Microbial community in biofilm on membrane surface of submerged MBR: effect of in-line cleaning chemical agent

2005 ◽  
Vol 51 (6-7) ◽  
pp. 201-207 ◽  
Author(s):  
B.-R. Lim ◽  
K.-H. Ahn ◽  
K.-G. Song ◽  
J.W. Cho
Keyword(s):  
Microbial Community ◽  
Membrane Surface ◽  
Cell Lysis ◽  
Chemical Agent ◽  
Chemical Cleaning ◽  
Organic Degradation ◽  
Community Pattern ◽  
Cleaning Agent ◽  
Quinone Profile

The objective of this study was to investigate the change in microbial community pattern with the effect of cleaning agent using a quinone profile that is used for membrane in-line chemical cleaning in SMBR. The dominant quinone types of biofilm were ubiquinone (UQs)-8, -10, followed by menaquinone (MKs)-8(H4), -7 and UQ-9, but those of suspended microorganisms were UQ-8, UQ-10 followed by MKs-8(H4), -7 and -11. Both UQ and MK contents decreased with increasing NaClO dosage and it seems that there is more resistance from UQ compared to MK. In addition, COD and DOC concentrations increased with increasing NaClO dosage up to 0.05 g-NaClO/g-SS. The organic degradation performance of the microbial community in the presence of NaClO was impaired. The present study suggested that larger added amounts of NaClO caused an inhibition of organic degradation and cell lysis.

Low-pressure membrane filtration with unconventional coagulation regimes

2005 ◽  
Vol 5 (5) ◽  
pp. 1-8 ◽  
Author(s):  
K.Y. Choi ◽  
B.A. Dempsey
Keyword(s):  
Activated Carbon ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Cross Flow ◽  
Chemical Cleaning ◽  
Sand Filters ◽  
Charge Neutralization ◽  
Floc Size ◽  
Filtration System ◽  
Pre Treatment

The objective of the research was to evaluate in-line coagulation to improve performance during ultrafiltration (UF). In-line coagulation means use of coagulants without removal of coagulated solids prior to UF. Performance was evaluated by removal of contaminants (water quality) and by resistance to filtration and recovery of flux after hydraulic or chemical cleaning (water production). We hypothesized that coagulation conditions inappropriate for conventional treatment, in particular under-dosing conditions that produce particles that neither settle nor are removed in rapid sand filters, would be effective for in-line coagulation prior to UF. A variety of pre-treatment processes for UF have been investigated including coagulation, powdered activated carbon (PAC) or granular activated carbon (GAC), adsorption on iron oxides or other pre-formed settleable solid phases, or ozonation. Coagulation pre-treatment is often used for removal of fouling substances prior to NF or RO. It has been reported that effective conventional coagulation conditions produced larger particles and this reduced fouling during membrane filtration by reducing adsorption in membrane pores, increasing cake porosity, and increasing transport of foulants away from the membrane surface. However, aggregates produced under sweep floc conditions were more compressible than for charge neutralization conditions, resulting in compaction when the membrane filtration system was pressurized. It was known that the coagulated suspension under either charge-neutralization or sweep floc condition showed similar steady-state flux under the cross-flow microfiltration mode. Another report on the concept of critical floc size suggested that flocs need to reach a certain critical size before MF, otherwise membranes can be irreversibly clogged by the coagulant solids. The authors were motivated to study the effect of various coagulation conditions on the performance of a membrane filtration system.

Orange juice ultrafiltration: characterisation of deposit layers and membrane surfaces after fouling and cleaning

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Nurul Hainiza Abd-Razak ◽  
Y. M. John Chew ◽  
Michael R. Bird
Keyword(s):  
Shear Stress ◽  
Orange Juice ◽  
Surface Coverage ◽  
Fluid Shear Stress ◽  
Membrane Surface ◽  
Regenerated Cellulose ◽  
Fluid Shear ◽  
Chemical Cleaning ◽  
Membrane Area ◽  
Software Analysis

Abstract The influence of feed condition and membrane cleaning during the ultrafiltration (UF) of orange juice for phytosterol separation was investigated. UF was performed using regenerated cellulose acetate (RCA) membranes at different molecular weight cut-off (MWCO) values with a 336 cm2 membrane area and a range of temperatures (10–40 °C) and different feed volumes (3–9 L). Fluid dynamic gauging (FDG) was applied to assess the fouling and cleaning behaviours of RCA membranes fouled by orange juice and cleaned using P3-Ultrasil 11 over two complete cycles. During the FDG testing, fouling layers were removed by fluid shear stress caused by suction flow. The cleanability was characterised by using ImageJ software analysis. A Liebermann-Buchard-based method was used to quantify the phytosterol content. The results show that RCA 10 kDa filters exhibited the best separation of phytosterols from protein in orange juice at 20 °C using 3 L feed with a selectivity factor of 17. Membranes that were fouled after two cycles showed higher surface coverage compared to one fouling cycle. The surface coverage decreased with increasing fluid shear stress from 0 to 3.9 Pa. FDG achieved 80–95% removal at 3.9 Pa for all RCA membranes. Chemical cleaning using P3-Ultrasil 11 altered both the membrane surface hydrophobicity and roughness. These results show that the fouling layer on RCA membranes can be removed by fluid shear stress without affecting the membrane surface modification caused by chemical cleaning.

Effects of biodegradable substrates and microbial concentration on the acclimation of microbes to acrylonitrile in aerobic submerged biofilter

1998 ◽  
Vol 38 (7) ◽  
pp. 81-89 ◽  
Author(s):  
Hong-Ying Hu ◽  
Koichi Fujie ◽  
Mamie Nozawa ◽  
Tsuyoshi Makabe ◽  
Kohei Urano
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Microbial Community ◽  
Community Change ◽  
Ecological Studies ◽  
Profile Method ◽  
Upper Limit ◽  
Quinone Profile ◽  
Microbial Film ◽  
Corynebacterium Sp ◽  
Complete Mineralization

The effects of coexistence-of biodegradable substrates and microbial concentration on the acclimation of microbes to acrylonitrile (AN) in an aerobic submerged biofilter were investigated on the basis of kinetic and ecological studies. The experimental results show that the acclimation of microbial film to AN was promoted by a higher microbial concentration in the biofilter and by the coexistence of glucose and peptone in the influent. It was clarified that the upper limit of AN loading to the biofilter for the ultimate degradation, i.e., complete mineralization, of the influent AN was about 2.0-2.2 kg/m3. d. In addition, a new microbial quinone profile method was applied for the analysis of the microbial community change in the biofilter. The change in quinone profiles of the microbial film during the acclimation to AN suggested that Brevibacterium sp., Pseudomonas aeruginosa and Corynebacterium sp. could contribute to the degradation of AN in the aerobic biofilter.

scholarly journals Chemical Cleaning of Ultrafiltration Membrane Fouled by Humic Substances: Comparison between Hydrogen Peroxide and Sodium Hypochlorite

2019 ◽  
Vol 16 (14) ◽  
pp. 2568 ◽  
Author(s):  
Kai Li ◽  
Shu Li ◽  
Tinglin Huang ◽  
Chongzhe Dong ◽  
Jiawei Li ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Humic Substances ◽  
Sodium Hypochlorite ◽  
Alkaline Condition ◽  
Chemical Cleaning ◽  
H2o2 Treatment ◽  
Cleaning Agent ◽  
Cleaning Agents ◽  
Cleaning Efficacy ◽  
By Products

Chemical cleaning is indispensable for the sustainable operation of ultrafiltration (UF) system in water and wastewater treatment. Sodium hypochlorite (NaClO) is an established cleaning agent for membranes subject to organic and microbial fouling, but concerns have been raised about the generation of toxic halogenated by-products during NaClO cleaning. Hydrogen peroxide (H2O2) is a potential “green” cleaning agent that can avoid the formation of halogenated by-products. In this work, cleaning efficacy of H2O2 and NaClO for UF membrane fouled by humic substances (HS) was evaluated under a wide pH range, and change of HS’s properties due to reaction with cleaning agents was examined. The cleaning efficacy of H2O2 was lower than that of NaClO at pH 3–9, but it increased to a level (91.4%) comparable with that of NaClO at pH 11. The extents of changes in properties and fouling potential of HS due to reacting with cleaning agents were consistent with their cleaning efficacy. H2O2 treatment at pH 11 significantly increased negative charge of HS molecules, decomposed high-MW molecules, and reduced its fouling potential. Therefore, considering treatment/disposal of cleaning waste and cleaning efficacy, H2O2 cleaning under strong alkaline condition can be a good choice for HS-fouled membrane.

scholarly journals Study on Chemical Cleaning Agent in Treatment of Abandoned Oil Pipeline

2019 ◽  
Vol 118 ◽  
pp. 01031
Author(s):  
Fajie Yang ◽  
Chunman Li ◽  
Jing Li ◽  
Hongtao Wang ◽  
Siyu Wu ◽  
...  
Keyword(s):  
Developed Countries ◽  
Environment Protection ◽  
Chemical Cleaning ◽  
The Public ◽  
Oil Pipeline ◽  
Cleaning Agent ◽  
Cleaning Agents ◽  
Standards And Guidelines ◽  
Safety And Environment ◽  
Very High

After pipeline construction burst china energy pipeline industry commonly faced with aging and abandonment problem. The study on pipeline abandonment was still in preliminary state, because there is nearly no pipeline abandonment standards and guidelines. Pipeline cleaning is the first step to dispose the abandoned pipeline to eliminate the risk of environment and safety. In foreign developed countries there are many chemical cleaning agents. But this chemical cleaning agent is not suitable for residual of chines pipeline because of oil difference between china and foreign country. The most of residual in china have a very high paraffin and resin-asphaltenes content. So preparation of chemical cleaning suitable for china residual is a challenge on the technology of abandonment pipeline. In this paper two kinds of chemical cleaning agent were prepared to clean the different type of residual. They are hydrophilic chemical cleaning agent and oil soluble chemical cleaning agent. The result of cleaning project shows that the both kind of chemical cleaning have good performance for the abandoned pipeline. The chemical cleaning agents will assist pipeline company to totally clean the abandoned pipeline to ensure the public safety and environment protection.

scholarly journals Stimulatory effects on bacteria induced by chemical cleaning cause severe biofouling of membranes

2020 ◽  
Vol 10 (1) ◽  
pp. 82-94
Author(s):  
Xueye Wang ◽  
Jinxing Ma ◽  
Zhichao Wu ◽  
Zhiwei Wang
Keyword(s):  
Membrane Surface ◽  
Oxygen Species ◽  
Cleaning Efficiency ◽  
Chemical Cleaning ◽  
Physiological Mechanisms ◽  
Homoserine Lactones ◽  
Membrane Surfaces ◽  
Enhanced Production ◽  
Membrane Biofouling ◽  
Microbial Regrowth

Abstract Chemical cleaning with hypochlorite is routinely used in membrane-based processes. However, a high-transient cleaning efficiency does not guarantee a low biofouling rate when filtration is restarted, with the physiological mechanisms largely remaining unknown. Herein, we investigated the microbial regrowth and surface colonization on membrane surfaces after NaOCl cleaning had been completed. Results of this study showed that the regrowth of model bacteria, Pseudomonas aeruginosa, was initially subject to inhibition due to the damage of key enzymes' activity and the accumulation of intracellular reactive oxygen species although the oxidative stress induced by NaOCl had been removed. However, with the resuscitation ongoing, the stimulatory effects became obvious, which was associated with the enhanced production of N-acyl homoserine lactones and the secretion of eDNA that ultimately led to more severe biofouling on the membrane surface. This study elucidates the inhibition–stimulation mechanisms involved in biofilm reformation (membrane biofouling) after membrane chemical cleaning, which is of particular significance to the improvement of cleaning efficiency and application of membrane technologies.

scholarly journals Defining the effect of the chemical concentration and solution pH on membrane chemical cleaning process

2019 ◽  
Vol 109 ◽  
pp. 00061
Author(s):  
Mykola Nechytailo ◽  
Olena Nahorna ◽  
Yevhenii Kosiuk
Keyword(s):  
Suspended Solids ◽  
Membrane Surface ◽  
Metal Salts ◽  
Chemical Concentration ◽  
Solution Ph ◽  
Chemical Cleaning ◽  
Negative Factor ◽  
Gel Layer ◽  
Chemical Washing ◽  
Active Substances

In the process of treating natural water from surface sources, precipitated substances are tend to be deposited on the ultrafiltration membrane, either as suspended solids or as gel structures, formed by humic substances with metal salts. Hydraulic washes are unable to remove gelled structures from the surface of the membranes. Consequently, the phenomenon of gelation on the surface of the membrane causes gradual decrease in productivity, which is a negative factor. Chemical washing of membranes is generally used to remove the gel layer from the membrane surface. In this paper, the range of compositions which effectively remove complex contaminants is proposed, and also the efficacy of both pH and changes in the concentration of active substances on the process of washing the membrane are analyzed.

Impact of chemical cleaning and air-sparging on the critical and sustainable flux in a flat sheet membrane bioreactor for municipal wastewater treatment

2008 ◽  
Vol 57 (12) ◽  
pp. 1873-1879 ◽  
Author(s):  
G. Guglielmi ◽  
D. Chiarani ◽  
D. P. Saroj ◽  
G. Andreottola
Keyword(s):  
Membrane Bioreactor ◽  
Municipal Wastewater ◽  
Membrane Surface ◽  
Municipal Wastewater Treatment ◽  
Chemical Cleaning ◽  
Critical Flux ◽  
Submerged Membrane Bioreactor ◽  
Flat Sheet ◽  
Exponential Trend ◽  
Flat Sheet Membrane

The paper discusses the experimental optimisation of both chemical and mechanical cleaning procedures for a flat-sheet submerged membrane bioreactor fed with municipal wastewater. Fouling was evaluated by means of the critical flux concept, which was experimentally measured by short-term flux-stepping tests. By keeping constant most important parameters of the biological process (MLSS, sludge age), two different chemical cleaning protocols (2,000 mg L−1 NaOCl and 200 mg L−1 NaOCl) were applied with different frequency and, after approximately 9 months of operation, the criticality threshold was determined under different values of SADm (specific aeration demand per unit of membrane surface area). The weaker and more frequent chemical cleaning regime (200 mg L−1, monthly) proved much more effective than the stronger and less frequent strategy (2,000 mg L−1, once every three months). The improvement of performances was quantified by two TMP-based parameters, the fouling rate and the ΔTMP (difference between TMP values during the increasing and decreasing phase of hysteresis). The best performing configuration was then checked over a longer period by running four long-term trials showing an exponential trend of the sub-critical fouling rate with the imposed flux.

scholarly journals Microbial community pattern detection in human body habitats via ensemble clustering framework

2014 ◽  
Vol 8 (Suppl 4) ◽  
pp. S7 ◽  
Author(s):  
Peng Yang ◽  
Xiaoquan Su ◽  
Le Ou-Yang ◽  
Hon-Nian Chua ◽  
Xiao-Li Li ◽  
...  
Keyword(s):  
Microbial Community ◽  
Human Body ◽  
Pattern Detection ◽  
Ensemble Clustering ◽  
Community Pattern
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