scholarly journals Treatment of industrial wastewater in the sequential membrane bioreactor

2016 ◽  
Vol 23 (2) ◽  
pp. 285-295 ◽  
Author(s):  
Anna Świerczyńska ◽  
Jolanta Bohdziewicz ◽  
Ewa Puszczało

Abstract The aim of presented study which was associated with modification of the various work cycle phases duration in the membrane bioreactor, was to reduce the concentration of phosphate phosphorus during the leachate co-treatment with dairy wastewater. The experimental set-up was comprised of the membrane bioreactor equipped with the immersed membrane module installed inside the reactor chamber, and the equalization tank. During the co-treatment experiment performance the excessive activated sludge was constantly removed from the membrane bioreactor in order to keep its concentration at 3.5 g/dm3. The load of the sludge with the contaminants was equal to 0.06 g COD/g d.m. d. The concentration of oxygen was equal to 3 mg/dm3. The share of the leachates in the co-treated mixture was equal to 10% vol. The membrane bioreactor worked as the sequential biological reactor, in two cycles per day. Duration of each phase was equal as follows: filling - 10 min - with concurrent mixing phase lasting for 4 h, aeration phase - 1 h, sedimentation - 30 min and removal from purified wastewater - 30 min. After 4 weeks under these conditions, the modification of the sequential membrane bioreactor’s work cycle was made. The duration of particular phases was shortened and two phases of denitrification and nitrification were introduced. Work cycle phases were modified as follows: filling - 10 min - with concurrent mixing phase lasting for 3 h, aeration phase - 4 h, mixing phase - 1 h, aeration phase - 3 h, sedimentation - 30 min and removal from purified wastewater - 30 min. Based on research, it was found that the change in membrane bioreactors’ work cycle affects the effectiveness of treated mixture. It was found that the applied modification of phases of the cycle of the MSBR did not affect the concentration of organic compounds and the no significant changes in the concentration of ammonium and nitrate nitrogen in the effluent from the bioreactor were observed, however, the total nitrogen removal efficiency increased by 50%. Alteration of MSBR reactor particular phases duration caused reduction of concentration of P-PO43 from 4.7 to 2.9 mg/dm3.

2005 ◽  
Vol 51 (10) ◽  
pp. 335-342 ◽  
Author(s):  
Z. Ujang ◽  
S.S. Ng ◽  
H. Nagaoka

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.


2011 ◽  
Vol 5 (4) ◽  
Author(s):  
Mathieu Viens ◽  
Guillaume Chauvette ◽  
Ève Langelier

In the field of tissue engineering, a bioreactor is a valuable instrument that mimics a physiological environment to maintain live tissues in vitro. Although bioreactors are conceptually relatively simple, the vast majority of current bioreactors (commercial and custom-built) are not fully adapted to current research needs. Designing the optimal bioreactor requires a very thorough approach to a series of steps in the product development process. These four basic steps are: (1) identifying the needs and technical requirements, (2) defining and evaluating the related concepts, (3) designing the apparatus and drawing up the blueprints, and (4) building and validating the apparatus. Furthermore, the design has to be adapted to the specific purpose of the research and how the tissues will be used. In the emerging field of bioreactor research, roadmaps are needed to assist tissue engineering researchers as they embark on this process. The necessary multidisciplinary expertise covering micromechanical design, mechatronics, viscoelasticity, tissue culture, and human ergonomics is not necessarily available to all research teams. Therefore, the challenge of adapting and conducting each step in the product development process is significant. This paper details our proposal for a roadmap to accompany researchers in identifying their needs and technical requirements: step one in the product development process. Our roadmap proposal is set up in two phases. Phase 1 is based on the analysis of the bioreactor use cycle and phase 2 is based on the analysis of one specific and critical step in the use cycle: conducting stimulation and characterization protocols with the bioreactor. A meticulous approach to these two phases minimizes the risk of forgetting important requirements and strengthens the probability of acquiring or designing a high performance bioreactor.


2017 ◽  
Vol 32 (4) ◽  
pp. 61-80 ◽  
Author(s):  
Ellen E. Best ◽  
Jennifer Kahle Schafer

ABSTRACT Practitioners routinely note that new staff lack documentation skills, communication skills, and strong Excel skills. Further, new staff report critical-thinking, written and oral communication, teamwork, and project management skills deserve greater emphasis in Master of Accountancy programs. The AICPA's (2014) Model Tax Curriculum suggests that active learning approaches be used to enable students to build communication, critical-thinking, and interpersonal skills. This case uses a realistic corporate tax return preparation experience to address these criticisms by focusing on four main areas: time management, communication, research, and technical skills. The case is divided into two phases. In Phase 1, students review client information, generate requests from the client for missing information, keep a log of hours spent on the project, research ambiguous issues, meet with the project “senior” to obtain guidance, and prepare electronic work papers. In Phase 2, students incorporate feedback from the senior's review of their work papers to make corrections, prepare a corporate tax return, and create a client letter. Student feedback about the project is positive.


Author(s):  
Srinivasan Sridhar ◽  
Nazmul Kazi ◽  
Indika Kahanda ◽  
Bernadette McCrory

Background: The demand for psychiatry is increasing each year. Limited research has been performed to improve psychiatrist work experience and reduce daily workload using computational methods. There is currently no validated tool or procedure for the mental health transcript annotation process for generating “gold-standard” data. The purpose of this paper was to determine the annotation process for mental health transcripts and how it can be improved to acquire more reliable results considering human factors elements. Method: Three expert clinicians were recruited in this study to evaluate the transcripts. The clinicians were asked to fully annotate two transcripts. An additional five subjects were recruited randomly (aged between 20-40) for this pilot study, which was divided into two phases, phase 1 (annotation without training) and phase 2 (annotation with training) of five transcripts. Kappa statistics were used to measure the inter-rater reliability and accuracy between subjects. Results: The inter-rater reliability between expert clinicians for two transcripts were 0.26 (CI 0.19 to 0.33) and 0.49 (CI 0.42 to 0.57), respectively. In the pilot testing phases, the mean inter-rater reliability between subjects was higher in phase 2 with training transcript (k= 0.35 (CI 0.052 to 0.625)) than in phase 1 without training transcript (k= 0.29 (CI 0.128 to 0.451)). After training, the accuracy percentage among subjects was significantly higher in transcript A (p=0.04) than transcript B (p=0.10). Conclusion: This study focused on understanding the annotation process for mental health transcripts, which will be applied in training machine learning models. Through this exploratory study, the research found appropriate categorical labels that should be included for transcripts annotation, and the importance of training the subjects. Contributions of this case study will help the psychiatric clinicians and researchers in implementing the recommended data collection process to develop a more accurate artificial intelligence model for fully- or semi-automated transcript annotation.


2014 ◽  
Vol 36 (5) ◽  
pp. 583-604 ◽  
Author(s):  
Julie Zide ◽  
Ben Elman ◽  
Comila Shahani-Denning

Purpose – The purpose of this paper is to identify the elements of a LinkedIn profile that hiring professionals focus on most, and then examine LinkedIn profiles in terms of these identified elements across different industries. Design/methodology/approach – The methodology was comprised of two phases. In the first phase, researchers interviewed hiring professionals to determine their usage of LinkedIn. In the second phase, LinkedIn group member profiles from three industries – HR, sales/marketing and industrial/organizational (I/O) psychology – were compared on the 21 variables identified in Phase 1 (n=288). Findings – χ2 and ANOVA tests showed significant differences with respect to ten of the LinkedIn variables in how people presented themselves across the three groups. There were also several gender differences found. Research limitations/implications – A general limitation was the use of a qualitative research approach. A limitation of Phase 1 was that only a small sample of New York City-based hiring professionals was interviewed. Perhaps a wider, more diverse sample would have yielded different variables. In terms of Phase 2, it is possible that just utilizing the second connections of the researchers limited the generalizability of findings. Practical implications – User unwillingness to fully complete the LinkedIn profile suggests that it may not have replaced the traditional resume yet. Sales/marketing professionals were more likely than HR and I/O psychology professionals to complete multiple aspects of a LinkedIn profile. Women were also less likely than men to provide personal information on their profiles. Originality/value – Most of the empirical research on social networking sites has focussed on Facebook, a non-professional site. This is, from the knowledge, the first study that systematically examined the manner in which people present themselves on LinkedIn – the most popular professional site used by applicants and recruiters worldwide.


2009 ◽  
Vol 3 (1) ◽  
pp. 1-15
Author(s):  
Glen T. Daigger ◽  
Andrew Hodgkinson ◽  
David Evans

2021 ◽  
Vol 232 (11) ◽  
Author(s):  
Caner Vural ◽  
Tuğba Topbaş ◽  
S. Tuğçe Dağlıoğlu ◽  
Özlem Dağlı ◽  
Rahime Oral ◽  
...  

Author(s):  
Moeini Babak ◽  
Barati Majid ◽  
Heidarimoghadam Rashid ◽  
Tapak Leili ◽  
Parsamajd Shahryar

Inadequate health literacy decreases physical activity. This study aimed to develop and examine psychometrics of physical activity health literacy in Iranian older adults. This methodological work was conducted in two phases. Phase 1 consisted of extensive studies review and qualitative study to extract and design the items. The psychometrics were measured in Phase 2 included content, faceconstruct validities, reliability, and stability. The collected data were analyzed in SPSS (version 25.0) and AMOS (version 24.0). The results of the exploratory factor analysis showed four factors— information evaluation, reading skill, perception, and decision making—and used information that explained 70.08% of the variance. The model’s fitness was supported by confirmatory factor analysis. Internal consistency based on Cronbach’s alpha was .89 with composite reliability >0.85. Stability was confirmed through the test–retest method and intraclass correlation coefficient (.89–1). Psychometrics of physical activity health literacy in Iranian older adults supported validity and reliability of the tool.


2003 ◽  
Vol 48 (1) ◽  
pp. 191-198 ◽  
Author(s):  
T.K. Chen ◽  
C.H. Ni ◽  
J.N. Chen ◽  
J. Lin

The membrane bioreactor (MBR) system has become more and more attractive in the field of wastewater treatment. It is particularly attractive in situations where long solids retention times are required, such as nitrifying bacteria, and physical retention critical to achieving more efficiency for biological degradation of pollutant. Although it is a new technology, the MBR process has been applied for industrial wastewater treatment for only the past decade. The opto-electronic industry, developed very fast over the past decade in the world, is high technology manufacturing. The treatment of the opto-electronic industrial wastewater containing a significant quantity of organic nitrogen compounds with a ratio over 95% in organic nitrogen (Org-N) to total nitrogen (T-N) is very difficult to meet the discharge limits. This research is mainly to discuss the treatment capacity of high-strength organic nitrogen wastewater, and to investigate the capabilities of the MBR process. A 5 m3/day capacity of MBR pilot plant consisted of anoxic, aerobic and membrane bioreactor was installed for evaluation. The operation was continued for 150 days. Over the whole experimental period, a satisfactory organic removal performance was achieved. The COD could be removed with an average of over 94.5%. For TOC and BOD5 items, the average removal efficiencies were 96.3 and 97.6%, respectively. The nitrification and denitrification was also successfully achieved. Furthermore, the effluent did not contain any suspended solids. Only a small concentration of ammonia nitrogen was found in the effluent. The stable effluent quality and satisfactory removal performance mentioned above were ensured by the efficient interception performance of the membrane device incorporated within the biological reactor. The MBR system shows promise as a means of treating very high organic nitrogen wastewater without dilution. The effluent of TKN, NOx-N and COD can fall below 20 mg/L, 30 mg/L and 50 mg/L.


Sign in / Sign up

Export Citation Format

Share Document