Application of novel Modified Biological Aerated Filter (MBAF) as a promising post-treatment for water reuse: Modification in configuration and backwashing process

Biological Aerated Filter (BAF) reactors due to their plentiful biomass, high shockability, high efficiency, good filtration, availability and lack of need for large land areas, are enjoying from great importance in advanced wastewater treatment. Therefore, in this study, Polystyrene Coated by Sand (PCS) was produced as a novel media and its application in a modified down-flow BAF structure for advanced wastewater treatment was assessed in two steps. In step one, the backwash effluent did not return to the system, while in step two backwash effluent returned to increase the water reuse efficiency. The backwash process was also studied through three methods of Top Backwashing (TB), Bottom Backwashing (BB), as well as Top and Bottom Backwashing Simultaneously (TBBS). The results showed that return of backwash effluent had no significant effect on the BAF effluent quality. In the second step similar to the first one with slight differences, the residual average concentrations of TSS, BOD5, and COD at the effluent were about 2.5, 8.2, and 25.5 mg/L, respectively. Additionally, in step two, the mean volume of disposal sludge/volume of treated water (v(ds)/v(tw)) decreased a large extent to about 0.088. In other words, the water reuse has increased to more than 99.91. The backwash time in methods of TB and BB were 65 and 35 min, respectively; however, it decreased in TBBS methods to 25 min. The concentrations of most effluent parameters in this system are in concordance with the 2012 EPA Agriculture Standards, even for irrigation of Non-processed agricultural crops and livestock water consumption. (C) 2017 Elsevier Ltd. All rights reserved

Resolution of scanning ultrasonic imaging systems with arbitrary transducer excitation

An analytical formulation is presented which predicts the imaging performance of broadband ultrasonic imaging systems. The effect of frequency dependent attenuation on image resolution is analysed. Examples of the case of a narrow RF pulse and a wideband FM chirp pulse excitation are presented. It is shown that as far as the imaging resolution is concerned it is possible to make a very good intuitive estimate of the « equivalent cw » frequency.On propose une formulation analytique permettant de prévoir les performances de systèmes imageurs ultrasonores large bande. L'effet de la dépendance en fréquence de l'atténuation sur la résolution de l'image est analysé. Des exemples concernant le cas d'une impulsion radiofréquence étroite et d'une excitation large bande balayée linéairement en fréquence sont présentés. On montre que dans la mesure où seule la résolution de l'image est considérée, il est possible de faire une très bonne estimation intuitive de la « fréquence continue équivalente »

Evaluation the Correlation between Turbidity and Total Suspended Solids with other Chemical Parameters in Yazd Wastewater Treatment Effluent Plant

Introduction: Expensive chemical tests are usually applied to control the efficiency of wastewater treatment plants. However, the cost of measuring these parameters is one of the challenges of the wastewater treatment plants. Using statistical methods has been evaluated for possibility of calculating expensive parameters by measuring the inexpensive parameters in this study. Materials and Methods: Initial sample number in this study was 87 cases that were collected from SBR effluent treatment plants of Yazd as a routine sampling for two years in March 2013 to March 2015. Total suspended solids (TSS) and turbidity parameters were defined as independent variables and twelve parameters including BOD5, COD, TKN, NH3+, NO3-, NO2-, TP, TH, Ca2+, Mn2+, alkalinity, and color were the dependent variables. Spearman test was used to investigate the significant relationship between independent and dependent variables. Linear regression analysis was used to determine the linear equation between TSS and turbidity as independent variables with BOD5, COD, TKN, NH3-, NO2-, TP and color as dependent variables. Results: The results of the regression equations in relation to turbidity and TSS with independent variables showed that the R value for color, TKN, NH3+, BOD5, COD, TP, and NO2- were 0.942 , 0.931 , 0.91 , 0.905 , 0.874 , 0. 872 and 0.86 respectively from the highest to the lowest. Conclusion: The measured values of BOD5, COD, TKN, TP, NO2-, NH3+, and color in laboratory were very close to those predicted through regression equations. Therefore, regression equations created in this study can be used to calculate expensive parameters

Subsurface Broadband Acoustic Microscopy of Solids using Aperture Lenses

The imaging of interior planes in a solid object involves difficulties with spherical aberration, with the elimination of the front surface echo, and with the need in some cases to use signal processing techniques in order to enhance the signal-to-noise ratio. This paper shows that suitably designed spherical lenses can be used to minimize the spherical aberration. The elimination of the front surface echo requires careful time-gating and very short, broadband pulses. It is shown by using extended chirp pulses, the signal-to-noise ratio for subsurface objects can be very greatly improved. A number of examples of the use of these techniques for NDE are presented.</p

Synthesis of polystyrene coated by sand (PCS) as a novel media in modified biological aerated filters (BAF) for advanced municipal wastewater treatment: a comparative assessment

In this study a novel media, polystyrene coated by sand (PCS) was made and then applied in a -pilot-scale down-flow biological aerated filter (BAF), named PCS BAF. The efficiency of PCS BAF reactor was compared with efficiencies of puzzolana BAF, gravel BAF, and polystyrene BAF in advanced domestic wastewater treatment through three stages. The inner structure of BAFs consisted of a media with a height of 150 cm for biological attached growth that was modified by a 20 cm layer of silica particles at the bottom of columns to increase the reactors' performance. The physical and chemical parameters of turbidity, BOD5, TCOD, and SCOD, as well as parameters related to backwashing were investigated for BAFs' efficiency. Results of this research indicated that PCS BAF can decrease the turbidity, BOD5, TCOD, and SCOD in the influent, from 20 NTU, 22, 53, and 36 mg/L, to a rate of 1.3 NTU, 9, 26, and 21 mg/L in the effluent, respectively. Moreover, the backwashing time required for PCS BAF was less than half of the other three BAF reactors and the backwashing interval was about once every 19 d

Assessment of hospitalization and mortality from exposure to PM10 using AirQ modeling in Ilam, Iran

The aims of this study were to assess the health impact of PM10 on inhabitants and to investigate the trend of PM10 concentrations in Ilam, Iran, from 2012 to 2015. For these aims, daily average concentration of PM10 was obtained from continuous monitoring stations in the study area. Mortality and morbidity due to PM10 were assessed by AirQ software developed by World Health Organization (WHO). Based on the results, the annual mean concentrations of PM10 in all of years were more than WHO guideline and PM10 concentration had a decreasing trend in this study period. Total mortality attributed to PM10 was found to be 49 cases in 2012, 25 in 2013, and 33 in 2014. Hospital admission due to respiratory diseases was the most impact due to PM10. Increase in relative risk (RR) with every 10 mu g/m(3) increase in PM10 from 2012 to 2015 years for total mortality, respiratory disease hospitalization, and hospital admissions were 0.6, 0.8, and 0.9, respectively. The results of this study indicated that air pollution is one of the major problems in this urban area and AirQ model as simple tool can help to design preventive and controlling programs in order to reduce human health effects of pollutants

LED visible light assisted photo-oxidation of acetaminophen using one-step synthesis of Cu,Fe@g-C3N4 nanosheet – Activated persulfate system in aqueous solutions

In this work, the synthesis of Iron (Fe) and Copper (Cu) co-doped g-C3N4 was performed using the thermal decomposition of urea while iron nitrate and copper nitrate were used as dopant precursors. The fabricated catalyst (Fe-Cu@g-C3N4) was coupled with visible light and used for acetaminophen (APAP) degradation. The synthesized catalyst was characterized via several techniques including XRD, BET, BJH, SEM, TEM, EDX, EDS Dot mapping, DLS, and UV–Vis deflective reflectance spectroscopy. The performed characterization tests confirmed the successful synthesis of Fe-Cu co-doped g-C3N4 with high purity, nano-sheet structure and high porosity (79.93 m2/g). The complete APAP decomposition efficiency was achieved under optimal experimental conditions including pH of 11, catalyst dosage of 10 mg/L, PS dosage of 1 mM, and APAP concentration of 4 mg/L. The scavenging tests confirmed the major contribution of sulfate radicals and consequently, hydroxyl radicals for APAP removal. In addition, the kinetics of APAP degradation was studied and it revealed the pseudo first–order kinetics with 0.0698 min−1 rate constant. Finally, a plausible and tentative decomposition pathway was proposed for APAP degradation. The results of this study confirmed that the LED/catalyst (Cu, Fe@g-C3N4)/PS process could be an efficient and robust process for antibiotic-containing wastewater including hospital wastewater

Evaluation and comparison of physicochemical properties, cytotoxicity and the ability of miRNA loading of different cationic liposomes for gene therapy application

Introduction: In the present study, various formulations of cationic liposomes were designed and prepared using different cationic lipids. It was performed to assess the physicochemical properties, miRNA loading ability and cellular toxicity rates of liposomes in order to use in gene therapy. Methods: Different cationic liposome formulations (F1-F4) containing various cationic lipids, DOTAP, DOTMA, DOAB and DDAB with DPPC, cholesterol and phospholipid DSPE-mPEG were synthesized. Prepared nanoparticles were evaluated in term of particle size, polydisparity index, surface charge and cytotoxicity for 48 and 72 h in two cell lines. By using gel electrophoresis, the ability of synthesized cationic liposomes to entrap miRNA was also compared. Results: All formulations were mono-dispersed. The particle size in F1, which contained DOTAP was lower than others (F2-F4) and its surface charge was more than them. Cationic liposomes based on DOTAP had no significant cytotoxicity as compared to other formulations. Also, F1 formulation was more capable to entrap miRNA than other formulas. Conclusion: DOTAP-based cationic liposomes can be used efficiently in the gene therapy process, especially for the transfer of miRNA as a new therapeutic agent in cancer therap

Assessment of Spatial Analysis Methods in Mapping of Air Pollution in Mashhad

Background: This study aimed to compare and evaluate the spatial and statistical models to predict PM2.5 concentrations at ground level and at the macro scale in Mashhad. Methods: To investigate the status of air pollution in the metropolis of Mashhad air, three interpolating models including Ordinary Kriging (OK), Universal Kriging (UK) and inverse distance weighting (IDW) were used. Root Mean Square Error (RMSE) and correlation coefficient (R2) were employed to compare three models and choose the best one. As well as to select the most optimal conditions for the implementation of both OK and UK, used from Standardized RMSE. Results: The results showed that the highest monthly average of PM2.5 was belonged to September and &ldquo;Sakhteman&rdquo; station (95.1 &mu;g/m3). Also, the lowest monthly average pollution had happened in &quot;Torogh&quot; station, in November (15.5 &mu;g/m3). According to the data, the OK had the lowest RMSE (10.601) compared to the UK and IDW. Lower RMSE represents lower error between the predicted and measured values. So, OK model selected as better one in interpolation. Also, Judging by correlation coefficient (R2), the highest correlation belonged to OK compared to other two models. UK model showed a greater standard error of predicts than OK. The greatest standard errors of prediction were related to areas that have more distance from air pollution monitoring stations. Conclusion: it should be noted that the production and use of geo-referenced maps could quickly provide spatial analyses, and because it can be combined with GIS, the user is able to investigate the influence the various concentrations of contaminants