scholarly journals Electrocoagulation (EC) for Reduction of Chemical Oxygen Demand (COD) of Surface Water

2012 ◽  
Vol 47 (1) ◽  
pp. 77-82 ◽  
Author(s):  
SH Rahman ◽  
SMN Islam ◽  
N Kaiser ◽  
Md M Rahman
Keyword(s):  
Surface Water ◽  
Research Work ◽  
Oxygen Demand ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Canal Surface ◽  
Canal Water ◽  
Time Period ◽  
Wide Range ◽  
Water Ph

Karnopara Canal water containing high COD values (1050 mg O2/L) was treated by electrocoagulation (EC) method covering a wide range of operating conditions such as, water pH, internal electrode distances, final pH, supplying 30V electricity for constant time period (30 minutes) through same electrode material (Al electrode). The effects of different operating parameters on the efficiency of the process were examined. Targeting to reduce the COD value within the recommended limit (200 mg O2/L), this research work was emphasized on EC treatment at the simplest and cheapest way. The batch experiment results showed that the high COD contained canal water can be effectively treated using electrocoagulation. The overall COD removal efficiencies have been obtained at 87.3%, under optimum operating conditions. Taking all the factors into account, it was found that polluted Karnopara canal water can be treated using EC consisting of Al electrodes without pre-adjustment of pH at laboratory. Therefore, EC technique to reduce high COD from canal surface water is found effective, cheaper and environmental friendly. DOI: http://dx.doi.org/10.3329/bjsir.v47i1.10728 Bangladesh J. Sci. Ind. Res. 47(1), 77-82, 2012

scholarly journals Design and Evaluation of LYSO/SiPM LIGHTENING PET Detector with DTI Sampling Method

Sensors ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 5820
Author(s):  
Zhenzhou Deng ◽  
Yushan Deng ◽  
Guandong Chen
Keyword(s):  
High Performance ◽  
Sampling Method ◽  
Average Energy ◽  
High Sensitivity ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Time Interval ◽  
Silicon Photomultiplier ◽  
Experimental Conditions ◽  
Wide Range

Positron emission tomography (PET) has a wide range of applications in the treatment and prevention of major diseases owing to its high sensitivity and excellent resolution. However, there is still much room for optimization in the readout circuit and fast pulse sampling to further improve the performance of the PET scanner. In this work, a LIGHTENING® PET detector using a 13 × 13 lutetium-yttrium oxyorthosilicate (LYSO) crystal array read out by a 6 × 6 silicon photomultiplier (SiPM) array was developed. A novel sampling method, referred to as the dual time interval (DTI) method, is therefore proposed to realize digital acquisition of fast scintillation pulse. A semi-cut light guide was designed, which greatly improves the resolution of the edge region of the crystal array. The obtained flood histogram shown that all the 13 × 13 crystal pixels can be clearly discriminated. The optimum operating conditions for the detector were obtained by comparing the flood histogram quality under different experimental conditions. An average energy resolution (FWHM) of 14.3% and coincidence timing resolution (FWHM) of 972 ps were measured. The experimental results demonstrated that the LIGHTENING® PET detector achieves extremely high resolution which is suitable for the development of a high performance time-of-flight PET scanner.

Optimization of leachate treatment using persulfate/H2O2 based advanced oxidation process: case study: Deir El-Balah Landfill Site, Gaza Strip, Palestine

2015 ◽  
Vol 73 (1) ◽  
pp. 102-112 ◽  
Author(s):  
Ahmed H. Hilles ◽  
Salem S. Abu Amr ◽  
Rim A. Hussein ◽  
Anwar I. Arafa ◽  
Olfat D. El-Sebaie
Keyword(s):  
Reaction Time ◽  
Advanced Oxidation Process ◽  
Gaza Strip ◽  
Oxygen Demand ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Leachate Treatment ◽  
Operating Variables ◽  
Treatment Processes ◽  
N Removal

The objective of this study was to investigate the performance of employing H2O2 reagent in persulfate activation to treat stabilized landfill leachate. A central composite design (CCD) with response surface methodology (RSM) was applied to evaluate the relationships between operating variables, such as persulfate and H2O2 dosages, pH, and reaction time, to identify the optimum operating conditions. Quadratic models for the following two responses proved to be significant with very low probabilities (<0.0001): chemical oxygen demand (COD) and NH3-N removal. The obtained optimum conditions included a reaction time of 116 min, 4.97 g S2O82−, 7.29 g H2O2 dosage and pH 11. The experimental results were corresponding well with predicted models (COD and NH3-N removal rates of 81% and 83%, respectively). The results obtained in the stabilized leachate treatment were compared with those from other treatment processes, such as persulfate only and H2O2 only, to evaluate its effectiveness. The combined method (i.e., /S2O82−/H2O2) achieved higher removal efficiencies for COD and NH3-N compared with other studied applications.

Optimization of Continuously Stirred Tank Bioreactor Design for Cost Minimization: Effect of Microbial Species and Operating Conditions

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Erin E Powell ◽  
Gordon A Hill
Keyword(s):  
Culture Medium ◽  
Operating Cost ◽  
Oxygen Demand ◽  
Design Strategy ◽  
Aeration Rate ◽  
Operating Conditions ◽  
Stirred Tank ◽  
Optimum Operating ◽  
Stirred Tank Bioreactor ◽  
Microbial Species

The operation of continuously stirred tank bioreactors (CSTBs) at minimum cost is a major concern of operators. In this work, a CSTB design strategy is presented where impeller stirring speed and aeration rate are optimized to meet the oxygen demand of growing cells, simultaneously minimizing the capital and operating cost. The operating cost is limited to the cost of utilities. The optimization scheme assumes a given fermentor tank size, and that the properties of the culture medium and the oxygen respiratory requirements of the microorganisms being cultivated are known. It is possible to choose between two different turbine impellers during the design process. The equations, constraints, and the CSTB design strategy employed by the program are described. The effect of microbial species, ions in the culture medium, impeller style, as well as changing CSTB size and biomass input density on the optimum operating conditions, is examined. The mass transfer coefficient, gas holdup, mixing speed, and aeration rate are all reported at optimized cost conditions. A study of the effects of various parameters on the CSTB design are shown.

Evaluation of Natural Flocculants for Conventional Water Treatment

2012 ◽  
Vol 248 ◽  
pp. 298-303
Author(s):  
Ayo Samuel Afolabi ◽  
Rudzani Sigwadi ◽  
Ambali Saka Abdulkareem ◽  
Corina Mary Mateescu
Keyword(s):  
Developing Countries ◽  
Water Treatment ◽  
Water Purification ◽  
Guar Gum ◽  
Research Work ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Raw Water ◽  
Aluminium Sulphate ◽  
The World

Drinking water is contaminated from the chemicals and biological impurities around the world mostly in rural area. These contaminations may come from natural sources and leaching of waste deposits which cause a major human health hazard in many parts of the world. There has been very little scientific research work into the use of natural flocculants to purify raw water. Most of the research studies that have been done on conventional water purification in developing countries have focussed on conventional water purification systems using inorganic and poly-electrolyte flocculants. Such systems are very expensive for rural communities in these developing countries as our objective is to provide water that is safe for human consumption by using facilities which can be constructed and operated at a reasonable cost. There is a need to evaluate natural flocculants for conventional water treatment in order to develop inexpensive ways for developing countries to purify their water. In this study, the natural flocculants such as Moringa seeds powder, Guar Gum seeds powder, aluminium sulphate and polyelectrolyte were tested in a jar test apparatus to determine the optimum operating conditions for water or wastewater treatment plants. The results showed that the addition of Moringa Oleifera seeds powder, Guar Gum seeds powder, aluminium sulphate and polyelectrolyte flocculants improved the quality of raw water. The raw water samples from all treatment plants showed a reduction in turbidity that was more than 70% when all the four flocculants applied synergistically.

A Study of a Turbine-Generator System for Low-Head Hydropower

1985 ◽  
Author(s):  
R. R. Mankbadi ◽  
S. Mikhail
Keyword(s):  
Interest Rates ◽  
Cost Benefit ◽  
Life Time ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Design Parameters ◽  
Turbine Generator ◽  
Generator System ◽  
Wide Range ◽  
Low Head

A method is outlined for determining the optimum operating conditions of a turbine-generator unit installed across a low-head irrigation structure for electrical power generation. For a given regulator’s characteristic, the unit’s rated power and design parameters are determined such that its cost-benefit ratio is minimum. The economical feasibility of the microhydro plant is studied by comparing its life-time cost to its life-time benefit. The benefit is determined by the cost of the corresponding energy generated through a diesel-driven generator set. The microhydro plant was found to be economically feasible over a wide range of inflation and interest rates.

scholarly journals Removal of aniline from aqueous solutions by activated carbon coated by chitosan

2015 ◽  
Vol 5 (4) ◽  
pp. 610-618 ◽  
Author(s):  
Qian Liu ◽  
Lujie Zhang ◽  
Pan Hu ◽  
Ruihua Huang
Keyword(s):  
Activated Carbon ◽  
Aqueous Solutions ◽  
Ph Value ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Order Kinetic ◽  
Factors Affecting ◽  
Adsorbent Dosage ◽  
Wide Range ◽  
Carbon Coated

In this work, activated carbon (AC) coated by chitosan was synthesized and characterized by Fourier transform infrared spectrophotometer and scanning electron microscope (SEM) techniques. The removal of aniline from aqueous solutions by AC coated by chitosan was investigated. The factors affecting the adsorption of aniline onto AC coated by chitosan, including the ratio of AC to chitosan, adsorbent dosage, pH value of solution, initial aniline concentration, and contact time were evaluated. These results showed that the optimum operating conditions were: the ratio of AC to chitosan = 0.5, adsorbent dosage = 0.2 g, and the adsorption of aniline from aqueous solutions had better removal in the concentration range of 20–50 mg/L. This adsorbent allowed high removal toward aniline in a wide range of pH. The equilibrium time was 100 minutes. The Freundlich model exhibited better correlation of the equilibrium adsorption data. The pseudo-second-order kinetic equation could better describe the kinetic behavior of aniline adsorption.

scholarly journals Removal of COD and BOD from biologically treated municipal wastewater by electrochemical treatment

2013 ◽  
Vol 5 (2) ◽  
pp. 475-481 ◽  
Author(s):  
Arun Kumar Sharma ◽  
A. K. Chopra
Keyword(s):  
Municipal Wastewater ◽  
Operating Cost ◽  
Operating Time ◽  
Sewage Treatment Plant ◽  
Oxygen Demand ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Initial Ph ◽  
Treated Municipal Wastewater ◽  
Maximum Removal

The present investigation observed the effect of current density (CD), operating time (OT), inter electrode distance (IED), electrode area (EA), initial pH and settling time (ST) using Fe-Fe electrode combination on the removal of chemical oxygen demand (COD) and biochemical oxygen demand (BOD) from biologically treated municipal wastewater (BTMW) of Sewage Treatment Plant (STP). The maximum removal of COD (92.35%) from BTMW was found with the optimum operating conditions of CD (2.82 A/m2), OT (40 mins.), IED (0.5 cm), EA (160 cm2), initial pH (7.5) and ST (60 min.), while the maximum removal of BOD (84.88%) was found with the ST (30 min.) at the same operating conditions. There was no need of pH adjustment of the BTMW during ET as the optimal removal efficiency was close to the pH of 7.5. Under optimal operating conditions, the operating cost was found to be 54.29 Rs./m3 / 1.08 US$/m3 in terms of the electrode consumption (78.48 x 10-5 kg Al/m3 ) and energy consumption (108.48 Kwh/m3).

scholarly journals Membrane Distillation Crystallization Hybrid Process for Zero Liquid Discharge in QAFCO Plant

2021 ◽  
Author(s):  
Mona Gulied ◽  
Sifani Zavahir ◽  
Tasneem Elmakki ◽  
Hazim Qiblawey ◽  
Bassim Hameed ◽  
...  
Keyword(s):  
Research Work ◽  
Membrane Distillation ◽  
Economic Feasibility ◽  
Operating Conditions ◽  
Hybrid Process ◽  
Optimum Operating ◽  
Low Grade ◽  
Water Recovery ◽  
Ongoing Research ◽  
Liquid Discharge

Qatar fertilizer company (QAFCO) is one of the world’s largest single site producer of ammonia and urea with production capacity of 12,900 metric tons per day. Currently, QAFCO faces major challenges in terms of water streams management that is generated from many processes such as wastewater from Harbor-Bosch process and brine solution from multi-stage flash (MSF) desalination process. To protect the environment; QAFCO has been making an effort to minimize the disposal of all types of water disposed into the sea. Here, this project proposes to develop a viable and economically effective process that can reach zero-liquid discharge (ZLD) of all processed water or wastewater from QAFCO facilities. The best method for ZLD is membrane distillation crystallization (MDC) hybrid process that concentrates and minimizes the volume of wastewater/brine streams to form solid through crystallizer. Membrane distillation (MD) is a thermally driven membrane process. It applies low-grade energy to create a thermal gradient across a microporous hydrophobic to vaporize water in the feed stream and condense the permeated vapor in the cold side. This research work aims to evaluate the performance of MDC for ZLD using commercial/fabricated electrospun nanofiber membrane (ENM) PVDF –base membranes at different type water streams. A general observation, higher water vapor flux and water recovery were exhibited at higher feed conductivity at 70°C. Moreover, the fabricated hydrophobic PVDF ENMs results confirmed the formation of nanofiber at the membrane surface using scanning electron microscopy (SEM). In addition, the water contact angle values of PVDF ENMs were greater than 100° and have stable mechanical and chemical properties. The ongoing research work will conduct a comparison between the optimum PVDF ENMs and the commercial MD membranes in terms of water recovery, salt rejection%, fouling/scaling, amount of collected solid and energy consumption at optimum operating conditions in MDC. In addition, it will perform a techno- economic feasibility assessment of the MDC hybrid process.

Development of a naturally derived coagulant for water and wastewater treatment

2002 ◽  
Vol 2 (5-6) ◽  
pp. 89-94 ◽  
Author(s):  
G. Folkard ◽  
J. Sutherland
Keyword(s):  
Oxygen Demand ◽  
Operating Conditions ◽  
Water Soluble ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Seed Kernel ◽  
Wet Season ◽  
Water And Wastewater Treatment ◽  
Treatment Unit ◽  
Wide Range

Seeds of the pan tropical tree, Moringa oleifera Lam. (M. oleifera) contain water soluble, positively charged proteins that act as an effective coagulant (molecular weight 13 kDa and isoelectric pH 10-11). Treatment studies are reviewed using the extracts of the crushed seed kernel and of the presscake (solids residue remaining after oil extraction). M. oleifera seed was incorporated into a pilot scale treatment system as a primary coagulant to clarify river water of 400 NTU in the wet season. Over 90% turbidity removal was achieved in the sedimentation stage at a dosage of 100 mgL-1. The filtrate turbidity was maintained well below 5 NTU. Subsequent trials were conducted in an adjacent works operating at 60 m3h-1. Treatment performance was comparable to that of using aluminium sulphate. Inlet turbidities of 270-380 NTU were consistently reduced to below 4 NTU. A comprehensive study was undertaken to evaluate the potential of using M. oleifera coagulant within a contact flocculation filtration (CFF) pilot rig. A wide range of operating conditions was evaluated in order to establish the useful “working envelope” for this process combination (filtration rates 5-20 mh-1, initial turbidities 20-50 NTU). Principal results are presented. As a coagulant within chemically enhanced primary sedimentation (CEPS) of a mixed wastewater, M. oleifera dosed at 150 mgL-1 gave additional removals (compared to a plain sedimentation control) of 40% biochemical oxygen demand (BOD) and chemical oxygen demand (COD) and in excess of 80% for suspended solids (SS). Subsequent laboratory work coupled an upflow anaerobic sludge blanket reactor (UASB) to CEPS. M. oleifera coagulant in the CEPS pre-treatment unit beneficially increased the ratio of soluble COD to volatile SS by a factor of ten compared to plain sedimentation and by a factor of three when dosing ferric chloride. The UASB yielded more biogas and gave enhanced COD removal. Recent work on the extraction and purification of the active coagulant components is reviewed and the prospects for commercialisation are considered.

Investigation of the System Parameters Affecting the Runtime of a Freezer Compartment

2012 ◽  
Author(s):  
Husnu Kerpicci ◽  
Onur Poyraz ◽  
Tolga N. Aynur ◽  
Ismail Teke
Keyword(s):  
Experimental Data ◽  
Energy Consumption ◽  
Empirical Model ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Experimental Setup ◽  
Airflow Rate ◽  
System Parameters ◽  
Evaporation Temperature ◽  
Wide Range

In this study, an experimental setup was built to evaluate the energy consumption of a freezer compartment by varying the runtime (i.e. the ratio of the compressor ON time to the total cycle time) of the system with the evaporation temperature and the airflow rate. Evaporation temperature and the normalized airflow rate were varied from −25°C to −28°C and from 0.8 to 1.4, respectively, thus the effects of these parameters on the runtime of the freezer were evaluated in a wide range of operating conditions. In addition, an empirical model that estimates the runtime within ± 4% compared to the experimental data was presented. By using the empirical model, optimum operating conditions (i.e. evaporation temperature and airflow rate) for the freezer were found with an energy saving of %13.8.

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