Showing 14 results for Coagulation
M Ahmadimoghadam, H Amiri,
Volume 3, Issue 2 (7-2010)
Abstract
Backgrounds and Objectives: Formaldehyde and phenol are key precursors in the industrial manufacture of resins. Toxicity of these compounds prevents function of microbial populations, so they affect the biological treatments. The aim of this study was investigation of TOC removal from phenol-formaldehyde resin manufacturing wastewater by electrocoagulation using Al- electrodes.
Materials and Methods: This study is the laboratory scale experiment was conducted as a pilot. Wastewater sample was adjusted in the desired pH, electrical conductivity and current density, then it was placed in to the reactor contains four electrodes in aluminum. The electrodes were connected to a DC power supply (0-40V, 0-3A). Samples were collected for TOC determination in the middle of cell at regular time intervals. Collected samples were analyzed using TOC analyzer.
Results:The results indicated that the optimum conditions for the removal of TOC were current density 75 A/m2, solution pH 4 and Conductivity 3 mS/cm. In this condition energy consumption was found 22.5 kWh m-3 after 60 min reaction.
Conclusion: This study shows that electrocoagulation of wastewater from phenol-formaldehyde resin manufacturing can be used as a pretreatment process.
F Kord Mostafapour, E Bazrafshan, H Kamani,
Volume 3, Issue 3 (10-2010)
Abstract
Backgrounds and Objectives:Arsenic is one of the most toxic and dangerous elements in drinking water that with increase in its application in agriculture, development of applications in agriculture, livestock, medicine, industry and other cases its entry to water resources and environment is much easier.Arsenic is a poisonous, cumulative substance and inhibitor of SH group enzymes and various studies revealed a significant correlation between high concentrations of arsenic in drinking water and liver cancer, nasal cavity cancer, lungs, skin, bladder and kidney cancer in men and women and prostate and liver in men. The aim of this was survey of arsenic removed from water using dissolved air floatation mechanism.
Materials and Methods: At present study in first step for determination best conditions of arsenic removal by dissolved air floatation method, optimum amount of coagulants determined and then synthetic solution of arsenic (50, 100 and 200 µg/L) prepared using sodium arsenate. In third step arsenic removal efficiency under various variables such as arsenic concentration, flocculation and floatation time and saturation pressure were analyzed. Finally residual arsenic concentration was determined by the silver diethyl dithiocarbamate method.
Results:Effect of optimum condition on arsenic removal efficiency at various initial concentration 50, 100 and 200 µg/Lshowed that the best coagulant for removal of arsenic is polyaluminumchloride. Also maximum efficiency (99.4%) was obtained in initial concentration equal 200 µg/L.
Conclusion: It can be concluded that dissolved air floatation method with poly aluminum chloride as coagulant have high efficiency for arsenic removal even at high concentrations and therefore this method can be used for removal of arsenic from water as a suitable and safe option.
A Dalvand, A Jonidi Jafari, M Gholami, A Ameri, N.m Mahmoodi,
Volume 4, Issue 1 (5-2011)
Abstract
Background and Objectives: Discharge of textile colored wastewater industries without providing enough treatment in water bodies, is harmful for human and aquatic organisms and poses serious damages to the environment. Most of conventional wastewater treatment methods don't have enough efficiency to remove textile dyes from colored wastewater thus in this research the efficiency of electrocoagulation treatment process with aluminum electrodes for treatment of a synthetic wastewater containing C.I. Reactive Red 198 in batch reactor was studied.
Material and Methods: The experiment conducted in a Plexiglas reactor with a working volume of 2L that equipped with 4 aluminum electrodes. The effects of operating parameters such as voltage, time of reaction, initial dye concentration and interelectrode distance on the color removal efficiency, electrical energy consumption and electrode consumption were investigated.
Results: in the optimum operational condition electrocoagulation, is able to remove color and COD as high as 99.1 and 84.3% in aluminum electrode in 75 minutes at 20 volt and 2 cm interelectrode distance, respectively. Under this condition, operating cost was 2986 rails per cubic meter of treated wastewater. Increase in the interelectrode distance and initial dye concentration,lead to the decrease in efficiency of dye and COD removal.While as the voltage and time of reaction increased, energy consumption, electrode consumption, final pH and color removal, increased too.
Conclusion: electrocoagulation process by aluminum electrode is an efficient and suitable method for reactive dye removal from colored wastewater.
A Mirzaei, A Takdastan, N Alavi Bakhtiarvand,
Volume 4, Issue 3 (10-2011)
Abstract
Backgrounds and Objectives: Selection of proper coagulants for turbidity removal and determination of effective methods to reduce coagulants dose and related costs in water treatment plants is of critical importance. The present study investigates the effect of returned sludge on improving the performance of poly-aluminum chloride (PAC) in turbidity, coliform bacteria, heterotrophic bacteria removal from drinking water during rapid mixing phase.
Materials and Methods: In order to determine the optimal returned sludge volume injected during rapid mixing with PAC for turbidity, total coliform and hetrophic bacteria, experiments were conducted based on variables such as injected silt volume (from 0 - 125 ml), and varying turbidities from 58 - 112 NTU. At the end of each JAR experiments, remaining turbidity , microbial parameters of samples were measured . Coagulant efficiency in turbidity removal and microbial parameters were determined by Covariance, Duncan analyses and graphs were drawn by MS Excel . The results statistically showed significant among variables (P<0.05).
Results: The results showed that the maximum turbidity removal efficiency of 98.92 at 30 ppm was 10 ml while the maximum turbidity removal efficiency of 98.31 at 10 ppm was 4 ml. The maximum total coliform removal efficiency of 95.68 obtained for 10 ppm in 10 cc injected sludge volume.
Conclusion: This study shows that addition of returned sludge to flash mixing can reduce the turbidity of samples.
M Khodadadi, M.t Samadi, A.r Rahmani,
Volume 4, Issue 3 (10-2011)
Abstract
Background and Objectives: Water pollution by pesticides has adverse effects on the environment and human health, as well .In recent years, advanced oxidation processes, have been gone through to a very high degree for pesticides removal. Poly-Aluminum chloride (PAC) used for water treatment, can be effective on pesticides removal. The aim of this research was to study the use of UV/O3 and PAC in the removal of pesticides from drinking water.
Materials and Methods: In this descriptive- analytical survey, specific concentrations of pesticides (1,5,10,15,20 ppm)namely Diazinon, Chlorpyrifos, Carbaril were prepared through addition to deionized water. Dichloromethane was used for samples&apos extraction, samples extracted with Liquid- Liquid & Solid-phase extraction , finally entered bath reactor at pH (6,7,9) .The samples then exposed to UV/O3at contact time of (0.5,1,1.5 and 2 hours) . In the PAC pilot , the effects of various concentrations of pesticides, and PAC - ranging (12/24 and 36 ppm) were investigated for the efficacy of pesticides removal. All samples analyzed by GC/MS/MS and HPLC.
Results: It was found that in UV/O3 reactor, with the rise of pH, decrease in pesticides concentration, and rise of contact time, the efficiency of removal increased too. In the PAC pilot, increase in PAC concentration and decrease in pesticides concentration , both increased the efficiency. Besides, both of the methods showed high efficiencies in the removal of both pesticides,i-e. halogenated Organophosphorus (Chlorpyrifos) , non- halogenated Organophosphorus (Diazinon) at the degree of over (%80 ) In case of carbamate pesticides (e.g. Carbaril) efficiency was over (>%90). One-Way Anova & Two -Way Anova were used to analyze the obtained data.
Conclusion: According these results these two methods are suggested for the removal of pesticides from aqueous solutions.
Edris Bazrafshan, Ahmad Joneidi Jaafari, Ferdos Kord Mostafapour, Hamed Biglari,
Volume 5, Issue 2 (10-2012)
Abstract
MicrosoftInternetExplorer4
Background and Objectives: Presence of humic acids in
water resources is important because it is a precursor to disinfection
by-products (DBPs) and affects many treatment processes. In this study, we
investigated the performance of electrocoagulation process duad with hydrogen
peroxide (creating Fenton process) in removal of humic acids (HA) from aqueous
environment.
Materials and Methods: The experiments were performed using a 1 L bipolar batch reactor (covered with
the aluminum foil) equipped with iron electrodes and connected to electric
source having electrical potential 10 V in bipolar mode. First, reactor was
filled up using aqueous solution containing 20 mg/L HA. Later, several working
parameters, such as initial pH (3, 5, 7, and 8), electrical conductivity
produced from adding 1, 1.5, 2 and 3 g/l KCl and reaction time were studied to
achieve the highest humic acid removal capacity. To follow the progress of the
treatment, hydrogen peroxide (50 mg/l) was added to reactor and then samples of
10 ml were taken at 5, 15, 30, 45, and 60 min and then filtered (0.45 μ) to
eliminate sludge formed during electrolysis. Finally, humic acid and iron
concentration was measured using TOC analyzer and atomic absorption method
respectively.
Results: Results of
this study showed that the most effective removal capacities of humic acid
(97.19%) could be achieved when the pH was kept 5(KCl 3g/l and reaction time 60
min). The share of Fenton and electrocoagulation process was %7.9 and %92.1
respectively. In addition, our results indicated that the removal efficiency of
humic acid with increase of pH and electrical conductivity parameters decreases
and increases respectively.
Conclusion: It can be
concluded that the Fenton process duad with electrocoagulation process has the
potential to be utilized for cost-effective removal of humic acid from aqueous
environments.
Mohammad Malakootian, Hassan Izanloo, Maryam Messerghany, Mohammad Mahdi Emamjomeh,
Volume 5, Issue 2 (10-2012)
Abstract
MicrosoftInternetExplorer4
Background and
Objectives: leachate from municipal solid waste
landfill is a strong sewage having hazardous toxic substances. It should
be
treated
by
choosing a
simple,
economical,
and eco-friendly method. The aim of this study is reduction of COD
from the
Qom City landfill leachate using electrocoagulation process.
Materials
and Methods: The experimental study
was carried out at bench scale using a batch reactor during 2010. We used a Plexiglas reactor having 0.7 liter
capacity, containing nine plate aluminum electrodes connected to a DC power supply (10-60V, 1-5A). Samples were
collected in the middle of cell at regular (every 10 minutes) time intervals.
The concentration of COD was determined using
a COD analyzer. The effects of different parameters
including current density (52.08, 69.44 mA/cm
2), electrolyte time (10, 20,30,40,50 and 60 min), and voltage range
(10, 20, 30, 40, 50 and 60 volt) were investigated.
Results: For a voltage of 60 V and electrolysis time 60 min, the COD removal
efficiency was increased from 48.7% for 52.08
mA/cm
2 to 77.4% for 69.44
mA/cm
2. The highest TSS removal
efficiency was obtained at the largest current input when the voltage and
electrolysis time were kept at 60V and 60 min respectively.
Conclusion: The results showed that the highest COD removal
efficiency (77.4%) was obtained when the current density was 69.44 Ma/cm
2 and the voltage and electrolysis time were kept at 60V and 60 min respectively. Power consumption for this removal level was measured to
be 431.26 kWh per kg COD removal. The results obtained revealed that the electrocoagulation
technology is an effective treatment process for landfill leachate.
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Edris Bazrafshan, Ferdos Kord Mostafapour, Mahdi Farzadkia, Kamaledin Ownagh, Hossein Jaafari Mansurian,
Volume 5, Issue 3 (10-2012)
Abstract
Background and Objectives: Slaughterhouse wastewater contains various and high amounts of organic
matter (e.g., proteins, blood, fat, and lard). In order to produce an effluent
suitable for stream discharge, chemical coagulation and electrocoagulation
techniques have been particularly explored at the laboratory pilot scale for
organic compounds removal from slaughterhouse effluent. The purpose of this
work was to investigate the feasibility of treating cattle-slaughterhouse
wastewater by combined chemical coagulation and electrocoagulation process to
achieve the required standards.
Materials and Methods:
At present study, slaughterhouse wastewater after initial analysis was tested
for survey of coagulation process using Poly aluminum chloride (PAC) at various
doses (25-100 mg/L). Then we measured the concentrations of wastewater
pollutants (BOD5, COD, TKN, TSS and fecal Coliforms). Later, we transferred the
effluent to the electrocoagulation unit and we evaluated the removal efficiency
of pollutants in the range 10 to 40 volts of electric potential during 60 min.
Results: It was found
that the efficiency of chemical coagulation process using poly-aluminum
chloride (PAC) as coagulant increases with increasing doses (from 25 to 100
mg/L) we achieved maximum removal efficiency during the chemical coagulation
for parameters of BOD5, COD, TSS, and TKN at 100 mg/L of PAC equivalent to
44.78%, 58.52%, 59.9%, and 39.58% respectively. Moreover, the results showed
that with increasing the electric potential and reaction time, the yield
increases linearly so that maximum removal efficiency at a dose of 100 mg/L
PAC, an electrical potential of 40 volts and a reaction time of 60 minutes for
the parameters BOD
5, COD, TSS, and TKN was 99.18% 99.25%, 82.55%,
and 93.97% respectively.
Conclusion: The
experiments demonstrated the effectiveness of combined chemical coagulation and
electrocoagulation processes for pollutants removal from the slaughterhouse
wastewaters. Consequently, this combined process can produce effluent
compliance with the effluent discharge standards.
Hamed Biglari, Edris Bazrafshan,
Volume 5, Issue 4 (2-2013)
Abstract
MicrosoftInternetExplorer4
Background and Objectives: Phenol is one of the most important organic chemicals
presenting in water and other environments. It not only brings about hygienic
problems but also results in forming 11 toxic priority pollutants in aqueous
environments. Hence, the performance of electrocoagulation process using iron
and aluminum sacrificial anodes was investigated for removal of phenol.
Materials and Methods: We used a glass tank in 1.56 L volume (effective volume 1 L) equipped with four
iron and aluminum plate electrodes to do experiments (bipolar mode). The tank
was filled with synthetic wastewater containing phenol in concentration of 5,
20, 40, and 70 mg/l and to follow the progress of the treatment, each sample
was taken at 20 min intervals for up to 80 min. The percent of phenol removal
was measured at pH 3, 5, 7, and 9 electrical potential range of 20, 40, and 60
volts and electrical conductivity of 1000, 1500, 2000, and 3000 µs/cm.
Results: It was found
that the most effective removal capacities of phenol (95 and 98 %) could be
achieved when the pH was kept 7 and 5 for iron and aluminum electrodes,
reaction time 80 min, electrical
conductivity 3000 µs/cm, initial concentration of phenol 5 mg/l, and electrical
potential in the range of 20-60 V.
Conclusion: The method
was found to be highly efficient and relatively fast compared with existing
conventional techniques and also it can be concluded that the electrochemical
process has the potential to be utilized for the cost-effective removal of
phenol from water and wastewater.
Marzieh Razavi, Mosen Saeedi, Ebrahim Jabaari,
Volume 6, Issue 3 (12-2013)
Abstract
Background & Objectives: In this study, treatability of wastewater from a laundry unit was investigated by applying electrocoagulation method in which two pairs of aluminum and iron electrodes were utilized. Electrocoagulation is a noble treatment method suitable for different kinds of wastewater which has been given a considerable attentions by researchers recently. Applying direct current to two or several suitable metallic electrode in a batch reactor containing effluent would result in flocks of metal hydroxide.
Materials & Methods: We studied the effect of different operational parameters such as pH, electrodes distance, intensity of electrical current, and type of electrodes on the treatment efficiencies.
Results: Aluminum electrodes showed better effects on the treatment efficiencies in nitrate and COD removal. Maximum phosphate removal (99.93%)took place at pH=7 using Al electrodes. Whereas, in the case of iron electrode, maximum nitrate and COD removal efficiencies were about 97.60 and 80% at pH=9 and pH=6 respectively. Operational cost analysis showed that the corresponding costs of Al application as an electrode is different from that of iron electrode application.
Conclusion: Although application of both iron and aluminum electrodes lead to obtaining considerable removal phosphate, nitrate and COD, iron electrodes could result in reasonable removals to meet Environmental Standards with lower operational costs.
A Heidari, R Nabizadeh, M Alimohammadi, M Gholami, A.h Mahvi,
Volume 8, Issue 1 (8-2015)
Abstract
Background and Objectives: Reduction of released extracellular polymeric substances (EPS) during sludge dewatering is one of the main challenges in sludge treatment process. The aim of this study was to investigate the EPS quantity changes within sludge dewatering by continues ultrasonic – electrocoagulation (US – EC) reactor under different conditions and to determine the most efficient case for reducing these substances. Materials and Methods: In this study, the EPS quantity changes in supernatant were compared after undergoing different conditions of ultrasonic (frequency of 35 and 130 KHz, detention time of 3,5,10, and 30 min) and electrocoagulation (voltage of 20, 30, and 40 V, detention time of 10, 20, and 30 min) processes were compared. Results: The research found that the maximum efficiency of the US-EC reactor was achieved at a frequency of 35 KHz and detention time of 5 min for ultrasonic with voltage of 40 V and at detention time of 30 min for electrocoagulation process as under these conditions total EPS concentration reduced by 69%. Conclusion: According to the results achieved, US – EC reactor significantly reduced the released EPS in supernatant in addition to dewatering sludge.
Mr Khani, Ah Mahvi, Ma Zazouli, Z Yousefi, Y Dadban Shahamat,
Volume 12, Issue 1 (5-2019)
Abstract
Background and Objective: Olive Mill Wastewater (OMWW) is one of the most polluted sanitary wastewaters that its ineffective treatment will cause severe pollution of the environment. In this study, OMWW treatment wasinvestigated using combined electrocoagulation and novel advanced oxidation process.
Materials and Methods: Biodegradability, efficiency and kinetics of removal of turbidity and organic matter from the OMWW by applying the operational parameters of electrocoagulation such as current density (0-0.77 A/dm2), type of anode electrode, reaction time (0-45 min) were investigated. Various types of advanced oxidation processes were performed to determine the the efficiency of removal of TOC and kinetics and biobegradability.
Results: The optimum condition for removing turbidity, BOD, TOC and consumed Iron anode electrod in electrocoagulation were 78%, 57%, 72% and 583 mg/ per liter of wastewater, respectively. Thus, the kinetic of TOC removal was first-order and was 0.027 min-1. The TOC removal efficiency of pretreated OMWW in oxidation processes of US, H2O2, SOP, O3 / H2O2, COP, COP/US and H2O2/COP/US were measured as 8%, 15%, 20%, 25%, 61%, 68% and 75%, respectively. The highest biodegradability index (BOD/TOC) in the COP/US/H2O2 process was increased 1.5 times.
Conclusion: The advenced oxidation process of COP/US/H2O2 follwed by electrocagulation demonstrated an effective treatment of OMWW and improved its biodegradability. Therefore, this process can be used for efficient treatment of OMWW in olive and similar industries.
Sh Goodarzi, Gh Shams Khoramabadi, M Esmaty, Ma Karami, A Hossein Panahi,
Volume 12, Issue 2 (9-2019)
Abstract
Background and Objective: Wastewater from pharmaceutical industry has high chemical oxygen demand as a result of the presence of organic drugs and antibiotics. In order to meet the environmental requirements, several treatment methods like chemical and electrochemical methods have been widely applied due to their high ability to remove organic compounds from pharmaceutical wastewater. Therefore, the present study aimed to evaluate the efficiency of chemical coagulation/Electro-Fenton treatment method to degrade the organic matter-containing pharmaceutical industry wastewater.
Materials and Methods: The experimental tests were carried out using batch mode. The chemical coagulation process was evaluated as a function of aluminum chloride concentration (25-300 mg/L) and pH (3-10). The effluent from chemical coagulation process was transferred to Electro-Fenton reactor. Effects of H2O2 concentration (100-4000 mg/L), reaction time (up to 120 min), voltage (10-30 V), and pH (3-10) were evaluated. The removal efficiency was determined in term of COD removal.
Results: The results showed that the highest removal of COD in the chemical coagulation was 49% (coagulant dose of 200 mg/L, and pH of 7). In addition, the Electro-Fenton process could be eliminating of 93.5% of COD at the optimum conditions concentration (100 mg/L H2O2, voltage of 20, pH of 3, and contact time of 30 min).
Conclusion: According to the results, it can be concluded that the combination of chemical and electrochemical processes was found to be effective methods for treatment of pharmaceutical wastewater in comparison to the application of each process separately. To reach to the maximum removal efficiency, the environmental parameters should be carefully controlled at their optimum values in each single process.
Arezoo Mahmoudi, Seyyed Alireza Mousavi, Danial Nayeri, Parastoo Darvishi,
Volume 15, Issue 3 (12-2022)
Abstract
Background and Objective: The consequence of using coagulant materials such as aluminum sulfate and ferric chloride in the coagulation unit of conventional water treatment plants can generate plenty of sludge that contains large amounts of coagulant, which in addition to environmental risks, will also possess disposal costs. Today, intending to preserve the environment and reduce treatment costs, researchers emphasize the recovery and reuse of coagulants from sludge. In this regard, the present study was proposed and implemented to recover and reuse water treatment plant sludge as a low-cost coagulant in wastewater treatment.
Materials and Methods: This research is an experimental-laboratory study. In order to recover the coagulant from the collected sludge, acid hydrolysis method was used. The physicochemical characteristics of the recovered sludge were also determined using FTIR, FE-SEM, and BET analysis. Moreover, the efficiency of recovered sludge in different doses (50 to 300 mg/L) on wastewater treatability in terms of COD, TSS, VSS, turbidity, phosphorus, and coliform indices was compared with aluminum sulfate, ferric chloride coagulants, also the results of the study were analyzed and presented using Excel software (version, 2016).
Results: According to the results, the prepared sludge had no crystalline structure with amorphous morphology. In addition, recovered coagulant from water treatment sludge has demonstrated high efficiency for wastewater treatment, so 66.6%, 82.49%, 79.66%, 80%, 65 %, 99.18% of COD, turbidity, TSS, VSS, phosphorus, total coliform were removed at the highest dosage of recovered coagulant (300 mg/L), respectively. Furthermore, the recovered coagulant dosage had a significant effect on the performance of the coagulation and flocculation process in wastewater treatment.
Conclusion: The results showed that recovered coagulant from the sludge of the water treatment plant can be considered an acceptable option with appropriate effectiveness in the wastewater treatment processes.
