Performance evaluation of various aerobic biological systems for the treatment of domestic wastewater at low temperatures

2008 ◽  
Vol 58 (4) ◽  
pp. 819-830 ◽  
Author(s):  
N. Sundaresan ◽  
L. Philip
Keyword(s):  
Performance Evaluation ◽  
Activated Sludge ◽  
Fluidized Bed ◽  
Removal Efficiency ◽  
Biological Systems ◽  
Domestic Wastewater ◽  
Cod Removal ◽  
Synthetic Wastewater ◽  
Activated Sludge Process ◽  
Cod Removal Efficiency

Studies were undertaken on the performance evaluation of three different types of aerobic reactors, namely, activated sludge process, fluidized bed reactor and submerged bed reactor. Initially synthetic wastewater was used for stabilizing the system and later domestic wastewater of IIT Madras was used as the feed for the biological systems. The hydraulic retention time was maintained as 24 h. The seed sludge was collected from IIT Madras sewage treatment plant. The inlet COD to the reactors with synthetic wastewater was 1,000±20 mg/L and with real wastewater, it was 150 to 350 mg/L. The performance of the reactors was evaluated based on the soluble COD and nitrogen removal efficiency. The pH, temperature, dissolved oxygen (DO) and mixed liquid suspended solid (MLSS) concentration were measured periodically. The reactors were acclimatized at 35°C in batch mode and changed to continuous mode at 30°C. After the systems attained its steady state at a particular temperature, the temperature was reduced from 35°C to 5°C stepwise, with each step of 5°C. The start-up time for submerged bed reactor was slightly more than fluidized and conventional activated sludge process. The COD removal efficiency of the three reactors was higher with synthetic wastewaters as compared to actual domestic wastewater. Submerged bed reactor was more robust and efficient as compared to activated sludge and fluidized bed reactors. The COD removal efficiency of the reactors was relatively good until the operating temperature was maintained at 15°C or above. At 10°C, submerged bed reactor was able to achieve 40% COD removal efficiency whereas; the fluidized bed and conventional ASP reactors were showing only 20% COD removal efficiency. At 5°C, almost all the systems failed. Submerged bed reactor showed around 20% COD removal efficiency. However, this reactor was able to regain its 90% of original efficiency, once the temperature was raised to 10°C. At higher temperatures, the nitrification efficiency of the reactors was above 80–90%. As the temperature reduced the nitrification efficiency has reduced drastically. In summary, submerged bed reactors seems to be a better option for treating domestic wastewaters at low temperature regions.

Effects of Molybdenum (VI) on the Denitrification Performance of Activated Sludge Process

2011 ◽  
Vol 183-185 ◽  
pp. 1400-1403
Author(s):  
Xue Zheng Meng ◽  
Xiang Sheng Cao ◽  
Jie Rui Li
Keyword(s):  
Activated Sludge ◽  
Removal Efficiency ◽  
Removal Rate ◽  
Nitrate Removal ◽  
Cod Removal ◽  
Activated Sludge Process ◽  
Inhibitory Effects ◽  
Batch Tests ◽  
Cod Removal Efficiency

The effects of molybdenum (Ⅵ) on the denitrification efficiency of activated sludge process were investigated with batch tests. The results indicated that up to 5 mg/L of Molybdenum (Ⅵ) concentrations in the liquor of activated sludge process could accelerate the nitrate removal rate, exhibiting maximum stimulation at 1 mg/L. Up to 4 mg/L of Molybdenum (Ⅵ) concentrations, the COD removal efficiency was enhanced. Up to 1mg/L of Molybdenum (Ⅵ) concentrations, the TTC-DHA was enhanced but higher concentration showed inhibitory effects. Based on the integrated effects of Molybdenum (Ⅵ) on nitrate and COD removal with the TTC-DHA change, 1mg/L of Molybdenum (Ⅵ) is proposed as the best concentration for denitrification of activated sludge.

scholarly journals Investigation of Heavy Metal Effects on the Anaerobic Co-Digestion Process of Waste Activated Sludge and Septic Tank Sludge

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Quang-Minh Nguyen ◽  
Duy-Cam Bui ◽  
Thao Phuong ◽  
Van-Huong Doan ◽  
Thi-Nham Nguyen ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Activated Sludge ◽  
Removal Efficiency ◽  
Biogas Production ◽  
Cod Removal ◽  
Septic Tank ◽  
Waste Activated Sludge ◽  
Digestion Process ◽  
Cod Removal Efficiency

The effect of copper, zinc, chromium, and lead on the anaerobic co-digestion of waste activated sludge and septic tank sludge in Hanoi was studied in the fermentation tests by investigating the substrate degradation, biogas production, and process stability at the mesophilic fermentation. The tested heavy metals were in a range of concentrations between 19 and 80 ppm. After the anaerobic tests, the TS, VS, and COD removal efficiency was 4.12%, 9.01%, and 23.78% for the Cu(II) added sample. Similarly, the efficiencies of the Zn(II) sample were 1.71%, 13.87%, and 16.1% and Cr(VI) efficiencies were 15.28%, 6.6%, and 18.65%, while the TS, VS, and COD removal efficiency of the Pb(II) added sample was recorded at 16.1%, 17.66%, and 16.03% at the concentration of 80 ppm, respectively. Therefore, the biogas yield also decreased by 36.33%, 31.64%, 31.64%, and 30.60% for Cu(II), Zn(II), Cr(VI), and Pb(II) at the concentration of 80 ppm, compared to the raw sample, respectively. These results indicated that Cu(II) had more inhibiting effect on the anaerobic digestion of the sludge mixture than Zn(II), Cr(VI), and Pb(II). The relative toxicity of these heavy metals to the co-digestion process was as follows: Cu (the most toxic) > Zn > Cr > Pb (the least toxic). The anaerobic co-digestion process was inhibited at high heavy metal concentration, which resulted in decreased removal of organic substances and produced biogas.

Effect of continuously dosing Cu(II) on pollutant removal and soluble microbial products in a sequencing batch reactor

2015 ◽  
Vol 72 (9) ◽  
pp. 1653-1661 ◽  
Author(s):  
YangWei Yan ◽  
YuWen Wang ◽  
Yan Liu ◽  
Xiang Liu ◽  
ChenChao Yao ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Extracellular Polymeric Substances ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Pollutant Removal ◽  
Cod Removal ◽  
Synthetic Wastewater ◽  
Soluble Microbial Products ◽  
Cod Removal Efficiency ◽  
Microbial Products

The effects of synthetic wastewater that contained 20 mg/L Cu(II) on the removal of organic pollutants in a sequencing batch reactor were investigated. Results of continuous 20 mg/L Cu(II) exposure for 120 days demonstrated that the chemical oxygen demand (COD) removal efficiency decreased to 42% initially, followed by a subsequent gradual recovery, which peaked at 78% by day 97. Effluent volatile fatty acid (VFA) concentration contributed 67 to 89% of the influent COD in the experimental reactor, which indicated that the degradation of the organic substances ceased at the VFA production step. Meanwhile, the varieties of soluble microbial products (SMP) content and main components (protein, polysaccharide, and DNA) were discussed to reveal the response of activated sludge to the toxicity of 20 mg/L Cu(II). The determination of Cu(II) concentrations in extracellular polymeric substances (EPS) and SMP throughout the experiment indicated an inverse relationship between extracellular Cu(II) concentration and COD removal efficiency.

Pilot-Scale Experiences on Anaerobic Fluidized-Bed Treatment of Brewery Wastes

1990 ◽  
Vol 22 (9) ◽  
pp. 157-166 ◽  
Author(s):  
G. K. Anderson ◽  
I. Ozturk ◽  
C. B. Saw
Keyword(s):  
Fluidized Bed ◽  
Removal Efficiency ◽  
Pilot Scale ◽  
Methanogenic Bacteria ◽  
Cod Removal ◽  
Organic Loading Rate ◽  
Cod Removal Efficiency ◽  
Wide Range ◽  
Monod Kinetic ◽  
Brewery Wastes

This paper covers the results of a pilot-plant study on the Anaerobic Fluidized-Bed Reactor (AFBR) treatment of brewery wastes. The AFBR was operated over a wide range of organic and hydraulic loading rates for a study period of more than eight months. The reactor consisted of a clear PVC column with a diameter of 165 mm and 3 m in height. Sand having a median diameter of 0.5 mm was used as the medium. The AFBR was fed with wastewaters collected from a local brewery. A COD removal efficiency of greater than 75% was observed at an organic loading rate (OLR) of 8.9 kg COD/m3 of expended bed/day for 82 days from start-up. The OLR was increased to greater than 14 kg COD/m3.d and a COD to methane conversion of 87% was achieved. Effects of OLR and COD removal efficiency on gas flowrate and on gas composition as well as concentrations of suspended solids (SS) and volatile acids (VA) were investigated. It was observed that biomass distribution along the height of the AFBR was not uniform and a strong stratification of biomass exists between the upper and lower parts of the system. The ecological structure of biomass was examined by SEM and clumps of methanogenic bacteria were identified. The Monod kinetic parameters were determined using steady-state operating data and compared to similar results given in the literature for the same waste.

Anaerobic Fluidized-Bed Treatment of Brewery Wastes and Bioenergy Recovery

1989 ◽  
Vol 21 (12) ◽  
pp. 1681-1684 ◽  
Author(s):  
I. Ozturk ◽  
G. K. Anderson ◽  
C. B. Saw
Keyword(s):  
Fluidized Bed ◽  
Removal Efficiency ◽  
Cod Removal ◽  
Organic Loading Rate ◽  
Utilization Rate ◽  
Specific Substrate ◽  
Cod Removal Efficiency ◽  
Start Up ◽  
Specific Substrate Utilization Rate ◽  
Brewery Wastes

This paper presents the results of a pilot plant study using an Anaerobic Fluidized Bed Reactor (AFBR) for treatment of brewery wastes. A COD removal efficiency of greater than 75% was observed at an organic loading rate (OLR) of 9.5 kg COD/m3-day for a Deriod of 82 days from start-up. COD removal efficiency was greater than 74% at an OLR of 14.6 kg COD/m3 expanded bed (e.b)-day. A COD to methane conversion of 87% was achieved. Experimental results have suggested that the COD removal efficiency of an AFBR is only a function of COD loading, and neither the feed COD nor HRT alone significantly affect the performance of the reactor. A linear relationship was found between the specific substrate utilization rate and the specific methane production rate. It was observed that the distribution of the biomass along the height of the reactor is not uniform, and the biomass hold-up near the top of the reactor may reach concentrations of greater than 20,000 mg/l.

Kinetic Analysis of COD Removal from Actual Domestic Wastewater in an Expanded Granular Sludge Bed (EGSB) Reactor

2012 ◽  
Vol 610-613 ◽  
pp. 1691-1695
Author(s):  
Chun Juan Dong ◽  
Qing Ye Pan
Keyword(s):  
Low Temperature ◽  
Removal Efficiency ◽  
Removal Rate ◽  
Experimental Studies ◽  
Domestic Wastewater ◽  
Pollutant Removal ◽  
Cod Removal ◽  
Utilization Rate ◽  
Cod Removal Efficiency ◽  
Pollutant Removal Rate

Treatment of actual domestic wastewater at ambient temperature, even low temperature is considered to be difficult by traditional systems. The present study is related to treatment of actual domestic wastewater in an EGSB reactor. The study showed the effectiveness of biological treatment of actual domestic wastewater involving appropriate microorganism and granules in an EGSB reactor. At 26°C, the reactor was operated at 18.7kg COD.m−3.d−1 of average organic loading and 83% high COD removal efficiency, and even at the highest loading rate of 57.12kgCOD.m−3.d−1, the COD removal efficiency still could attain to 68%. Varied influent flow need to supply varied optimal and thus to ensure the optimal removal effect. Low temperature would cause pollutant removal rate decrease. However, enhancing could optimize the contact of sludge and wastewater and thus strengthen the performance effect. Modified Stover–Kincannon model was applied to data obtained from experimental studies in EGSB reactor. Treatment efficiencies of the reactor were investigated at different hydraulic retention times (0.5-1.3h) and different operation temperature (15°C, 26°C). The modified Stover–Kincannon model was best fitted to the EGSB reactor, and the substrate utilization rate( ), saturation constant value( ), and actual pollutant removal rate( ) were found to be , , and for 26°C, , , and for 15°C( before increasing ), and , , and for 15°C(after increasing ). Low temperature could cause decrease and thus cause distinct decreasing of COD removal efficiency. However, increasing could increase and accordingly increase COD removal efficiency.

The effect of operational conditions on the performance of UASB reactors for domestic wastewater treatment

2005 ◽  
Vol 52 (1-2) ◽  
pp. 299-305 ◽  
Author(s):  
R.C. Leitão ◽  
J.A. Silva-Filho ◽  
W. Sanders ◽  
A.C. van Haandel ◽  
G. Zeeman ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Municipal Wastewater ◽  
Domestic Wastewater ◽  
Pilot Scale ◽  
Cod Removal ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Operational Conditions ◽  
Cod Removal Efficiency ◽  
Uasb Reactors

In this investigation, the performance of Upflow Anaerobic Sludge Blanket (UASB) reactors treating municipal wastewater was evaluated on the basis of: (i) COD removal efficiency, (ii) effluent variability, and (iii) pH stability. The experiments were performed using 8 pilot-scale UASB reactors (120 L) from which some of them were operated with different influent COD (CODInf ranging from 92 to 816 mg/L) and some at different hydraulic retention time (HRT ranging from 1 to 6 h). The results show that decreasing the CODInf, or lowering the HRT, leads to decreased efficiencies and increased effluent variability. During this experiment, the reactors could treat efficiently sewage with concentration as low as 200 mg COD/L. They could also be operated satisfactorily at an HRT as low as 2 hours, without problems of operational stability. The maximum COD removal efficiency can be achieved at CODInf exceeding 300 mg/L and HRT of 6 h.

scholarly journals Bioaugmentation as a Tool To Protect the Structure and Function of an Activated-Sludge Microbial Community against a 3-Chloroaniline Shock Load

2003 ◽  
Vol 69 (3) ◽  
pp. 1511-1520 ◽  
Author(s):  
Nico Boon ◽  
Eva M. Top ◽  
Willy Verstraete ◽  
Steven D. Siciliano
Keyword(s):  
Microbial Community ◽  
Activated Sludge ◽  
Real Time ◽  
Removal Efficiency ◽  
Real Time Pcr ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Cod Removal ◽  
Shock Load ◽  
Volume Index ◽  
Cod Removal Efficiency

ABSTRACT Bioaugmentation of bioreactors focuses on the removal of xenobiotics, with little attention typically paid to the recovery of disrupted reactor functions such as ammonium-nitrogen removal. Chloroanilines are widely used in industry as a precursor to a variety of products and are occasionally released into wastewater streams. This work evaluated the effects on activated-sludge reactor functions of a 3-chloroaniline (3-CA) pulse and bioaugmentation by inoculation with the 3-CA-degrading strain Comamonas testosteroni I2 gfp. Changes in functions such as nitrification, carbon removal, and sludge compaction were studied in relation to the sludge community structure, in particular the nitrifying populations. Denaturing gradient gel electrophoresis (DGGE), real-time PCR, and fluorescent in situ hybridization (FISH) were used to characterize and enumerate the ammonia-oxidizing microbial community immediately after a 3-CA shock load. Two days after the 3-CA shock, ammonium accumulated, and the nitrification activity did not recover over a 12-day period in the nonbioaugmented reactors. In contrast, nitrification in the bioaugmented reactor started to recover on day 4. The DGGE patterns and the FISH and real-time PCR data showed that the ammonia-oxidizing microbial community of the bioaugmented reactor recovered in structure, activity, and abundance, while the number of ribosomes of the ammonia oxidizers in the nonbioaugmented reactor decreased drastically and the community composition changed and did not recover. The settleability of the activated sludge was negatively influenced by the 3-CA addition, with the sludge volume index increasing by a factor of 2.3. Two days after the 3-CA shock in the nonbioaugmented reactor, chemical oxygen demand (COD) removal efficiency decreased by 36% but recovered fully by day 4. In contrast, in the bioaugmented reactor, no decrease of the COD removal efficiency was observed. This study demonstrates that bioaugmentation of wastewater reactors to accelerate the degradation of toxic chlorinated organics such as 3-CA protected the nitrifying bacterial community, thereby allowing faster recovery from toxic shocks.

scholarly journals Study of COD Removal Efficiency from Synthetic Wastewater by Photocatalytic Process

2014 ◽  
Vol 19 (3) ◽  
pp. 255-259 ◽  
Author(s):  
Orawan Rojviroon ◽  
Thammasak Rojviroon ◽  
Sanya Sirivithayapakorn
Keyword(s):  
Removal Efficiency ◽  
Cod Removal ◽  
Synthetic Wastewater ◽  
Photocatalytic Process ◽  
Cod Removal Efficiency

Treatability of cefazolin antibiotic formulation effluent with O3 and O3/H2O2 processes

2007 ◽  
Vol 55 (10) ◽  
pp. 217-225 ◽  
Author(s):  
G. Iskender ◽  
A. Sezer ◽  
I. Arslan-Alaton ◽  
F. Germirli Babuna ◽  
O.S. Okay
Keyword(s):  
Acute Toxicity ◽  
Activated Sludge ◽  
Removal Efficiency ◽  
Inhibition Test ◽  
Cod Removal ◽  
Cod Removal Efficiency

The effect of applying ozonation and perozonation to antibiotic cefazolin-Na formulation effluents were investigated in this study. Twenty minutes of ozonation at a rate of 1,500 mg/L-h was observed to remove COD by 38%, whereas a COD removal efficiency of 40% was achieved via H2O2 enhanced ozonation (same conditions + 31.25 mM H2O2). Both of the pretreatment alternatives were monitored to elevate the BOD5/COD ratio from 0.01 to 0.08. The initially inert COD was reduced by 38% using ozonation and by 60% employing H2O2 enhanced ozonation. In terms of the lowest achievable effluent COD levels after bio-treatment, ozonation was observed to yield a residual COD of 205 mg L−1, while a residual COD of 135 mg L−1 was involved for perozonation. According to the results of acute toxicity on Phaedactylum tricornutum, ozonated and perozonated samples exhibited more toxicity than the untreated effluent after 4 days. The activated sludge inhibition test demonstrated that both of the pretreatment alternatives efficiently eliminated the inhibition of investigated formulation effluent.

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