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.

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.

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.

Ultrafiltration membrane separation for anaerobic wastewater treatment

1994 ◽  
Vol 30 (12) ◽  
pp. 321-327 ◽  
Author(s):  
Ahmadun Fakhru'l-Razi
Keyword(s):  
Wastewater Treatment ◽  
Membrane Separation ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Reactor Performance ◽  
Water And Wastewater Treatment ◽  
Active Biomass ◽  
Biomass Loss ◽  
Scientists And Engineers ◽  
Uf Membranes

Membrane technology has attracted a lot of attention from scientists and engineers in recent years as a new separation process. Various membrane technologies such as reverse osmosis (RO), ultrafiltration (UF) and microfiltration (MF) have been successfully used for a variety of water and wastewater treatment applications. In this study UF membranes of 10 000 nominal molecular weight limit were used in conjunction with an anaerobic reactor to treat wastewater from a brewery. The UF membranes serve to retain active biomass in the reactor, which is essential for a good reactor performance and for the production of a clear final effluent. The reactor was operated over a range of hydraulic retention times and organic loading rates (OLR) in order to evaluate its treatment efficiency. Six steady states were attained over a range of mixed liquor suspended solids (31 000-38 000 mg 1−1). The maximum organic loading rate applied was 19.7 kg COD m−3 d−1 resulting in a methane yield of 0.27 1 CH4 g−1 COD. The percentages of COD removal achieved were above 96%. The results indicated that the UF membranes were capable of efficient biomass-effluent separation thus preventing any biomass loss from the reactor and have potential for treating industrial wastewaters.

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.

The efficacy of ozone as a pre- and post-treatment option for UASB-treated food processing wastewaters

2005 ◽  
Vol 52 (1-2) ◽  
pp. 167-173 ◽  
Author(s):  
G.O. Sigge ◽  
T.J. Britz ◽  
P.C. Fourie ◽  
C.A. Barnardt
Keyword(s):  
Treatment Option ◽  
Food Processing ◽  
Loading Rate ◽  
Post Treatment ◽  
Cod Removal ◽  
Uasb Reactor ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Reactor Performance ◽  
Cod Reduction

The efficiency of ozone as a pre- and post-treatment to UASB treatment was investigated, followed by a study into UASB reactor performance with ozonated wastewater as substrate. Combinations of pre- and/or post-ozonation with UASB treatment gave better results than ozonation or UASB alone and COD reductions of 53.0–98.9% were achieved for treatment of canning and winery wastewaters. A UASB reactor was fed with pre-ozonated cannery wastewater for over 70 d. COD removal improved from between 58.8 and 64.4% to between 85.3 and 91.8% after pre-ozonated substrate feed commenced. Subsequent increases in organic loading rate (OLR) from 2.4 to 3.4 kgCOD m−3.d−1 did not affect reactor performance. By including a final post-ozonation treatment to this UASB effluent a total COD reduction of 99.2% was achieved.

Pilot-scale anaerobic co-digestion of municipal biomass waste and waste activated sludge in China: Effect of organic loading rate

2012 ◽  
Vol 32 (11) ◽  
pp. 2056-2060 ◽  
Author(s):  
Xiao Liu ◽  
Wei Wang ◽  
Yunchun Shi ◽  
Lei Zheng ◽  
Xingbao Gao ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Loading Rate ◽  
Pilot Scale ◽  
Organic Loading Rate ◽  
Waste Activated Sludge ◽  
Organic Loading ◽  
Biomass Waste

Effect of Organic Loading Rate on Aerobic Granulation. I: Reactor Performance

2004 ◽  
Vol 130 (10) ◽  
pp. 1094-1101 ◽  
Author(s):  
Joo-Hwa Tay ◽  
Shun Pan ◽  
Yanxin He ◽  
Stephen Tiong Lee Tay
Keyword(s):  
Loading Rate ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Reactor Performance ◽  
Aerobic Granulation
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