/L phenols. The degradation rate of phenols reaches 97% in 48h. The results show that Stenotrophomonas maltophilia K279a can be applied to the aerobic process with high proportion of phenols

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