scholarly journals Biodegradation of main carbon sources in vinasse stillage by a mixed culture of bacteria: influence of temperature and pH of the medium

2018 ◽  
Vol 78 (4) ◽  
pp. 764-775 ◽  
Author(s):  
Agnieszka Ryznar-Luty ◽  
Edmund Cibis ◽  
Krzysztof Lutosławski
Keyword(s):  
Mixed Culture ◽  
Organic Pollutants ◽  
Carbon Sources ◽  
Oxygen Demand ◽  
Aerobic Biodegradation ◽  
Medium Ph ◽  
Initial Ph ◽  
Fourth Series ◽  
Soluble Chemical Oxygen Demand ◽  
Available Carbon

Abstract The aim of the study was to examine how temperature and the pH influence the progress and efficiency of an aerobic biodegradation process, where major organic pollutants are removed from beet molasses vinasse by a mixed culture of Bacillus bacteria. It was conducted in an aerated bioreactor with a stirring system in four experimental series, each composed of five processes run at temperatures of 27, 36, 45, 54 and 63 °C. In the first and second series, medium pH was not controlled, the initial pH amounted to 6.5 and 8.0, respectively. In the third and fourth series, medium pH was controlled at 6.5 and 8.0, respectively. Under optimal conditions, the pollution load of the vinasse stillage expressed as soluble chemical oxygen demand was removed with an 88.73% efficiency. The bacterial culture assimilated all organic pollutants simultaneously, but the rate of assimilation was different. An exception was the process of betaine assimilation, which intensified only when readily available carbon sources were depleted in the medium. Synthesis and assimilation of organic acids were observed in all experiments. Advantages of the proposed method include: possibility of its use at high temperatures, and no necessity for medium pH adjustment during the process.

scholarly journals Efficiency of aerobic biodegradation of beet molasses vinasse under non-controlled pH: conditions for betaine removal / Efektywność tlenowej biodegradacji buraczanego wywaru melasowego przy nieregulowanym pH podłoża: określenie warunków usunięcia betainy

2015 ◽  
Vol 41 (1) ◽  
pp. 3-14 ◽  
Author(s):  
Agnieszka Ryznar-Luty ◽  
Edmund Cibis ◽  
Małgorzata Krzywonos ◽  
Tadeusz Miśkiewicz
Keyword(s):  
High Efficiency ◽  
Oxygen Demand ◽  
Aerobic Biodegradation ◽  
Batch Processes ◽  
Bacterial Strains ◽  
Beet Molasses ◽  
Initial Ph ◽  
Solids Separation ◽  
Soluble Chemical Oxygen Demand ◽  
Ph Conditions

Abstract The aim of the study was to establish such conditions that would provide high-efficiency aerobic biodegradation of beet molasses vinasse with a mixed culture of thermo- and mesophilic bacteria of the genus Bacillus in batch processes without controlling the pH of the medium. Particular consideration was given to the betaine removal (the main pollutant of vinasse), which accounted for as much as 37.6% of total organic carbon. Biodegradation was performed in a stirred tank reactor at 27-63°C with initial pH (pH0) of 6.5 and 8.0. Efficiency of biodegradation was expressed in terms of reduction in SCODsum, which is a sum of SCOD (soluble chemical oxygen demand, i.e. COD determined after suspended solids separation) and theoretical COD of betaine. The values achieved at 27 and 36°C with pH0 = 8.0 exceeded 77.7%, whereas those obtained at 36 and 45°C with pH0 = 6.5 were higher than 83.6%. The high biodegradation efficiency obtained in the four processes is attributable to the betaine removal by the bacterial strains used in the study. Maximal extent of reduction in SCODsum (85.41%), BOD5 (97.91%) and TOC (86.32%), and also the fastest rate of biodegradation (1.17 g O2/l∙h) was achieved at 36°C and pH0 = 8.0

Highly efficient enhancement of municipal sludge dewaterability using persulfate activation with nZVI/HA

2019 ◽  
Vol 79 (7) ◽  
pp. 1309-1315
Author(s):  
Hao Li ◽  
Lei Song ◽  
Baohong Han ◽  
Hongwei Song ◽  
Runying Bai ◽  
...  
Keyword(s):  
Oxygen Demand ◽  
Potential Method ◽  
Municipal Sludge ◽  
Volume Percentage ◽  
Sludge Flocs ◽  
Reduction Efficiency ◽  
Initial Ph ◽  
Soluble Chemical Oxygen Demand ◽  
Persulfate Activation ◽  
Sludge Dewaterability

Abstract This study presents a sulfate radical-based oxidation method for improving municipal sludge dewaterability by combining persulfate and nanoscale zero-valent iron supported on humic acid (nZVI/HA-PS). Sludge dewaterability using persulfate activation with nZVI/HA was assessed for specific resistance to filterability (SRF), time to filter (TTF), settling volume percentage (SV30) and water content (Wc). The influencing factors, such as mass ratios of nZVI to HA, initial pH, PS dosage and nZVI/HA nanocomposite dosage, were investigated. Experimental results indicated that the SRF reduction efficiency of the sludge reached 86.47% using initial concentrations of 1.2 mmol/gVSS PS and 300 mg/L nZVI/HA. The soluble chemical oxygen demand (SCOD) of sludge supernatants increased from 79 mg/L to 710 mg/L under optimum conditioning, indicating that sludge flocs were effectively decomposed. Economic analysis demonstrated that the nZVI/HA-PS conditioning process is a potential method for improving sludge dewaterability.

The Effects of Alkaline Treatment on Excess Sludge Supernatant Characteristics

2013 ◽  
Vol 361-363 ◽  
pp. 1046-1049 ◽  
Author(s):  
Ting Ting Li ◽  
Zhi Min Fu
Keyword(s):  
Ph Value ◽  
Sodium Hydroxide Solution ◽  
Alkali Treatment ◽  
Oxygen Demand ◽  
Alkaline Treatment ◽  
Maximum Amount ◽  
Batch Experiments ◽  
Excess Sludge ◽  
Initial Ph ◽  
Soluble Chemical Oxygen Demand

The effect of alkali treatment on excess sludge supernatant characteristics was studied in this experiment. 4 mol/L sodium hydroxide solution was utilized to adjust the initial pH value of excess sludge to 9.0, 11.0 and 13.0. Batch experiments were operated in 35 °C shaking bath for 12 h. The soluble chemical oxygen demand (SCOD), protein and polysaccharide concentration in excess sludge supernatant was measured every 3 h. The experimental results showed that maximum amount of protein, polysaccharide and SCOD were obtained when the initial pH value was 13.0.

scholarly journals Ozonation of return activated sludge for disintegration and solubilisation with synthesized titanium oxide as catalyst

2018 ◽  
Vol 34 ◽  
pp. 02009
Author(s):  
S.F.Z. Mohd Sarif ◽  
S.S. Alias ◽  
F. Muhammad Ridwan ◽  
K.S. Ku Salim ◽  
C.Z.A. Abidin ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Oxygen Demand ◽  
Total Suspended Solid ◽  
Suspended Solid ◽  
Catalytic Ozonation ◽  
Lower Amount ◽  
Sludge Flocs ◽  
Initial Ph ◽  
Soluble Chemical Oxygen Demand ◽  
Ozonation Process

Ozonation of activated sludge in the present of titanium dioxide (TiO2) as catalyst to enhance the production of hydroxyl radical was evaluated in comparison to the sole ozonation process. In this process, the catalytic ozontion showed improvement in increasing ozone consumption and improving activated sludge disintegration and solubilisation. The reduction of total suspended solid (TSS), volatile suspended solid (VSS) and soluble chemical oxygen demand (SCOD) solubilisation was better in the catalytic ozonation system. Initial pH 7 of activated sludge was found best to disintegrate and solubilise the sludge flocs. However upon additional of sodium hydroxide (NaOH) in pH adjustment enhanced the solubilisation of organic matter from the flocs and cells, making the initial pH 9 is the best condition for activated sludge solubilisation. Yet the initial pH 7 of activated sludge supernatant was the best condition to achieve SCOD solubilisation due to sludge floc disintegration, when it had stronger correlation between TSS reduction and SCOD solubilisation (R2=0.961). Lower amount of catalyst of 100 mgTiO2/gTSS was found to disintegrate and solubilise the activated sludge better with 30.4% TSS reduction and 25.2% SCOD solubilisation efficiency, compared to 200 mgTiO2/gTSS with 21.9% and 17.1% TSS reduction and SCOD solubilisation, respectively.

Advanced nitrogen elimination by encapsulated nitrifiers

2003 ◽  
Vol 48 (8) ◽  
pp. 19-26 ◽  
Author(s):  
M. Sievers ◽  
K.-D. Vorlop ◽  
J. Hahne ◽  
M. Schlieker ◽  
S. Schäfer
Keyword(s):  
Hydraulic Retention Time ◽  
Carbon Sources ◽  
Oxygen Demand ◽  
Reaction Rates ◽  
Substantial Contribution ◽  
Reaction Volume ◽  
Nitrification Process ◽  
Soluble Chemical Oxygen Demand ◽  
Nitrogen Elimination ◽  
Denitrification Process

By introducing a mixed population of nitrifiers encapsulated in gel lens beads a more selective nitrification process was found in treatment of settled sewage in lab scale at a hydraulic retention time (HRT) of about 30 to 60 minutes. The reaction rates for oxidation of soluble chemical oxygen demand (SCOD) were found to vary between 25 to 150 mg/L·h while nitrification takes place around 50 mg nitrogen per hour and litre reaction volume. However, based on this SCOD removal in the nitrification step, a consequent post-denitrification process without nitrate recycle and dosage of external carbon sources has been proven to reach substantial nitrate elimination of up to 20 mg nitrogen per litre at COD/N-ratios of approx. 6 in settled sewage. At such COD/N-ratios, suitable nitrogen elimination seems to be possible, because the bioflocs of settled sewage, produced so far by SCOD oxidation and entrapment of particulate COD, are passing through the nitrification process having a substantial contribution to the denitrification rate additionally to the remaining SCOD.

Anaerobic/aerobic biodegradation of pentachlorophenol using GAC fluidized bed reactors: optimization of the empty bed contact time

1997 ◽  
Vol 36 (6-7) ◽  
pp. 107-115 ◽  
Author(s):  
Gregory J. Wilson ◽  
Amid P. Khodadoust ◽  
Makram T. Suidan ◽  
Richard C. Brenner
Keyword(s):  
Fluidized Bed ◽  
Oxygen Demand ◽  
Aerobic Biodegradation ◽  
Fluidized Bed Reactors ◽  
Reactor Performance ◽  
Reactor Operation ◽  
Significant Cost ◽  
Second Stage ◽  
Primary Substrate ◽  
Chlorinated Phenolic Compounds

An integrated reactor system has been developed to remediate pentachlorophenol (PCP) containing wastes using sequential anaerobic and aerobic biodegradation. Anaerobically, PCP was degraded to predominately equimolar concentrations (>99%) of monochlorophenol (MCP) in two GAC fluidized bed reactors at Empty Bed Contact Times (EBCTs) ranging from 18.6 to 1.15 hours. However, at lower EBCTs, MCP concentrations decreased to less than 10% of the influent PCP concentration suggesting mineralization. The optimal EBCT was determined to be 2.3 hours based on PCP conversion to MCPs and stable reactor operation. Decreasing the EBCT fourfold did not inhibit degradation of PCP and its intermediates, thus allowing removal of PCP at much lower detention time and resulting in a significant cost advantage. Analytical grade PCP was fed via syringe pumps into two fluidized bed reactors at influent concentrations of 100 mg/l and 200 mg/l, respectively. Acting as the primary substrate, ethanol was also fed into the reactors at concentrations of 697 and 1388 mg/l. Effluent PCP and chlorinated phenolic compounds were analyzed weekly to evaluate reactor performance. Biodegradation pathways were also identified. 3-chlorophenol (CP) was the predominant MCP and varied simultaneously with 3,5-dichlorophenol (DCP) concentrations. Likewise, 4-CP concentrations varied simultaneously with 3,4-DCP concentrations. A second stage aerobic GAC fluidized bed reactor was added after the anaerobic reactor to completely mineralize the remaining MCP and phenols. Data show no presence of phenol and MCP in the effluent or on the GAC. Overall, the chemical oxygen demand (COD) fed to the system was reduced from 75 g/d in the influent to less than 1.5 g/d in the effluent.

scholarly journals The Use of Sodium Carbonate—Hydrogen Peroxide (2/3) in the Modified Fenton Reaction to Degradation PAHs in Coke Wastewater

Proceedings ◽  
2019 ◽  
Vol 16 (1) ◽  
pp. 44
Author(s):  
Kozak ◽  
Włodarczyk-Makuła
Keyword(s):  
Hydrogen Peroxide ◽  
Organic Pollutants ◽  
Sodium Carbonate ◽  
Uv Light ◽  
Oxygen Demand ◽  
Organic Matrix ◽  
Coke Wastewater ◽  
Polycyclic Aromatic ◽  
Pahs Concentration ◽  
Modified Fenton

The aim of the research was to determine the effectiveness of removing micro-organic pollutants, including PAHs, using the modified Fenton method. The tested material was pretreated coke wastewater, in which the initial chemical oxygen demand (COD) value and initial polycyclic aromatic hydrocarbons (PAHs) concentration were determined. The samples were then subjected to an oxidation procedure. Before the process, the pH was adjusted to 3.5–3.8. Next, the following doses of sodium carbonate—hydrogen peroxide (2/3): 1.2 g/L, 1.5 g/L and 2 g/L, and a constant dose of iron sulphate were added. The next step was exposing the samples to UV light for 6 min and separating the organic matrix from the samples of wastewater. After the tests, the final value of the COD and the final PAHs concentration were determined. The average content of organic pollutants in pretreated coke wastewater determined by the COD index was 538 mg/L, and after the oxidation process, the COD index decreased in the range from 9 to 29%. The efficiency of the degradation of the sum of 16 PAHs was varied and was in the range of 94–97.6%. The research results show that sodium carbonate—hydrogen peroxide (2/3) can be used for the degradation of organic pollutants, such as PAHs, in the modified Fenton process.

Biofuel production from bio-waste by biological and physical conversion processes

2019 ◽  
Vol 38 (1) ◽  
pp. 69-77
Author(s):  
Noppawan Photong ◽  
Jaruwan Wongthanate
Keyword(s):  
Water Hyacinth ◽  
Oxygen Demand ◽  
Cassava Starch ◽  
Biofuel Production ◽  
Conversion Process ◽  
Electricity Production ◽  
Biological Conversion ◽  
Initial Ph ◽  
Biomethane Production ◽  
Product Standard

This research is focused on the feasibility of biofuel from water hyacinth mixed with cassava starch sediment by biological and physical conversion processes and the comparison of the gross electricity production in these processes. The biological conversion process produced biomethane by anaerobic digestion. The optimal conditions of biomethane production were a ratio of water hyacinth and cassava starch sediment at 25:75, initial pH of 7.5, thermophilic temperature (55 ± 2°C) and C/N ratio of 30. The maximum biomethane yield measured was 436.82 mL CH4 g chemical oxygen demand (COD)−1 and the maximum COD removal was 87.40%. The physical conversion process was bio-briquette. It was found that the ratios of water hyacinth and cassava starch sediment at 10:90, 20:80, 30:70, 40:60 and 50:50 were the best ratio of fuel properties and close to the Thai Community Product Standard, with heating values of 15.66, 15.43, 15.10, 14.88 and 14.58 MJ kg−1, respectively. Moreover, results showed that the gross electricity production of the biological conversion process (biomethane) was 3.90 kWh and the gross electricity production of the physical conversion process (bio-briquette) from the ratios of water hyacinth and cassava starch sediment at 10:90, 20:80, 30:70, 40:60 and 50:50 were 1.52, 1.50, 1.47, 1.45 and 1.42 kWh, respectively.

Electrochemical Treatment of Simulated Dye Wastewater

2012 ◽  
Vol 441 ◽  
pp. 555-558
Author(s):  
Feng Tao Chen ◽  
San Chuan Yu ◽  
Xing Qiong Mu ◽  
Shi Shen Zhang
Keyword(s):  
Current Density ◽  
Oxygen Demand ◽  
Electrochemical Treatment ◽  
Dye Wastewater ◽  
Electrolysis Time ◽  
Electrochemical Degradation ◽  
Mild Conditions ◽  
Thermal Decomposition Method ◽  
Initial Ph ◽  
Effects Of Ph

The Ti/SnO2-Sb2O3/PbO2 electrodes were prepared by thermal decomposition method and its application in the electrochemical degradation of a heteropolyaromatic dye, Methylene blue (MB), contained in simulated dye wastewater were investigated under mild conditions. The effects of pH, current density and electrolysis time on de-colorization efficiency were also studied. Chemical oxygen demand (COD) was selected as another parameter to evaluate the efficiency of this degradation method on treatment of MB wastewater. The results revealed that when initial pH was 6.0, current density was 50 mA·cm2, electrolysis time was 60 min, Na2SO4 as electrolyte and its concentration was 3.0 g·dm3, the de-colorization and COD removal efficiency can reach 89.9% and 71.7%, respectively.

scholarly journals Modelization of Nutrient Removal Processes at a Large WWTP Using a Modified ASM2d Model

2018 ◽  
Vol 15 (12) ◽  
pp. 2817 ◽  
Author(s):  
Jakub Drewnowski ◽  
Jacek Makinia ◽  
Lukasz Kopec ◽  
Francisco-Jesus Fernandez-Morales
Keyword(s):  
Nutrient Removal ◽  
Carbon Sources ◽  
Oxygen Demand ◽  
Full Scale ◽  
Biological Nutrient Removal ◽  
Organic Substrates ◽  
Modified Model ◽  
Rate Limiting Step ◽  
Uptake Rates ◽  
Rate Limiting

The biodegradation of particulate substrates starts by a hydrolytic stage. Hydrolysis is a slow reaction and usually becomes the rate limiting step of the organic substrates biodegradation. The objective of this work was to evaluate a novel hydrolysis concept based on a modification of the activated sludge model (ASM2d) and to compare it with the original ASM2d model. The hydrolysis concept was developed in order to accurately predict the use of internal carbon sources in enhanced biological nutrient removal (BNR) processes at a full scale facility located in northern Poland. Both hydrolysis concepts were compared based on the accuracy of their predictions for the main processes taking place at a full-scale facility. From the comparison, it was observed that the modified ASM2d model presented similar predictions to those of the original ASM2d model on the behavior of chemical oxygen demand (COD), NH4-N, NO3-N, and PO4-P. However, the modified model proposed in this work yield better predictions of the oxygen uptake rate (OUR) (up to 5.6 and 5.7%) as well as in the phosphate release and uptake rates.

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