Nitrification studies on fertilizer wastewaters in activated sludge and biofilm reactors

1995 ◽  
Vol 32 (12) ◽  
pp. 141-148 ◽  
Author(s):  
Ferhan Çeçen ◽  
Elvan Orak ◽  
Pinar Gökçin
Keyword(s):  
Dissolved Oxygen ◽  
Activated Sludge ◽  
Continuous Flow ◽  
Removal Rate ◽  
Ammonia Concentration ◽  
Biofilm Reactor ◽  
Operating Conditions ◽  
Nitrite Accumulation ◽  
Operational Conditions ◽  
Oxygen Concentrations

Nitrification characteristics of a high-strength fertilizer wastewater were studied in a batch activated sludge and a continuous-flow biofilm reactor. In a batch activated sludge system one of the most decisive factors was the pH control. The results in terms of ammonium decrease and nitrite build-up were fitted to kinetic models and it was shown that in the absence of inhibitory factors like high free ammonia or nitrous acid build-up the behaviour was similar to that in the case of low-strength wastes. Continuous-flow studies in the biofilm reactor at different loading rates and dissolved oxygen concentrations indicated that such a biofilm reactor could be employed in the treatment of highly nitrogenous fertilizer wastes. Depending on operating conditions such as dissolved oxygen concentration and loading rate an effluent ammonia concentration as low as 4 mg NH4−N/L could be achieved. In the dissolved oxygen ranges of 3.2 mg/L–3.5 mg/L the system reached the maximum removal rate of 0.17 kg NH4−N/m3.d. When the dissolved oxygen was increased to 4.9 mg/L, removal rates as high as 0.41 kg NH4−N/m3.d could be obtained. Also in continuous-flow operation nitrite accumulation reached in some cases a considerable degree depending on the bulk nitrogen and dissolved oxygen concentrations. The nitrite accumulation in the effluent stream varied from 4–180 mg NO2−N/L depending on operational conditions.

The combined effects of carbon/nitrogen ratio, suspended biomass, hydraulic retention time and dissolved oxygen on nutrient removal in a laboratory-scale anaerobic–anoxic–oxic activated sludge biofilm reactor

2017 ◽  
Vol 77 (1) ◽  
pp. 248-259 ◽  
Author(s):  
D. S. Manu ◽  
Arun Kumar Thalla
Keyword(s):  
Dissolved Oxygen ◽  
Activated Sludge ◽  
Retention Time ◽  
Nutrient Removal ◽  
Hydraulic Retention Time ◽  
Appropriate Technology ◽  
Biofilm Reactor ◽  
Operating Conditions ◽  
Biological Nutrient Removal ◽  
Suspended Biomass

Abstract The current trend in sustainable development deals mainly with environmental management. There is a need for economically affordable, advanced treatment methods for the proper treatment and management of domestic wastewater containing excess nutrients (such as nitrogen and phosphorus) which can cause eutrophication. The reduction of the excess nutrient content of wastewater by appropriate technology is of much concern to the environmentalist. In the current study, a novel integrated anaerobic–anoxic–oxic activated sludge biofilm (A2O-AS-biofilm) reactor was designed and operated to improve the biological nutrient removal by varying reactor operating conditions such as carbon to nitrogen (C/N) ratio, suspended biomass, hydraulic retention time (HRT) and dissolved oxygen (DO). Based on various trials, it was seen that the A2O-AS-biofilm reactor achieved good removal efficiencies with regard to chemical oxygen demand (95.5%), total phosphorus (93.1%), ammonia nitrogen concentration (NH4+-N) (98%) and total nitrogen (80%) when the reactor was maintained at C/N ratio of 4, suspended biomass of 3 to 3.5 g/L, HRT of 10 h, and DO of 1.5 to 2.5 mg/L. Scanning electron microscopy (SEM) of suspended and attached biofilm showed a dense structure of coccus and bacillus bacteria with the diameter ranging from 0.3 to 1.2 μm. The Fourier transform infrared (FTIR) spectroscopy results indicated phosphorylated macromolecules and carbohydrates mix or bind with extracellular proteins in exopolysaccharides.

Treatment of nitrogen and phosphorus in highly concentrated effluent in SBR and SBBR processes

2004 ◽  
Vol 50 (6) ◽  
pp. 269-276 ◽  
Author(s):  
V. Pambrun ◽  
E. Paul ◽  
M. Spérandio
Keyword(s):  
Dissolved Oxygen ◽  
Batch Reactor ◽  
Ammonium Phosphate ◽  
Ammonia Concentration ◽  
Biofilm Reactor ◽  
Phosphate Removal ◽  
Nitrite Accumulation ◽  
Nitrogen And Phosphorus ◽  
Ammonium Accumulation ◽  
High Ammonia

Various sludge treatment processes produced supernatant with high ammonia concentration from 500 to 2,000 mgN/L and generally high phosphate concentration. Conversion of ammonia into nitrite via partial nitrification has proven to be an economic way, reducing oxygen and external COD requirements during the nitrification/denitrification process. Two processes with biomass retention are studied simultaneously: the sequencing batch reactor (SBR) and the sequencing batch biofilm reactor (SBBR). At a temperature of 30°C, the inhibition of nitrite-oxidizing bacteria due to high ammonia concentration has been studied in order to obtain a stable nitrite accumulation. This work has confirmed the effect of pH and dissolved oxygen on nitrite accumulation performance. During a two month starting period, both processes led to nitrite accumulation without nitrate production when pH was maintained above 7.5. From a 500 mgN/L effluent, the performance of the SBR, and the SBBR, reached respectively about 0.95gN-NO2−/gN-NH4+, and 0.4gN-NO2−/gN-NH4+. The SBBR appears to be more stable facing disturbances in dissolved oxygen conditions. Finally, the maximal phosphate removal rates obtained in the SBR reached 90%, and 70% in the SBBR, depending on ammonium accumulation in the reactor. Ammonium phosphate precipitation is likely to occur, as was suggested by crystals observation in the reactor.

Evaluation of hybrid processes for nitrification by comparing MBBR/AS and IFAS configurations

2007 ◽  
Vol 55 (8-9) ◽  
pp. 43-49 ◽  
Author(s):  
E. Germain ◽  
L. Bancroft ◽  
A. Dawson ◽  
C. Hinrichs ◽  
L. Fricker ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Biofilm Reactor ◽  
Nitrite Accumulation ◽  
Removal Rates ◽  
Solids Retention ◽  
Different Temperatures ◽  
Suspended Biomass ◽  
The Media ◽  
Population Counts ◽  
Ammonia Oxidising Bacteria

An integrated fixed-film activated sludge (IFAS) pilot plant and a moving bed biofilm reactor coupled with an activated sludge process (MBBR/AS) were operated under different temperatures, carbon loadings and solids retention times (SRTs). These two types of hybrid systems were compared, focusing on the nitrification capacity and the nitrifiers population of the media and suspended biomass alongside other process performances such as carbonaceous and total nitrogen (TN) removal rates. At high temperatures and loadings rates, both processes were fully nitrifying and achieved similarly high carbonaceous removal rates. However, under these conditions, the IFAS configuration performed better in terms of TN removal. Lower temperatures and carbon loadings led to lower carbonaceous removal rates for the MBBR/AS configuration, whereas the IFAS configuration was not affected. However, the nitrification capacity of the IFAS process decreased significantly under these conditions and the MBBR/AS process was more robust in terms of nitrification. Ammonia oxidising bacteria (AOB) and nitrite oxidising bacteria (NOB) population counts accurately reflected the changes in nitrification capacity. However, significantly less NOBs than AOBs were observed, without noticeable nitrite accumulation, suggesting that the characterisation method used was not as sensitive for NOBs and/or that the NOBs had a higher activity than the AOBs.

Anaerobic digestion of waste activated sludge combined with ozone post-treatment and recycling

2003 ◽  
Vol 48 (4) ◽  
pp. 61-68 ◽  
Author(s):  
A. Battimelli ◽  
C. Millet ◽  
J.P. Delgenès ◽  
R. Moletta
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Removal Rate ◽  
Operating Conditions ◽  
Cod Removal ◽  
Process Efficiency ◽  
Recycling Rate ◽  
Waste Activated Sludge ◽  
Digested Sludge ◽  
Combined Process

The aim of the study was to determine the performances of a combined ozone/anaerobic digestion system for waste activated sludge reduction. The objective was the estimation of the process efficiency and stability when keeping constant influent flow while increasing recycled chemically treated flow. The ozonation step consisted in a partial oxidation (0.16 g O3/g SS) of the anaerobic mesophilic digested sludge. Chemical treatment of digested sludge resulted in a threefold COD solubilization and a decrease of SS of 22%. Some of the advantages of digested sludge ozonation were: deodorization, better settlement and a reduction in viscosity. However there were drawbacks: foaming during ozonation and, at high ozone doses, poorer filterability. The anaerobic digestion was carried out over 6 months with an increasing recycling of ozonated flow. Suspended solids removal rate and COD removal rate were compared with initial operating conditions for the biological reactor and the whole combined process. The optimum recycling rate was 25% with increases of SS removal and COD removal of 54% and 66% respectively when considering the combined process; corresponding to a decrease of the hydraulic retention time from 24 days to 19 days.

scholarly journals Influence of dissolved oxygen on nitrification kinetics in a circulating bed reactor

1998 ◽  
Vol 37 (4-5) ◽  
pp. 189-193 ◽  
Author(s):  
V. Lazarova ◽  
R. Nogueira ◽  
J. Manem ◽  
L. Melo
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
Municipal Wastewater ◽  
Ammonia Concentration ◽  
Pilot Scale ◽  
Biofilm Reactor ◽  
Laboratory Scale ◽  
Nitrification Rate ◽  
Nitrification Kinetics ◽  
Laboratory Scale Reactor

The influence of dissolved oxygen concentration in nitrification kinetics was studied in a new biofilm reactor, the circulating bed reactor (CBR). The study was carried out partly at laboratory scale with synthetic water containing inorganic carbon and nitrogen compounds, and partly at pilot scale for secondary and tertiary nitrification of municipal wastewater. The experimental results showed that either the ammonia or the oxygen concentration could be limiting for the nitrification rate. The transition from ammonia to oxygen limiting conditions occurred for an oxygen to ammonia concentration ratio of about 1.5 - 2 gO2/gN-NH4+ for both laboratory- and pilot-scale reactors. The nitrification kinetics of the laboratory-scale reactor was close to a half order function of the oxygen concentration, when oxygen was the rate limiting substrate.

Exploration of rapid start-up of the CANON process from activated sludge inoculum in a sequencing biofilm batch reactor (SBBR)

2015 ◽  
Vol 73 (3) ◽  
pp. 535-542 ◽  
Author(s):  
Yangfan Deng ◽  
Xiaoling Zhang ◽  
Ying Miao ◽  
Bo Hu
Keyword(s):  
Nitrogen Removal ◽  
Dna Analysis ◽  
Removal Rate ◽  
Batch Reactor ◽  
Ammonia Concentration ◽  
Nitrite Accumulation ◽  
Start Up ◽  
Fast Start ◽  
Total Nitrogen Removal ◽  
Canon Process

In this study, a laboratory-scale sequencing biofilm batch reactor (SBBR) was employed to explore a fast start-up of completely autotrophic nitrogen removal over nitrite (CANON) process. Partial nitrification was achieved by controlling free ammonia concentration and operating at above 30 °C; then the reactor was immediately operated with alternating periods of aerobiosis and anaerobiosis to start the anammox process. The CANON process was successfully achieved in less than 50 d, and the total-nitrogen removal efficiency and the nitrogen removal rate were 81% and 0.14 kg-N m−3 d−1 respectively. Afterwards, with the increasing of ammonium loading rate a maximum nitrogen removal rate of 0.39 kg-N m−3 d−1 was achieved on day 94. DNA analysis showed that ‘Candidatus Brocadia’ was the dominant anammox species and Nitrosomonas was the dominant aerobic ammonium-oxidizing bacteria in the CANON reactor. This study revealed that due to shortening the persistent and stable nitrite accumulation period the long start-up time of the CANON process can be significantly reduced.

Understanding the contribution of biofilm in an integrated fixed-film-activated sludge system (IFAS) designed for nitrogen removal

2015 ◽  
Vol 71 (10) ◽  
pp. 1500-1506 ◽  
Author(s):  
P. Moretti ◽  
J. M. Choubert ◽  
J. P. Canler ◽  
O. Petrimaux ◽  
P. Buffiere ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Loading Rate ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Biofilm Growth ◽  
Operational Conditions ◽  
Solids Concentration ◽  
Fixed Film ◽  
Autotrophic Biomass

The objective of this study is to improve knowledge on the integrated fixed-film-activated sludge (IFAS) system designed for nitrogen removal. Biofilm growth and its contribution to nitrification were monitored under various operating conditions in a semi-industrial pilot-scale plant. Nitrification rates were observed in biofilms developed on free-floating media and in activated sludge operated under a low sludge retention time (4 days) and at an ammonia loading rate of 45–70 gNH4-N/kgMLVSS/d. Operational conditions, i.e. oxygen concentration, redox potential, suspended solids concentration, ammonium and nitrates, were monitored continuously in the reactors. High removal efficiencies were observed for carbon and ammonium at high-loading rate. The contribution of biofilm to nitrification was determined as 40–70% of total NOx-N production under the operating conditions tested. Optimal conditions to optimize process compacity were determined. The tested configuration responds especially well to winter and summer nitrification conditions. These results help provide a deeper understanding of how autotrophic biomass evolves through environmental and operational conditions in IFAS systems.

scholarly journals Inorganic carbon removal from refinery wastewater by using TiO2/ZnO/Fenton photocatalyst

2018 ◽  
Vol 20 (2) ◽  
pp. 216-225
Keyword(s):  
Inorganic Carbon ◽  
Treatment Time ◽  
Removal Rate ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Refinery Wastewater ◽  
Operational Conditions ◽  
Operating Variables ◽  
Solar Photocatalyst ◽  
Quadratic Models

The aim of this study is to investigate the performance of the solar photocatalyst of TiO2/ZnO/Fenton process to treat the refinery wastewater and remove inorganic carbon (IC) which potentially toxic to human, aquatic and microorganism life. Central composite design with response surface methodology was used to evaluate the relationships between operating variables for TiO2 dosage, ZnO dosage, Fe2+ dosage, H2O2 dosage, and pH to identify the optimum operating conditions. Quadratic models for inorganic carbon (IC) removal and residual iron prove to be significant with low probabilities (<0.0001). The (IC) removal rates and residual iron correspond well with the predicted models. The maximum removal rate for IC and residual iron was 92.3% and 0.013, respectively at optimum operational conditions of a TiO2 dosage (0.3 g/l), ZnO dosage (0.58 g/l), Fe2+ dosage (0.02 g/l), H2O2 dosage (2.7 g/l), and pH (7). The treatment process achieved higher degradation efficiencies for IC and reduced the treatment time comparing with other related processes.

scholarly journals ComammoxNitrospiraare the dominant ammonia oxidizers in a mainstream low dissolved oxygen nitrification reactor

2018 ◽  
Author(s):  
Paul Roots ◽  
Yubo Wang ◽  
Alex F. Rosenthal ◽  
James S. Griffin ◽  
Fabrizio Sabba ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Activated Sludge ◽  
Removal Rate ◽  
Ammonia Removal ◽  
Biological Nutrient Removal ◽  
Ammonia Oxidizing Bacteria ◽  
Ammonia Oxidizers ◽  
Total Abundance ◽  
Low Dissolved Oxygen ◽  
Activated Sludge Processes

AbstractRecent findings show that a subset of bacteria affiliated withNitrospira, a genus known for its importance in nitrite oxidation for biological nutrient removal applications, are capable ofcompleteammoniaoxidation (comammox) to nitrate. Early reports suggested that they were absent or present in low abundance in most activated sludge processes, and thus likely functionally irrelevant. Here we show the accumulation of comammoxNitrospirain a nitrifying sequencing batch reactor operated at low dissolved oxygen (DO) concentrations. Actual mainstream wastewater was used as influent after primary settling and an upstream pre-treatment process for carbon and phosphorus removal. The ammonia removal rate was stable and exceeded that of the treatment plant’s parallel full-scale high DO nitrifying activated sludge reactor. 16S rRNA sequencing showed a steady accumulation ofNitrospirato 53% total abundance and a decline in conventional ammonia oxidizing bacteria to <1% total abundance over 400+ days of operation. After ruling out other known ammonia oxidizers, qPCR confirmed the accumulation of comammoxNitrospirabeginning around day 200, to eventually comprise 94% of all detectedamoAand 4% of total bacteria by day 407. Quantitative fluorescence in-situ hybridization confirmed the increasing trend and high relative abundance ofNitrospira. These results demonstrate that comammox can be metabolically relevant to nitrogen transformation in wastewater treatment, and can even dominate the ammonia oxidizing community. Our results suggest that comammox may be an important functional group in energy efficient nitrification systems designed to operate at low DO levels.

Treatment of Tannery Wastewater and Moving-Bed Biofilm Reactor

2020 ◽  
Vol 17 ◽  
Author(s):  
Henrique Rech ◽  
Caroline Agustini ◽  
Mariliz Gutterres
Keyword(s):  
Activated Sludge ◽  
Surface Area ◽  
Biofilm Reactor ◽  
Operating Conditions ◽  
Tannery Wastewater ◽  
Organic Load ◽  
Moving Bed Biofilm Reactor ◽  
Leather Industry ◽  
Filling Fraction ◽  
Moving Bed

Abstract:: The leather industry is a fundamental sector, especially in countries with highly developed livestock as they use rawhide to produce high-value leather products. The leather-making process uses different chemicals and is a source of environmental pollution if the wastewater is not properly treated. Therefore, the purpose of this study is to analyze a Moving- Bed Biofilm Reactor (MBBR) as a new technology for the biological treatment of tannery wastewater. This system incorporates benefits provided by suspended growth systems, which are already consolidated in treating wastewater, including activated sludge and the advantage of growth adhered to biocarriers that have a large surface area. Therefore, incorporating activated sludge into MBBR enables the removal of both organic and nitrogen pollutants. Studies have shown that MBBR treatment efficiency depends on biocarrier surface area, composition, texture, and reactor operating conditions, such as filling fraction, hydraulic retention time, dissolved oxygen, and volumetric organic load.

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