scholarly journals Performance of a membrane bioreactor in extreme concentrations of bisphenol A

2018 ◽  
Vol 77 (6) ◽  
pp. 1505-1513 ◽  
Author(s):  
Yassine Ouarda ◽  
Mehdi Zolfaghari ◽  
Patrick Drogui ◽  
Brahima Seyhi ◽  
Gerardo Buelna ◽  
...  
Keyword(s):  
Bisphenol A ◽  
Removal Efficiency ◽  
Retention Time ◽  
Membrane Bioreactor ◽  
Heterotrophic Bacteria ◽  
Oxygen Demand ◽  
Ammonia Removal ◽  
Biodegradation Rate ◽  
Solid Retention Time ◽  
Submerged Membrane Bioreactor

Abstract In this study, a submerged membrane bioreactor was used to study the effect of low and high bisphenol A (BPA) concentration on the sludge biological activity. The pilot was operated over 540 days with hydraulic retention time and solid retention time of 5.5 hours and 140 days, respectively. As a hydrophobic compound, BPA was highly adsorbed by activated sludge. In lower concentrations, the biodegradation rate remained low, since the BPA concentration in the sludge was lower than 0.5 mg/g TS; yet, at an influent concentration up to 15 mg/L, the biodegradation rate was increasing, resulting in 99% BPA removal efficiency. The result for chemical oxygen demand removal showed that BPA concentration has no effect on the heterotrophic bacteria that were responsible for the organic carbon degradation. In higher concentrations, up to 16 mg of BPA was used for each gram of sludge as a source of carbon. However, the activity of autotrophic bacteria, including nitrifiers, was completely halted in the presence of 20 mg/L of BPA or more. Although nitrification was stopped after day 400, ammonia removal remained higher than 70% due to air stripping. Assimilation by bacteria was the only removal pathway for phosphorus, which resulted in an average 35% of P-PO4 removal efficiency.

scholarly journals Dynamics of Archaeal and Bacterial Communities in Response to Variations of Hydraulic Retention Time in an Integrated Anaerobic Fluidized-Bed Membrane Bioreactor Treating Benzothiazole Wastewater

Archaea ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Yue Li ◽  
Qi Hu ◽  
Da-Wen Gao
Keyword(s):  
Fluidized Bed ◽  
Removal Efficiency ◽  
Retention Time ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Hydraulic Retention Time ◽  
Oxygen Demand ◽  
High Strength ◽  
Service Period ◽  
Miseq Platform

An integrated anaerobic fluidized-bed membrane bioreactor (IAFMBR) was investigated to treat synthetic high-strength benzothiazole wastewater (50 mg/L) at a hydraulic retention time (HRT) of 24, 18, and 12 h. The chemical oxygen demand (COD) removal efficiency (from 93.6% to 90.9%), the methane percentage (from 70.9% to 69.27%), and the methane yield (from 0.309 m3 CH4/kg·CODremoved to 0.316 m3 CH4/kg·CODremoved) were not affected by decreasing HRTs. However, it had an adverse effect on membrane fouling (decreasing service period from 5.3 d to 3.2 d) and benzothiazole removal efficiency (reducing it from 97.5% to 82.3%). Three sludge samples that were collected on day 185, day 240, and day 297 were analyzed using an Illumina® MiSeq platform. It is striking that the dominant genus of archaea was always Methanosaeta despite of HRTs. The proportions of Methanosaeta were 80.6% (HRT 24), 91.9% (HRT 18), and 91.2% (HRT 12). The dominant bacterial genera were Clostridium in proportions of 23.9% (HRT 24), 16.4% (HRT 18), and 15.3% (HRT 12), respectively.

Treatment of Landfill Leachate by Combined Submerged Membrane Bioreactor (SMBR) and Electrochemical Oxidation

2020 ◽  
Vol 12 (7) ◽  
pp. 953-960
Author(s):  
Bo Peng ◽  
Di Qiu ◽  
Xiaogang Wu
Keyword(s):  
Electrochemical Oxidation ◽  
Removal Efficiency ◽  
Landfill Leachate ◽  
Membrane Bioreactor ◽  
Carbon Particle ◽  
Three Dimensional ◽  
Oxygen Demand ◽  
Ammonia Nitrogen ◽  
Chloride Ions ◽  
Submerged Membrane Bioreactor

To efficiently treat landfill leachate, we prepared a new integrated submerged membrane bioreactor (SMBR) and oxidation technology. Our results, under organic loading rates of 2.0–2.3 kg COD/(m3 ·d), showed that through SMBR we can acquire removal efficiencies of 91.2% and 87.3% for ammonia and chemical oxygen demand (COD), respectively. A Ti/RuO2–IrO2 anode and stainless-steel cathode combination was engaged to carry out electrochemical oxidation of SMBR permeate. Ammonia and COD were removed after 3 h electrochemical oxidation (at 40 mA/cm2 current density), and achieved 93.5% and 66.9% removal efficiency with activated carbon particle electrode introduced in the three-dimensional electrodes, respectively. The higher removal efficiency for ammonia nitrogen than COD can be rendered by excited chloride ions, as they affect the competition between organic matter and ammonia nitrogen. Thus, SMBR combined with electrochemical oxidation possesses good prospects to be applied for efficient reduction of ammonia and COD in landfill leachates.

The effect of aeration and non-aeration time on simultaneous organic, nitrogen and phosphorus removal using an intermittent aeration membrane bioreactor

2002 ◽  
Vol 46 (9) ◽  
pp. 193-200 ◽  
Author(s):  
Z. Ujang ◽  
M.R. Salim ◽  
S.L. Khor
Keyword(s):  
Removal Efficiency ◽  
Retention Time ◽  
Phosphorus Removal ◽  
Organic Nitrogen ◽  
Membrane Bioreactor ◽  
Synthetic Wastewater ◽  
Intermittent Aeration ◽  
Nitrogen And Phosphorus ◽  
Solid Retention Time ◽  
Aeration Time

A laboratory-scale membrane bioreactor (MBR) was fed with synthetic wastewater to investigate the possibility of simultaneous removal of organic, nitrogen and phosphorus by intermittent aeration. The MBR consists of two compartments using a microfiltration membrane with 0.2 mm pore size and a surface area of 0.35 m2. Hydraulic retention time was set at 24 hours and solid retention time 25 days. MLSS concentration in the reactor was in the range of 2,500-3,800 mg/L. The MLSS internal recycling ratio was maintained at 100% influent flow rate. Intermittent aeration was applied in this study to provide an aerobic-anaerobic cycle. Three stages of operations were conducted to investigate the effect of aeration and non-aeration on simultaneous organic and nutrient removal. In Stage 1, time cycles of aeration and non-aeration were set at 90/150 min and 150/90 min in the first and second compartment, the removal efficiency was 97%, 94% and 70% for COD, nitrogen and phosphorus respectively. In Stage 2, time cycles of aeration and non-aeration were set at 60/120 min and 120/60 min in the first and second compartment, the removal efficiency was 97%, 96% and 71% for COD, nitrogen and phosphorus respectively. In Stage 3, time cycles of aeration and non-aeration were set at 120/120 min and 120/120 min in compartment 1 and 2, the removal efficiency was 98%, 96% and 78% for COD, nitrogen and phosphorus respectively. Results show that longer non-aeration time in the second compartment provided better performances of biological phosphorus removal.

Effect of 200 days' sludge retention time on performance of a pilot scale submerged membrane bioreactor for high strength industrial wastewater treatment

2006 ◽  
Vol 53 (11) ◽  
pp. 269-276 ◽  
Author(s):  
C.T. Hay ◽  
D.D. Sun ◽  
S.L. Khor ◽  
J.O. Leckie
Keyword(s):  
Retention Time ◽  
Industrial Wastewater ◽  
Membrane Bioreactor ◽  
Hydraulic Retention Time ◽  
High Strength ◽  
Pilot Scale ◽  
Submerged Membrane Bioreactor ◽  
Sludge Retention Time ◽  
Organic Removal ◽  
Sludge Concentration

A high strength industrial wastewater was treated using a pilot scale submerged membrane bioreactor (MBR) at a sludge retention time (SRT) of 200 d. The MBR was operated at a high sludge concentration of 20 g/L and a low F/M ratio of 0.11 during 300 d of operation. It was found that the MBR could achieve COD and TOC overall removal efficiencies at more than 99 and 98% TN removal. The turbidity of the permeate was consistently in the range of 0.123 to 0.136 NTU and colour254 absorbance readings varied from 0.0912 to 0.0962 a.u. cm−1. The sludge concentration was inversely proportional to the hydraulic retention time (HRT), yielded excellent organic removal and extremely low sludge production (0.0016 kgVSS/day).

Influence of HRT (hydraulic retention time) and SRT (solid retention time) on the hydrolytic pre-treatment of urban wastewater

2001 ◽  
Vol 44 (4) ◽  
pp. 7-14 ◽  
Author(s):  
P. Ligero ◽  
A. De Vega ◽  
M. Soto
Keyword(s):  
Retention Time ◽  
Volatile Fatty Acids ◽  
Oxygen Demand ◽  
Phase Iii ◽  
Urban Wastewater ◽  
Solid Retention Time ◽  
Start Up ◽  
Pre Treatment ◽  
Two Parameters ◽  
Hydrolysis Of

This work presents the results obtained from a study on the pretreatment of urban wastewater using a digester that acted as a system for the retention of solids (sedimentation-filtration), hydrolysis of the retained solids and acidification of the dissolved substances. After start-up (Phase I), the digester was operated at hydraulic retention times (HRT) of 4.4, 3.4 and 2.2 h and at solid retention times (SRT) of 24, 16 and 14 d, during Phases II, III and IV, respectively. The retention and removal of suspended solids (SS) was maintained slightly above 60%, independently of HRT and SRT. Conversely, eliminated chemical oxygen demand (COD) decreased slightly upon reducing HRT and SRT. The influence of these two parameters on the generation of volatile fatty acids (VFA) is more notable, reaching effluent VFA concentration of 29 (Phase II), 96 (Phase III), and 107 (Phase IV) mg COD/l. VFA to SS generation ratios were 0.13 (II), 0.35 (III), and 0.48 (IV) g VFACOD/g SS added. Optimum values were reached at an HRT of 2.2 h. Taking 100 kg influent COD as a base, the conversion of different kinds of COD was as follows (in kg influent:kg effluent): VFACOD (4:17), non-VFA soluble COD (45:23), VSSCOD (51:23). Simultaneously to these conversions, 2 kg VSSCOD are generated as purge stream and 35 kg COD are eliminated during the process.

scholarly journals The potential of ultrasonic membrane anaerobic systems in treating slaughterhouse wastewater

2015 ◽  
Vol 5 (3) ◽  
pp. 293-300 ◽  
Author(s):  
N. H. Abdurahman ◽  
Y. M. Rosli ◽  
N. H. Azhari ◽  
Hayder A. Bari
Keyword(s):  
Steady State ◽  
Removal Efficiency ◽  
Retention Time ◽  
Suspended Solids ◽  
Oxygen Demand ◽  
Yield Coefficient ◽  
Slaughterhouse Wastewater ◽  
Mixed Liquor ◽  
Solids Retention Time ◽  
Solids Retention

Direct discharge of slaughterhouse wastewater causes serious environmental pollution due to its high chemical oxygen demand (COD), total suspended solids (TSS) and biochemical oxygen demand. In this study, an ultrasonic-assisted membrane anaerobic system was used as a novel method for treating slaughterhouse wastewater. Six steady states were achieved, using concentrations of 7,800–13,620 mg/l for mixed liquor suspended solids and 5,359–11,424 mg/l for mixed liquor volatile suspended solids (MLVSS). Kinetic equations were used to describe the kinetics of treatment at organic loading rates of 3–11 kg COD/m3/d. The removal efficiency of COD was 94.8–96.5% with hydraulic retention times of 308.6–8.7 days. The growth yield coefficient was found to be 0.52 g VSS/g. COD was 0.21 d−1 and methane gas production rate was 0.24–0.56 l/g COD/d. Steady-state influent COD concentrations increased from 8,000 mg/l in the first steady state to 25,400 mg/l in the sixth steady state. The minimum solids retention time, θcmin obtained from the three kinetic models was 6–14.4 days. The k values were 0.35–0.519 g COD/g VSS.d and μmax values were between 0.26 and 0.379 d−1. The solids retention time decreased from 600 to 14.3 days. The complete treatment reduced the COD content and its removal efficiency reached 94.8%.

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