Removal of organic halogens (AOX) from municipal wastewater by powdered activated carbon (PAC)/activated sludge (AS) treatment

1997 ◽  
Vol 35 (10) ◽  
pp. 147-153 ◽  
Author(s):  
C. Bornhardt ◽  
J. E. Drewes ◽  
M. Jekel
Keyword(s):  
Activated Carbon ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Activated Carbons ◽  
Treatment Plant ◽  
Volume Index ◽  
Enhancement Effect ◽  
Simultaneous Treatment ◽  
Volatile Solids ◽  
Organic Halogens

The effectiveness of different treatments with powdered activated carbons (PAC) to reduce the AOX-levels in municipal wastewater was investigated in a bench-scale activated sludge (AS) treatment plant. The PAC was added either directly to the aerated basin (simultaneous PAC-treatment), or to a partial stream of clarified effluent, which was treated with PAC in an agitated tank and recirculated to the aerated basin (subsequent PAC-treatment with recirculation). The standard advanced biological treatment reduced the AOX-content by 24%. In the pilot-plant, three types of powdered activated carbons were tested for a simultaneous treatment. The treatment with 100 mg/l PICA PCO Super produced an additional reduction of AOX by 20%, whereas a dosage of 50 mg/l NORIT W-20 showed no enhancement effect, and W-35 led to an additional AOX-removal of about 9%. Also, an improved removal of DOC, NH4-N and PO4-P was observed. In all cases, the PAC addition caused a significantly improved settling of the AS, reducing the sludge-volume-index, and increasing the content of volatile solids of the PAC-sludge. In general, no evidence of a synergistic effect of the PAC addition to activated sludge, nor bioregeneration of the activated carbon, could be observed. This suggests, that the observed effects probably are caused only by simple adsorption.

The sorption capacity of long-time aerated activated sludge demonstrated with 2,6-dimethylphenol

1999 ◽  
Vol 39 (8) ◽  
pp. 131-138 ◽  
Author(s):  
H. Gulyas ◽  
U. Heldt ◽  
I. Sekoulov
Keyword(s):  
Activated Carbon ◽  
Activated Sludge ◽  
Specific Surface ◽  
Sorption Capacity ◽  
Municipal Wastewater ◽  
Solid Phase ◽  
Tap Water ◽  
Treatment Plant ◽  
Pilot Scale ◽  
Hazardous Substance

The aim of this study was to evaluate the influence of the duration of activated sludge aeration on sorption capacity of the sludge for the hazardous substance 2,6-dimethylphenol (DMP). DMP was not degraded by normal activated sludge of a pilot scale treatment plant for municipal wastewater as shown by BOD measurements. Sludge aeration was performed for up to 50 days. In sorption assays the mixed liquor suspensions aerated for different times were added to solutions of DMP (10 to 50 mg/l) in tap water in order to give biomass concentrations of 1 g MLSS/l in the sorption assay. Also a sorption isotherm with different concentrations of activated sludge aerated for 50 days with a constant initial DMP concentration was recorded. In the experiments solid phase DMP concentrations of up to 20.9 mg DMP/g MLSS were found depending on aeration time of the activated sludge. Sorption equilibria were reached within short periods (about 10 min). DMP sorption capacity of activated sludge reached a maximum on the 43rd day of aeration and decreased afterwards. But the sorption capacity of sludge aerated for 43 days was significantly lower (about 40% removal of DMP at 1 g MLSS/l from an aqueous solution containing about 50 mg DMP/l) than the adsorption capacity of activated carbon (100% removal of DMP at 1 g activated carbon/l). On the other hand, activated sludge which had been aerated for an optimum period represents a rather good and cheap sorbent for the refractory DMP, considering the low specific surface of activated sludge compared to the specific surface of activated carbon. However, an appropriate method for removal of the sludge loaded with DMP has to be chosen in order to protect the environment against spreading of the hazardous compound DMP. A multistage biosorption process for DMP removal from industrial wastewater is suggested.

Performance analysis of anoxic selector in upgrading activated sludge process in tropical climate

2005 ◽  
Vol 52 (4) ◽  
pp. 27-37 ◽  
Author(s):  
Y.S. Cao ◽  
K.H. Teo ◽  
W.A. Yuen ◽  
W.Y. Long ◽  
B. Seah
Keyword(s):  
Activated Sludge ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Stable State ◽  
Tropical Climate ◽  
Reaction Rates ◽  
Volume Index ◽  
Activated Sludge Process ◽  
Municipal Wastewater Treatment ◽  
Sludge Settleability

The paper describes and analyses the performance of anoxic selectors in upgrading activated sludge process in a municipal wastewater treatment plant under tropical climate, where poor sludge settleability is a problem due to elevated temperature. Site monitoring and laboratory experiment were conducted to study the denitrification, sludge settleability, kinetics, mass balance, pH and alkalinity variation in the system. The sludge settleability measured in Sludge Volume Index (SVI) was observed to improve with the increasing degree of denitrification in the anoxic selector. Under well-developed stable state, an average SVI value of 136 ml/g was achieved, which was significantly lower than the value of 250 ml/g before the application of anoxic selector. The specific reaction rates for denitrification and nitrification at 30°C were 0.06 mg NO3-N/mg MLSS day and 0.08 mg NH4-N/mg MLSS day, respectively. The overall efficiencies of nitrification and denitrification were 86 percent and 55.4 percent, respectively, with an alkalinity recovery ratio of 15.4 percent. 32 percent of total COD removed was used up as electron donor in the denitrification process. However, due to absence of the internal Mixed Liquor Recirculation (MLR), a higher degree of denitrification occurred in the secondary sedimentation tank than in the anoxic zone. Issues for further studies are also discussed.

A modified anaerobic digestion process with chemical sludge pre-treatment and its modelling

2014 ◽  
Vol 69 (11) ◽  
pp. 2350-2356 ◽  
Author(s):  
N. M. Hai ◽  
S. Sakamoto ◽  
V. C. Le ◽  
H. S. Kim ◽  
R. Goel ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Biogas Production ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Municipal Wastewater Treatment ◽  
Simulation Accuracy ◽  
Volatile Solids ◽  
Pre Treatment

Activated Sludge Models (ASMs) assume an unbiodegradable organic particulate fraction in the activated sludge, which is derived from the decay of active microorganisms in the sludge and/or introduced from wastewater. In this study, a seasonal change of such activated sludge constituents in a municipal wastewater treatment plant was monitored for 1.5 years. The chemical oxygen demand ratio of the unbiodegradable particulates to the sludge showed a sinusoidal pattern ranging from 40 to 65% along with the change of water temperature in the plant that affected the decay rate. The biogas production in a laboratory-scale anaerobic digestion (AD) process was also affected by the unbiodegradable fraction in the activated sludge fed. Based on the results a chemical pre-treatment using H2O2 was conducted on the digestate to convert the unbiodegradable fraction to a biodegradable one. Once the pre-treated digestate was returned to the digester, the methane conversion increased up to 80% which was about 2.4 times as much as that of the conventional AD process, whilst 96% of volatile solids in the activated sludge was digested. From the experiment, the additional route of the organic conversion processes for the inert fraction at the pre-treatment stage was modelled on the ASM platform with reasonable simulation accuracy.

Comparison of anoxic granulation in USB reactors with various inocula

2010 ◽  
Vol 64 (2) ◽  
Author(s):  
Katarína Galbová ◽  
Petra Pagáčová ◽  
Miloslav Drtil ◽  
Ivana Jonatová
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Volume Index ◽  
Municipal Wastewater Treatment ◽  
Granulation Process ◽  
Volumetric Loading ◽  
Anoxic Granulation

AbstractAnoxic granulation process with four different inocula was monitored in a laboratory post-denitrification up-flow sludge bed (USB) reactor. Wastewater containing 20 mg L−1 NO3-N and methanol as an organic carbon source was used. Gradual increase of mass volumetric loading (B v) and hydraulic loading (γ) resulted in spontaneous granulation of anoxic biomass both from flocculant activated sludge and from anaerobic granulated sludge. With flocculant activated sludge as the inoculum, anoxic granules sedimentation properties and maximum loadings of the USB reactor depended on the sludge volume index (SVI) of the inoculum. B v,max achieved in the USB reactor with flocculant inoculum from a municipal wastewater treatment plant (SVI = 208 mL g−1) was only 4.2 kg of COD per m3 per day and 0.7 kg of NO3-N per m3 per day. B v,max using flocculant inoculum from an industrial wastewater treatment plant (SVI = 170 mL g−1) was 8.1 kg of COD per m3 per day and 1.35 kg of NO3-N per m3 per day. With anaerobic granulated inoculum (SVI range 8–11 mL g−1), markedly higher loadings in the USB reactor and lower SVI values of anoxic granulated biomass were achieved. Values of B v,max were in the range of 16.1–22.4 kg of COD per m3 per day and of 2.7–3.7 kg of NO3-N per m3 per day (depending on the inoculum and the granulation procedure). It was proved that anaerobic granulated sludge is not just an inoculum, it is also a carrier for new denitrification biomass.

Activated sludge plant facing grape harvest period – a case study

1996 ◽  
Vol 34 (11) ◽  
pp. 25-32 ◽  
Author(s):  
P. Chudoba ◽  
R. Pujol
Keyword(s):  
Activated Sludge ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Organic Pollution ◽  
Worst Case ◽  
Wine Production ◽  
Original Solution ◽  
Treated Effluent ◽  
Nominal Capacity ◽  
Sludge Settleability

Most of municipal activated sludge plants located in wine production regions receive winery wastewaters during the grape harvest period which lasts usually only a few weeks. A drastic increase in organic pollution (COD, BOD) during this period generates a temporary overloading, resulting very often in biological problems such as decreased sludge settleability, sludge floc disintegration, increased SS concentration in treated effluent and in the worst case a complete plant failure. In order to work satisfactorily even during those temporary overloading periods, the plant has to be oversized. This strategy is rather costly, because such a plant has to run below its nominal capacity during a major part of the year. An original solution has been proposed and successfully tested at a municipal wastewater treatment plant in Eguisheim, France. The proposed technique is based on the addition of a mineral material with a low particle size, whose presence positively influences the physical behaviour of the sludge and will allow the nominal capacity of the plant to be surpassed without any important modification. The modification of the sludge structure around the added powdered material improved significantly the sludge settleability (DSVI< 160 ml/g) and enabled the plant to treat organic pollution several times higher than the nominal level.

scholarly journals Erythromycin Resistance-Conferring Plasmid pRSB105, Isolated from a Sewage Treatment Plant, Harbors a New Macrolide Resistance Determinant, an Integron-Containing Tn402-Like Element, and a Large Region of Unknown Function

2007 ◽  
Vol 73 (6) ◽  
pp. 1952-1960 ◽  
Author(s):  
A. Schlüter ◽  
R. Szczepanowski ◽  
N. Kurz ◽  
S. Schneiker ◽  
I. Krahn ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Unknown Function ◽  
Municipal Wastewater ◽  
Ralstonia Eutropha ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Macrolide Resistance ◽  
Municipal Wastewater Treatment ◽  
Erythromycin Resistance ◽  
Modification System

ABSTRACT The erythromycin resistance plasmid pRSB105 was previously isolated from an activated sludge bacterial community of a municipal wastewater treatment plant. Compilation of the complete pRSB105 nucleotide sequence revealed that the plasmid is 57,137 bp in size and has a mean G+C content of 56.66 mol%. The pRSB105 backbone is composed of two different replication and/or partitioning modules and a functional mobilization region encoding the mobilization genes mobCDE and mobBA. The first replicon (Rep1) is nearly identical to the corresponding replication module of the multiresistance plasmid pRSB101 isolated from an unknown activated sludge bacterium. Accordingly, pRSB101 and pRSB105 are sister plasmids belonging to a new plasmid family. The second replicon (Rep2) of pRSB105 was classified as a member of the IncP-6 group. While Rep1 confers replication ability only in γ-proteobacteria, Rep2 extents the host range of the plasmid since it is also functional in the β-proteobacterium Ralstonia eutropha. Plasmid pRSB105 harbors the macrolide resistance genes mel and mph, encoding, respectively, a predicted ABC-type efflux permease and a macrolide-2′-phosphotransferase. Erythromycin resistance is mainly attributed to mel, whereas mph contributes to erythromycin resistance to a lesser extent. The second resistance region, represented by an integron-containing Tn402-like element, includes a β-lactam (oxa10) and a trimethoprim (dfrB2) resistance gene cassette. In addition to antibiotic resistance modules, pRSB105 encodes a functional restriction/modification system and two nonresistance regions of unknown function. The presence of different mobile genetic elements that flank resistance and nonresistance modules on pRSB105 indicates that these elements were involved in acquisition of accessory plasmid modules. Comparative genomics of pRSB105 and related plasmids elucidated that pRSB105 evolved by integration of distinct modules from different plasmid sources, including Pseudomonas aeruginosa plasmids, and thus represents a mosaic plasmid.

Activated sludge diffusion for efficient simultaneous treatment of municipal wastewater and odor in a membrane bioreactor

2021 ◽  
Vol 415 ◽  
pp. 128765
Author(s):  
Fuqiang Fan ◽  
Ronghua Xu ◽  
Depeng Wang ◽  
Junshi Tao ◽  
Yifeng Zhang ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Membrane Bioreactor ◽  
Municipal Wastewater ◽  
Simultaneous Treatment

Interpretation of Experimental Data with Regard to the Activated Sludge Model No.1 and Calibration of the Model for Municipal Wastewater Treatment Plants

1992 ◽  
Vol 25 (6) ◽  
pp. 167-183 ◽  
Author(s):  
H. Siegrist ◽  
M. Tschui
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Municipal Wastewater Treatment ◽  
Activated Sludge Model

The wastewater of the municipal treatment plants Zürich-Werdhölzli (350000 population equivalents), Zürich-Glatt (110000), and Wattwil (20000) have been characterized with regard to the activated sludge model Nr.1 of the IAWPRC task group. Zürich-Glatt and Wattwil are partly nitrifying treatment plants and Zürich-Werdhölzli is fully nitrifying. The mixing characteristics of the aeration tanks at Werdhölzli and Glatt were determined with sodium bromide as a tracer. The experimental data were used to calibrate hydrolysis, heterotrophic growth and nitrification. Problems arising by calibrating hydrolysis of the paniculate material and by measuring oxygen consumption of heterotrophic and nitrifying microorganisms are discussed. For hydrolysis the experimental data indicate first-order kinetics. For nitrification a maximum growth rate of 0.40±0.07 d−1, corresponding to an observed growth rate of 0.26±0.04 d−1 was calculated at 10°C. The half velocity constant found for 12 and 20°C was 2 mg NH4-N/l. The calibrated model was verified with experimental dam of me Zürich-Werdhölzli treatment plant during ammonia shock load.

Mesophilic and Thermophilic Digestion of Thickened Waste Activated Sludge: A Comparative Study

2010 ◽  
Vol 113-116 ◽  
pp. 450-458 ◽  
Author(s):  
Yong Zhi Chi ◽  
Yu You Li ◽  
Min Ji ◽  
Hong Qiang ◽  
Heng Wei Deng ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Treatment Plant ◽  
Methane Content ◽  
Waste Activated Sludge ◽  
Digested Sludge ◽  
Anaerobic Digestion Process ◽  
Digestion Process ◽  
Significant Difference

This paper presents an experimental study over 204 days on anaerobic degradation of thickened waste activated sludge (TWAS) from a municipal wastewater treatment plant (WWTP). The experiments were conducted under thermophilic (55°C) and mesophilic (35°C) condition, respectively, by using the semi-continuous flow completely mixed reactors. The influent total solids (TS), hydraulic retention time (HRT) and chemical oxygen demand (COD) loading levels were around 4%, 30 days and 1.67 kg-CODCr•m-3•d-1 , respectively. During the opration period, the thermophilic anaerobic digestion process (TADP) and the mesophilic anaerobic digestion process (MADP) were stable and well-functioned without ammonia inhibition. Particulate organic matters reduction of TADP was superior to that of MADP. This result implies that TADP has higher sludge reduction efficiency than MADP. According to the simulated chemical formula of TWAS, C5.85H9.75O3.96N, and the stoichiometric equation, the methane content and the ammonia yield in the anaerobic process could be calculated, which were consistent with the experimental results. The methane yield of TADP was a little higher than that of MADP. The statistical mean values of methane content for TADP and MADP were 60.97% and 62.38%, respectively.According to paired t-test, there was a significant difference in methane content between TADP and MADP(α=0.01, n=62). Compared with the mesophilic digested sludge, the dewaterability of thermophilic digested sludge was lower.

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