Strategies for chemical cleaning in large scale membrane bioreactors

2008 ◽  
Vol 57 (3) ◽  
pp. 457-463 ◽  
Author(s):  
C. Brepols ◽  
K. Drensla ◽  
A. Janot ◽  
M. Trimborn ◽  
N. Engelhardt
Keyword(s):  
Large Scale ◽  
Membrane Bioreactor ◽  
Effective Means ◽  
Membrane Bioreactors ◽  
Ex Situ ◽  
Chemical Cleaning ◽  
Membrane Cleaning ◽  
Cleaning Agents ◽  
Cleaning Procedures ◽  
Alkaline Cleaning

Systematically testing alternative cleaning agents and cleaning procedures on a large scale municipal membrane bioreactor, the Erftverband optimized the cleaning strategies and refined the original cleaning procedures for the hollow fiber membranes in use. A time-consuming, intensive ex-situ membrane cleaning twice a year was initially the regular routine. By introducing the effective means of cleaning in place in use today, which employs several acidic and oxidative/alkaline cleaning steps, intensive membrane cleaning could be delayed for years. An overview and an assessment of various cleaning strategies for large scale plants are given.

Kinetic evaluation of nitrification performance in an immobilized cell membrane bioreactor

2016 ◽  
Vol 73 (12) ◽  
pp. 2904-2912 ◽  
Author(s):  
D. Güven ◽  
E. Ubay Çokgör ◽  
S. Sözen ◽  
D. Orhon
Keyword(s):  
Residence Time ◽  
Retention Time ◽  
Model Calibration ◽  
Membrane Bioreactor ◽  
Hydraulic Retention Time ◽  
Membrane Bioreactors ◽  
High Rate ◽  
Immobilized Cell ◽  
Chemical Cleaning ◽  
Kinetic Evaluation

Abstract High rate membrane bioreactor (MBR) systems operated at extremely low sludge ages (superfast membrane bioreactors (SFMBRs)) are inefficient to achieve nitrogen removal, due to insufficient retention time for nitrifiers. Moreover, frequent chemical cleaning is required due to high biomass flux. This study aims to satisfy the nitrification in SFMBRs by using sponge as carriers, leading to the extension of the residence time of microorganisms. In order to test the limits of nitrification, bioreactor was run under 52, 5 and 2 days of carrier residence time (CRT), with a hydraulic retention time of 6 h. Different degrees of nitrification were obtained for different CRTs. Sponge immobilized SFMBR operation with short CRT resulted in partial nitrification indicating selective dominancy of ammonia oxidizers. At higher CRT, simultaneous nitrification–denitrification was achieved when accompanying with oxygen limitation. Process kinetics was determined through evaluation of the results by a modeling study. Nitrifier partition in the reactor was also identified by model calibration.

scholarly journals Optimization of In Situ Backwashing Frequency for Stable Operation of Anaerobic Ceramic Membrane Bioreactor

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 545 ◽  
Author(s):  
Rathmalgodage Thejani Nilusha ◽  
Tuo Wang ◽  
Hongyan Wang ◽  
Dawei Yu ◽  
Junya Zhang ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Filtration ◽  
Membrane Bioreactor ◽  
Ceramic Membrane ◽  
Pure Water ◽  
Ex Situ ◽  
Stable Operation ◽  
Chemical Cleaning ◽  
Cake Layer

The cost-effective and stable operation of an anaerobic ceramic membrane bioreactor (AnCMBR) depends on operational strategies to minimize membrane fouling. A novel strategy for backwashing, filtration and relaxation was optimized for stable operation of a side stream tubular AnCMBR treating domestic wastewater at the ambient temperature. Two in situ backwashing schemes (once a day at 60 s/day, and twice a day at 60 s × 2/day) maintaining 55 min filtration and 5 min relaxation as a constant were compared. A flux level over 70% of the initial membrane flux was stabilized by in situ permeate backwashing irrespective of its frequency. The in situ backwashing by permeate once a day was better for energy saving, stable membrane filtration and less permeate consumption. Ex situ chemical cleaning after 60 days’ operation was carried out using pure water, sodium hypochlorite (NaOCl), and citric acid as the order. The dominant cake layer was effectively reduced by in situ backwashing, and the major organic foulants were fulvic acid-like substances and humic acid-like substances. Proteobacteria, Firmucutes, Epsilonbacteria and Bacteroides were the major microbes attached to the ceramic membrane fouling layer which were effectively removed by NaOCl.

Package plant of extended aeration membrane bioreactors: a study on aeration intensity and biofouling control

2005 ◽  
Vol 51 (10) ◽  
pp. 335-342 ◽  
Author(s):  
Z. Ujang ◽  
S.S. Ng ◽  
H. Nagaoka
Keyword(s):  
Membrane Bioreactor ◽  
Membrane Surface ◽  
Membrane Bioreactors ◽  
Detergent Solution ◽  
Nutrients Removal ◽  
Membrane Cleaning ◽  
Detergent Enzyme ◽  
Suspended Biomass ◽  
Biofouling Control ◽  
Set Up

Biofouling control is important for effective process of membrane bioreactor (MBR). In this study, phenomena of biofouling for immersed type extended aeration MBR with two different anti-fouling aeration intensities were studied through a laboratory set up. The objectives of this study were (a) to observe biofouling phenomena of MBR that operates under different anti-fouling bubbling intensity, and simultaneously monitors performance of the MBR in organic carbon and nutrients removal; (b) to compare effectiveness of detergent and detergent-enzyme cleaning solutions in recovering biofouled membranes that operated in the extended aeration MBR. For MBR, which operated under continuous anti-fouling aeration, deposition and accumulation of suspended biomass on membrane surface were prohibited. However, flux loss was inescapable that biofilm layer was the main problem. Membrane cleaning was successfully carried out with detergent-enzyme mixture solutions and its effectiveness was compared with result from cleaning with just detergent solution.

Experimental evaluation of intermittent aeration of a hollow fibre membrane bioreactor

2011 ◽  
Vol 63 (6) ◽  
pp. 1217-1223 ◽  
Author(s):  
Bart Verrecht ◽  
Christopher James ◽  
Eve Germain ◽  
Wenjing Ma ◽  
Simon Judd
Keyword(s):  
Large Scale ◽  
Membrane Bioreactor ◽  
Weather Conditions ◽  
Hollow Fibre ◽  
Membrane Bioreactors ◽  
High Flux ◽  
Intermittent Aeration ◽  
Small Plant ◽  
Membrane Aeration ◽  
Net Flux

Intermittent membrane aeration provides a substantially improved energy efficiency in hollow fibre-based immersed membrane bioreactors (HF iMBRs). The benefits of intermittent aeration have been assessed with respect to sustaining a target flux and/or limiting the fouling rate to a sustainable level based on a small plant using full-scale HF modules. Results show that for the same specific aeration demand per unit of permeate produced (SADp), fouling rates were significantly lower for 10 s filtration, 30 s relaxation (“10:30” intermittent aeration) compared to 10:10 and continuous aeration. At a net flux (Jnet) of 23.3 litres m−2 h−1 (LMH), a SADp of 4.6 was found sufficient to sustain operation, this value being up to 75% and 50% lower compared to continuous and 10:10 aeration respectively. This empirical data was compared with heuristic data from 5 large scale HF iMBR plants, which revealed that 10:30 aeration can sustain a relatively high flux (up to 25.3 LMH) under dry weather conditions in warm climates, with the recorded SADp ranging from 5.3–10.9.

scholarly journals Membrane fouling control and cleaning technology of ceramic membrane treating wastewater

2019 ◽  
Vol 118 ◽  
pp. 04023
Author(s):  
Guoqiang Ma ◽  
Shoubin Zhang ◽  
Yanming Yang ◽  
Liping Qiu ◽  
Guicai Liu ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Ceramic Membrane ◽  
Effective Means ◽  
Stable Operation ◽  
Efficient Technology ◽  
Chemical Cleaning ◽  
Membrane Cleaning ◽  
Membrane Technique ◽  
Cleaning Methods ◽  
Cleaning Technology

Ceramic membrane technique was a new and efficient technology for wastewater treatment and used more and more widely in recent years. Controlling membrane fouling was the key method to ensure the efficient and stable operation of ceramic membrane. In this paper, the causes, influencing factors and control methods of ceramic membrane fouling were summarized. As one of the most effective means to control membrane fouling, several common membrane cleaning methods, such as physical cleaning, chemical cleaning, ultrasonic cleaning and combined cleaning, were introduced. And the application of ceramic membrane cleaning was presented too. Then the future directions for ceramic membrane techniquresearching was prospected.

scholarly journals Mathematical modelling of flux recovery during chemical cleaning of tubular membrane fouled with whey proteins

2009 ◽  
pp. 135-144 ◽  
Author(s):  
Natasa Lukic ◽  
Svetlana Popovic ◽  
Jelena Markovic
Keyword(s):  
Mathematical Modelling ◽  
Pore Diameter ◽  
Whey Proteins ◽  
Process Efficiency ◽  
Chemical Cleaning ◽  
Tubular Membrane ◽  
Cleaning Agents ◽  
Naoh Solution ◽  
Cleaning Procedures ◽  
Insight Into

Membrane process efficiency in the dairy industry is impaired by the formation of deposits during filtration processes. This work describes cleaning procedures for ceramic tubular membrane (50 nm) fouled with whey proteins. Also, mathematical modelling was performed to obtain models which allow deeper insight into the mechanisms involved during cleaning procedures. The caustic solutions (0.2%w/w, 0.4%w/w and 1.0%w/w NaOH) and the mixture of two commercial detergents (0.8%w/w P3-ultrasil 69+0.5% w/w P3-ultrasil 67 and 1.2% P3-ultrasil 69+0.75 P3-ultrasil 67) were used as chemical cleaning agents. The results showed that the best flux recovery was achieved with 0.4%w/w NaOH solution. After analyzing the experimental data, five parameter and six parameter kinetic models were suggested for alkali and detergent cleaning, respectively. The changes of total and specific resistances, as well as the change of the effective pore diameter and deposit thickness during cleaning are estimated by applying these models.

Enhanced membrane bioreactor process without chemical cleaning

2010 ◽  
Vol 61 (10) ◽  
pp. 2575-2580 ◽  
Author(s):  
S. Krause ◽  
B. Zimmermann ◽  
U. Meyer-Blumenroth ◽  
W. Lamparter ◽  
B. Siembida ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Membrane Filtration ◽  
Membrane Bioreactors ◽  
Chemical Cleaning ◽  
Effluent Quality ◽  
Free Process ◽  
Small Footprint ◽  
Cleaning Procedures ◽  
The Cost

In membrane bioreactors (MBR) for wastewater treatment, the separation of activated sludge and treated water takes place by membrane filtration. Due to the small footprint and superior effluent quality, the number of membrane bioreactors used in wastewater treatment is rapidly increasing. A major challenge in this process is the fouling of the membranes which results in permeability decrease and the demand of chemical cleaning procedures. With the objective of a chemical-free process, the removal of the fouling layer by continuous physical abrasion was investigated. Therefore, particles (granules) were added to the activated sludge in order to realise a continuous abrasion of the fouling layer. During operation for more than 8 months, the membranes showed no decrease in permeability. Fluxes up to 40 L/(m2 h) were achieved. An online turbidity measurement was installed for the effluent control and showed no change during this test period. For comparison, a reference (standard MBR process without granules) was operated which demonstrated permeability loss at lower fluxes and required chemical cleaning. Altogether with this process an operation at higher fluxes and no use of cleaning chemicals will increase the cost efficiency of the MBR-process.

Applied Research in Membrane Fouling in the Membrane Bioreactor Systems with Large-scale Equipment

2019 ◽  
Vol 1 (1) ◽  
pp. 1-10
Author(s):  
Kong Linghan ◽  
Zhao Weidian ◽  
Ran Deqin ◽  
Hui Bing ◽  
Lu Linguo ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Large Scale ◽  
Membrane Bioreactor ◽  
Applied Research

Conservation of animal genetic resources: approaches and technologies for in situ and ex situ conservation

2008 ◽  
Vol 42 ◽  
pp. 71-85 ◽  
Author(s):  
J.A. Woolliams ◽  
O. Matika ◽  
J. Pattison
Keyword(s):  
Rural Communities ◽  
Genetic Resources ◽  
Large Scale ◽  
Production Systems ◽  
Regional Distribution ◽  
Livestock Production ◽  
Ex Situ ◽  
Animal Genetic Resources ◽  
The Face ◽  
Livestock Products

SummaryLivestock production faces major challenges through the coincidence of major drivers of change, some with conflicting directions. These are:1. An unprecedented global change in demands for traditional livestock products such as meat, milk and eggs.2. Large changes in the demographic and regional distribution of these demands.3. The need to reduce poverty in rural communities by providing sustainable livelihoods.4. The possible emergence of new agricultural outputs such as bio-fuels making a significant impact upon traditional production systems.5. A growing awareness of the need to reduce the environmental impact of livestock production.6. The uncertainty in the scale and impact of climate change. This paper explores these challenges from a scientific perspective in the face of the large-scale and selective erosion of our animal genetic resources, and concludes thai there is a stronger and more urgent need than ever before to secure the livestock genetic resources available to humankind through a comprehensive global conservation programme.

scholarly journals mRNA-Based Vaccines

Vaccines ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 390
Author(s):  
Frank Kowalzik ◽  
Daniel Schreiner ◽  
Christian Jensen ◽  
Daniel Teschner ◽  
Stephan Gehring ◽  
...  
Keyword(s):  
Large Scale ◽  
New Technologies ◽  
Vaccine Development ◽  
Effective Means ◽  
Cost Effective ◽  
Clinical Applications ◽  
Cell Mediated Immunity ◽  
Healthy Individuals ◽  
Emerging Pathogens ◽  
Cell Genome

Increases in the world’s population and population density promote the spread of emerging pathogens. Vaccines are the most cost-effective means of preventing this spread. Traditional methods used to identify and produce new vaccines are not adequate, in most instances, to ensure global protection. New technologies are urgently needed to expedite large scale vaccine development. mRNA-based vaccines promise to meet this need. mRNA-based vaccines exhibit a number of potential advantages relative to conventional vaccines, namely they (1) involve neither infectious elements nor a risk of stable integration into the host cell genome; (2) generate humoral and cell-mediated immunity; (3) are well-tolerated by healthy individuals; and (4) are less expensive and produced more rapidly by processes that are readily standardized and scaled-up, improving responsiveness to large emerging outbreaks. Multiple mRNA vaccine platforms have demonstrated efficacy in preventing infectious diseases and treating several types of cancers in humans as well as animal models. This review describes the factors that contribute to maximizing the production of effective mRNA vaccine transcripts and delivery systems, and the clinical applications are discussed in detail.

Sign in / Sign up

Export Citation Format

Share Document