Optimization of a Treatment System of Wastewater Streams for Electrochemical Cr(VI) Reduction: Selective versus Centralized Treatment

2018 ◽  
Vol 16 (11) ◽  
Author(s):  
Adrián López-Yañez ◽  
Jorge Ramirez-Muñoz ◽  
Alejandro Alonso ◽  
Luis G. Cota ◽  
Jhonny Pérez Montiel
Keyword(s):  
Hexavalent Chromium ◽  
Minimum Cost ◽  
Electrical Energy ◽  
Electrical Current ◽  
Electrochemical Process ◽  
Effluent Treatment ◽  
Treated Wastewater ◽  
Total Annual Cost ◽  
Optimal Solutions ◽  
Selective Treatment

Abstract The problem of the optimization of selective treatment systems of wastewater streams contaminated with hexavalent chromium [Cr(VI)] is investigated. In order to comply with the Mexican environmental norm of Cr(VI) for treated wastewater streams at minimum cost, a nonlinear programming (NLP) model for the electrochemical reduction of hexavalent chromium to trivalent chromium was developed. The model incorporates a variable reaction rate, which is a function of the Cr(VI) concentration and the electrical current density of the electrochemical process. For this purpose, a basic superstructure of the effluent treatment is proposed. The superstructure is composed of three continuous electrochemical reactors without recirculation, and it may produce either a series and/or parallel design topology. The NLP model was used to minimize the objective function, defined as the total annual cost (TAC), which includes the capital cost of each electrochemical reactor, the electrical energy cost and the cost of the treatment of the wastewater streams. In order to investigate the solution set of the proposed NLP model, i. e., to improve the possibilities of obtaining optimum solutions based on economic criteria, a multi-start algorithm was implemented. Two example problems are used to show the versatility of the model and different local optimal solutions were obtained for each case study. The results show that a selective treatment of wastewater streams based on the search of local optimal solutions yields significant savings with respect to a centralized treatment design.

scholarly journals Electrochemical removal of pyrite scale using green formulations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Musa Ahmed ◽  
Ibnelwaleed A. Hussein ◽  
Abdulmujeeb T. Onawole ◽  
Mohammed A. Saad ◽  
Mazen Khaled
Keyword(s):  
Hydrogen Sulfide ◽  
Current Density ◽  
Iron Sulfide ◽  
Chelating Agent ◽  
Electrical Current ◽  
Electrochemical Process ◽  
Chemical Dissolution ◽  
Hydrocarbon Production ◽  
Rotational Rate ◽  
Diethylenetriamine Pentaacetic Acid

AbstractPyrite scale formation is a critical problem in the hydrocarbon production industry; it affects the flow of hydrocarbon within the reservoir and the surface facilities. Treatments with inorganic acids, such as HCl, results in generation toxic hydrogen sulfide, high corrosion rates, and low dissolving power. In this work, the dissolution of pyrite scale is enhanced by the introduction of electrical current to aid the chemical dissolution. The electrolytes used in this study are chemical formulations mainly composed of diethylenetriamine-pentaacetic acid–potassium (DTPAK5) with potassium carbonate; diethylenetriamine pentaacetic acid sodium-based (DTPANa5), and l-glutamic acid-N, N-diacetic acid (GLDA). DTPA and GLDA have shown some ability to dissolve iron sulfide without generating hydrogen sulfide. The effect of these chemical formulations, disc rotational rate and current density on the electro-assisted dissolution of pyrite are investigated using Galvanostatic experiments at room temperature. The total iron dissolved of pyrite using the electrochemical process is more than 400 times higher than the chemical dissolution using the same chelating agent-based formulation and under the same conditions. The dissolution rate increased by 12-folds with the increase of current density from 5 to 50 mA/cm2. Acid and neutral formulations had better dissolution capacities than basic ones. In addition, doubling the rotational rate did not yield a significant increase in electro-assisted pyrite scale dissolution. XPS analysis confirmed the electrochemical dissolution is mainly due to oxidation of Fe2+ on pyrite surface lattice to Fe3+. The results obtained in this study suggest that electro-assisted dissolution is a promising technique for scale removal.

Microbial Desalination Cells for Low Energy Drinking Water

2021 ◽  
Author(s):  
Juan Arévalo ◽  
Juan Manuel Ortiz ◽  
Eduard Borràs-Camps ◽  
Victor Monsalvo-Garcia ◽  
Maria D. Kennedy ◽  
...  
Keyword(s):  
Drinking Water ◽  
Wastewater Treatment ◽  
Sea Water ◽  
Electrical Energy ◽  
Energy System ◽  
Electrochemical Reactor ◽  
Treated Wastewater ◽  
External Energy ◽  
Design And Optimization ◽  
Pre Treatment

The world's largest demonstrator of a revolutionary energy system in desalination for drinking water production is in operation. MIDES uses Microbial Desalination Cells (MDC) in a pre-treatment step for reverse osmosis (RO), for simultaneous saline stream desalination and wastewater treatment. MDCs are based on bio-electro-chemical technology, in which biological wastewater treatment can be coupled to the desalination of a saline stream using ion exchange membranes without external energy input. MDCs simultaneously treat wastewater and perform desalination using the energy contained in the wastewater. In fact, an MDC can produce around 1.8 kWh of bioelectricity from the energy contained in 1 m3 of wastewater. Compared to traditional RO, more than 3 kWh/m3 of electrical energy is saved. With this novel technology, two low-quality water streams (saline stream, wastewater) are transformed into two high-quality streams (desalinated water, treated wastewater) suitable for further uses. An exhaustive scaling-up process was carried out in which all MIDES partners worked together on nanostructured electrodes, antifouling membranes, electrochemical reactor design and optimization, life cycle assessment, microbial electrochemistry and physiology expertise, and process engineering and control. The roadmap of the lab-MDC upscaling goes through the assembly of a pre-pilot MDC, towards the development of the demonstrator of the MDC technology (patented). Nominal desalination rate between 4-11 Lm-2h-1 is reached with a current efficiency of 40 %. After the scalability success, two MDC pilot plants were designed and constructed consisting of one stack of 15 MDC pilot units with a 0.4 m2 electrode area per unit. This book presents the information generated throughout the EU funded MIDES project and includes the latest developments related to desalination of sea water and brackish water by applying microbial desalination cells. ISBN: 9781789062113 (Paperback) ISBN: 9781789062120 (eBook)

scholarly journals Application of electrochemical treatment for the removal of triazine dye using aluminium electrodes

2020 ◽  
Vol 69 (4) ◽  
pp. 345-354 ◽  
Author(s):  
Sakthisharmila Palanisamy ◽  
Palanisamy Nachimuthu ◽  
Mukesh Kumar Awasthi ◽  
Balasubramani Ravindran ◽  
Soon Woong Chang ◽  
...  
Keyword(s):  
Oxygen Demand ◽  
Electrical Energy ◽  
Reactive Dye ◽  
Product Formation ◽  
Electrochemical Treatment ◽  
Electrochemical Process ◽  
Spectral Studies ◽  
Textile Dye ◽  
Electrode Consumption ◽  
Electrocoagulation Process

Abstract Textile effluents contain triazine-substituted reactive dyes that cause health problems such as cancer, birth defects, and hormone damage. An electrochemical process was employed effectively to degrade azo reactive dye with the aim of reducing the production of carcinogenic chemicals during biodegradation. Textile dye C.I. Reactive Red 2 (RR2), a model pollutant that contains dichloro triazine ring, was subjected to the electrocoagulation process using aluminium (Al) electrodes. A maximum of 97% of colour and 72% of chemical oxygen demand (COD) removal efficiencies were achieved and 9.5 kWh/kg dye electrical energy and 0.8 kg Al/kg dye electrode consumption were observed. The dye removal mechanism was studied by analysing the results of UV-Vis spectra of RR2 and treated samples at various time intervals during electrocoagulation. Fourier transform infrared (FTIR) spectra and energy dispersive X-ray (EDX) spectral studies were used for analysing the electrocoagulated flocs. The results indicate that in this process the dye gets removed by adsorption and there is no significant carcinogenic by-product formation during the degradation of dye.

Interaction Between Solid Copper Jets and Powerful Electrical Current Pulses

2010 ◽  
Vol 78 (2) ◽  
Author(s):  
Patrik Appelgren ◽  
Torgny E. Carlsson ◽  
Andreas Helte ◽  
Tomas Hurtig ◽  
Anders Larsson ◽  
...  
Keyword(s):  
Current Pulse ◽  
Current Density ◽  
Energy Deposition ◽  
Current Flow ◽  
Contact Region ◽  
Electrical Energy ◽  
Electrical Current ◽  
Separation Distance ◽  
Flow Through ◽  
Solid Copper

The interaction between a solid copper jet and an electric current pulse is studied. Copper jets that were created by a shaped-charge device were passed through an electrode configuration consisting of two aluminum plates with a separation distance of 150 mm. The electrodes were connected to a pulsed-power supply delivering a current pulse with amplitudes up to 250 kA. The current and voltages were measured, providing data on energy deposition in the jet and electrode contact region, and flash X-ray diagnostics were used to depict the jet during and after electrification. The shape of, and the velocity distributions along, the jet has been used to estimate the correlation between the jet mass flow through the electrodes and the electrical energy deposition. On average, 2.8 kJ/g was deposited in the jet and electrode region, which is sufficient to bring the jet up to the boiling point. A model based on the assumption of a homogenous current flow through the jet between the electrodes underestimates the energy deposition and the jet resistance by a factor 5 compared with the experiments, indicating a more complex current flow through the jet. The experimental results indicate the following mechanism for the enhancement of jet breakup. When electrified, the natural-formed necks in the jet are subjected to a higher current density compared with other parts of the jet. The higher current density results in a stronger heating and a stronger magnetic pinch force. Eventually, the jet material in the neck is evaporated and explodes electrically, resulting in a radial ejection of vaporized jet material.

Flexible Valveless Pump for Bio Applications

2019 ◽  
Author(s):  
Masoud Naghdi ◽  
Farhad Farzbod ◽  
Paul M. Goggans
Keyword(s):  
Liquid Metal ◽  
Lorentz Force ◽  
Permanent Magnets ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
Electrical Current ◽  
Electromechanical Actuators ◽  
Valveless Pump ◽  
Metal Wires ◽  
Lorentz Force Law

Abstract In electromechanical actuators Lorentz force law is used to convert electrical energy into rotational or linear mechanical energy. In these conventional electromechanical actuators, rigid wires conducts the electrical current and as such the types of motion generated by these actuators are limited. Recent advances in liquid metal alloys permit designing electrical wires that are stretchable. These flexible wires have been used to fabricate various flexible connections, sensors and antennas. However, there have been very little efforts to use these stretchable liquid metal wires as actuators. Building upon our previous work in this area, we have made a flexible pump which can be used in bio applications. In this design we placed a flexible polymeric substrate filled by liquid metal Galinstan between two permanent magnets. Since the pump should convey the biological cells suspended along the fluid flow, utilizing check valves may increase the risk of clog in the inlet or outlet. Therefore, our design is based on the nozzle/diffuser concept. This new pump can be considered as a peristaltic and valve-less mechanical pumps which utilizes the Lorentz force law as the actuating mechanism.

Dial-a-Ride Problem with Users’ Accept/Reject Decisions Based on Service Utilities

2020 ◽  
Vol 2674 (10) ◽  
pp. 55-67
Author(s):  
Xiaotong Dong ◽  
David Rey ◽  
S. Travis Waller
Keyword(s):  
Minimum Cost ◽  
Collective Choice ◽  
Profit Margin ◽  
User Preference ◽  
Computational Time ◽  
Optimal Solutions ◽  
Mobility Service ◽  
Shared Mobility ◽  
Computationally Expensive ◽  
The Impact

The classic dial-a-ride problem (DARP) aims at designing the minimum-cost routing that accommodates all requests under a set of constraints. However, several modeling and computational challenges have hindered the successful deployment of dial-a-ride solutions. This work proposes incorporating user preference decisions within a rich DARP formulation. Specifically, it is considered that two travel modes are available: a shared mobility (DARP) service and a private travel option. Utility functions for each travel mode are integrated and it is assumed that the utility of the shared mobility service depends on the collective choice of travelers whereas the utility of private travel is fixed. Assuming that travelers are rational and seek to maximize their trip utility, extra variables and constraints are added to ensure that all requests are served by the mode with the higher utility. The behavior of the proposed integrated DARP with formulation of user preference constraints is examined by comparing the optimal solutions and computational time of this model with its classic DARP counterpart. Furthermore, the impact of various formulations of fare and the tolerance of the integrated DARP model is explored. Results show that user-personalized fare formulation improves model tolerance and profit margin, albeit it is rather computationally expensive.

scholarly journals Analog tachometer as an indicator motorcycle machine wearing based on moving coil

2018 ◽  
Vol 43 ◽  
pp. 01004
Author(s):  
Dhanis Woro Fittrin Selo Nur Giyatno ◽  
Tommy Richard Orlando ◽  
Nining Supriatin
Keyword(s):  
Control Unit ◽  
Electrical Energy ◽  
Electrical Current ◽  
Maintenance Cost ◽  
Current Sensing ◽  
Variable Resistor ◽  
Rotary Machine ◽  
System A ◽  
Machine Reliability ◽  
Electronic Instrumentation

As an increasing highly mobility and high traffic, the necessary of motorcycle is highly increasing. The condition makes user ride motorcycle with highly speed in highly frequency. Then, these conditions make motorcycle machine reliability is highly decreasing. Finally, it made machine is run to damage and maintenance cost to be high. Analog tachometer is an electronic instrumentation that proposed to solve these problems. Actually, instrumentation system of tachometer is an electromechanical system. A wire in a control unit is embedded into shaft of crank. Then, magnet in control unit will convert rotary machine energy into electrical energy with d’Arsonval meter. Current sensor and small variable resistor are the kind of sensor that are used in tachometer. Small variable resistor is used for tuning and recalibration. Utilization small variable resistor in tachometer circuit is make calibration and recalibration current sensing of electrical current that rectified by diode. Tachometer for counting rotation per minute (RPM) motorcycle machine is built up. The tachometer has capability to count RPM motorcycle machine 1,000 – 13.000 RPM. The range is reliable as an indicator for user to minimize motorcycle machine wearing.

scholarly journals Modeling optimal solutions with the use of heat technologies based on graph theory

2018 ◽  
Vol 193 ◽  
pp. 03002 ◽  
Author(s):  
Natalya Trukhina ◽  
Ella Okolelova
Keyword(s):  
Graph Theory ◽  
Energy Saving ◽  
Minimum Cost ◽  
Optimal Solutions ◽  
Graphical Modeling ◽  
Construction Company ◽  
Construction Enterprises ◽  
Construction Companies ◽  
Improved Performance ◽  
Main Factor

The article describes the types of energy efficient technologies focused on energy saving. The presented technologies have significantly improved performance, while the disadvantage is high cost, which is the main factor preventing the introduction of energy saving technologies in construction. In this regard, solve the problem of optimizing the choice of the possible heat saving technologies of construction enterprises based on their financial and production capabilities based on graph theory. As a result, identify the technology yielding the greatest effect at minimum cost. The decision process is formalized as a graphical structure. In this case, the problem of finding the optimal solutions solved in graph theory. Graphical modeling of the structure of relations allows to visualize and organize variants of the consistent use of energy-saving technologies construction companies. On the basis of the construction of adjacency matrices organization of construction production is planned based on the use of energy-saving technologies determines the best combination of the ability of the construction company and the effectiveness to the execution of the technology.

Optimal Temperature and Current Cycles for Curing of Composites Using Embedded Resistive Heating Elements

2003 ◽  
Vol 125 (1) ◽  
pp. 126-136 ◽  
Author(s):  
A. Mawardi ◽  
R. Pitchumani
Keyword(s):  
Optimization Technique ◽  
Electrical Current ◽  
Optimal Number ◽  
Optimal Solutions ◽  
Resistive Heating ◽  
Cure Cycle ◽  
Time Optimal ◽  
Numerical Process ◽  
Process Constraints ◽  
Inside Out

Curing is an important and time consuming step in the fabrication of thermosetting-matrix composite products. The use of embedded resistive heating elements providing supplemental heating from within the material being cured has been shown in previous studies (Ramakrishnan, Zhu, and Pitchumani, 2000, J. Manuf. Sci. Eng., 122, pp. 124–131; and Zhu and Pitchumani, 2000, Compos. Sci. Technol., 60, 2699–2712.) to offer significant improvements in cure cycle time and cure uniformity, due to the inside-out curing. This paper addresses the problem of determining the temperature and electrical current cycles, as well as the placement configuration of the conductive mats, for time-optimal curing of composites using embedded resistive heating elements. A continuous search simulated annealing optimization technique is utilized coupled with a numerical process simulation model to determine the optimal solutions for selected process constraints. Optimization results are presented over a range of material systems and different numbers of conductive mats to assess the effects of materials reactivity on the optimal number of conductive mats.

scholarly journals Detection of Tannery Effluents Induced DNA Damage in Mung Bean by Use of Random Amplified Polymorphic DNA Markers

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Abhay Raj ◽  
Sharad Kumar ◽  
Izharul Haq ◽  
Mahadeo Kumar
Keyword(s):  
Dna Damage ◽  
Mung Bean ◽  
Control Plant ◽  
Effluent Treatment ◽  
Treated Wastewater ◽  
Tannery Effluent ◽  
Genotoxic Effects ◽  
Tannery Effluents ◽  
Treated Effluent ◽  
Treated Effluents

Common effluent treatment plant (CETP) is employed for treatment of tannery effluent. However, the performance of CETP for reducing the genotoxic substances from the raw effluent is not known. In this study, phytotoxic and genotoxic effects of tannery effluents were investigated in mung bean (Vigna radiata (L.) Wilczek). For this purpose, untreated and treated tannery effluents were collected from CETP Unnao (UP), India. Seeds of mung bean were grown in soil irrigated with various concentrations of tannery effluents (0, 25, 50, 75, and 100%) for 15 days. Inhibition of seed germination was 90% by 25% untreated effluent and 75% treated effluent, compared to the control. Plant growth was inhibited by 51% and 41% when irrigated with untreated and treated effluents at 25% concentration. RAPD technique was used to evaluate the genotoxic effect of tannery effluents (untreated and treated) irrigation on the mung bean. The RAPD profiles obtained showed that both untreated and treated were having genotoxic effects on mung bean plants. This was discernible with appearance/disappearance of bands in the treatments compared with control plants. A total of 87 RAPD bands were obtained using eight primers and 42 (48%) of these showed polymorphism. Irrigating plants with untreated effluent caused 12 new bands to appear and 18 to disappear. Treated effluent caused 8 new bands and the loss of 15 bands. The genetic distances shown on the dendrogram revealed that control plants and those irrigated with treated effluent were clustered in one group (joined at distance of 0.28), whereas those irrigated with untreated effluent were separated in another cluster at larger distance (joined at distance of 0.42). This indicates that treated effluent is less genotoxic than the untreated. Nei’s genetic similarity indices calculated between the treatments and the control plants showed that the control and the plants irrigated with treated tannery effluent had a similarity index of 0.75, the control and plants irrigated with untreated 0.65, and between the treatments 0.68. We conclude that both untreated and treated effluents contain genotoxic substances that caused DNA damage to mung beans. CETP Unnao removes some, but not all, genotoxic substances from tannery effluent. Consequently, use of both untreated and treated wastewater for irrigation poses health hazard to human and the environment.

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