Development and testing of a fully adaptable membrane bioreactor fouling model for a sidestream configuration system

This article is available through the Brunel Open Access Publishing Fund. Copyright © 2013 MDPI AGA dead-end filtration model that includes the three main fouling mechanisms mentioned in Hermia (i.e., cake build-up, complete pore blocking, and pore constriction) and that was based on a constant trans-membrane pressure (TMP) operation was extensively modified so it could be used for a sidestream configuration membrane bioreactor (MBR) situation. Modifications and add-ons to this basic model included: alteration so that it could be used for varying flux and varying TMP operations; inclusion of a backwash mode; it described pore constriction (i.e., irreversible fouling) in relation to the concentration of soluble microbial products (SMP) in the liquor; and, it could be used in a cross flow scenario by the addition of scouring terms in the model formulation. The additional terms in this modified model were checked against an already published model to see if they made sense, physically speaking. Next this modified model was calibrated and validated in Matlab© using data collected by carrying out flux stepping tests on both a pilot sidestream MBR plant, and then a pilot membrane filtration unit. The model fit proved good, especially for the pilot filtration unit data. In conclusion, this model formulation is of the right level of complexity to be used for most practical MBR situations

Comparing and contrasting traditional membrane bioreactor models with novel ones based on time series analysis

Copyright @ 2013 MDPI AGThis article has been made available through the Brunel Open Access Publishing Fund.The computer modelling and simulation of wastewater treatment plant and their specific technologies, such as membrane bioreactors (MBRs), are becoming increasingly useful to consultant engineers when designing, upgrading, retrofitting, operating and controlling these plant. This research uses traditional phenomenological mechanistic models based on MBR filtration and biochemical processes to measure the effectiveness of alternative and novel time series models based upon input–output system identification methods. Both model types are calibrated and validated using similar plant layouts and data sets derived for this purpose. Results prove that although both approaches have their advantages, they also have specific disadvantages as well. In conclusion, the MBR plant designer and/or operator who wishes to use good quality, calibrated models to gain a better understanding of their process, should carefully consider which model type is selected based upon on what their initial modelling objectives are. Each situation usually proves unique.This article is made available through the Brunel Open Access Publishing Fund

Analysing flux decline in dead-end filtration

Can we rely on the analysis of flux decline to evaluate the risks of a filter media to be clogged during filtration of a given particle suspension? This important issue can be dealt with a macroscopic approach described in this paper. We seek to identify and quantify the successive prevailing mechanisms which occur during a filtration run, directly and solely from experimental flux data. This is achieved from the collection of experimental data (filtrate volume V vs. time t) and the use of the differential equation (d2t/dV2) = k(dt/dV)n. A methodology is then proposed to define and validate experimental procedures with the purpose of quantifying occurring fouling mechanism. For the purpose of illustrating its valuable impact for a bench marking procedure, the methodology has been applied on a model system composed of a bentonite suspension and a series of microfiltration membranes of different structures

Towards understanding EC coupling protein expression with age

Sarcopenia is characterised by a decrease in muscle specific force that can only partially be attributed to muscle atrophy. Changes in fiber type composition of muscle have also been observed in humans with age. Additionally, it is suggested that excitation contraction coupling (EC coupling) is impaired in aging by uncoupling of the two calcium channels facilitating EC coupling, the dihydropyridine receptor (DHPR) and the ryanodine receptor (RyR1), perhaps due to a decrease in expression of the DHPR alpha1s subunit which has been demonstrated in rodents. Changes in DHPR beta1a subunit expression have also been reported in aging mice but not investigated in humans. The 12kDa FK506 binding protein (FKBP12) stabilizes RyR1 in the closed state. Its dissociation from RyR1 causes a ""leaky"" channel and decreased EC coupling. Furthermore, RyR1 has two variably spliced regions, ASI and ASII, thought to be developmentally regulated. The ASI region, which lies close to a DHPR beta1a binding site, affects EC coupling. The juvenile isoform (ASI(-)RyR1) shows enhanced calcium release during EC coupling and its overexpression is linked to myopathy in myotonic dystrophy. Regeneration in aging muscle due to increased denervation and reinnervation can give rise to immature muscle fibers with higher levels of the juvenile isoforms of some proteins. Therefore the aim of this study was to investigate the fiber type distribution as well as levels of RyR1, DHPR alpha1s, beta1a, and FKBP12 in aged human muscle from 42 donors (aged 40-90yr) undergoing knee (vastus medialis) and hip replacements (gluteus minimus and gluteus medius). The levels of ASI splice variant transcripts in the muscle were investigated using RT-PCR. Furthermore, the effect of the addition of beta1a to recombinant ASI splice variant channels in lipid bilayers was investigated. Vastus medialis was predominantly fast twitch, whereas gluteus minimus and gluteus medius were predominantly slow twitch fibers. Contrary to expectation, age affected fiber type composition differently in the three human muscles. Also, contrary to rodent studies, no significant difference in the human expression levels of the RyR1, DHPR alpha1s and beta1a or FKBP12 with age was found. The ASI(+)RyR1:ASI(-)RyR1 ratio showed no significant change with age, however, an unexpected strong correlation between the fiber type and splice variant was found. In muscle with a high fraction of slow-twitch fibers, ASI(-)RyR1 predominates and vice versa. This novel finding suggests the ASI splice variants are fiber type specific rather than developmentally regulated. Finally, novel lipid bilayer results showed that ASI(+)RyR1 was activated more by 10nM beta1a than ASI(-)RyR1, but was similarly activated by 50nM beta1a, indicating a higher affinity of ASI(+)RyR1 for beta1a. Although no significant difference in expression levels of EC coupling proteins with age in humans was found, the discovery of fiber type specificity in RyR1 splice variants is important. This has not been shown before and provides a paradigm shift in understanding skeletal muscle changes in myotonic dystrophy. The discovery of different isoform affinities for beta1a may explain differences between EC coupling in fast and slow twitch fibers and changes in EC coupling in myotonic dystrophy

Pengaruh religiusitas dan dukungan sosial terhadap subjective well-being mahasiswa rantau di masa pandemi covid-19

Pandemi COVID-19 memberikan dampak bagi mahasiswa rantau akibat kuliah daring dan kondisi marantau yang dialami mahasiswa memberi afek negatif seperti stress karena culture shock dan penyesuian terhadap tantangan baru baik dosen, rekan, akademisi, tekanan, hubungan pribadi, dll serta mempresepikan diri tidak diterima di tempat baru, mengalami tingkat harga diri yang rendah, tidak puas, dirasakannya diskriminasi, dan menarik diri dari aktivitas sosial. Masalah tersebut menjadi ukuran terhadap subjective well-being mahasiswa rantau, sehingga perlu adanya prediktor yang mampu meningkatkan SWB mahasiswa rantau dimasa Pandemi COVID-19 seperti religiusitas dan dukungan sosial. Tujuan penelitian untuk mengetahui pengaruh religiusitas dan dukungan sosial terhadap subjective well-being mahasiswa rantau dimasa Pandemi COVID-19. Pengambilan sampling menggunkan purposive sampling. Subjek yang terlibat sebanyak 100 orang dengan usia 18-25 tahun. Pengambilan data menggunakan skala religiusitas dengan 36 item α= 0.924, dukungan sosial 27 item α = 0,917, dan SWB menggunakan skala PANAS α = 0.772 dan Life satisfaction α = 0.886. Analisis data menggunakan analisis regresi linier berganda. Hasil penelitian menunjukan koefsien korelasi koefisien regresi religiusitas sebesar 0,172 dan dukungan sosial sebesar 0,875 dengan p = 0,000<0,05 artinya religiusitas dan dukungan sosial berpengaruh signifikan secara bersama-sama terhadap subjective well-being mahasiswa rantau dimasa Pandemi COVID-19

Laboratory Studies on Granular Filters and Their Relationship to Geotextiles for Stormwater Pollutant Reduction

Applications of geotextiles within tertiary stormwater treatment systems and for stormwater infiltration can provide a substrate for biofilm formation, enabling biological treatment of contaminants. Geotextiles can serve as an efficient part of stormwater filtration within the urban water environment. The project assessed the applications of three experimental granular filters as a sustainable urban drainage system (SUDS) for the decomposition of organic pollutant loading present in stormwater. The three filter rigs were packed with alternating layers of filter media consisting of gravel, pea gravel, sand and either a single, double or no layer of geotextile membrane. A nonwoven geotextile was layered within the filter media. The hydraulic loading capacity for the three filters matched that commonly used with conventional sand filters systems. Water quality parameters were quantified by measuring suspended solids, chemical oxygen demand, dissolved oxygen, pH, nitrate-nitrogen, and phosphate concentrations. It was found that Filter Rig No. 3 (upper and lower geotextile membrane) and Filter Rig No. 2 (single geotextile membrane) had a significant statistical difference in treatment performance from Filter Rig No. 1 (no geotextile membrane)

Pengembangan Usaha Petani Ubi Ungu di Rokan Hilir

Produksi ubi ungu di Provinsi Riau mengalami peningkatan dari tahun ke tahun yang diiringi dengan peningkatan jumlah penanaman. Pada tahun 2010 merupakan triwulan IV dengan luas panen 187,00 ha dengan produktivitas 1.602.400,00 kg, sedangkan pada tahun 2011 berada pada triwulan IV dengan luas panen 218,00 ha dengan produktivitas 2,30.000,00 kg. Dengan produsen ubi ungu dalam Provinsi Riau meliputi 10 kabupaten / kota, yaitu Indragiri Hulu, Indragiri Hilir, Pelalawan, Siak, Rokan Hilir, Rokan Hulu, RokanHilir, Bengkalis, Pekanbaru dan Dumai. (BPS Provinsi Roau, 2011). Daerah penghasil ubi ungu di Kota Pekanbaru meliputi empat kecamatan, yaitu Kecamatan Tampan, Kabupaten Tenayan Raya, Kabupaten Rumbai dan Kabupaten Rumbai Pesisir. Daerah ini merupakan daerah dataran rendah dimana banyak petani yang membudidayakan tanaman ubi ungu untuk memenuhi kebutuhan buah di Kota Pekanbaru.Untuk mengatasi masalah limbah buah hortikultura seperti ubi ungu dapat dilakukan dengan cara membuat jajanan sehat seperti kripik ubi ungu. Tujuan dari kegiatan ini adalah untuk menggali ide-ide inovatif, meningkatkan kreativitas, menanamkan jiwa wirausaha, melatih mental dan mengajar untuk bekerja keras dan bertanggung jawab. Ada beberapa kendala yang dihadapi yaitu (1) keterbatasan modal. (2) Rendahnya motivasi wirausaha dengan bahan utama ubi jalar. (3) Tidak ada keragaman produk olahan ubi jalar. (4) Tidak adanya pengemasan dan pemasaran ubi ungu. Kegiatan yang akan dilakukan dalam program PKM ini antara lain upaya pengembanga

Religiosity and Social Support as Predictors for Subjective Well-Being of Overseas Students during Pandemic

The Covid-19 pandemic, which led to the wide use of online services to conduct lectures and other academic-related services, negatively impacted the well-being of overseas students. Therefore, it is necessary to have predictors that can increase their subjective well-being (SWB). The purpose of this study is to determine the effect of religiosity and social support on SWB of overseas students during the pandemic. A quantitative correlational study was employed with data collected from 100 people aged 18-25 through a purposive sampling technique. The SWB of the respondents were measured to determine their religiosity, social support, the Positive and Negative Affect Schedule (PANAS), as well as Life Satisfaction scales. The multiple linear regression analysis results showed that religiosity and social support simultaneously significantly affected students' SWB during the pandemic, while social support partially affected SWB