Pre-ozonation in the activated sludge process: fate of nitrogen species

2011 ◽  
Vol 63 (11) ◽  
pp. 2513-2519 ◽  
Author(s):  
J. H. Garcia-Orozco ◽  
A. Vargas-Martinez ◽  
M. A. Ayala-Arnez
Keyword(s):  
Activated Sludge ◽  
Organic Nitrogen ◽  
Oxygen Demand ◽  
Dry Weight ◽  
Nitrification Rate ◽  
Yield Coefficient ◽  
Base System ◽  
Nitrogen Species ◽  
Activated Sludge Reactor ◽  
Fate Of Nitrogen

The objective of this research was to include ozonation prior to an activated sludge treatment and investigate the effect on the nitrogen species, their fate and the consequences of this oxidation upon the biomass. Three parallel treatment systems were used: the base system, where feed went directly to the activated sludge reactor, and two others, where the influent was ozonated at two different dosages, 15 and 25 mg/L of influent, prior to the biological reactors. The results from the ozonation chamber show a high oxidation capacity of the entering ammonia and organic nitrogen, proportional to the ozone dose. The oxidation product was nitrate. No de-nitrification was expected because a high oxygen concentration (4 mg/L) was maintained in the reactors. The reactors receiving ozonated influent showed a lower assimilation of nitrogen by the biomass. The sludge nitrogen content resulted in 11, 9.3 and 7.4% dry-weight corresponding to no-ozone, low ozone and high ozone dosages, respectively. In spite of the lower ammonia available in the ozonated flows, the corresponding reactors showed a higher specific nitrification rate. The ozonated system also performed better in terms of chemical oxygen demand (COD) and biochemical oxygen demand (BOD5) removals, besides showing a higher true biomass yield coefficient.

Application of excess activated sludge ozonation in an SBR Plant. Effects on substrate fractioning and solids production

2008 ◽  
Vol 58 (1) ◽  
pp. 239-245 ◽  
Author(s):  
M. Naso ◽  
A. Chiavola ◽  
E. Rolle
Keyword(s):  
Activated Sludge ◽  
Organic Nitrogen ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Batch Tests ◽  
Plant Effects ◽  
Removal Processes ◽  
Biological Nitrogen ◽  
Ozonation Process

This paper provides new insights on the application of the ozonation process for the reduction of the activated sludge production in a sequencing batch reactor (SBR). The study was performed in two identical lab-scale SBRs plant, one for experimental activities (Exp SBR) and one used as control (Control SBR), both fed with domestic sewage. A fraction of the activated sludge collected from the Exp SBR at the end of the aerobic react phase was periodically subjected to ozonation for 30 minutes at three different specific dosages (0.05, 0.07 and 0.37 g O3/gSS) and then recirculated before the beginning of the following cycle. Recirculation of the ozonated sludge to the Exp SBR did not appreciably affect the efficiency of the biological nitrogen and carbon removal processes. Nonetheless, an improvement of the denitrification kinetic was observed. Mixed liquor volatile and suspended solids (MLSS and MLVSS, respectively) concentrations in the reactor decreased significantly with time for long term application of the ozonation treatment. Kinetic batch tests on unstressed sludge taken from Control SBR indicated that the different oxidant dosages (0.05, 0.07 and 0.37 g O3/gSS) and durations of the ozonation process (10, 20 and 30 minutes) used remarkably affected chemical oxygen demand (COD) and organic nitrogen fractioning. In particular, soluble and biodegradable fractions seemed to be higher at lower dosage and longer contact time.

Application of cigarette filter rods as biofilm carrier in an integrated fixed-film activated sludge reactor

2013 ◽  
Vol 67 (8) ◽  
pp. 1793-1801 ◽  
Author(s):  
Ahmad Sabzali ◽  
Mahnaz Nikaeen ◽  
Bijan Bina
Keyword(s):  
Activated Sludge ◽  
Loading Rate ◽  
Oxygen Demand ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Cigarette Filter ◽  
Biofilm Reactors ◽  
Biofilm Carrier ◽  
Fixed Film ◽  
Activated Sludge Reactor

Bio-carriers are an important component of integrated fixed-film activated sludge (IFAS) processes. In this study, the capability of cigarette filter rods (CFRs) as a bio-carrier in IFAS processes was evaluated. Two similar laboratory-scale IFAS systems were operated over a 4-month period using Kaldnes-K3 and CFRs as IFAS media. The process performance was studied by using chemical oxygen demand (COD). The organic loading rate was in the range 0.5–2.8 kgCOD/(m3·d). The COD average removal efficiencies were 89.3 and 93.9% for Kaldnes-K3 (reactor A) and cigarette filters (reactor B), respectively. The results demonstrate that the performance of the IFAS reactor containing CFRs was comparable to the reactor using Kaldnes. The CFRs, which have a high porous surface area and entrapment ability for microbial cells, could be successfully used in biofilm reactors as a bio-carrier.

Effect of chemical oxygen demand load on the nitrification and microbial communities in activated sludge from an aerobic nitrifying reactor

2020 ◽  
Vol 66 (1) ◽  
pp. 59-70
Author(s):  
Dan Li ◽  
Xihong Liang ◽  
Zhengwei Li ◽  
Yao Jin ◽  
Rongqing Zhou ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Chemical Oxygen Demand ◽  
Microbial Communities ◽  
High Throughput Sequencing ◽  
Oxygen Demand ◽  
Nitrification Rate ◽  
Culture Time ◽  
Degradation Rates ◽  
Significant Difference ◽  
Over Time

In this study, we explored the effect of chemical oxygen demand (COD) load on the nitrification and microbial communities in activated sludge isolated from an aerobic nitrifying tank. The activated sludge was cultured in three different COD groups: L-COD, 200 mg/L; M-COD, 1200 mg/L; H-COD, 4200 mg/L. The results indicated that the COD exerts a negligible effect on the nitrogen removal ability within the first 24 h. However, the nitrification rate decreased with culture time; the ammonium degradation rates were found to be 80.26%, 57.56%, and 43.43% at 72 h in the three COD groups, respectively. These values correspond to decreases of 19.40%, 41.83%, and 51.48%, respectively, in relation to those observed at 24 h. The activated sludge in the different COD groups exhibited similar community compositions after 24 h, as assessed by Illumina high-throughput sequencing, while a significant difference in the relative abundances of some organisms occurred after 48 and 72 h. Proteobacteria was the main phylum, with a relative abundance of >51.45%. The genera Aridibacter, Paracoccus, Nitrospira, and Nitrosomonas were suppressed by COD load over time. This study may contribute to our knowledge about the nitrification ability and microbial communities in activated sludge at different COD load levels.

Grease biodegradation: is bioaugmentation more effective than natural populations for start-up?

1996 ◽  
Vol 34 (5-6) ◽  
pp. 303-308 ◽  
Author(s):  
Leopoldo Mendoza-Espinosa ◽  
Tom Stephenson
Keyword(s):  
Activated Sludge ◽  
Natural Populations ◽  
Oxygen Demand ◽  
Cod Removal ◽  
Batch Reactors ◽  
Optimum Conditions ◽  
Start Up ◽  
Degradation Rates ◽  
Activated Sludge Reactor ◽  
Micro Organisms

Investigations were undertaken in order to compare the grease degradation rates for a natural population of acclimatised activated sludge micro-organisms with a commercial bioaugmentation product (bioadditive) under optimum conditions in laboratory-scale batch reactors. Lard was chosen as the source of grease because it contains the fatty acids more commonly found in urban wastewaters. During acclimatisation, the bioadditive reactor achieved a slightly better chemical oxygen demand (COD) removal efficiency than the activated sludge reactor. Therefore, under optimum conditions, activated sludge was able to degrade grease at nearly the same rate as a bioadditive solution. Moreover, the bioadditive and the activated sludge reactors had very similar kinetics of COD removal under different grease concentrations. It was concluded that the use of natural activated sludge micro-organisms was sufficient to acclimatise biological processes to removing grease.

Nutrient balancing for enhanced activated sludge reactor performance: UK perspective

2000 ◽  
Vol 41 (12) ◽  
pp. 223-231 ◽  
Author(s):  
J. E. Burgess ◽  
J. Harkness ◽  
P. J. Longhurst ◽  
T. Stephenson
Keyword(s):  
Activated Sludge ◽  
Industrial Wastewater ◽  
Pantothenic Acid ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Toxicity Tests ◽  
Reactor Performance ◽  
Positive Effects ◽  
Activated Sludge Reactor ◽  
Nutrient Balancing

Trace metals (K, Fe, Mg, Cu, Ca, Mn, Al, Zn, Mo, Co) and vitamins (biotin, niacin, pyridoxine, lactoflavin, thiamine, pantothenic acid) were tested for enhancing chemical oxygen demand (COD) and toxicity removal in activated sludge treating trade effluent. Rapid respirometry screening indicated that micronutrient addition could not ameliorate macronutrient deficiencies, but could significantly improve the degradation of hard COD in the wastewater (up to 4.24 kg COD/kg MLSS/d, i.e. 320% of the control) with no significant effect on the air requirement of the sludge. Several positive effects led to the conclusion that micronutrients have the potential to optimise the process performance of activated sludge plants treating industrial wastewater. Porous pots were used to further trial eight of the micronutrients. The retention of biomass in the pots was increased in all cases. Improvements in the degradation of COD (up to 260% of the control) were observed while biological oxygen demand (BOD) degradation was not affected. This implied the use of recalcitrant substrate components as a food source. Toxicity tests showed that the effluents from the experimental porous pots were less toxic than the control effluents. The effects of niacin addition in activated sludge treatment of industrial waste at pilot-scale were: improved sludge handling, increased COD, ammonia, suspended solids and phosphorus removal. Several industrialists saw micronutrient addition as a route to successful adaptation of processes to accommodate toxicity– based legislation.

Validating the Colloid model to optimise the design and operation of both moving-bed biofilm reactor and integrated fixed-film activated sludge systems

2014 ◽  
Vol 69 (7) ◽  
pp. 1552-1557 ◽  
Author(s):  
J. Albizuri ◽  
P. Grau ◽  
M. Christensson ◽  
L. Larrea
Keyword(s):  
Activated Sludge ◽  
Oxygen Demand ◽  
Biofilm Reactor ◽  
Nitrification Rate ◽  
Moving Bed Biofilm Reactor ◽  
Moving Bed ◽  
Fixed Film ◽  
Solids Retention ◽  
Lower Effect ◽  
Activated Sludge Systems

The paper presents a systematic study of simulations, using a previously calibrated Colloid model, from which it was found that: (i) for pure moving-bed biofilm reactor (MBBR) processes with tertiary nitrification conditions (no influent chemical oxygen demand (COD)), dissolved oxygen = 5 mg/L and residual NH4-N > 4 mgN/L, a nitrification rate of 1.2 gN/(m2d) was obtained at 10 °C. This rate decreases sharply when residual NH4-N is lower than 2 mgN/L, (ii) for MBBR systems with predenitrification–nitrification zones and COD in the influent (soluble and particulate), the nitrification rate (0.6 gN/(m2d)) is half of that in tertiary nitrification due to the effect of influent colloidal XS (particulate slowly biodegradable COD) and (iii) for integrated fixed-film activated sludge (IFAS) processes the nitrification rate in the biofilm (0.72 gN/(m2d)) is 20% higher than for the pure MBBR due to the lower effect of influent XS since it is adsorbed onto flocs. However, it is still 40% lower than the tertiary nitrification rate. In the IFAS, the fraction of the nitrification rate in suspension ranges from 10 to 70% when the aerobic solids retention time varies from 1.4 to 6 days.

Evaluation of aerobic and anaerobic treatment of Kraft pulp mill effluent for organochlorines removal

2006 ◽  
Vol 1 (3) ◽  
Author(s):  
A. P. Buzzini ◽  
M. A. Nolasco ◽  
A. M. Springer ◽  
E. C. Pires
Keyword(s):  
Activated Sludge ◽  
Black Liquor ◽  
Oxygen Demand ◽  
Pulp Mill ◽  
Anaerobic Treatment ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Individual Values ◽  
Activated Sludge Reactor

The purposes of the experiments described in this paper were to evaluate the performance of an upflow anaerobic sludge blanket (UASB) activated sludge reactor, both bench scale reactors, in the treatment of wastewaters containing organochlorines compounds, which simulate a kraft plant wastewater. Both reactors received a wastewater prepared with diluted black liquor and a mixture of organochlorines: 2 Chlorophenol (2 CP); 2,4 Dichlorophenol (2,4 DCP); 2,6 Dichlorophenol (2,6 DCP); 2,4,6 Trichlorophenol (2,4,6 TCP); and Tetrachlorocatechol (TeCC). The activated sludge reactor also received 4, 5, 6 Trichloroguaiacol (4, 5, 6 TCG). The chemical oxygen demand (COD) and organochlorine concentrations in the effluent indicated that the two systems displayed a similar performance in terms of COD removal, with average efficiencies of 79% for the UASB reactor and of 77% for the activated sludge reactor. The average individual values for organochlorine removal efficiency, the first figure representing the UASB reactor removal, were: 99.9% and 91% for the 2 CP; 97% and 80% for the 2,4 DCP; 94% and 80% for the 2,6 DCP; 99% and 75% for the 2,4,6 TCP; and 93% and 90% for the TeCC. Both systems showed to be capable of treating pulp plant wastewaters containing chlorophenols, with a certain advantage for the anaerobic system from the standpoint of removal efficiencies.

Extended Aeration Activated Sludge Reactor (EAASR) for Removal of Nitrobenzene: Air Stripped or Biologically Removed?

2016 ◽  
Vol 14 (1) ◽  
pp. 453-461 ◽  
Author(s):  
Olcayto Keskinkan ◽  
Alev Çakır ◽  
Ayşe Erkuş ◽  
Turan Yılmaz ◽  
Çağatayhan Bekir Ersu
Keyword(s):  
Activated Sludge ◽  
Oxygen Demand ◽  
Bacterial Degradation ◽  
Synthetic Wastewater ◽  
Organic Chemical ◽  
Removal Mechanism ◽  
Air Stripping ◽  
Free Swimming ◽  
Kinetic Evaluation ◽  
Activated Sludge Reactor

AbstractIn this study, the performance of an extended aeration activated sludge reactor (EAASR) was investigated for the removal of nitrobenzene (NB), a commonly used organic chemical in various industries. In a set of experiments, increasing NB concentrations between 1 and 800 mg/L were applied to the EAASR. Synthetic wastewater containing NB was successfully treated up to 92.0 and 100.0% in terms of chemical oxygen demand (COD) and NB removal. The major NB removal mechanism in this EAASR was assessed to be air stripping after kinetic evaluation as compared to somewhat limited bacterial degradation of NB. Although NB is known to be toxic, the removal efficiency of NB was never below 97.4% even at high NB concentrations. Under lower NB concentrations, it was found that the bacterial floc formation was intact with existing Ciliata and Rotifera. However, at higher NB concentrations, free swimming Ciliata and Rotifera specimens disappeared while the flocs became smaller and dispersed.

Process evaluation of HASP with IMET system through SNR and SDNR for the efficient management of Sewage Treatment Plant

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Young H. Yoon ◽  
Jae R. Park ◽  
Sang W. Ahn ◽  
Kwang B. Ko ◽  
Kyung J. Min ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Linear Regression Analysis ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Reaction Rates ◽  
Nitrification Rate ◽  
Activated Sludge Process ◽  
Type Experiment ◽  
Batch Type ◽  
Nitrification And Denitrification

Hybrid Activated Sludge Process (HASP) with IMET was developed and applied to an activated sludge process for the advanced nutrient treatment in Korea. The characteristics of nitrogen removal from the HASP were investigated through a kinetic study by batch-type experiment. Online DB analysis produced from the IMET was conducted for the nutrient removal performance in the field demonstration plant treating 10,000 m3/day in G city of Korea. In this paper, we aimed to determine the effect of increasing NHM4+-N load on the specific nitrification rate (SNR) and the specific denitrification rate (SDNR) through a batch-type experiment, and to estimate the net reaction time for the phase-transfer rate using online DB analysis in the HASP operation. Experimental results include: (1) both the nitrification and denitrification followed first-order kinetics; (2) the maximum SNR and SDNR were 4.0301 mgN/gVSS·hr and 2.785 mgN/gVSS·hr, respectively; (3) comparison of reaction rates between nitrification and denitrification from the non-linear regression analysis found that nitrification rate was higher than denitrification.

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