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.

Influence of the heavy metals concentration on the anaerobic co-digestion performance of activated sludge and Olive mill wastewater

2021 ◽  
Author(s):  
khalideh Al bkoor Alrawashdeh
Keyword(s):  
Heavy Metals ◽  
Activated Sludge ◽  
Removal Efficiency ◽  
Biogas Production ◽  
Olive Mill Wastewater ◽  
Organic Load ◽  
High Concentration ◽  
Digestion Process ◽  
The Impact ◽  
Olive Mill

Abstract The influence of heavy metals (HMs) on the anaerobic co-digestion process (AD) of activated sludge and olive mill wastewater (50% v/v) was studied. Biogas production, methane CH4 concentration, and removal efficiency of the TS, VS, and TCOD were investigated in mesophilic conditions. The toxicity and inhibitory effects of HMs at different concentrations (15–60 ppm) on the digestion process were specified.A high concentration of HMs has resulted in a significant decrease in AD performance in terms of organic load degradation, biogas production, CH4 content, TCOD removal efficiency, and inhibition of hydrogenotrophic-methanogenic bacteria. The toxicity of HMs can be arranged according to TS removal: Cu > Zn ≈ Cr > Pb, according to TCOD removal efficiency: Cu > Cr > Zn > Pb, biogas production: Cu > Zn ≈ Cr > Pb, CH4 content: Cu > Zn > Cr > Pb. Also, the results showed that the methanogenic stage was influenced negatively and more than the acetogenic stage, where Pb < 30 ppm had a lower inhibitor effect on the digestion, while the lowest concentration of Cu(II) leads to the significant inhibition of the AD process is ≥ 10 ppm. At the concentration of 60 ppm of Pb, Zn, Cr, and Cu, the COD removal efficiency was 17.07%, 15.64%, 19.13%, and 20.53% respectively, TS removal was 17.31%, 13.44%, 16.28%, and 10.37 respectively, the VS removal was 19.4%, 14.445, 7.94% and 5.17%, respectively. Also, at the concentration of 60 ppm, biogas production has decreased by 51.55%, 66.46%, 68.1%, and 73.91%, respectively.Novelty statement This study provides new data specifying the inhibitor HMs concentration and the impact of HMs at the various concentrations on the anaerobic co-digestion of active sludge and olive mill wastewater

Effects of copper and zinc on the anaerobic co-digestion process of waste activated sludge and septic tank sludge

2020 ◽  
Vol 173 ◽  
pp. 34-40
Author(s):  
Duy-Cam Bui ◽  
Quang-Minh Nguyen ◽  
Xuan-Quang Chu ◽  
JiHoon Kim ◽  
Kitae Park ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Septic Tank ◽  
Waste Activated Sludge ◽  
Digestion Process ◽  
Copper And Zinc

Effect of trace metals on the anaerobic degradation of volatile fatty acids in molasses stillage

1995 ◽  
Vol 32 (12) ◽  
pp. 121-129 ◽  
Author(s):  
A. Espinosa ◽  
L. Rosas ◽  
K. Ilangovan ◽  
A. Noyola
Keyword(s):  
Trace Metals ◽  
Propionic Acid ◽  
Removal Efficiency ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Cod Removal ◽  
Uasb Reactor ◽  
Organic Load ◽  
Methanogenic Activity ◽  
Cod Removal Efficiency

A laboratory UASB reactor was fed with cane molasses stillage at organic loadings from 5 to 21.5 kg COD/m3 d. With an organic load of 17.4 kg COD/m3 d, an accumulation of VFA, principally propionic acid, was observed due to little bioavailability or lack of trace metals (Fe, Ni, Co and Mo). Associated to this, the performance of the UASB reactor was low (44% COD removal efficiency), with an alkalinity ratio above 0.4. The addition of Fe (100 mg/l), Ni (15 mg/l), Co (10 mg/l) and Mo (0.2 mg/l) to the influent reduced significantly the level of propionic acid (5291mg/l to 251 mg/l) and acetic acid (1100 mg/l to 158 mg/l). The COD removal efficiency increased from 44% to 58%, the biogas production from 10.7 to 14.8 l/d (NTP) and 0.085 to 0.32 g CH4-COD/g SSV d for specific sludge methanogenic activity with propionic acid as substrate. These improved results were obtained with high COD (68.9 g/l) and organic load (21.5 kg COD/m3 d).

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.

Sludge deterioration in a full scale UASB reactor after a pH drop working under low loading conditions

2008 ◽  
Vol 57 (5) ◽  
pp. 797-802 ◽  
Author(s):  
L. Borzacconi ◽  
I. López ◽  
M. Passeggi ◽  
C. Etchebehere ◽  
R. Barcia
Keyword(s):  
Removal Efficiency ◽  
Biogas Production ◽  
Industrial Process ◽  
Full Scale ◽  
Cod Removal ◽  
Normal Operation ◽  
Uasb Reactor ◽  
Organic Load ◽  
Reactor Performance ◽  
Cod Removal Efficiency

A full scale UASB reactor treating the effluent of a malting plant was operated during nearly two years. During 37 weeks of operation the reactor worked with a COD removal efficiency of 80% and a biogas production of nearly 300 m3/d with a methane content of 77%. After the start up and during these months of operation the volumetric organic load was 4 kgCOD/m3.d and the specific organic load was between 0.2–0.4 kgCOD/kgVSS.d. The sludge SMA in this period was around 0.25 kgCOD/kg VSS.d. On week 37 as a result of a problem at the industrial process the pH in the reactor dropped to a value of 4.8. After pH recovering, the reactor worked with fluctuating COD values in the exit and showed a downward trend in the COD removal efficiency. On week 81 the presence of filaments in the granules was detected. High proportion of Chloroflexi filaments were detected by FISH in the sludge. Changes in the microbial population caused by the low pH probably destabilize the reactor performance. The presence of filamentous granules in the sludge and its further growing could be encouraged by the pH drop and the low specific organic load applied to the reactor. The low specific organic load was a consequence of the high VSS content in the UASB reactor, due to the lack of purges. The length of the filaments attached to the granules grew throughout time. In order to eliminate the sludge with poor settlement properties a recycle was applied to the reactor. As a consequence, low amount of granular sludge stayed in the reactor. At the end, COD concentration in the influent reached higher values than in normal operation; at the same time a complete sludge wash out occurred. On the other hand, using the same sludge (after the recycle implementation) in a bench scale reactor the good properties of the sludge were completely recovered.

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.

scholarly journals Disintegration of Wastewater Activated Sludge (WAS) for Improved Biogas Production: A Mini Review

2018 ◽  
Author(s):  
Stanisław Wacławek ◽  
Klaudiusz Grübel ◽  
Daniele Silvestri ◽  
Vinod V.T. Padil ◽  
Maria Ząbkowska-Wacławek ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Sustainable Management ◽  
Fermentation Process ◽  
Wastewater Treatment Plants ◽  
Biogas Production ◽  
Waste Activated Sludge ◽  
Rapid Urbanization ◽  
Biogas Yield ◽  
Digestion Process ◽  
Physical And Chemical

Due to rapid urbanization, the quantity of wastewater treatment plants (WWTP) has increased, and with it the amount of waste generated by them. Sustainable management of this waste can lead to the creation of energy-rich biogas through the fermentation process. This review presents recent advances in the anaerobic digestion process resulting in greater biogas production. Disintegration techniques for enhancing waste activated sludge fermentation can be generally partitioned into biological, physical and chemical, each of which are covered in this review. These disintegration techniques were compared mainly in terms of their biogas yield. It was found that ultrasonic and microwave disintegration provides the highest biogas yield (&gt;500%); however, they are also the most energy demanding (&gt;10,000 kJ kg-1 total solids).

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.

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