Solid mining residues from Ni extraction applied as nutrients supplier to anaerobic process: optimal dose approach through Taguchi's methodology

2006 ◽  
Vol 54 (9) ◽  
pp. 209-219 ◽  
Author(s):  
I. Pereda ◽  
R. Irusta ◽  
S. Montalvo ◽  
J.L. del Valle
Keyword(s):  
Removal Efficiency ◽  
Methane Production ◽  
Volatile Fatty Acids ◽  
Nitrogen Concentration ◽  
Cod Removal ◽  
Synthetic Wastewater ◽  
Control Factor ◽  
Anaerobic Process ◽  
Cod Removal Efficiency ◽  
Mining Residues

The use of solid mining residues (Cola) which contain a certain amount of Ni, Fe and Co, to stimulate anaerobic processes was evaluated. The effect over methane production and chemical oxygen demand (COD) removal efficiency was analysed. The studies were carried out in discontinuous reactors at lab scale under mesophilic conditions until exhausted. 0, 3, 5 and 7 mgCola l−1 doses were applied to synthetic wastewater. Volatile fatty acids (VFA) and sucrose were used as substrate, sulphur and nitrogen concentration, being the noise variable. Cola addition at dose around 5 mg l−1, turned out to be stimulating for the anaerobic process. It was the factor that most influenced on methane production rate together with VFA and high content of volatile suspended solids. In the case of methane yield, pH was the control factor of strongest influence. Higher values of COD removal efficiency were obtained when the reactors were operated with sucrose at relatively low pH and at the smallest concentration of nitrogen and sulphur. Solid residues dose and the type of substrate were the factors that had most influence on COD removal efficiency.

Phenolic refinery wastewater biodegradation by an expanded granular sludge bed reactor

2005 ◽  
Vol 52 (1-2) ◽  
pp. 391-396 ◽  
Author(s):  
F.J. Almendariz ◽  
M. Meraz ◽  
A.D. Olmos ◽  
O. Monroy
Keyword(s):  
Toxic Effect ◽  
Removal Efficiency ◽  
Methane Production ◽  
Granular Sludge ◽  
Cod Removal ◽  
Organic Load ◽  
Refinery Wastewater ◽  
Mineral Supplements ◽  
Cod Removal Efficiency

Refinery spent caustics (SC) were diluted with sour waters (SW) in a ratio 1:7, neutralized with CO2 (SC/SWCO2) and 83% of H2S was striped during this procedure, remaining an aromatic portion that contained 2123, 2730 and 1379 mg L−1 of phenol, p-cresol and o-cresol, respectively. The mixture was treated anaerobically in an EGSB reactor fed with 1.5 gCOD L−1 d−1, without mineral supplements causing loss of COD removal efficiency that dropped to 23%, methane production ceased and no phenol or cresols were biodegraded. The EGSB experiments were resumed by feeding the reactor with nutrients and phenol at 1.0 gCOD L−1 d−1. The mixture SC/SWCO2 added to the phenol load, was step increased from 0.10 to 0.87 gCOD L−1 d−1 maximum. When total organic load was increased to 1.6, COD removal efficiency was 90% and at the highest load attained, 1.87, efficiency dropped to 23% attributed to the toxic effect produced by cresols.

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.

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).

Anaerobic degradation of carbon capture reclaimer MEA waste

2013 ◽  
Vol 67 (11) ◽  
pp. 2549-2559 ◽  
Author(s):  
S. Wang ◽  
J. Hovland ◽  
R. Bakke
Keyword(s):  
Removal Efficiency ◽  
Carbon Capture ◽  
Loading Rate ◽  
Nitrogen Concentration ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Cod Removal ◽  
Methane Yield ◽  
Organic Loading Rate ◽  
Cod Removal Efficiency

The anaerobic biodegradation of reclaimer MEA (monoethanolamine) waste (MEAw) with easily degradable co-substrates was investigated in a laboratory-scale bioreactor at room temperature during a 160 d experimental run. The reactor that was constructed with three phases to facilitate attached biofilm and suspended biomass retention for degradation of the complex and challenging MEAw performed well. A feed strategy of step-wise increasing organic loading rate (OLR) by either increasing feed MEAw concentration or the hydraulic loading rate was applied. The system performance was evaluated by chemical oxygen demand (COD) removal efficiency, methane yield, MEA removal, and the accumulation of ammonia and volatile fatty acid (VFA). The total COD removal efficiency initially was 93% when the feed was mainly easily degradable co-substrate. The total removal dropped to 75% at the end when MEAw constituted 60% of the feed COD. Ion chromatography results show that the MEA and some unidentified feed chemicals were almost completely consumed. The main products of MEAw degradation were ammonia, VFAs and biogas. The ammonia nitrogen concentration reached about 2.0 g/L, which may explain the observed inhibition of acetoclastic methanogenesis leading to acetate accumulation. Methane accounted for up to 80% of the biogas generated. The highest methane yield was 0.34 L/g-COD while the yield was 0.16 L/g-COD at the highest load. This study shows that more than 80% reclaimer MEAw COD degradation with a co-substrate can be maintained in a hybrid anaerobic bioreactor operated in a wide loading range.

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

Two-phase anaerobic treatment of cheese whey

1999 ◽  
Vol 40 (1) ◽  
pp. 289-295 ◽  
Author(s):  
Gülüm Yılmazer ◽  
Orhan Yenigün
Keyword(s):  
Removal Efficiency ◽  
Volatile Fatty Acids ◽  
Cheese Whey ◽  
Cod Removal ◽  
Organic Loading Rate ◽  
Continuous Stirred Tank Reactor ◽  
Two Phase ◽  
Anaerobic Filter ◽  
Cod Removal Efficiency ◽  
Acidogenic Reactor

Performance of two-phase anaerobic digestion of cheese whey was investigated in a system consisting of a continuous stirred tank reactor (CSTR) as the acidogenic reactor and an upflow anaerobic filter (UFAF) as the methanogenic reactor. The acidogenic reactor was operated at various hydraulic retention times (HRTs) between 18 hours and 4 days. The results showed that an optimum HRT for the acidogenic reactor with the same organic loading rate (OLR) between 0.5-2 g COD/MLSS day was 24 hours. At this retention time the acidification rate increased up to a maximum of 50%. Volatile fatty acids (VFAs) produced in the acidogenic reactor operating at an HRT of 24 hours were 52% acetic acid, with 14% propionic, 27% butyric and 7% isovaleric acids. Operating the acidogenic reactor at this HRT, the effluent was fed to the upflow anaerobic filter. Here HRT was varied between 3-6 days for the best COD removal efficiency and biogas production. At an HRT of 4 days a 90% soluble effluent COD removal efficiency was obtained with an outmost biogas yield of 0.55 m3/kg COD removed.

Evaluation of UASB Reactor Performance During Start-Up Operation Using Glucose Bearing Synthetic Wastewater

2020 ◽  
Vol 9 (1) ◽  
pp. 32-51
Author(s):  
Revanuru Subramanyam
Keyword(s):  
Removal Efficiency ◽  
Loading Rate ◽  
Granular Sludge ◽  
Cod Removal ◽  
Synthetic Wastewater ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Cod Removal Efficiency ◽  
Start Up ◽  
Seed Sludge

This research article describes start-up performance of an UASB (Upflow Anaerobic Sludge Blanket) reactor in terms of chemical oxygen demand (COD) removal efficiency, biogas production, sludge loading rate (SLR), volatile fatty acids (VFA), pH, alkalinity, total solids (TS) and volatile suspended solids (VSS), fed with synthetic wastewater with increased concentrations of glucose. The reactor was loaded up to an OLR (Organic Loading Rate) of 15 kg COD m-3 d-1 and achieved a COD removal efficiency of 82 ±3%. The results showed that digested seed sludge was successfully acclimatized and transformed finally into granular sludge within a period of 120 days. An increase in the accumulation of VFA at high OLRs showed that methanogenesis could be the rate-limiting step in the reactor operation. The SLR and VSS/TS ratio were increased with an increase in OLR. During the initial stages, uniform distribution of VSS concentration and later on maximum VSS concentration were found at port number two at a height of 350 mm. The carbon balance depicts that the maximum percentage of influent COD converted to methane COD. An increase in specific methanogenic activity values with the age of sludge confirmed the transformation of the seed sludge in to a granular sludge.

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.

Physicochemical and Microbial Monitoring of UASB Sludge during Start-Up of Mesophilic Reactor

2005 ◽  
Vol 277-279 ◽  
pp. 552-558
Author(s):  
Yeong Hee Ahn ◽  
Young Jin Song ◽  
Hyo Seob Kim ◽  
You Jin Lee ◽  
Sung Hoon Park
Keyword(s):  
Production Rate ◽  
Removal Efficiency ◽  
Methane Production ◽  
Cod Removal ◽  
Laser Scanning Microscopy ◽  
Volume Index ◽  
Maximum Value ◽  
Cod Removal Efficiency ◽  
Start Up ◽  
Methane Production Rate

Anaerobically digested sludge was seeded in a mesophilic UASB reactor and the sludge was monitored for seven months to better understand the start-up process of the reactor. The reactor was fed with synthetic wastewater containing glucose. As the COD loading rate increased stepwise (from 1 to 4 g COD l-1 d-1), the methane production rate increased. COD removal efficiency was maintained to be greater than 90% after day 36. Maximum value of the methane production rate (6.0-6.5 l d-1) was achieved from day 152 and remained stable afterward. Although the reactor showed steady performance in terms of COD removal efficiency and methane production under constant hydraulic retention time (HRT) or COD loading rates, physicochemical and microbial properties of UASB sludge kept changing during the initial 5 months of operation. Specific methanogenic activity was initially negligible but increased until day 150, and then remained constant (0.72 + 0.11 g CH4-COD g-1 VSS d-1) afterward. Sludge volume index showed that the settling ability of UASB sludge gradually improved until it reached a plateau in day 120. Improved settling-ability could provide a basis for keeping bed height constant despite shortened HRT. The mean diameter of the UASB sludge gradually increased until approximately day 150 and maintained a maximum value (0.48 mm) afterward. Confocal laser scanning microscopy revealed F420-based autofluorescence of physical and optical sections of UASB sludge, suggesting the locations of autofluorescent methanogens in the UASB sludge during the start-up period. During the initial operation of the reactor, autofluorescence showed random and uneven distribution inside the sludge. However, autofluorescence appeared as an inner layer near the edge of the sludge with time, suggesting more abundant or active methanogens in this layer. The highest autofluorescence was observed in the range of 20 to 28 µm depth from the surface of granule as determined by optical slicing of UASB sludge. The results obtained in this study provide insight into UASB sludge development that involves dynamic changes in physicochemical and microbial aspects during the start-up period.

Process Characteristics Study of Anaerobic Baffled Reactor (ABR)

2010 ◽  
Vol 160-162 ◽  
pp. 1551-1557
Author(s):  
Lu Ning ◽  
Jin Liu
Keyword(s):  
Removal Efficiency ◽  
Ph Value ◽  
Granular Sludge ◽  
Cod Removal ◽  
Synthetic Wastewater ◽  
Anaerobic Baffled Reactor ◽  
Process Characteristics ◽  
Cod Removal Efficiency ◽  
Start Up ◽  
The Matrix

In this paper, Anaerobic Baffled Reactor (ABR) was applied to treat the synthetic wastewater in the matrix of starch and glucose. the reactor was started using low loading start-up , VLR controlled at 0.59~11.05kgCOD/m3•d, there are some granular sludge appeared after running 18 days. The figure and size of granular sludge in each compartment revealed different characteristics due to the changing of OLRs and shear force between gas and liquid in each compartment. The COD removal efficiency was higher than 90% and steady when the reactor’s start-up finished.When the anaerobic granular sludge appeared in the reactor, the VLR was 1.29kgCOD/(m3•d)、COD removal efficiency was 83％、hydraulic surface loading was 0.078m3/m2.h and an HRT was 30h. The VLR had remarkable influence on COD removal efficiency、VFA、pH and ALK. When VLR was 5.57kgCOD/(m3•d), COD removal efficiency and ALK were the minimum, VFA in the outflow exceeded 1000mg/L, reactor’s efficiency decreased .The reactor recovered after adjusting VLR and ALK value. Compared with the third and fourth compartments, the first and second compartments were less sensitive to changing of VFA. When pH deviated from adapt range, the COD removal efficiency was decreased obviously, so pH value was kept in the range of 6.2 to 6.5 for the later stage of experiments.

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