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.

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.

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 Improved sludge dewaterability and hydrolysis performance after pretreatment with Fenton's reagent

2017 ◽  
Vol 77 (1) ◽  
pp. 204-210 ◽  
Author(s):  
Hongying Yuan ◽  
Yuping Yang ◽  
Jian Yuan ◽  
Yanning Wang ◽  
Yameng Song ◽  
...  
Keyword(s):  
Volatile Fatty Acids ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Fenton’S Reagent ◽  
Excess Sludge ◽  
Reaction Conditions ◽  
Fenton's Reagent ◽  
Soluble Polysaccharide ◽  
Soluble Chemical Oxygen Demand ◽  
Sludge Dewaterability

Abstract The dewaterability of excess sludge significantly improved upon pretreatment with Fenton's reagent in this study. After 0.9 g/L of Fe2+ and 5.0 g/L of H2O2 were added to the sludge, and reacted for 2 h at pH = 4, the specific resistance to filtration (SRF) of the excess sludge decreased from an initial value of 29.74 × 1012 m/kg to 6.49 × 1012 m/kg. The factors that affected this improvement in sludge dewaterability as evaluated by SRF reduction showed the following order: H2O2 > pH > Fe2+ > reaction time. Furthermore, the hydrolysis performance of the sludge under the optimal reaction conditions was investigated. The results indicated that the concentration of soluble chemical oxygen demand in the supernatant increased almost 14 times compared to raw sludge, and the contents of soluble protein and soluble polysaccharide were more than 8 and 17 times higher, respectively, than for the untreated situation. However, the amounts of ammonia nitrogen (NH4+-N) and phosphate (PO43−-P) released from the sludge showed different trends: NH4+-N increased by 200%, while PO43−-P decreased by 82%. The production of volatile fatty acids (VFAs) from the treated sludge showed that total VFAs increased by 66%, and iso-butylacetic acid was the dominant product among the total VFAs.

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 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

Observations on ozone treatment of excess sludge

2007 ◽  
Vol 56 (9) ◽  
pp. 167-175 ◽  
Author(s):  
Y.X. Zhao ◽  
J. Yin ◽  
H.L. Yu ◽  
N. Han ◽  
F.J. Tian
Keyword(s):  
Total Nitrogen ◽  
Total Phosphorus ◽  
Organic Phosphorus ◽  
Substantial Reduction ◽  
Oxygen Demand ◽  
Ozone Treatment ◽  
Sludge Flocs ◽  
Ozone Dose ◽  
Soluble Chemical Oxygen Demand ◽  
Extracellular Materials

This work experimentally studied the effects of ozonation treatment on waste sludge. During the treatment process, various parameters characterizing sludge were investigated. A substantial reduction in the volume of sludge and the release of intracellular and extracellular materials were observed. With the increase of ozone dose, the settleability and water content of sludge improved obviously, but the filterability of sludge deteriorated drastically. In addition, the evolution of particle size was evaluated, which proved the breakup of sludge flocs and cells. There existed a threshold of ozone dose which was 0.04 gO3/gMLSS in this work. Above the threshold, the soluble chemical oxygen demand (SCOD), protein, carbohydrate, total nitrogen and total phosphorus in supernatant increased remarkably and the electron transport system (ETS) sludge activity decreased. Organic nitrogen and organic phosphorus occupied the main part of total nitrogen and total phosphorus in the supernatant.

Effect of Pypocholoride Pretreatment on the Disintegration of Excess Sludge

2013 ◽  
Vol 864-867 ◽  
pp. 1333-1336 ◽  
Author(s):  
Ling Ling Wang ◽  
De Dong Sun ◽  
Jing Jing Ren ◽  
Chun Ma ◽  
Jun Hao ◽  
...  
Keyword(s):  
Reaction Time ◽  
Sewage Sludge ◽  
Chemical Oxygen Demand ◽  
Sodium Hypochlorite ◽  
Cell Walls ◽  
Oxygen Demand ◽  
Excess Sludge ◽  
Organic Matters ◽  
Sludge Flocs ◽  
Soluble Chemical Oxygen Demand

This article focuses on the effects of pretreatment on sewage sludge with sodium hypochlorite addition. The solubilization of organic matters of sludge was investigated. It was found that the pypocholoride treatment provided a efficient process to release organics from sludge flocs. When the ClO-dose was about 21mg /g SS with a reaction time of 3 hours, the supernatant soluble chemical oxygen demand (SCOD), total nitrogen (TN), total phosphorus (TP), protein and polysaccharide increased by 400%, 67%, 1791%, 635%, 214%, and 556%, respectively. After hypochlorite pretreatment, the sludge extracelluar polymers (EPS) were disintegrated and the cell walls were broken. Then the intracellular organic matters were released into the supernatant, leading to the increase of organic matters in the supernatant.

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.

Anaerobic co-digestion of winery waste and waste activated sludge: assessment of process feasibility

2013 ◽  
Vol 69 (2) ◽  
pp. 269-277 ◽  
Author(s):  
C. Da Ros ◽  
C. Cavinato ◽  
F. Cecchi ◽  
D. Bolzonella
Keyword(s):  
Activated Sludge ◽  
Biogas Production ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Waste Activated Sludge ◽  
Organic Loading ◽  
Operational Conditions ◽  
Loading Rates ◽  
Thermophilic Conditions ◽  
Soluble Chemical Oxygen Demand

In this study the anaerobic co-digestion of wine lees together with waste activated sludge in mesophilic and thermophilic conditions was tested at pilot scale. Three organic loading rates (OLRs 2.8, 3.3 and 4.5 kgCOD/m3d) and hydraulic retention times (HRTs 21, 19 and 16 days) were applied to the reactors, in order to evaluate the best operational conditions for the maximization of the biogas yields. The addition of lee to sludge determined a higher biogas production: the best yield obtained was 0.40 Nm3biogas/kgCODfed. Because of the high presence of soluble chemical oxygen demand (COD) and polyphenols in wine lees, the best results in terms of yields and process stability were obtained when applying the lowest of the three organic loading rates tested together with mesophilic conditions.

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