Biological Nutrient Removal from Municipal and Industrial Wastewater Using a Twin Circulating Fluidized Bed Bioreactor

Biological nutrient removal (BNR) refers to removal of carbon (C), nitrogen (N) and phosphorus (P) from wastewater (WW) by the aid of various microorganisms. Because of the public concern for the environment C, N and P effluent standards have become stricter. Different BNR processes such as suspended growth and attached growth have been studied during the last three decades in order to meet the increasingly stringent discharge standards. In this work, two novel processes called Twin Fluidized Bed Bioreactor (TFBBR) and Twin Circulating Fluidized Bed Bioreactor (TCFBBR) were developed and tested for BNR from municipal WW. Both TFBBR and TCFBBR comprise of an anoxic column and an aerobic column with particle recirculation between the two reactors achieved mechanically (TFBBR) and hydraulically (TCFBBR). Moreover, a newly developed system called Anaerobic Fluidized-Circulating Fluidized Bed Bioreactor (AF-CFBBR) was developed and tested to accomplish BNR from high strength industrial WW. AF-CFBBR comprises of an anaerobic, an anoxic and an aerobic columns. In all three aforementioned systems, fine carrier media are employed for biofilm attachment. After the development of biofilm, the particles are called biofilm-coated particles. TFBBR and TCFBBR were operated at organic, nitrogen and phosphorus loading rates (OLR, NLR and PLR) of up to 2.8 kg COD/m3×d and 4.5 kg COD/m3×d, 0.3 kg N/m3×d and 0.5 kg N/m3×d and 0.041 kg P/m3×d respectively to study the performance of the system with respect to biological nutrient removal. The nitrification rates based on biofilm surface area in TFBBR and TCFBBR were 0.91 g N/m2×d and 1.26 g N/m2×d respectively and the denitrification rates based on biofilm surface area in TFBBR and TCFBBR were 0.65 g N/m2×d and 1.32 g N/m2×d respectively. Both systems removed \u3e96% organic matter, 84%-88% nitrogen and 12%-50% phosphorus at overall hydraulic retention time of (HRT) 2h. TFBBR and TCFBBR achieved long SRTs of 72-108 d and 37-40 d respectively, which rationalized the very low observed yield of 0.06-0.07 g VSS/g COD and 0.09-0.1 g VSS/g COD. The AF-CFBBR demonstrated 99.7% COD removal, 84% nitrogen removal, with a very low sludge yield of 0.017 g VSS/g COD while treating a wastewater containing 10700 mg COD/L and 250-300 mg NH3-N/L. The system was operated at an organic loading rate (OLR) of 35 kg COD/m3·d based on the AF volume and 1.1 kg N/m3·d based on the CFBBR at an overall HRT of less than 12 h in the AF-CFBBR. The nitrification, denitrification and organic removal rates based on aerobic, anoxic and anaerobic biofilm surface area in AF-CFBBR respectively were 2.6 g N/m2×d, 9.03 g N/m2×d and 12.1 g COD/m2×d. Additionally, the inhibitory effect of nitrate on methanogenic activities in a high rate anaerobic fluidized bed with organic loading rate of above 35 kg COD/m3·d was studied in order to evaluate the feasibility of simultaneous denitrification and methanogenic activities (SDM) in a high rate anaerobic system. Terminal settling velocity and bed expansion of biofilm-coated particles as the two main hydrodynamic criteria in a fluidized bed, were studied. Archimedes was superior to Reynolds number for drag coefficient and bed expansion definitions. A new equation for determining drag force on fluidized bed bio-film coated particle (Fd) as an explicit function of terminal settling velocity was generated based on Archimedes numbers (Ar) of the biofilm coated particle. The proposed equation adequately predicted the terminal settling velocity of other literature data with an accuracy of \u3e90%. A new equation based on Archimedes number was proposed to calculate bed expansion index of biofilm-coated particles, which predicted the existing experimental data with less standard error than all other literature equations that related bed expansion to Reynolds number. A two-phase and three-phase predictive fluidization model based on the characteristics of a system such as media type and size, flow rates, and reactor cross sectional area was proposed to calculate bed expansion, solid, liquid and gas hold up, specific surface area of the biofilm particles. The model was subsequently linked to 1d AQUIFAS APP software (Aquaregen) to model two and three phase fluidized bed bioreactors. The model was validated for biological nutrient removal using the experimental data from a Twin Circulating Fluidized Bed Bioreactors (TCFBBR) treating synthetic and municipal wastewater. Two-sided t-tests showed that there were no statistically significant difference between the experimental and the modeled TCOD, SCOD, NH3-N, NOx-N

The Structure and Stability of Selected, 2-D Self-Gravitating Systems.

Models of radially and vertically extended self-gravitating disks orbiting around a central point mass are relevant to the dynamics of astrophysical systems and are thought to be common in many galaxies. The gravity driven instabilities in these accretion disks are now believed to be a possible mechanism for star formation via disk fragmentation (Shu, Adams, & Lizano 1987, Adams, Rudin & Shu 1989; Christodoulou 1995). We quantify these regions of instability using a simple toroidal model of an accretion disk. We choose the two-dimensional axisymmetric, incompressible slender disks to examine and map out these principal modes of gravity driven instabilities. Through stability analyses and numerical simulations we have found that only the gravity driven intermediate modes (see Goodman and Narayan 1988) are important in all self-gravitating accretion disks with small or moderate axis ratios. The P-mode instability found by Papalaizou and Pringle (1983) is unlikely to play a role in the dynamics of realistic disk systems. Next, we extend the existing numerical methods for constructing equilibrium structures to include nonaxisymmetric systems. We have developed a new computational technique to obtain two-dimensional, nonaxisymmetric, compressible systems with nontrivial internal motions. We have constructed two types of two-dimensional configurations: infinite cylinders and infinitesimally thin disks. The infinite cylinders have been primarily restricted to elliptic-like boundaries but the disks have exhibited much more flexibility in their geometries. At smaller axis ratios, they become dumbbells or loosely coupled binaries. The topology and dynamics of the flow is governed by the presence of vortices and stagnation points. In our simulation it is shown that there are equilibrium configurations that can only exist in the presence of internal differential motions and not in uniformly rotating models. This indicates that in general, the equilibrium structures of these nonaxisymmetric configurations are dependent not just on the constant frame rotation but perhaps even more importantly on the internal differential fluid motion. This is especially important when we construct nonaxisymmetric models with high T/$\vert$W$\vert,$ where T and W are the kinetic and the gravitational potential energy respectively. In these systems, most of the contribution to T/$\vert$W$\vert$ comes from internal rotation

Assesing interactivity in the websites of human rights organizations\u27 websites in Egypt

The Internet has many advantages over the other media in the provision of information services especially in the field of human rights. In Egypt the image of the human rights organization has been affected severely after the Egyptian revolution due to continuous media attack on them; therefore, it became vital to change this image. As the websites is the primary tool that permits the organizations to connect with their audience and permit the audience to know their activities, analyzing the websites of the human rights in Egypt from user perspective become vital This study aims to assess the interactivity and public involvement allowed by the sites to see whether they use their websites in an efficient way that permit them to reach their audience nationally and internationally or not, moreover, it tries to figure out reasons behind this level of interactivity. “Reception based analysis†technique was used for the first time in Egypt, to map both the interactivity level and the amount of public engagement allowed by the site in a sample of 10 existing human rights websites along with Heeter and Burgeon 7 dimensions of interactivity (content and availability of choice, effort user must exert, responsiveness to users, ease of adding information, facilitation of interpersonal communication, modality and information rich, and ability to make two ways communication ) ; Moreover , interviews with experts and official working in the field of human rights was used to know more in depth data about the barriers that confront the websites developers of human rights organizations in Egypt Using the reception based analysis technique gives the study the advantage of understanding how the users sees different dimensions of interactivity and public engagement in the websites of human right NGOs. The results of the analysis indicated the overall level of opportunities for interactivity in the websites of human rights NGOs in Egypt is very low; moreover, the overall level of public engagement allowed by the site is low. Moreover, the results of the interviews revealed that lack of funds, lack of media and IT specialists in the organization, and technological gap were the main problems that confront the organization while maintaining interactivity of their website

A study on measuring the quality of university website

During the past few years, many organizations try to provide some of their services through their websites. This would help them provide fast and reliable services to various people around the world. In this paper, we present an empirical survey to measure the relative performance of a university website in Iran using Parasuraman's technological readiness index. The proposed study uses a standard questionnaire and distributes it among 387 active website users and the results are analyzed using structural equation modeling. The proposed study of this paper considers the effects of four factors including efficiency, accessibility, achievement and security on customer loyalty via two variables of trust and satisfaction. The results demonstrate that three components of trust, efficiency and achievement play essential role on customer loyalty

Lateral rectus muscle disinsertion and reattachment to the lateral orbital wall in exotropic Duane syndrome: a case report

<p>Abstract</p> <p>Introduction</p> <p>The surgical correction of anomalous movement such as upshoot in Duane syndrome is challenging. Lateral rectus muscle disinsertion and reattachment to the lateral orbital wall is a new approach used to minimize or eliminate the effects of co-contraction including globe retraction, palpebral fissure narrowing and anomalous vertical movement.</p> <p>Case presentation</p> <p>We report a case of a 7-year-old boy who underwent this procedure for severe upshoot, globe retraction and exotropia in the left eye due to Duane syndrome. The patient achieved satisfactory ocular alignment following surgery. Upshoot and globe retraction were substantially improved.</p> <p>Conclusion</p> <p>Lateral rectus muscle disinsertion and reattachment to the lateral orbital wall is a safe and effective procedure for weakening of the anomalous lateral rectus muscle in Exotropic Duane Syndrome.</p

Expression of an innate immune element (mouse hepcidin-1) in baculovirus expression system and the comparison of its function with synthetic human hepcidin-25

Hepcidin is an innate immune element which decreases the iron absorption from diet and iron releasing from macrophage cell. In contrast to the chemical iron chelators, there has been limited effort applied to the specific use of hepcidin as a new drug for decreasing the iron overload. Hepcidin is produced in different biological systems. For instance, E-coli is used for human hepcidin expression, however, post-translational modification is impaired. We have used a simple baculovirus expression system (BES) to improve the hepcidin folding and activity. Hepcidin Messenger Ribonucleic acid (mRNA) was isolated from mouse liver cells and its complementary Deoxyribonucleic acid (cDNA) was produced and amplified. PFastBac HTB vector was used for recombinant bacmid production. Recombinant baculovirus was produced using SF-9 cell line. The mouse hepcidin-1 protein was expressed in a large quantity and functional tests were performed for this recombinant peptide. The yield of hepcidin in BES was 20 μg/mL and anti-histidine (anti-His) tag antibody was used for the confirmation of hepcidin on western blot nitrocellulose paper. Functional tests showed that mouse hepcidin accumulates iron in the macrophage cell line J774A.1 up to 63%. In addition, our data showed that the mouse hepcidin-1 has less toxicity compared to the synthetic human hepcidin-25 (p = 0.000). © 2011 by School of Pharmacy