Influence of organic loading rate on membrane fouling in membrane separation activated sludge process

2000 ◽  
Vol 41 (10-11) ◽  
pp. 355-362 ◽  
Author(s):  
N. Nagaoka ◽  
S. Kono ◽  
S. Yamanishi ◽  
A. Miya
Keyword(s):  
Activated Sludge ◽  
Membrane Fouling ◽  
Loading Rate ◽  
Membrane Separation ◽  
Membrane Surface ◽  
Organic Loading Rate ◽  
Sudden Increase ◽  
Organic Loading ◽  
Filtration Resistance ◽  
Scale Experiment

A Laboratory-scale experiment was conducted to investigate the influence of organic loading rate to a reactor on the bio fouling in a membrane separation activated sludge system. A flat-sheet-type membrane module was used and the change of the pressure and the filtration resistance were measured. Using synthetic substrate, TOC loading rate was set in the range between 0.3 g l–1 day–1 and 1.5g l–1 day–1. Also an experiment on the consolidation characteristics of sludge accumulated on membrane was conducted. A mathematical model was developed to simulate temporal changes of suction pressure, flux and filtration resistance considering accumulation, detachment and consolidation of bacterial extracellular polymers on the membrane surface. A reactor with higher loading rate showed sudden increase of trans-membrane pressure, while a reactor with lower loading rate showed delayed increase of the pressure. The experimental results were simulated well by the developed model.

Modeling of biofouling by extracellular polymers in a membrane separation activated sludge system

1998 ◽  
Vol 38 (4-5) ◽  
pp. 497-504 ◽  
Author(s):  
H. Nagaoka ◽  
S. Yamanishi ◽  
A. Miya
Keyword(s):  
Activated Sludge ◽  
Loading Rate ◽  
Membrane Separation ◽  
Membrane Surface ◽  
Organic Loading Rate ◽  
Sudden Increase ◽  
Organic Loading ◽  
Reactor Performance ◽  
Filtration Resistance ◽  
Activated Sludge System

A Laboratory-scale experiment was conducted to investigate the mechanism of the bio-fouling in the submerged membrane separation activated sludge system. Flat-sheet-type membrane module was used and the change of the pressure and the filtration resistance was measured. Two reactors were operated in parallel to investigate the influence of organic loading rate on the reactor performance. A mathematical model was developed to simulate temporal changes of suction pressure, flux and filtration resistance considering accumulation, detachment and consolidation of EPS on the membrane surface. Parameters in the model were determined so that the calculated results fit to the measured variation curves. The high load reactor (1.5g-TOC L−1 day−1) showed a sudden increase of the pressure and a decrease of flux after 40th days, which could not be recovered even by membrane cleanings, while the low load reactor (0.5g-TOC L−1 day−1) showed little increase of the pressure until 120th days. The measured pattern of the flux, the pressure and the resistance were well explained by the developed model. Using the model, influence of operational parameters, such as organic loading rate, flux and shear stress working on the membrane, on the reactor performance was evaluated. It was concluded that the flux is the most influential parameter and when the flux is more than a critical value, which is as low as 0.1 m day−1, maximum time during which the set flux can be maintained becomes very short.

Effect of loading rate and intermittent aeration cycle on nitrogen removal in membrane separation activated sludge process

2002 ◽  
Vol 46 (8) ◽  
pp. 119-126 ◽  
Author(s):  
H. Nagaoka ◽  
C. Kudo
Keyword(s):  
Activated Sludge ◽  
Nitrogen Removal ◽  
Loading Rate ◽  
Membrane Separation ◽  
Organic Loading Rate ◽  
Aeration Tank ◽  
Activated Sludge Process ◽  
Intermittent Aeration ◽  
Organic Loading ◽  
Mixed Liquor

The performance of the submerged membrane separation activated sludge process with intermittent aeration was investigated in a laboratory scale experiment by changing organic loading rate and intermittent aeration cycle. A rectangular PVC tank was used as an aeration tank, in which a flat-sheet type Micro-Filtration membrane made of poly-olefin with a pore size of 0.2 mm was submerged. Organic loading rate to the reactor was set at 0.3 and 0.8 g-TOC/L/day. C/N ratio in the feed was set at around 5.0 for every condition. Aeration cycle was changed from 10 min-10 min (aeration - stop) to 120 min-120 min in different organic loading conditions. Flux through the membrane was set at 0.25 m/day. Membrane fouling proceeded rapidly in 0.8 g-TOC/L/day conditions. However, when organic loading rate was 0.3 g-TOC/L/day, bacterial metabolic substances were degraded rapidly compared to the production, thereby decreasing viscosity in mixed liquor. Nitrogen removal rate was between 60% and 80% for 0.8 g-TOC/L/day loading, and between 50% and 65% for 0.3 g-TOC/L/day loading. And the nitrogen removal was highest in 40 min to 60 min aeration cycle conditions. Too short aeration cycle did not result in sufficiently long anoxic periods for denitrification while too long a cycle resulted in unnecessary anaerobic periods after depletion of nitrate. Intermittent aeration was effective also for decreasing viscosity in mixed liquor.

Application of cigarette filter rods as biofilm carrier in an integrated fixed-film activated sludge reactor

2013 ◽  
Vol 67 (8) ◽  
pp. 1793-1801 ◽  
Author(s):  
Ahmad Sabzali ◽  
Mahnaz Nikaeen ◽  
Bijan Bina
Keyword(s):  
Activated Sludge ◽  
Loading Rate ◽  
Oxygen Demand ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Cigarette Filter ◽  
Biofilm Reactors ◽  
Biofilm Carrier ◽  
Fixed Film ◽  
Activated Sludge Reactor

Bio-carriers are an important component of integrated fixed-film activated sludge (IFAS) processes. In this study, the capability of cigarette filter rods (CFRs) as a bio-carrier in IFAS processes was evaluated. Two similar laboratory-scale IFAS systems were operated over a 4-month period using Kaldnes-K3 and CFRs as IFAS media. The process performance was studied by using chemical oxygen demand (COD). The organic loading rate was in the range 0.5–2.8 kgCOD/(m3·d). The COD average removal efficiencies were 89.3 and 93.9% for Kaldnes-K3 (reactor A) and cigarette filters (reactor B), respectively. The results demonstrate that the performance of the IFAS reactor containing CFRs was comparable to the reactor using Kaldnes. The CFRs, which have a high porous surface area and entrapment ability for microbial cells, could be successfully used in biofilm reactors as a bio-carrier.

scholarly journals Performance of AnMBR in Treatment of Post-consumer Food Waste: Effect of Hydraulic Retention Time and Organic Loading Rate on Biogas Production and Membrane Fouling

2021 ◽  
Vol 8 ◽  
Author(s):  
Javkhlan Ariunbaatar ◽  
Robert Bair ◽  
Onur Ozcan ◽  
Harish Ravishankar ◽  
Giovanni Esposito ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Food Waste ◽  
Membrane Fouling ◽  
Loading Rate ◽  
Biogas Production ◽  
Cod Removal ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Side Stream ◽  
Removal Efficiencies

Anaerobic digestion of food waste (FW) is typically limited to large reactors due to high hydraulic retention times (HRTs). Technologies such as anaerobic membrane reactors (AnMBRs) can perform anaerobic digestion at lower HRTs while maintaining high chemical oxygen demand (COD) removal efficiencies. This study evaluated the effect of HRT and organic loading rate (OLR) on the stability and performance of a side-stream AnMBR in treating diluted fresh food waste (FW). The reactor was fed with synthetic FW at an influent concentration of 8.24 (± 0.12) g COD/L. The OLR was increased by reducing the HRT from 20 to 1 d. The AnMBR obtained an overall removal efficiency of >97 and >98% of the influent COD and total suspended solids (TSS), respectively, throughout the course of operation. The biological process was able to convert 76% of the influent COD into biogas with 70% methane content, while the cake layer formed on the membrane gave an additional COD removal of 7%. Total ammoniacal nitrogen (TAN) and total nitrogen (TN) concentrations were found to be higher in the bioreactor than in the influent, and average overall removal efficiencies of 17.3 (± 5) and 61.5 (± 3)% of TAN and TN, respectively, were observed with respect to the bioreactor concentrations after 2 weeks. Total phosphorus (TP) had an average removal efficiency of 40.39 (± 5)% with respect to the influent. Membrane fouling was observed when the HRT was decreased from 7 to 5 d and was alleviated through backwashing. This study suggests that the side-stream AnMBR can be used to successfully reduce the typical HRT of wet anaerobic food waste (solids content 7%) digesters from 20 days to 1 day, while maintaining a high COD removal efficiency and biogas production.

Impact of Organic Loading Rate and DO on Filamentous Bulking Sludge and the Study of its Characteristics in Membrane Bioreactor

2010 ◽  
Vol 113-116 ◽  
pp. 1280-1284 ◽  
Author(s):  
Yu Tian ◽  
Xin Ying Su ◽  
Lin Chen ◽  
Tian Ling Jiang
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Loading Rate ◽  
Organic Loading Rate ◽  
Filamentous Bacteria ◽  
Organic Loading ◽  
High Substrate Concentration ◽  
Filamentous Bulking ◽  
And Control ◽  
The Impact

The membrane fouling behaviors and fouling mechanism of filamentous bulking sludge in membrane bioreactor (MBR) have been reported in recent studies. However, few studies have been conducted towards the causes and control of filamentous bulking sludge in MBR. In order to make clear the conditions of filamentous bacteria overgrowth in MBR, the impact of DO and organic loading rate on filamentous growth and its characteristics were investigated in this paper. The results showed that overgrowth of filamentous bacteria occurred under a relatively high substrate concentration (organic loading rate was 0.61 KgCOD/(KgMLSS•d), and DO was above 2 mg/L) in MBR. Nutrient removal effect can not be deteriorated under filamentous bulking sludge, with average 95, 57 and 92% removal efficiencies of COD, TN and TP respectively. The particle size of filamentous sludge was larger than that of normal sludge and the filamentous bacteria produced more SMP and EPS than floc forming bacteria.

scholarly journals Change of foulant concentration in an anaerobic membrane bioreactor

2020 ◽  
Author(s):  
Susumu Hasegawa ◽  
Genki Murakami ◽  
Ryosuke Takagi ◽  
Hideto Matsuyama
Keyword(s):  
Liquid Chromatography ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Loading Rate ◽  
Membrane Bioreactors ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Excess Sludge ◽  
Anaerobic Membrane Bioreactors ◽  
High Rejection

Abstract Anaerobic membrane bioreactors (AnMBRs) have many advantages, such as producing methane gas for energy generation and little excess sludge. However, membrane fouling is a serious problem because the foulant, which causes the membrane to foul, may get rejected by the membrane and accumulate in the reactor, resulting in an acceleration of membrane fouling. However, there is no information related to a change in the foulant concentration in an AnMBR. Therefore, we examined the changes in the foulant concentration in the reactor, related to membrane fouling in an AnMBR. For the influent, reactor solution, and effluent, the concentration of each component of the foulant was analyzed by using a liquid chromatography-organic carbon detector (LC-OCD). It was found that fouling in the AnMBR was closely related to the components in the reactor, and the main foulant of the ultrafiltration (UF) membrane was biopolymers (BPs). BP accumulated in the reactor because of a high rejection by the UF membrane. However, once the BP accumulated in the reactor was biodegraded, the concentration of BP decreased with time even under a high organic loading rate of 1.9kg TOC/m3/day.

Nitrogen removal by submerged membrane separation activated sludge process

1999 ◽  
Vol 39 (8) ◽  
pp. 107-114 ◽  
Author(s):  
H. Nagaoka
Keyword(s):  
Activated Sludge ◽  
Membrane Fouling ◽  
Membrane Separation ◽  
Removal Rate ◽  
Experimental Result ◽  
Activated Sludge Process ◽  
Intermittent Aeration ◽  
Membrane Process ◽  
Extracellular Polymers ◽  
Scale Experiment

The performance of the submerged membrane separation activated sludge (SMAS) process with intermittent aeration was investigated in a laboratory scale experiment. By intermittent aeration (30 minutes cycle), nitrogen was removed successfully (95% removal rate) from influent containing NH4-N and acetic acid. A mathematical model was developed to simulate the performance of the SMAS considering the behavior of extracellular polymers (production, degradation, accumulation on the membrane and consolidation) and the experimental result was successfully simulated by the model. Degradation of EPS was accelerated by intermittent operation, which suggests that the combination of biological denitrification with the membrane separation process is advantageous in the prevention of membrane fouling in the BOD-removal-type membrane process.

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