scholarly journals Simulation of Wastewater Depolution Processes by Advanced Biological Methods

2020 ◽  
Vol 71 (10) ◽  
pp. 150-160
Author(s):  
Oana Stela Mirel ◽  
Constantin Florescu
Keyword(s):  
Bacterial Flora ◽  
Animal Manure ◽  
Synthetic Wastewater ◽  
Second Phase ◽  
Inexpensive Method ◽  
Experimental Procedure ◽  
Denitrifying Microorganisms ◽  
Slow Mixing ◽  
Biological Methods ◽  
Ammonium Compounds

This paper presents the results from a study which simulates wastewater depollution processes using advanced biological methods. The experimental research was performed in a static biological reactor, equipped with an air compressor and an agitator / mixer. Synthetic wastewater, prepared with the addition of glucose, was fed into the reactor. The wastewater was subjected to alternating cycles of aeration and slow mixing, for consecutive 3 h intervals within the reactor to ensure the necessary conditions for the reduction of nitrogen based organic compounds within the wastewater. In the successive aeration processes, aerobic / nitrifying microorganisms which developed within the reactor, facilitated the decomposition of organic substances into nitrites and then into nitrates. By stopping aeration and starting the slow mixing cycle the anaerobic / denitrifying microorganisms growing in the reactor consume the necessary oxygen from nitrates and release free nitrogen into the atmosphere, thus completing the process of advanced depollution. Therefore, the experimental procedure highlights the existence of two distinct phases in the development of the depollution process. In the first phase, the biological process is initiated using glucose in order to promote the growth of the bacterial flora. In the second phase (the regime phase), the reduction of mineral and organic pollutants from the wastewater is ensured. The activity of microorganisms in the biological reactor can be further supported by the recirculation of activated sludge retained in the secondary decanter. The proposed technology offers a fast, safe and relatively inexpensive method for advanced wastewater depollution. Bioreactors of this type are recommended in wastewater treatment schemes in the hearth of rural localities, agro-zootechnical complexes and tourist units with seasonal activities due to their fluctuations in hourly wastewater flow rates. Similar approaches can also be considered for the elimination of ammonium compounds in groundwater polluted with animal manure.

Upgrading Wastewater Treatment by Water Hyacinth in Developing Countries

1990 ◽  
Vol 22 (7-8) ◽  
pp. 153-160 ◽  
Author(s):  
Pradeep Kumar ◽  
R. J. Garde
Keyword(s):  
Wastewater Treatment ◽  
Water Hyacinth ◽  
Treatment Plant ◽  
Cod Removal ◽  
Treatment System ◽  
Synthetic Wastewater ◽  
Second Phase ◽  
Treatment Unit ◽  
Batch Studies ◽  
New Treatment

With increasing stress on existing wastewater treatment systems, it is necessary either to upgrade the treatment unit(s) or install an entirely new treatment plant. Obviously, the upgrading is preferred over the alternative of having a new system. Keeping this in view, in the present project, an attempt has been made to explore the possibility of upgrading existing facultative ponds using water hyacinth. Bench-scale batch studies were designed to compare the performance of hyacinth treatment system with facultative ponds. Investigations were carried out with synthetic wastewater having COD in the range of 32.5-1090 mg/l. The efficiency of COD removal in water hyacinth ponds was 15-20 percent more than the facultative ponds. Based on the results, an empirical model has been proposed for COD removal kinetics. In the second phase of the project a hyacinth pond was continuously operated. BOD, COD, TS, TN, TP, pH, and DO were regularly monitored. However, the DO of the effluent from hyacinth treatment system was considerably reduced. Effluent should be aerated before it is discharged. The results indicate that the existing facultative ponds can be stalked with water hyacinth to improve their performance as well as hyacinth treatment systems can be installed to support the conventional treatment.

scholarly journals Electrodegradation of Acid Mixture Dye through the Employment of Cu/Fe Macro-Corrosion Galvanic Cell in Na2SO4 Synthetic Wastewater

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4580
Author(s):  
Mateusz Kuczyński ◽  
Mateusz Łuba ◽  
Tomasz Mikołajczyk ◽  
Bogusław Pierożyński ◽  
Agnieszka Jasiecka-Mikołajczyk ◽  
...  
Keyword(s):  
Electrochemical Techniques ◽  
Electrical Energy ◽  
Galvanic Cell ◽  
Synthetic Wastewater ◽  
Acid Mixture ◽  
Ac Impedance Spectroscopy ◽  
Wastewater Purification ◽  
Physical Chemical ◽  
Iron Anode ◽  
Biological Methods

Traditional wastewater purification processes are based on a combination of physical, chemical, and biological methods; however, typical electrochemical techniques for removing pollutants require large amounts of electrical energy. In this study, we report on a process of wastewater purification, through continuous anodic dissolution of iron anode for aerated Cu/Fe galvanic cell in synthetic Na2SO4 wastewater solution. Electrochemical experiments were conducted by means of a laboratory size electrolyzer, where electrocoagulation along with electrooxidation phenomena were examined for wastewater containing Acid Mixture dye. The above was visualized through the employment of electrochemical (cyclic voltammetry and ac impedance spectroscopy techniques) along with instrumental spectroscopy analyses.

scholarly journals USE OF BRAZILIAN CLAYS FOR THE REMOVAL OF CHROMIUM IONS PRESENT IN INDUSTRIAL EFFLUENTS

2009 ◽  
Vol 06 (11) ◽  
pp. 11-16
Author(s):  
Alexandre Andrade CERQUEIRA ◽  
Mônica Regina da Costa MARQUES
Keyword(s):  
Batch Reactor ◽  
Industrial Effluents ◽  
Synthetic Wastewater ◽  
Chromium Nitrate ◽  
X Ray Diffraction ◽  
Experimental Procedure ◽  
X Ray ◽  
Anion Effect ◽  
Chromium Ions ◽  
Synthetic Clay

This study aimed to evaluate the ability to remove an ion Cr (III) in synthetic wastewater using a Brazilian clay. We evaluated the influence of the concentration of cation and anion effect on the ability of removal of chromium ions in effluent inorganic synthetic clay for montmorillonite (F-II) Fulmont provided by the industry. The clay was characterized by X-ray diffraction and chemical analysis. The tests were performed by removal of two different methods: in batch reactor and filtration in a column of clay. Tests were conducted at different pH `s (2-10), the mass of clay and solution of chromium nitrate (III) used in each test was 2g and 25 ml respectively. The efficiency of removal was determined by atomic absorption analysis of the supernatants. Preliminary results showed the efficiency of removal of chromium ions by the Brazilian clay. It was observed that the concentration of the solution, the experimental procedure and the presence of anions influenced the process of exchange, with the best results when used dilute solutions in the presence of nitrate ion and technology in filtration column resulting in removal of up to 100% of chromium (III).

scholarly journals Ammonium Recovery from Biocatalytic Calcification Reactor Effluent by Struvite Precipitation

2017 ◽  
Vol 19 (2) ◽  
pp. 251-256 ◽  
Keyword(s):  
Ph Value ◽  
Ammonium Phosphate ◽  
Chemical Precipitation ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Magnesium Ammonium Phosphate ◽  
Magnesium Ammonium ◽  
S Period ◽  
Slow Mixing ◽  
Biological Methods

Chemical precipitation is a suitable method for the recovery and removal of ammonium in water and a fertilizer known as MAP (magnesium ammonium phosphate; MgNH4PO4.6H2O; struvite) is obtained. Additionally, the advantage of this method is that environmental conditions do not have any effect compared to biological methods. In this study, the recovery of ammonium (Cmean=348 mg NH4 +/L ± 38.1; n=25) occurred after the hydrolysis of urea in the biocatalytic calcification reactor (BCR) effluent and it precipitated as struvite. The effects of operating parameters, such as different phosphate and magnesium sources, Mg2+:NH4+:PO43- molar ratio, pH value, mixing speed-time, and fertilizer effect, were examined. The precipitates were characterized by X-ray diffraction and scanning electron micrograph. The optimum molar ratio of Mg2+:NH4+:PO43− was determined as 1.25:1:1. Studies using different pH ranges (7–10) and this molar ratio showed that the ammonium recovery of approximately 96% was reached at a pH value of 9.36. It was seen that the rapid mixing (200 rpm) of 30-s period and the slow mixing (30 rpm) of 2-min period were sufficient for MAP precipitation. Struvite that was obtained after precipitation was used as a fertilizer and it was observed to have a positive effect on plant growth.

Treatment of Wastewater with a Low Concentration of Organics Using an Anaerobic Fluidized Bed Reactor

1992 ◽  
Vol 25 (7) ◽  
pp. 179-191 ◽  
Author(s):  
A. L. F. C. Maragno ◽  
J. R. Campos
Keyword(s):  
Fluidized Bed ◽  
Bovine Liver ◽  
Fluidized Bed Reactor ◽  
Synthetic Wastewater ◽  
Second Phase ◽  
Nitrogen And Phosphorus ◽  
Hydraulic Residence Time ◽  
The Mean ◽  
Anaerobic Fluidized Bed Reactor ◽  
Phase Phase

In this work performed in the Laboratory of Sanitation of São Carlos Engineering School- University of São Paulo, the results obtained from the operation of a laboratory scale anaerobic fluidized bed reactor are presented for the treatment of a synthetic wastewater with a mean COD of 557 and 700 mg/l during the two phases in which the reactor was studied. In the first phase (Phase A) the mean hydraulic residence time () was maintained at 1.0 h and in the second phase (Phase B), 1.5 h. The duration of each phase, counted from the initial startup period, was 197 days and 108 days, respectively. The reactor was constructed using an acrylic tube of 1.50 m height and a total volume of 10.5 1. The support material consisted of sand with the grains retained between sieves with openings of 0.210 mm and 0.149 mm. The total height of the fluidized bed was maintained at 1.40 m throughout the experiment. The reactor was operated at ambient temperature (13°C to 31°C), and was fed with synthetic wastewater composed mainly of bovine liver extract, glucose, sodium bicarbonate and ammonium acetate. The results of physical and chemical analyses: pH, alkalinity, temperature, volatile acids, COD, nitrogen and phosphorus are presented. An evaluation was also made during the experiment of the thickness of the biofilm gathered on the sand grains collected over the whole height of the reactor. The mean efficiency of COD removal attained was 62% for the first phase and 71% for the second phase.

Use of lysis and recycle to control excess sludge production in activated sludge treatment: bench scale study and effect of chlorinated organic compounds

2002 ◽  
Vol 46 (10) ◽  
pp. 55-61 ◽  
Author(s):  
M.A. Nolasco ◽  
A.L.O. Campos ◽  
A.M. Springer ◽  
E.C. Pires
Keyword(s):  
Activated Sludge ◽  
Removal Efficiency ◽  
Control Unit ◽  
Pulp And Paper ◽  
Synthetic Wastewater ◽  
Second Phase ◽  
Excess Sludge ◽  
Chlorinated Compounds ◽  
Treatment Unit ◽  
Bench Scale

The most widely used treatment system in the pulp and paper industry - the activated sludge - produces high quantities of sludge which need proper disposal. In this paper a modified activated sludge process is presented. A synthetic wastewater, prepared to simulate the effluent of bleached and unbleached pulp and paper plant wastewater, was submitted to treatment in a bench scale aerobic reactor. The excess sludge was lysed in a mechanical mill - Kaddy™ mill - and totally recycled to the aeration tank. In the first phase the synthetic wastewater, without the chlorinated compounds, was fed to the reactor. In the second phase increasing dosages of the chlorinated compounds were used. Total recycle of excess sludge after disintegration did not produce adverse effects. During the first phase average COD removal efficiency was 65% for the control unit, which operated in a conventional way, and 63% for the treatment unit, which operated with total recycle. During the second phase the COD removal efficiency increased to 77% in the control unit and 75% in the treatment unit. Chlorinated organics removal was 85% in the treatment unit and 86% for the control unit. These differences are not significant.

scholarly journals Optimization of Initial Turbidity and Coagulant Concentration to Remove Turbidity Using Moringa oleifera Seed

2020 ◽  
Vol 42 (2) ◽  
pp. 47-54
Author(s):  
Bong Min Kim ◽  
Hee Yun Lee ◽  
Johng-Hwa Ahn
Keyword(s):  
Response Surface ◽  
Surface Analysis ◽  
Moringa Oleifera ◽  
Response Surface Analysis ◽  
Synthetic Wastewater ◽  
Optimal Conditions ◽  
Turbidity Removal ◽  
Mixing Speed ◽  
Rapid Mixing ◽  
Slow Mixing

Objective:Coagulation of <i>Moringa oleifera</i> seeds was studied to determine the optimal conditions in treating a turbid water.Method:Jar-test experiments were performed at various rapid mixing (90-250 rpm; 1-2 min), slow mixing (10-60 rpm; 10-50 min), initial turbidity (100-500 NTU), coagulant doses (200-1,500 mg/L), and pH (2-12) in synthetic wastewater. Response surface analysis was used to optimize the coagulation in jar-test experiments.Results and Discussion:The optimal conditions for turbidity removal with <i>M. oleifera</i> were 200 rpm of rapid-mixing speed for 1 min, 40 rpm of slow-mixing speed for 20 min, and pH 8. The coagulation efficiency was found to be dependent on initial turbidity of water samples. Highest turbidity removals (96.5%) were obtained for water with very high initial turbidity (500 NTU). The effects of initial turbidity and coagulant dose were successfully analyzed by the response surface analysis. Within the design boundaries, turbidity removal was more sensitive to changes in initial turbidity than to changes in coagulant dose.Conclusions:The quadratic model between initial turbidity and coagulant for turbidity removal was shown. <i>M. oleifera</i> can be used as a potential coagulant especially for high turbidity water.

Grain Refinement in Titanium-Erbium Alloys

1974 ◽  
Vol 32 ◽  
pp. 522-523
Author(s):  
B. B. Rath ◽  
J. E. O'Neal ◽  
R. J. Lederich
Keyword(s):  
Electron Microscopy ◽  
Size Distribution ◽  
Grain Refinement ◽  
Grain Growth ◽  
Volume Fraction ◽  
Pure Titanium ◽  
Systematic Investigation ◽  
Second Phase ◽  
Titanium Matrix ◽  
Average Size

Addition of small amounts of erbium has a profound effect on recrystallization and grain growth in titanium. Erbium, because of its negligible solubility in titanium, precipitates in the titanium matrix as a finely dispersed second phase. The presence of this phase, depending on its average size, distribution, and volume fraction in titanium, strongly inhibits the migration of grain boundaries during recrystallization and grain growth, and thus produces ultimate grains of sub-micrometer dimensions. A systematic investigation has been conducted to study the isothermal grain growth in electrolytically pure titanium and titanium-erbium alloys (Er concentration ranging from 0-0.3 at.%) over the temperature range of 450 to 850°C by electron microscopy.

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