scholarly journals Design of a column test bench for the evaluation of alternative absorbent materials in wastewater treatment

2021 ◽  
Vol 958 (1) ◽  
pp. 012007
Author(s):  
M Mayacela ◽  
L Maldonado ◽  
F Morales ◽  
R Peñafiel

Abstract One of the most used processes for wastewater treatment is filtration, still having unknowns related to the new possible absorbent materials which can provide better pollutant removal. This project proposes a column test bench capable of working with different materials, particle diameters (> 0.35mm) and densities and densities with three columns of 1.5 m length and 4 inches of diameter.. To perform this project, the type of reactive material for the filter medium was identified, considering the nominal and critical size of the fine sand (0.35m), as a basis for determining the design of the length, diameter of the and thickness column. The design conditions were taken so that the hydraulic system can function as a slow and rapid filter. The most critical operating conditions were selected, Qmax: 16.72 lpm and Filtration Rate: 19.80 m / h. Under these operating conditions, a hydraulic head loss of 2.77 m was obtained within the sand column. The result of this research is the design of a column test system that can work under different hydraulics conditions and absorbent materials with sizes greater than 0.35 mm, intended for the investigation of wastewater treatment from car washers and the removal of heavy metals. The final cost of building the column test is about 25% of the commercial price system.


Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 337
Author(s):  
Sara Mesa Medina ◽  
Ana Rey ◽  
Carlos Durán-Valle ◽  
Ana Bahamonde ◽  
Marisol Faraldos

Two commercial activated carbon were functionalized with nitric acid, sulfuric acid, and ethylenediamine to induce the modification of their surface functional groups and facilitate the stability of corresponding AC-supported iron catalysts (Fe/AC-f). Synthetized Fe/AC-f catalysts were characterized to determine bulk and surface composition (elemental analysis, emission spectroscopy, XPS), textural (N2 isotherms), and structural characteristics (XRD). All the Fe/AC-f catalysts were evaluated in the degradation of phenol in ultrapure water matrix by catalytic wet peroxide oxidation (CWPO). Complete pollutant removal at short reaction times (30–60 min) and high TOC reduction (XTOC = 80 % at ≤ 120 min) were always achieved at the conditions tested (500 mg·L−1 catalyst loading, 100 mg·L−1 phenol concentration, stoichiometric H2O2 dose, pH 3, 50 °C and 200 rpm), improving the results found with bare activated carbon supports. The lability of the interactions of iron with functionalized carbon support jeopardizes the stability of some catalysts. This fact could be associated to modifications of the induced surface chemistry after functionalization as a consequence of the iron immobilization procedure. The reusability was demonstrated by four consecutive CWPO cycles where the activity decreased from 1st to 3rd, to become recovered in the 4th run. Fe/AC-f catalysts were applied to treat two real water matrices: the effluent of a wastewater treatment plant with a membrane biological reactor (WWTP-MBR) and a landfill leachate, opening the opportunity to extend the use of these Fe/AC-f catalysts for complex wastewater matrices remediation. The degradation of phenol spiked WWTP-MBR effluent by CWPO using Fe/AC-f catalysts revealed pH of the reaction medium as a critical parameter to obtain complete elimination of the pollutant, only reached at pH 3. On the contrary, significant TOC removal, naturally found in complex landfill leachate, was obtained at natural pH 9 and half stoichiometric H2O2 dose. This highlights the importance of the water matrix in the optimization of the CWPO operating conditions.



2012 ◽  
Vol 573-574 ◽  
pp. 521-525
Author(s):  
Nan Zhang ◽  
Pu Liu ◽  
Ben Quan Fu ◽  
Li Na Wang

In this paper, nanometer titanium dioxide was synthesized by a simple reaction. The prepared adsorbent was characterized by surface area and porosimetry analyzer and it was used for the removal of heave metals in industrial wastewater. The main parameters affecting the adsorption of heavy metals including pH, adsorption condition and elution condition have been investigated in detail. Under the optimized operating conditions, most of the target heavy metals could be fast removed. The adsorbent could be simply regenerated by hydrochloric acid. Thus, the prepared nanometer titanium dioxide was an adsorbent which is suitable for the removal of heavy metals in industrial wastewater.



1992 ◽  
Vol 25 (11) ◽  
pp. 379-386
Author(s):  
G. J. O'Brien

Federal guidelines have been issued which regulate the aqueous discharge concentrations of priority pollutants for the organic chemicals, plastics, and synthetic fibers (OCPSF) Industries. Insufficient data existed in the literature to allow estimations of the removal of priority pollutants by a wastewater treatment plant (WWTP). The removals of eighteen organic xenobiotics were measured in parallel, aerated, continuous, mixed reactors. The influent to the pilot plants was primary effluent from an industrial 30 million gal./day wastewater treatment facility. The kinetic coefficients which characterize removal by biodegradation, powdered activated carbon (PAC) adsorption and air-stripping were obtained, and the values were used to estimate WWTP performance. Agreement between the steady-state model predictions and the WWTP data was surprisingly good for most of the compounds in spite of unsteady-state operation and the six millionfold scaleup. For compounds where severe transients occurred, the steady state model was unsatisfactory. The model was used to design a second stage “PACT” unit and to determine source control requirements. The model also can be used to estimate the relative importance of the three removal mechanisms in order to adjust WWTP operating conditions to enhance the removal of specific compounds.



2012 ◽  
Vol 65 (9) ◽  
pp. 1648-1653 ◽  
Author(s):  
S. Beier ◽  
C. Cramer ◽  
C. Mauer ◽  
S. Köster ◽  
H. Fr. Schröder ◽  
...  

Membrane bioreactor (MBR) technology is a very reliable and extensively tested solution for biological wastewater treatment. Nowadays, separate treatment of highly polluted wastewater streams especially from hospitals and other health care facilities is currently under investigation worldwide. In this context, the MBR technology will play a decisive role because an effluent widely cleaned up from solids and nutrients is absolutely mandatory for a subsequent further elimination of organic trace pollutants. Taking hospital wastewater as an example, the aim of this study was to investigate to what extent MBR technology is an adequate ‘pre-treatment’ solution for further elimination of trace pollutants. Therefore, we investigated – within a 2-year period – the performance of a full-scale hospital wastewater treatment plant (WWTP) equipped with a MBR by referring to conventional chemical and microbiological standard parameters. Furthermore, we measured the energy consumption and tested different operating conditions. According to our findings the MBR treatment of the hospital wastewater was highly efficient in terms of the removal of solids and nutrients. Finally, we did not observe any major adverse effects on the operation and performance of the MBR system which potentially could derive from the composition of the hospital wastewater. In total, the present study proved that MBR technology is a very efficient and reliable treatment approach for the treatment of highly polluted wastewater from hospitals and can be recommended as a suitable pre-treatment solution for further trace pollutant removal.



Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1835 ◽  
Author(s):  
Luis Perez-Mercado ◽  
Cecilia Lalander ◽  
Christina Berger ◽  
Sahar Dalahmeh

The potential of biochar as a filter medium for onsite wastewater treatment was investigated in five sub-studies. Sub-study 1 compared pollutant removal from wastewater using pine-spruce biochar, willow biochar and activated biochar (undefined biomass) filters. Sub-study 2 investigated the effects of particle size (0.7, 1.4 and 2.8 mm) on pollutant removal using pine-spruce biochar filters. In sub-studies 3 and 4, the effects of the hydraulic loading rate (HLR; 32–200 L m−2) and organic loading rates (OLR; 5–20 g biochemical oxygen demand (BOD5) m−2) on pollutant removal using pine-spruce biochar filters were investigated, while sub-study 5 compared pollutant removal in pine-spruce biochar filters and in sand. The removal of chemical oxygen demand (COD), total nitrogen (Tot-N), ammonium nitrogen (NH4-N), phosphates (PO4-P) and total phosphorus (Tot-P) was monitored in all sub-studies. All types of biochar and all particle sizes of pine-spruce biochar achieved a high degree of removal of organic material (COD > 90%). Removal of Tot-P and PO4-P was higher in willow biochar and activated biochar (>70%) than in pine-spruce biochar during the first two months, but then decreased to similar levels as in pine-spruce biochar. Among the particle sizes tested, 0.7 mm pine-spruce biochar showed the lowest amount of Tot-P removal, while 2.8 mm pine-spruce biochar showed the lowest level of NH4-N removal. Different OLRs and HLRs did not influence COD removal (94–95%). Pine-spruce biochar showed a better degree of removal of Tot-N than sand. In conclusion, biochar is a promising filter medium for onsite wastewater treatment as a replacement or complement to sand, achieving high and robust performance regardless of the parent material, particle size or loading conditions.



2014 ◽  
Vol 42 (1) ◽  
pp. 2-15
Author(s):  
Johannes Gültlinger ◽  
Frank Gauterin ◽  
Christian Brandau ◽  
Jan Schlittenhard ◽  
Burkhard Wies

ABSTRACT The use of studded tires has been a subject of controversy from the time they came into market. While studded tires contribute to traffic safety under severe winter conditions by increasing tire friction on icy roads, they also cause damage to the road surface when running on bare roads. Consequently, one of the main challenges in studded tire development is to reduce road wear while still ensuring a good grip on ice. Therefore, a research project was initiated to gain understanding about the mechanisms and influencing parameters involved in road wear by studded tires. A test method using the institute's internal drum test bench was developed. Furthermore, mechanisms causing road wear by studded tires were derived from basic analytical models. These mechanisms were used to identify the main parameters influencing road wear by studded tires. Using experimental results obtained with the test method developed, the expected influences were verified. Vehicle driving speed and stud mass were found to be major factors influencing road wear. This can be explained by the stud impact as a dominant mechanism. By means of the test method presented, quantified and comparable data for road wear caused by studded tires under controllable conditions can be obtained. The mechanisms allow predicting the influence of tire construction and variable operating conditions on road wear.



Author(s):  
Q. Kim ◽  
S. Kayali

Abstract In this paper, we report on a non-destructive technique, based on IR emission spectroscopy, for measuring the temperature of a hot spot in the gate channel of a GaAs metal/semiconductor field effect transistor (MESFET). A submicron-size He-Ne laser provides the local excitation of the gate channel and the emitted photons are collected by a spectrophotometer. Given the state of our experimental test system, we estimate a spectral resolution of approximately 0.1 Angstroms and a spatial resolution of approximately 0.9 μm, which is up to 100 times finer spatial resolution than can be obtained using the best available passive IR systems. The temperature resolution (<0.02 K/μm in our case) is dependent upon the spectrometer used and can be further improved. This novel technique can be used to estimate device lifetimes for critical applications and measure the channel temperature of devices under actual operating conditions. Another potential use is cost-effective prescreening for determining the 'hot spot' channel temperature of devices under normal operating conditions, which can further improve device design, yield enhancement, and reliable operation. Results are shown for both a powered and unpowered MESFET, demonstrating the strength of our infrared emission spectroscopy technique as a reliability tool.



2020 ◽  
Vol 13 (2) ◽  
pp. 126-140
Author(s):  
Jing Gan ◽  
Xiaobin Fan ◽  
Zeng Song ◽  
Mingyue Zhang ◽  
Bin Zhao

Background: The power performance of an electric vehicle is the basic parameter. Traditional test equipment, such as the expensive chassis dynamometer, not only increases the cost of testing but also makes it impossible to measure all the performance parameters of an electric vehicle. Objective: A set of convenient, efficient and sensitive power measurement system for electric vehicles is developed to obtain the real-time power changes of hub-motor vehicles under various operating conditions, and the dynamic performance parameters of hub-motor vehicles are obtained through the system. Methods: Firstly, a set of on-board power test system is developed by using virtual instrument (Lab- VIEW). This test system can obtain the power changes of hub-motor vehicles under various operating conditions in real-time and save data in real-time. Then, the driving resistance of hub-motor vehicles is analyzed, and the power performance of hub-motor vehicles is studied in depth. The power testing system is proposed to test the input power of both ends of the driving motor, and the chassis dynamometer is combined to test so that the output efficiency of the driving motor can be easily obtained without disassembly. Finally, this method is used to carry out the road test and obtain the vehicle dynamic performance parameters. Results: The real-time current, voltage and power, maximum power, acceleration time and maximum speed of the vehicle can be obtained accurately by using the power test system in the real road experiment. Conclusion: The maximum power required by the two motors reaches about 9KW, and it takes about 20 seconds to reach the maximum speed. The total power required to maintain the maximum speed is about 7.8kw, and the maximum speed is 62km/h. In this article, various patents have been discussed.



2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Young Kyung Kim ◽  
Keunje Yoo ◽  
Min Sung Kim ◽  
Il Han ◽  
Minjoo Lee ◽  
...  

Abstract Bacterial communities in wastewater treatment plants (WWTPs) affect plant functionality through their role in the removal of pollutants from wastewater. Bacterial communities vary extensively based on plant operating conditions and influent characteristics. The capacity of WWTPs can also affect the bacterial community via variations in the organic or nutrient composition of the influent. Despite the importance considering capacity, the characteristics that control bacterial community assembly are largely unknown. In this study, we discovered that bacterial communities in WWTPs in Korea and Vietnam, which differ remarkably in capacity, exhibit unique structures and interactions that are governed mainly by the capacity of WWTPs. Bacterial communities were analysed using 16S rRNA gene sequencing and exhibited clear differences between the two regions, with these differences being most pronounced in activated sludge. We found that capacity contributed the most to bacterial interactions and community structure, whereas other factors had less impact. Co-occurrence network analysis showed that microorganisms from high-capacity WWTPs are more interrelated than those from low-capacity WWTPs, which corresponds to the tighter clustering of bacterial communities in Korea. These results will contribute to the understanding of bacterial community assembly in activated sludge processing.



Membranes ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 461
Author(s):  
Fu Yang ◽  
Zhengkun Huang ◽  
Jun Huang ◽  
Chongde Wu ◽  
Rongqing Zhou ◽  
...  

Ultrafiltration is a promising, environment-friendly alternative to the current physicochemical-based tannery wastewater treatment. In this work, ultrafiltration was employed to treat the tanning wastewater as an upstream process of the Zero Liquid Discharge (ZLD) system in the leather industry. The filtration efficiency and fouling behaviors were analyzed to assess the impact of membrane material and operating conditions (shear rate on the membrane surface and transmembrane pressure). The models of resistance-in-series, fouling propensity, and pore blocking were used to provide a comprehensive analysis of such a process. The results show that the process efficiency is strongly dependent on the operating conditions, while the membranes of either PES or PVDF showed similar filtration performance and fouling behavior. Reversible resistance was the main obstacle for such process. Cake formation was the main pore blocking mechanism during such process, which was independent on the operating conditions and membrane materials. The increase in shear rate significantly increased the steady-state permeation flux, thus, the filtration efficiency was improved, which resulted from both the reduction in reversible resistance and the slow-down of fouling layer accumulate rate. This is the first time that the fouling behaviors of tanning wastewater ultrafiltration were comprehensively evaluated, thus providing crucial guidance for further scientific investigation and industrial application.



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