Treatment of septage using single and two stage activated sludge batch reactors systems

1995 ◽  
Vol 32 (9-10) ◽  
pp. 95-104 ◽  
Author(s):  
A. D. Andreadakis ◽  
G. Kondili ◽  
D. Mamais ◽  
A. Noussi
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Removal Rate ◽  
Substantial Reduction ◽  
Subsequent Treatment ◽  
Batch Reactors ◽  
Two Stage ◽  
Second Stage ◽  
Nitrogen Concentrations ◽  
Stage System

The cyclic or sequencing batch activated sludge process was applied for the treatment of septage originating from cesspools serving non-sewered areas. Single and two stage systems were investigated in bench scale units. The single stage aerated system was capable in removing practically all the biodegradable COD and producing a well stabilised excess sludge with excellent settling and thickening characteristics. With respect to nitrogen the average removal rate was to the order of 70%, but the performance was unstable due to periodic strong inhibition of the nitrification process. Subsequent treatment in a second stage aerated unit improved nitrification but did not result in higher nitrogen removal rates due to the increased concentrations of oxidised nitrogen. An anoxic second stage post denitrification unit resulted in an overall nitrogen removal of 88%, through a substantial reduction of nitrates. Further improvement of the system, with nitrogen removal of about 95% and average effluent nitrogen concentrations lower than 10 mg.1−1, can be achieved by adoption of a two stage system consisting of a first aerated stage unit, followed by a second stage unit with alternating aerated and anoxic cycles and addition of external carbon during the anoxic cycle.

Comparative studies on differently arranged activated sludge systems

1994 ◽  
Vol 30 (11) ◽  
pp. 263-269
Author(s):  
A. Jobbágy ◽  
C. P. L. Grady ◽  
G. Morsányi ◽  
L. Nyeste ◽  
J. Simon
Keyword(s):  
Activated Sludge ◽  
Great Influence ◽  
Treatment Plant ◽  
Cost Effective ◽  
Synthetic Wastewater ◽  
Two Stage ◽  
Second Stage ◽  
In Series ◽  
Stage System ◽  
Flow Through

Rearrangement of existing treatment facilities for optimum bioreactor configuration offers a cost-effective upgrading possibility. Model experiments were performed to determine how the configuration of bioreactors of a given total volume can influence system performance, with the goal of influencing planned modifications of activated sludge plants in Hungary. In the first experiment, two bioreactors arranged in series were compared to two in parallel. In the second experiment, a two-stage system with sludge recycle around each stage was compared to a single-sludge selector system. In the last experiment, three types of selectors (two anoxic and one aerobic) were evaluated for addition to a conventional, flow-through activated sludge system. The experiments were performed with dairy-type synthetic wastewater and with effluent from the primary clarifier of an existing municipal treatment plant. Reactor arrangement had a great influence on the effectiveness of the treatment, primarily by inducing significantly different sludge structures. The in-series reactor arrangement proved to be, in every respect (effluent COD, residual detergent, and sludge characteristics), more efficient than the parallel arrangement. The two-stage system produced more sludge than the selector system, and the SVI values of the second stage of the two-stage system were extremely unfavorable. However, the effluent from the second stage was significantly clearer. Separating the selector from the flow-through reactor improved the sludge settling considerably. This facilitated an increased hydraulic load in the secondary clarifier and thereby in the whole treatment system.

scholarly journals Upflow packed bed Anammox reactor used in two-stage deammonification of sludge digester effluent

2018 ◽  
Vol 78 (9) ◽  
pp. 1843-1851 ◽  
Author(s):  
İ. Çelen-Erdem ◽  
E. S. Kurt ◽  
B. Bozçelik ◽  
B. Çallı
Keyword(s):  
Removal Efficiency ◽  
Nitrogen Removal ◽  
Municipal Wastewater ◽  
Removal Rate ◽  
Treatment Plant ◽  
Packed Bed ◽  
Municipal Wastewater Treatment ◽  
Two Stage ◽  
N Removal ◽  
Total Nitrogen Removal

Abstract The sludge digester effluent taken from a full scale municipal wastewater treatment plant (WWTP) in Istanbul, Turkey, was successfully deammonified using a laboratory scale two-stage partial nitritation (PN)/Anammox (A) process and a maximum nitrogen removal rate of 1.02 kg N/m3/d was achieved. In the PN reactor, 56.8 ± 4% of the influent NH4-N was oxidized to NO2-N and the effluent nitrate concentration was kept below 1 mg/L with 0.5–0.7 mg/L of dissolved oxygen and pH of 7.12 ± 12 at 24 ± 4°C. The effluent of the PN reactor was fed to an upflow packed bed Anammox reactor where high removal efficiency was achieved with NO2-N:NH4-N and NO3-N:NH4-N ratios of 1.32 ± 0.19:1 and 0.22 ± 0.10:1, respectively. The results show that NH4-N removal efficiency up to 98.7 ± 2.4% and total nitrogen removal of 87.7 ± 6.5% were achieved.

Assessment of Inocula and N-Removal Performance of Anaerobic Ammonium Oxidation (ANAMMOX) for the Treatment of Aged Landfill Leachates

2012 ◽  
Vol 518-523 ◽  
pp. 2391-2398
Author(s):  
Yan He ◽  
Gong Ming Zhou ◽  
Min Sheng Huang ◽  
Min Tong
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Removal Rate ◽  
Granular Sludge ◽  
Nitrogen Loading ◽  
Anaerobic Granular Sludge ◽  
Landfill Leachates ◽  
N Removal ◽  
Start Up ◽  
Anammox Process

Three kinds of seeding sludge, i.e. conventional activated sludge, anaerobic granular sludge and the nitrifying activated sludge from the nitritation reactor treating aged leachates were evaluated in batch mode to screen the optimized inoculum for the rapid start-up of ANAMMOX reactor. The feasibility of the ANAMMOX process for the treatment of aged leachates was also investigated in a modified upflow anaerobic sludge blanket (UASB, 0.05m3). The batch experiments revealed that the nitrifying activated sludge from the nitritation reactor could respectively achieve the NRR (nitrogen removal rate) of 0.0365 kg N/(m3.d) and the ARR (ammonium removal rate) of 0.013 kg N/(m3.d) on day 12, which were greatly higher than those of the other two tested sludge samples. The mixture of the aforementioned nitrifying activated sludge and anaerobic granular sludge was established as an effective inoculum for the prompt start-up of ANAMMOX reactor. The maximum total nitrogen removal rate of 0.826 kg N/(m3.d) could be obtained for the treatment of “old” leachates under NLR (nitrogen loading rate) of 1.028 kg N/(m3.d). It is concluded that the N-removal performance of ANAMMOX process is still to be improved for actual engineering application to aged landfill leachates.

scholarly journals Impact of Protozoan Grazing on Nitrification and the Ammonia-And-Nitrite-Oxidizing Bacterial Communities in Activated Sludge

2021 ◽  
Author(s):  
Amy Jean Pogue
Keyword(s):  
Activated Sludge ◽  
Ammonia Oxidation ◽  
Heterotrophic Bacteria ◽  
Grazing Pressure ◽  
Batch Reactors ◽  
Protozoan Grazing ◽  
Nitrite Oxidizing Bacteria ◽  
Nitrogen Concentrations ◽  
Nitrite Nitrate

The effect of protozoan grazing on nitrification rates under different conditions was examined. The spatial distribution of ammonia -and nitrite- oxidizing bacteria (AOB and NOB) in activated sludge was also examined using FISH/CSLM. Batch reactors were monitored for ammonia, nitrite, nitrate, and total nitrogen concentrations and bacterial numbers in the presence and absence of cycloheximide, a protozoan inhibitor. In the absence of protozoan grazing, rates of nitrification were lower than in batches with protozoa. Spatially, both AOB and NOB were found clustered within the floc and neither inhibiting the protozoa or inhibiting ammonia oxidation appeared to lower the amount of AOB and NOB present or their position. These results suggest that a reduction in protozoan grazing pressure allowed the heterotrophic bacteria to proliferate which caused a corresponding decrease in the rate of nitrification. These results suggest that AOB and NOB are less active in the absence of protozoa and indicates the role of protozoa in the cycling of nitrogen.

Temperature-phased anaerobic digestion of wastewater sludges

1997 ◽  
Vol 36 (6-7) ◽  
pp. 367-374 ◽  
Author(s):  
Yue Han ◽  
Shihwu Sung ◽  
Richard R. Dague
Keyword(s):  
Activated Sludge ◽  
Biogas Production ◽  
Single Stage ◽  
Fecal Coliforms ◽  
Waste Activated Sludge ◽  
State University ◽  
Iowa State University ◽  
Second Stage ◽  
Volatile Solids ◽  
Stage System

The temperature-phased anaerobic bioreactor (TPAB) has been under study by Dague and co-workers at Iowa State University. The temperature-phased approach involves a two-stage reactor system with the first stage operated at a thermophilic temperature (commonly 55°C) and the second stage operated at a mesophilic temperature (commonly 35°C). The purpose of laboratory study was to compare the performance of the temperature-phased system with the conventional single-stage mesophilic system for treating mixtures of primary and waste activated sludge. Of particular interest in the research was a comparison of the two systems from the standpoint of coliform reduction, volatile solids (VS) destruction, and biogas production. The temperature-phased system achieved complete destruction of total and fecal coliforms over a range of SRTs from 11 to 28 days. The concentration of fecal coliforms in the effluent from the temperature-phased system never exceeded 1000 MPN/g total solids (TS), which can meet the U.S. Code of Federal Regulations, Title 40 (40 CFR), Part 503 coliform requirements for Class A sludge. At the optimal SRTs ranging from 11 to 17 days, the capacity of VS removal of temperature-phased system was more than double that of the conventional single-stage system. The foaming problem associated with the digestion of waste activated sludge was eliminated.

scholarly journals Microbial community similarity and dissimilarity inside and across full-scale activated sludge processes for simultaneous nitrification and denitrification

2020 ◽  
Vol 81 (2) ◽  
pp. 333-344
Author(s):  
Jianfeng Wen ◽  
Mark W. LeChevallier ◽  
Wendong Tao
Keyword(s):  
Microbial Community ◽  
Dissolved Oxygen ◽  
Activated Sludge ◽  
Relative Abundance ◽  
Nitrogen Removal ◽  
Full Scale ◽  
Batch Reactors ◽  
Simultaneous Nitrification And Denitrification ◽  
Sequencing Batch Reactors ◽  
Mixed Liquor

Abstract Simultaneous nitrification and denitrification under low dissolved oxygen conditions is an energy-saving modification of the activated sludge process to achieve efficient nitrogen removal. Geographically distinct full-scale treatment plants are excellent platforms to address the links of microbial community with operating parameters. Mixed liquor samples were collected from a sequencing batch reactor plant, oxidation ditch plant, and step-feed activated sludge plant. Next-Generation Sequencing of the samples showed that the microbial communities were similar at the phylum level among the plants, being dominated by Proteobacteria. Microbial composition of functional groups was similar between the react fill and react phases of the sequencing batch reactors, among four sequencing batch reactors, and among four oxidation ditches. Nitrospira was the only identified genus of autotropic nitrifying bacteria with a relative abundance of 2.2–2.5% in the oxidation ditches and 0.4–0.7% at the other plants. Heterotrophic nitrifying–aerobic denitrifying bacteria were dominated by Dechloromonas with a relative abundance of 0.4–1.0%. Microbial community composition and nitrogen removal mechanisms were related to overall level and local zonation of dissolved oxygen, mixed liquor suspended solids concentration, nitrogen and organic loadings, and solids retention time. Low dissolved oxygen and low organic and nitrogen loadings favored growth of Nitrospira.

Sewage-treatment under substantial load variations in winter tourism areas – a full case study

2004 ◽  
Vol 50 (7) ◽  
pp. 147-155 ◽  
Author(s):  
S. Winkler ◽  
N. Natsché ◽  
T. Gamperer ◽  
M. Dum
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Nutrient Removal ◽  
Sewage Treatment ◽  
Activated Sludge Process ◽  
Two Stage ◽  
Winter Tourism ◽  
Load Variations ◽  
Sudden Load

The sewage-load variations in winter tourism areas are characterized by sudden increases - in the ange of a factor two to three - within only a few days at the start and the end of the tourist season, especially at Christmas. The sudden load increases occur during periods of low wastewater temperatures, which is an additional demanding factor with respect to nitrogen removal. A full case study was carried out at WWTP Saalfelden, which is located near one of Austria's largest skiing resorts. The plant is designed for 80,000 PE and built according to the HYBRID®-concept, which is a special two stage activated sludge process for extensive nutrient removal.

Aerated denitrification in full-scale activated sludge facilities

1997 ◽  
Vol 35 (10) ◽  
pp. 103-110 ◽  
Author(s):  
Mervyn C. Goronszy ◽  
Gunnar Demoulin ◽  
Mark Newland
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Plug Flow ◽  
Domestic Wastewater ◽  
Initial Reaction ◽  
Biological Phosphorus Removal ◽  
Reaction Volume ◽  
Variable Volume ◽  
Mode Of Operation ◽  
Nitrogen Concentrations

The practice of manipulating activated sludge reaction environments to obtain maximum nitrogen removal has been optimized using cyclic activated sludge technology. In its simplest form, the sequences of fill aeration, settle and decant are consecutively and continuously operated in a compartmented variable volume reactor in which an initial reaction volume performs the function of a biological selector using biomass from a final reaction volume. The technology incorporates the principles of biological accumulation-regeneration processing in which a variable volume plug-flow reaction environment precedes a variable volume complete-mix reaction environment, both of which are typically in continuous fluid communication. This configuration and mode of operation allows removal performance in domestic wastewater treatment applications to meet less than 5 mgL−1 total nitrogen discharge limits. Low nitrogen concentrations are obtained using modified aeration sequences only in which the bulk phase sequenced dissolved oxygen concentration is typically less than 2 mgL−1 in a ramped profile beginning at zero. By that means a simultaneous or co-current nitrification-denitrification mechanism is obtained. Cycle manipulation required to maintain high nitrogen removal performance during less than design loadings is addressed. In-basin monitoring illustrates nitrogen removal performance obtained in domestic wastewater applications. This mode of operation is also important to the efficacy of biological phosphorus removal where available readily degradable soluble substrate is near to limiting.

Kinetic study on nitrification of ammonium nitrogen-enriched synthetic wastewater using activated sludge

2020 ◽  
Vol 81 (1) ◽  
pp. 62-70
Author(s):  
Roumi Bhattacharya ◽  
Debabrata Mazumder
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Suspended Solids ◽  
Removal Rate ◽  
Nitrogen Concentration ◽  
Ammonium Nitrogen ◽  
Synthetic Wastewater ◽  
Yield Coefficient ◽  
Ammonium Oxidation ◽  
Consecutive Reaction

Abstract Nitrification of ammonium nitrogen (NH4+-N)-bearing synthetic wastewater was performed in a batch-activated sludge reactor by varying the initial ammonium nitrogen concentration up to 400 mg/L at a pH of 8.1 ± 0.2 and temperature of 36 ± 2 °C for developing the process kinetics using acclimatised biomass. Maximum ammonium nitrogen removal efficiency of 98.3% was achieved with initial ammonium nitrogen and mixed liquor suspended solids concentration of 235 mg/L and 2,180 mg/L, respectively, at 48 h batch period. Based on the experimental results, kinetic constants for ammonia nitrogen removal following Monod's approach were obtained as maximum substrate removal rate coefficient = 0.057 per day, yield coefficient = 0.336 mg volatile suspended solids/mg ammonium nitrogen, half velocity constant = 12.95 mg NH4+-N/L and endogenous decay constant = 0.02 per day. Nitrification is a consecutive reaction with ammonium oxidation as the first step followed by nitrite oxidation. The overall rate of nitrite and nitrate formation was observed to be 1.44 per day and 0.34 per day, respectively.

scholarly journals Promotion of partial nitritation-anammox process by improving granule proportion

2017 ◽  
Vol 75 (11) ◽  
pp. 2580-2585 ◽  
Author(s):  
Jun Cheng ◽  
Liang Zhang ◽  
Yandong Yang ◽  
Shujun Zhang ◽  
Xiaoyu Han ◽  
...  
Keyword(s):  
Nitrogen Removal ◽  
System Performance ◽  
Mass Fraction ◽  
Removal Rate ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Ammonium Oxidation ◽  
Partial Nitritation ◽  
Granule Fraction ◽  
Anammox Process

For enhancing the partial nitritation-anammox (PN/A) process, the effects of granule fraction on system performance were investigated in this study. Two sequencing batch reactors (SBRs) were inoculated with PN/A biomass with a floc mass fraction of 53%. In SBR1, when the nitrogen removal rate (NRR) was stable, flocculent sludge was gradually discharged from the reactor using a screen, and the granule fraction was therefore increased. However, nitrogen removal was not improved and finally deteriorated due to the loss of nitritation activity. In SBR2, most flocculent sludge was eliminated and granular proportion was maintained at over 90% by controlling a short settling and decanting time. NRR was low initially but gradually improved to 1.23 kg N/(m3·d), which was 54% higher than SBR1. Ammonium oxidation activities of flocs and granules were respectively measured. Results suggested that the increase of nitritation activity in the granules was the main reason for the improvement of nitrogen removal in SBR2.

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