scholarly journals Influence of nanoparticles on filterability of fruit-juice industry wastewater using submerged membrane bioreactor

2017 ◽  
Vol 76 (3) ◽  
pp. 705-711 ◽  
Author(s):  
Guler Turkoglu Demirkol ◽  
Nadir Dizge ◽  
Turkan Ormanci Acar ◽  
Oyku Mutlu Salmanli ◽  
Nese Tufekci

In this study, polyethersulfone (PES) ultrafiltration membrane surface was modified with nano-sized zinc oxide (nZnO) and silver (nAg) to improve the membrane filterability of the mixed liquor and used to treat fruit-juice industry wastewater in a submerged membrane bioreactor (MBR). The nAg was synthesized using three different methods. In the first method, named as nAg-M1, PES membrane was placed on the membrane module and nAg solution was passed through the membrane for 24 h at 25 ± 1 °C. In the second method, named as nAg-M2, PES membrane was placed in a glass container and it was shaken for 24 h at 150 rpm at 25 ± 1 °C. In the third method, named as nAg-M3, Ag nanoparticles were loaded onto PES membrane in L-ascorbic acid solution (0.1 mol/L) at pH 2 for 24 h at 150 rpm at 25 ± 1 °C. For the preparation of nZnO coated membrane, nZnO nanoparticles solution was passed through the membrane for 24 h at 25 ± 1 °C. Anti-fouling performance of pristine and coated membranes was examined using the submerged MBR. The results showed that nZnO and nAg-M3 membranes showed lower flux decline compared with pristine membrane. Moreover, pristine and coated PES membranes were characterized using a permeation test, contact angle goniometer, and scanning electron microscopy.

2008 ◽  
Vol 57 (12) ◽  
pp. 1873-1879 ◽  
Author(s):  
G. Guglielmi ◽  
D. Chiarani ◽  
D. P. Saroj ◽  
G. Andreottola

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.


2017 ◽  
Vol 63 (4) ◽  
pp. 219-226 ◽  
Author(s):  
Yaroslav M. Stanishevskiy ◽  
Nadezhda P. Sachivkina ◽  
Yuriy V. Tarasov ◽  
Yury I. Philippov ◽  
Sergey A. Sokolov ◽  
...  

An increase in the accuracy of monitoring of glucose concentration indicators and an increase in the running time of glucose sensors are promising directions in the field of diabetology. One of the ways to extend the lifetime of a sensor is its complete implantation excluding direct communication with the skin surface. For effective long-term functioning in the patient’s body, the surface of an implantable sensor should be highly biocompatibile: it should not induce allergic and inflammatory reactions as well as the demarcation reaction (formation of a dense connective tissue capsule). Earlier, a group of authors developed a glucose-permeable membrane and a biocompatible coating comprising a complex of nadroparin with transesterified polyethylene glycol and γ-aminopropyl triethoxysilane, which formed a protein repellent hydrogel on the membrane surface. Aims. To evaluate the biocompatibility of the experimental coated membrane implanted into laboratory animals. Methods. The experimental prospective controlled study involved 60 laboratory animals (Wistar albino rats). The animals were divided into 3 groups of 20 animals each. Animals of each group were implanted with the standard, or experimental, or experimental coated membrane. After implantation, the skin condition in the implantation area was visually assessed for 90 days. After 90 days, the tissue condition around the implant was evaluated histologically. Results. No serious allergic or inflammatory reactions in the implantation area were detected in all three groups of animals within 90 days of the follow-up period. In the case of the experimental coated membrane, a significantly low score was graded based on visual assessment of the skin reactions. In the histological analysis, the tissue condition in the implantation area of the coated membranes was characterized by significantly lower density of a connective tissue capsule and the presence of vascularization areas at the contact between of the membrane surface and the surrounding tissue. Conclusion. In experimental animals, the tested coating significantly inhibits formation of a connective tissue capsule around the implant and reduces the intensity of skin reactions after implantation. Further clinical studies of coated membranes in humans are required to verify their biocompatibility.


2017 ◽  
Vol 76 (7) ◽  
pp. 1715-1725 ◽  
Author(s):  
Hanife Sari Erkan ◽  
Guleda Onkal Engin

The paper mill industry produces high amounts of wastewater and, for this reason, stringent discharge limits are applied for sustainable reclamation and reuse of paper mill industry wastewater in many countries. Submerged membrane bioreactor (sMBR) systems can create new opportunities to eliminate dissolved substances present in paper mill wastewater including. In this study, a sMBR was operated for the treatment of paper mill industry wastewater at 35 h of hydraulic retention time (HRT) and 40 d of sludge retention time (SRT). The chemical oxygen demand (COD), NH3-N and total phosphorus (TP) removal efficiencies were found to be 98%, 92.99% and 96.36%. The results demonstrated that sMBR was a suitable treatment for the removal of organic matter and nutrients for treating paper mill wastewater except for the problem of calcium accumulation. During the experimental studies, it was noted that the inorganic fraction of the sludge increased as a result of calcium accumulation in the reactor and increased membrane fouling was observed on the membrane surface due to the calcification problem encountered. The properties of the sludge, such as extracellular polymeric substances (EPS) and soluble microbial products (SMP), relative hydrophobicity, zeta potential and floc size distribution were also monitored. According to the obtained results, the total EPS was found to be 43.93 mg/gMLSS and the average total SMP rejection by the membrane was determined as 66.2%.


2020 ◽  
Vol 81 (4) ◽  
pp. 744-752
Author(s):  
S. Ahmed ◽  
S. Chung ◽  
N. Sohail ◽  
I. A. Qazi ◽  
A. Justin

Abstract Biofouling is unwanted accumulation of microbial population on the membrane surface which limits the use of membrane bioreactor (MBR) in the market. Disruption of the biofilm formation by Quorum Quenching (QQ) by using cell entrapping beads (CEBs) is an approach with great potential to control membrane biofouling as the beads used provide not only mitigating effect on biofilm formation, by interfering Quorum Sensing, but also physical forces to detach the biofilm from the membrane surface. This research aimed to develop QQ-CEB with locally available chemicals in Pakistan and its application to evaluate the QQ effect together with physical and chemical cleaning. Various CEBs were made of different mixtures of sodium alginate and polyvinyl alcohol (PVA) and their quality was tested considering physical and biological aspects. Rhodococcus sp. BH4 and Pseudomonas putida were entrapped in the CEBs and then introduced in MBR as one of biofouling control methods along with standard backwash and chemical backwash. The CEBs made of specific concentration of PVA were proven to be more durable and helpful in mitigating biofouling as compared to that of sodium alginate. An MBR operated with PVA-alginate QQ CEBs together with chemical backwash showed the best performance without deterioration of effluent quality.


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