Treatment of low strength wastewater using compact submerged aerobic fixed film (SAFF) reactor filled with high specific surface area synthetic media

Abstract Studies on laboratory-scale submerged aerobic fixed film reactor (SAFF) packed with synthetic media having specific surface area of 165 m2/m3 with a void volume of 89% were carried out to assess its performance under various organic loading rates (OLR) and hydraulic retention times (HRT). Synthetic wastewater having chemical oxygen demand (COD) and biochemical oxygen demand (BOD) of 400 ± 10% and 210 ± 10% mg/L respectively was fed and the reactor was subjected to OLRs ranging from 0.37 to 1.26 kg COD/m3.d. It was observed that steady sloughing of biofilm occurs within the SAFF reactor all the times and average concentration of sloughed biomass in the effluent was 26 mg/L. The COD and BOD removal efficiencies varied between 85 and 89% and 86 to 94%, respectively. The kinetic studies demonstrated that SAFF reactor followed Stover–Kincannon and Grau models, with high correlation coefficients (R2) of 0.9977 and 0.9916, respectively. Thus, the values of kinetic coefficients such as maximum substrate utilization rate, Umax = 64.1 g/(L.d); saturation value constant, KB = 72.31 g/(L.d) and Grau second-order substrate removal rate constant, Ks = 2.44 day−1 can be useful to develop and design large scale SAFF reactors. Finally, the study reveals that the optimum range for OLR can vary within 0.68–0.94 kg COD/m3.d.

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Preparation of Adsorbent from Blue Coke Powder and its Application in Coking Wastewater

Materials Science Forum ◽

10.4028/www.scientific.net/msf.695.553 ◽

2011 ◽

Vol 695 ◽

pp. 553-556

Author(s):

Yu Hong Tian ◽

Xin Zhe Lan ◽

Qiu Li Zhang ◽

Juan Qin Xue ◽

Yong Hui Song ◽

...

Keyword(s):

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Removal Rate ◽

Nitrogen Concentration ◽

Ammonia Nitrogen ◽

Raw Material ◽

Coking Wastewater ◽

Adsorption Time ◽

Coke Powder

The low-cost blue coke industrial by-product, blue coke powder was used as raw material for the production of porous carbons adsorbent by steam activating at temperature of 800°C under the atmosphere of N2 for 60 minutes. The specific surface area and pore properties of the adsorbent were characterized by using N2 adsorption-desorption isotherms. Furthermore, the adsorption effects of the adsorbent for ammonia nitrogen in coking wastewater were investigated in terms of particle size, dosage of absorbent and adsorption time. The results show that the specific surface area is 620.94m2/g, the total pore volume is 0.4442cm3/g and the average mesopore size is 4.5808nm, the adsorbent possesses predominant mesoporous structures. In aeration, the removal rate of ammonia nitrogen can reach to 39.5% under the conditions of the ammonia nitrogen concentration of 625mg/L, the dosage of adsorbent 10g/L at the adsorption time of 60 minutes.

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Valorization of Moroccan Bentonite Deposits: “Purification and Treatment of Margin by the Adsorption Process”

Molecules ◽

10.3390/molecules26185528 ◽

2021 ◽

Vol 26 (18) ◽

pp. 5528

Author(s):

Hanane Ait Hmeid ◽

Mustapha Akodad ◽

Mourad Baghour ◽

Abdelmajid Moumen ◽

Ali Skalli ◽

...

Keyword(s):

Phenolic Compounds ◽

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Adsorption Process ◽

Oxygen Demand ◽

Exchange Capacity ◽

Diffraction Peak ◽

Basal Spacing ◽

Degree Of Hydration

The main objective of this work was to contribute to the reduction in the contamination of phenolic compounds contained in margin by an adsorption process on two types of raw bentonite. The margin used in the studies was collected from a semi-modern oil mill located in the Nador–Morocco region. The results of the physico-chemical analyses showed that the effluents of the oil mills showed that they are highly polluted, particularly in terms of the total suspended solids (TSS), chemical oxygen demand (COD), and iron content of around 154.82 (mg/L), and copper content of 31.72 (mg/L). The mineralogy of bentonites studied by X-ray diffraction (XRD) reveals the existence of two types of montmorillonite; theoretically, the diffraction peak (001) of the montmorillonite appears at 15 Å, with a basal spacing that corresponds to a calcium pole, and the diffraction peak (001) appears at 12Å, with a basal spacing that corresponds to a sodium pole. The specific surface area of the bentonite used is characterized by a large specific surface area, varying between 127.62 m2·g−1 and 693.04 m2·g−1, which is due to the presence of hydrated interleaved cations. This surface is likely to increase in aqueous solution depending on the solid/liquid ratio that modulates the degree of hydration. With a high cation exchange capacity (CEC) (146.54 meq/100 g), samples of margin mixed with raw bentonites at different percentages vary between 5% and 100%. The potential of Moroccan bentonite for the phenol adsorption of 9.17 (g/L) from aqueous solutions was investigated. Adsorption tests have confirmed the effectiveness of these natural minerals in reducing phenolic compounds ranging from 8.72% to 76.23% contained in the margin and the efficiency of heavy metal retention through microelements on raw bentonites. The very encouraging results obtained in this work could aid in the application of adsorption for the treatment of margin.

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Performance of anaerobic packed-bed system with different media characteristics

Water Science & Technology ◽

10.2166/wst.1996.0582 ◽

1996 ◽

Vol 34 (5-6) ◽

pp. 453-459 ◽

Cited By ~ 2

Author(s):

Joo-Hwa Tay ◽

S. Jeyaseelan ◽

Kuan-Yeow Show

Keyword(s):

Specific Surface ◽

Pore Size ◽

Surface Area ◽

Removal Efficiency ◽

Specific Surface Area ◽

Oxygen Demand ◽

Specific Area ◽

Packed Bed ◽

Cod Removal ◽

Cod Removal Efficiency

The effects of media specific surface area, porosity, and pore size on the performance of upflow anaerobic packed-bed reactors (APBRs) were examined in the laboratory. The results showed that, the APBR containing media of the lowest surface area but the largest pore size and porosity, demonstrated the highest chemical oxygen demand (COD) removal efficiencies of 90% and 73% at loading rates of 8 and 16 g COD/L.day, respectively. An increase of over 40% in specific area in an APBR had not improved the removal efficiency, instead it produced 16% lower in COD removal efficiency at loading rate of 16 g COD/L.d. A study on the effects of effluent recycle indicates that the APBR having the largest pore size and porosity benefited from the recirculation. The reactor exhibited an increase in overall COD removal efficiency of 8% and a substantial decrease in effluent COD concentration of 30%. The results suggest that media pore size and porosity play a more significant role than media specific surface area in the performance of upflow APBRs.

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Study of Sludge Particles Formed during Coagulation of Synthetic and Municipal Wastewater for Increasing the Sludge Dewatering Efficiency

Water ◽

10.3390/w11010101 ◽

2019 ◽

Vol 11 (1) ◽

pp. 101

Author(s):

Lech Smoczynski ◽

Slawomir Kalinowski ◽

Igor Cretescu ◽

Michal Smoczynski ◽

Harsha Ratnaweera ◽

...

Keyword(s):

Wastewater Treatment ◽

Specific Surface ◽

Size Distribution ◽

Surface Area ◽

Specific Surface Area ◽

Municipal Wastewater ◽

Wastewater Sludge ◽

Synthetic Wastewater ◽

Dye Molecules ◽

Sludge Dewatering

Municipal wastewater sludge was produced by chemical coagulation of synthetic wastewater (sww) based on Synthene Scarlet P3GL disperse dye and real municipal wastewater (nww), coagulated by commercial coagulants PAX (prepolymerised aluminum coagulant) and PIX (a ferric coagulant based on Fe2(SO4)3). An attempt was made to correlate the sludge’s dewatering capacity (in terms of capillary suction time—CST) with operation parameters for wastewater treatment, size distribution and specific surface area of the sludge particles. It was found that the presence of phosphate ions in the system facilitates the removal efficiency of the above-mentioned dye (L) due to the interaction between the dye molecules and H2PO4− ions. Unlike sww, negatively charged organic substances (sorg) in nww are directly adsorbed on the surface of colloidal particles {Fe(OH)3} and {Al(OH)3} (prtc). It was also discovered that an increase in the dose of a coagulant led to an increase of CST for sww sludge and to a decrease of CST for nww sludge. It has been suggested that flocs composed of spherical {Al(OH)3} units possessed more internal space for water than aggregates consisting of rod-shaped {Fe(OH)3} units and, consequently, it is more difficult to remove water from Al-sww sludge than from Fe-sww. The results obtained showed that smaller particles dominate in sww sludge, while larger particles are prevalent in nww sludge. To explain this distinct difference in the size distribution of particles in sludge obtained with the use of Al3+ and Fe3+, simple models of aggregation and agglomeration-flocculation processes (aaf) of treated wastewater have been proposed. Except for PIX in nww, the analyzed particles of the investigated types of sludge were characterized by similar specific surface area (Sps), regardless of the kind of sludge or the applied coagulant. Slightly larger, negatively-charged sorg bridges, anchored directly on the surface of positive prtc are more effective in closing the structure of nww sludge than small L bridges of the dye molecules anchored on the surface of prtc via H2PO4−. All the discovered aspects could lead to improved performance of wastewater treatment plants (WWTP) by increasing the efficiency of sludge dewatering.

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Selective adsorption of organic dyes by porous hydrophilic silica aerogels from aqueous system

Water Science & Technology ◽

10.2166/wst.2018.313 ◽

2018 ◽

Vol 78 (2) ◽

pp. 402-414 ◽

Cited By ~ 13

Author(s):

Wei Wei ◽

Huihui Hu ◽

Xuelin Ji ◽

Zaoxue Yan ◽

Wei Sun ◽

...

Keyword(s):

Particle Size ◽

Specific Surface ◽

Size Distribution ◽

Surface Area ◽

Specific Surface Area ◽

Silica Aerogel ◽

Organic Dyes ◽

Removal Rate ◽

Cationic Dyes ◽

Average Particle

Abstract Hydrophilic silica aerogel (HSA) was obtained by sol-gel method and dried at ambient conditions and further studied for the removal of organic dyes in water. Silica aerogel was characterized by its morphology, porous structure, specific surface area and particle size distribution by scanning electron microscopy, Brunauer–Emmett–Teller and pore size distribution. The HSA after calcination had a specific surface area of 888.73 m2/g and an average particle size of 2.6341 nm. Moreover, adsorption properties of the HSA toward organic dyes – adsorption conditions, kinetics data, and equilibrium model – were investigated. The removal rate of cationic dyes (rhodamine B (RhB), methylene blue (MB) and crystal violet (CV)) by HSA was up to 90%, while the removal rate of anionic dye (acid orange 7) was not more than 30%. The maximum adsorptions were: RhB 191.217 mg/g, MB 51.1601 mg/g and CV 24.85915 mg/g, respectively. Based on the adsorption mechanism of HSA for cationic/anionic dyes, the conclusion confirmed the prospect of HSA as effective adsorbent to treat cationic dyes wastewater.

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