This document summarizes a study that investigated the potential of three Pseudomonas bacterial species (P. florescence, P. paucimobilis, and Pseudomonas sp.) to remove lead and crude oil from wastewater from an oil refinery in Alexandria, Egypt. The study found high removal efficiencies for lead (over 90%) and oil (56.8-68.8%) when treating wastewater in batches with different bacteria to wastewater ratios. P. florescence was the most effective at removing contaminants. The optimal ratio was 1:2 bacteria to wastewater. The study recommends using Pseudomonas bacteria, especially P. florescence, for bioremediation
Biosorption of Copper (II) Ions by Eclipta Alba Leaf Powder from Aqueous Solu...ijtsrd
The removal of heavy metals from industrial wastewater is of great concern as heavy metals are non-biodegradable, toxic elements that cause serious health problems if disposed of in the surrounding environment. The present study, Karisalangkani (Eclipta Alba) leaves were used for the adsorption of heavy metals like copper (Cu (II)) ions. The bio sorbent was characterized using SEM and BET analysis. The bio sorption experiments are conducted through batch system. The operating parameters studied were initial metal ion concentration, adsorbent dosage, initial solution pH, contact time and effect of temperature Adsorption equilibrium is achieved in 30 min and the adsorption kinetics of Cu (II) is found to follow a pseudo-second-order kinetic model. Equilibrium data for Cu (II) adsorption are fitted well by Langmuir isotherm model. The maximum adsorption capacity for Cu (II) ions is estimated to be 9.2 mgg at 25 °C. The experimental result shows that the materials have good potential to remove heavy metals from effluent and good potential as an alternate low cost adsorbent. Due to their outstanding adsorption capacities, Eclipta Alba is excellent sorbents for the removal of copper (II) ions. B. Kavitha | R. Arunadevi"Biosorption of Copper (II) Ions by Eclipta Alba Leaf Powder from Aqueous Solutions" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-5 , August 2018, URL: http://www.ijtsrd.com/papers/ijtsrd17156.pdf http://www.ijtsrd.com/chemistry/environmental-chemistry/17156/biosorption-of-copper-ii-ions-by-eclipta-alba-leaf-powder-from-aqueous-solutions/b-kavitha
Opportunities and constraints of using the innovative adsorbents for the remo...Dr. Md. Aminul Islam
The presence of cobalt(II) in wastewater is an emergent concern because of its toxicity at elevated concentration.
Co(II) is a non-biodegradable, carcinogenic and mutagenic pollutant released from natural, industrial and
manmade sources. In recent years, the control of water that has been polluted with Co(II) has been an emergent
issue. The release of Co(II) into waterways is undesirable because ingestion of high levels of Co(II) may cause
severe health issues including cancer. The current review discusses the different adsorbents such as carbonaceous and activated carbon materials, nanosized metal oxides, low-cost natural materials, clay minerals and
nanocomposites employed by researchers to treat Co(II)-polluted water. The systems used have been assessed in
terms of overall Co(II) sorption capacity. Special emphasis has been given to the environmental conditions such
as contact time, solution pH, initial Co(II) concentration, temperature, and mineral dosage. Moreover, empirical
and surface complexation modeling (SCM) of the sorption systems is summarized. Natural materials, agricultural
waste materials, and bio sorbents exhibited outstanding Co(II) sorption performance. The current investigation
provides an overview of the state of the Co(II) removal studies performed by using various adsorbents.
Biosorption of Copper (II) Ions by Eclipta Alba Leaf Powder from Aqueous Solu...ijtsrd
The removal of heavy metals from industrial wastewater is of great concern as heavy metals are non-biodegradable, toxic elements that cause serious health problems if disposed of in the surrounding environment. The present study, Karisalangkani (Eclipta Alba) leaves were used for the adsorption of heavy metals like copper (Cu (II)) ions. The bio sorbent was characterized using SEM and BET analysis. The bio sorption experiments are conducted through batch system. The operating parameters studied were initial metal ion concentration, adsorbent dosage, initial solution pH, contact time and effect of temperature Adsorption equilibrium is achieved in 30 min and the adsorption kinetics of Cu (II) is found to follow a pseudo-second-order kinetic model. Equilibrium data for Cu (II) adsorption are fitted well by Langmuir isotherm model. The maximum adsorption capacity for Cu (II) ions is estimated to be 9.2 mgg at 25 °C. The experimental result shows that the materials have good potential to remove heavy metals from effluent and good potential as an alternate low cost adsorbent. Due to their outstanding adsorption capacities, Eclipta Alba is excellent sorbents for the removal of copper (II) ions. B. Kavitha | R. Arunadevi"Biosorption of Copper (II) Ions by Eclipta Alba Leaf Powder from Aqueous Solutions" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-5 , August 2018, URL: http://www.ijtsrd.com/papers/ijtsrd17156.pdf http://www.ijtsrd.com/chemistry/environmental-chemistry/17156/biosorption-of-copper-ii-ions-by-eclipta-alba-leaf-powder-from-aqueous-solutions/b-kavitha
Opportunities and constraints of using the innovative adsorbents for the remo...Dr. Md. Aminul Islam
The presence of cobalt(II) in wastewater is an emergent concern because of its toxicity at elevated concentration.
Co(II) is a non-biodegradable, carcinogenic and mutagenic pollutant released from natural, industrial and
manmade sources. In recent years, the control of water that has been polluted with Co(II) has been an emergent
issue. The release of Co(II) into waterways is undesirable because ingestion of high levels of Co(II) may cause
severe health issues including cancer. The current review discusses the different adsorbents such as carbonaceous and activated carbon materials, nanosized metal oxides, low-cost natural materials, clay minerals and
nanocomposites employed by researchers to treat Co(II)-polluted water. The systems used have been assessed in
terms of overall Co(II) sorption capacity. Special emphasis has been given to the environmental conditions such
as contact time, solution pH, initial Co(II) concentration, temperature, and mineral dosage. Moreover, empirical
and surface complexation modeling (SCM) of the sorption systems is summarized. Natural materials, agricultural
waste materials, and bio sorbents exhibited outstanding Co(II) sorption performance. The current investigation
provides an overview of the state of the Co(II) removal studies performed by using various adsorbents.
Isolation and Characterization of Nickel Tolerant Bacterial Strains from Elec...Agriculture Journal IJOEAR
Abstract— In the present study, an attempt was made to isolate and characterize nickel tolerant bacterial strains from the electroplating effluent contaminated soil. The effluent sample was collected at the direct outlet of electroplating industry and analyzed for physico-chemical characteristics such as pH (6.5), temperature (33), electrical conductivity (15.1 ms/cm), total solids (2309mg/l), total dissolved solids (5573 mg/l), chloride (0.20mg/l), sodium (0.13ppm), calcium (2.23ppm), potassium (0.20ppm), Biological Oxygen Demand (4200mg/l), Chemical Oxygen Demand (5243 mg/l) and nickel (4.063ppm). Enumeration of total bacterial population from the electroplating effluent contaminated soil sample was made in nutrient agar medium. Sixteen bacterial colonies were selected based on their abundance growth all of them were identified through morphological and biochemical characteristics. All the sixteen bacterial isolates were screened for its metal tolerance using nutrient agar medium incorporated with nickel metal. Based on the better growth performance, six bacterial strains were selected as potential metal tolerant organism. The selected metal tolerant bacterial strains were further characterized in the various environmental conditions such as pH (5, 7 & 9) temperature (5°C, 28°C, 37°C & 45°C) and concentration of metal ions (100ppm, 200ppm, 300ppm & 400ppm) for 5 days. The result reveals that one bacterial strain, Pseudomonas sp 1 was showed better growth in nickel metal based medium with pH 7 at 37°C temperature.
Vegetables are grown all over the world for human needs and proper supply nutritional supplement. Recently due to various anthropogenic activities such as mining, industrialization and agricultural activities like application of pesticides, fungicides and fertilizers, heavy metals are released in to the atmosphere, soil and water. These released heavy metals enter into the plant system through various physiological processes and it affects the plant growth and development. The concentration of heavy metals in the environment varies due to various activities and it becomes toxic when it reaches above the permissible limits. Accumulation of heavy metals occurs only when the vegetable crops are exposed to heavy metal contaminated environment, thus it enters into the food chain. When these heavy metals contaminated vegetables are consumed by human beings it causes various severe health ailments. In order to reduce the heavy metal toxicity, proper remediation steps have to be carried out in soil and irrigation water. Before consumption of any vegetables washing has to be done to reduce the adhered heavy metal particulates and through these simple steps we can remove the heavy metal adhered on the vegetable surface.
Analysis of Heavy Metals in fish,water and sediment from Bay of Bengalinventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
HEAVY METAL POLLUTION AND REMEDIATION IN URBAN AND PERI-URBAN AGRICULTURE SOILSchikslarry
Throughout the world, there is a long tradition of farming intensively within and at the edge of cities (Smit et al., 1996). However, most of these peri-urban lands are contaminated with pollutants including heavy metals, such as Cu, Zn, Pb, Cd, Ni, and Hg. The major sources of heavy metal contamination in agricultural soils are discharge of effluents from domestic sources, coal-burning power plants, non-ferrous metal smelters, iron and steel plants, dumping of sewage sludge and metal chelates from different industries. Once the heavy metals are released into soils, plants can absorb and bio-accumulate these heavy metals and thereby affect humans and animals’ health upon consumption (Seghal et al., 2014). Hence, there is a great need to develop effective technologies for sustainable management and remediation of the contaminated soils. There are conventionally physicochemical soil remediation engineering techniques, such as soil washing, incineration, solidification, vapour extraction, thermal desorption, but they destroy the plant productive properties of soils. Moreover, they are usually extremely expensive, limiting their extensive application, particularly in developing countries and for remediation of agricultural soils (Kokyo et al., 2014). Phytoremediation has been increasingly receiving attentions over the recent decades, as an emerging, affordable and eco-friendly approach that utilizes the natural properties of plants to remediate contaminated soils (Wang et al., 2003). Phytoremediation includes phytovolatilization, phytostabilization, and phytoextraction using hyper-accumulator species or a chelate-enhancement strategy. The future of this technique is still mainly in the research phase, and many different Hyperaccumulators and crops that can be cultivated in heavy metal contaminated are still being tested.
Removal of heavy metals (Cr, Cd, Ni and Pb) using fresh water algae (Utricula...Innspub Net
A study was conducted to check the efficiency of different fresh water algae for removing heavy metals (Cr, Cd, Ni and Pb) from contaminated water. The three most abundant indigenous algal species namely Ulothrix tenuissima, Oscillatoria tenuis and Zygogonium ericetorum were collected from fresh water channels of Parachinar, Pakistan and brought to the laboratory of Soil and Environmental Sciences Department at the University of Agriculture, Peshawar Pakistan for proper identification. To check the efficiency for removing heavy metals artificial contaminated water was prepared and was inoculated with mix culture of above mentioned algae and incubated for 10 days. After incubation algal species were removed from water through centrifugation and was dried, digested and analyzed for heavy metals. The results showed that the concentration of all heavy metals was substantially reduced in the algal inoculated contaminated water. The analysis of algal biomass showed that considerable amount of metals and other elements were recovered in algae. Among the tested algal species, Zygogonium ericetorum showed maximum removal Ni(99.40ug) and Cr(66.84ug) from contaminated water followed by Oscillatoria tenuis with 84ug(Ni) and 64.83ug(Cr) respectively. However Oscillatoria tenuis showed maximum removal of Cd(41.00ug) than the other algal species. Similarly Zygogonium ericetorum showed maximum removal of Pb (451ug) followed by Ulothrix tenuissima where 441ug was recorded. Highest amount Cd, and Ni were recovered in Zygogonium ericetorum biomass while highest amount of Cr and Pb were recorded in the biomass of Oscillatoria tenuis. Finally it could be concluded that algae have efficiently removed heavy metals from contaminated water. Further research is needed to test other algal species for removal of heavy metal and other elements from the contaminated water.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Heavy metals and its effects on plants and environmentHaider Ali Malik
Heavy metals are natural constituents of the earth’s crust , but indiscriminate human activities have drastically altered their geochemical cycles and biochemicals balance.
Any toxic metals may be called heavy metals.
Since heavy metals have a propensity to accumulate in selective body organs.
The average safety levels in food or water are often misleading high.
Heavy is any metal or metalloid of environmental concern.
Heavy metals are metallic element that have relatively high density usually greater than 5 g/cm3, or their density is greater than the density of water.
Isolation and Characterization of Nickel Tolerant Bacterial Strains from Elec...Agriculture Journal IJOEAR
Abstract— In the present study, an attempt was made to isolate and characterize nickel tolerant bacterial strains from the electroplating effluent contaminated soil. The effluent sample was collected at the direct outlet of electroplating industry and analyzed for physico-chemical characteristics such as pH (6.5), temperature (33), electrical conductivity (15.1 ms/cm), total solids (2309mg/l), total dissolved solids (5573 mg/l), chloride (0.20mg/l), sodium (0.13ppm), calcium (2.23ppm), potassium (0.20ppm), Biological Oxygen Demand (4200mg/l), Chemical Oxygen Demand (5243 mg/l) and nickel (4.063ppm). Enumeration of total bacterial population from the electroplating effluent contaminated soil sample was made in nutrient agar medium. Sixteen bacterial colonies were selected based on their abundance growth all of them were identified through morphological and biochemical characteristics. All the sixteen bacterial isolates were screened for its metal tolerance using nutrient agar medium incorporated with nickel metal. Based on the better growth performance, six bacterial strains were selected as potential metal tolerant organism. The selected metal tolerant bacterial strains were further characterized in the various environmental conditions such as pH (5, 7 & 9) temperature (5°C, 28°C, 37°C & 45°C) and concentration of metal ions (100ppm, 200ppm, 300ppm & 400ppm) for 5 days. The result reveals that one bacterial strain, Pseudomonas sp 1 was showed better growth in nickel metal based medium with pH 7 at 37°C temperature.
Vegetables are grown all over the world for human needs and proper supply nutritional supplement. Recently due to various anthropogenic activities such as mining, industrialization and agricultural activities like application of pesticides, fungicides and fertilizers, heavy metals are released in to the atmosphere, soil and water. These released heavy metals enter into the plant system through various physiological processes and it affects the plant growth and development. The concentration of heavy metals in the environment varies due to various activities and it becomes toxic when it reaches above the permissible limits. Accumulation of heavy metals occurs only when the vegetable crops are exposed to heavy metal contaminated environment, thus it enters into the food chain. When these heavy metals contaminated vegetables are consumed by human beings it causes various severe health ailments. In order to reduce the heavy metal toxicity, proper remediation steps have to be carried out in soil and irrigation water. Before consumption of any vegetables washing has to be done to reduce the adhered heavy metal particulates and through these simple steps we can remove the heavy metal adhered on the vegetable surface.
Analysis of Heavy Metals in fish,water and sediment from Bay of Bengalinventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
HEAVY METAL POLLUTION AND REMEDIATION IN URBAN AND PERI-URBAN AGRICULTURE SOILSchikslarry
Throughout the world, there is a long tradition of farming intensively within and at the edge of cities (Smit et al., 1996). However, most of these peri-urban lands are contaminated with pollutants including heavy metals, such as Cu, Zn, Pb, Cd, Ni, and Hg. The major sources of heavy metal contamination in agricultural soils are discharge of effluents from domestic sources, coal-burning power plants, non-ferrous metal smelters, iron and steel plants, dumping of sewage sludge and metal chelates from different industries. Once the heavy metals are released into soils, plants can absorb and bio-accumulate these heavy metals and thereby affect humans and animals’ health upon consumption (Seghal et al., 2014). Hence, there is a great need to develop effective technologies for sustainable management and remediation of the contaminated soils. There are conventionally physicochemical soil remediation engineering techniques, such as soil washing, incineration, solidification, vapour extraction, thermal desorption, but they destroy the plant productive properties of soils. Moreover, they are usually extremely expensive, limiting their extensive application, particularly in developing countries and for remediation of agricultural soils (Kokyo et al., 2014). Phytoremediation has been increasingly receiving attentions over the recent decades, as an emerging, affordable and eco-friendly approach that utilizes the natural properties of plants to remediate contaminated soils (Wang et al., 2003). Phytoremediation includes phytovolatilization, phytostabilization, and phytoextraction using hyper-accumulator species or a chelate-enhancement strategy. The future of this technique is still mainly in the research phase, and many different Hyperaccumulators and crops that can be cultivated in heavy metal contaminated are still being tested.
Removal of heavy metals (Cr, Cd, Ni and Pb) using fresh water algae (Utricula...Innspub Net
A study was conducted to check the efficiency of different fresh water algae for removing heavy metals (Cr, Cd, Ni and Pb) from contaminated water. The three most abundant indigenous algal species namely Ulothrix tenuissima, Oscillatoria tenuis and Zygogonium ericetorum were collected from fresh water channels of Parachinar, Pakistan and brought to the laboratory of Soil and Environmental Sciences Department at the University of Agriculture, Peshawar Pakistan for proper identification. To check the efficiency for removing heavy metals artificial contaminated water was prepared and was inoculated with mix culture of above mentioned algae and incubated for 10 days. After incubation algal species were removed from water through centrifugation and was dried, digested and analyzed for heavy metals. The results showed that the concentration of all heavy metals was substantially reduced in the algal inoculated contaminated water. The analysis of algal biomass showed that considerable amount of metals and other elements were recovered in algae. Among the tested algal species, Zygogonium ericetorum showed maximum removal Ni(99.40ug) and Cr(66.84ug) from contaminated water followed by Oscillatoria tenuis with 84ug(Ni) and 64.83ug(Cr) respectively. However Oscillatoria tenuis showed maximum removal of Cd(41.00ug) than the other algal species. Similarly Zygogonium ericetorum showed maximum removal of Pb (451ug) followed by Ulothrix tenuissima where 441ug was recorded. Highest amount Cd, and Ni were recovered in Zygogonium ericetorum biomass while highest amount of Cr and Pb were recorded in the biomass of Oscillatoria tenuis. Finally it could be concluded that algae have efficiently removed heavy metals from contaminated water. Further research is needed to test other algal species for removal of heavy metal and other elements from the contaminated water.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Heavy metals and its effects on plants and environmentHaider Ali Malik
Heavy metals are natural constituents of the earth’s crust , but indiscriminate human activities have drastically altered their geochemical cycles and biochemicals balance.
Any toxic metals may be called heavy metals.
Since heavy metals have a propensity to accumulate in selective body organs.
The average safety levels in food or water are often misleading high.
Heavy is any metal or metalloid of environmental concern.
Heavy metals are metallic element that have relatively high density usually greater than 5 g/cm3, or their density is greater than the density of water.
Gold mines and impact of heavy metals on the environmentIAEME Publication
This research report puts light on the research and the study of gold mining plant in Oman and its assessment and its contribution of gold mining into various other environmental media on the
basis of heavy metals. In this research study, various samples were collected from crop plants,stream waters and soil of the plant area of gold mining.
Removal of Heavy Metals from Aqueous Solution Using Ion Exchange Resin MBHPE-TKPijsrd.com
The aim of this study is to synthesis of TKP (MBHPE-TKP) resin for the removal of heavy metals from aqueous solution. Ion exchange resins are polymers that are capable of exchanging particular ions within the polymer with ions in a solution that is passed through them. This ability is also seen in various natural systems such as soils and living cells. The synthetic resins are used primarily for purifying water, but also for various other applications including separating out some elements. Factorial design of experiments is employed to study the effect of above factors pH, time and sorbent used. The new synthesized resins i.e. MBHPE–TKP is hydrophilic and biodegradable, so after effluent treatment used resins can be disposed off without facing any environmental problem .This study focuses on synthesis of new cation exchange resin (MBHPE – TKP) and developing method for treatment of highly contaminated industrial effluents.
Discussed about Sources of Heavy metals , Sources of Heavy metals , Bioremediation, Biosorption by Fungi, Algae, Bacteria , Factors affecting Biosorption , Heavy metals relation with human beings
Food security in a growing population with limited natural resources is one of
the most important issues of the world. Accumulation of heavy metals in food and
their concentrations increase and reaching to a risk limit can threaten human health.
The purpose of this study, is to study the heavy metals lead and cadmium in
vegetables, cultured on spinach and watercress at 10 Gardens of Ardabil. This study is
cross-sectional and 81 samples in water, soil, and spinach and watercress were
prepared during the months of June, July and August in 2015 and after preparation
according to the standard methods and using atomic absorption spectrophotometer
(Perkin Elmer) for the determination of heavy metals. SPSS software was used for data
analysis. The results showed that the mean level of lead and cadmium in all samples
were less than the EPA standard. Between studied orchards in terms of the amount of
cadmium and lead no statistically significant different was seen. The independent ttest
showed that in terms of cadmium between two species of spinach and watercress
there found a significant difference at the 5% level so that the amount of cadmium in
spinach was more than the watercress. Since the concentration of heavy metals in all
samples at second and third stages in July and August were zero, but in the first step
in June, the amount of heavy metals have been found in some samples showed that
all three samples of first cut had more contamination than second and third cut. And
in this case, the concentration of heavy metal pollution in hibernation at vegetable
gardens Ardabil is possible. The results of spinach cadmium amount in the first cut in
the three garden of viz.,3, 6 and 10 showed that in the garden (3), the amount of
cadmium in water is higher than the standard and is concentrated in spinach and the
gardens of 6 and 10 Cadmium in the soil of the gardens, is slightly higher that is
condensed in spinach thus it can be considered that spinach in terms of cadmium has
bioaccumulation.
Effects of heavy metals' toxicity on plants and enhancement of plant defense ...Agriculture Journal IJOEAR
Abstract— Today’s [e.g., “heavy metals (HMs)”] caused by anthropogenic activities have negative impacts on our environment and food productions. HMs can be classified as either essential or nonessential. A trace of essential HMs, such as Cu, Mo, and Zn, can be necessary for plant metabolism, but excess of them can harm the plant growth and development. Nonessential HMs, however, are toxic for plant metabolism and have damaging effects on enzyme activity, photosynthetic properties, cell membrane, permeability and eventually plant growth. Plants with avoidance and tolerance against stress could manage extreme HM stress in soils so that with special mechanisms, such as specific translation and metal accumulation, can elevate abiotic and biotic stress in plants. Moreover, in cells with mechanisms such as [e.g., “Metallothionein (MTs)”] (metal binding proteins) or [e.g., “Phytochelatin (PCs)”] storage and crystallization could reduce the HM stress in the cell wall, plasma membrane, cytosol, tonoplast and vacuoles. Meanwhile, the role of Si-mediation in detoxification of HMs is so bold. Si-mediation with increasing antioxidant, reducing lipid peroxidation, and increasing efficiency of photosynthetic properties elevates the HMs and other biotic and abiotic stresses in plants.
Research Inventy : International Journal of Engineering and Scienceresearchinventy
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
Agricultural by-Products/Waste as Dye and Metal Ions Adsorbents: A Reviewresearchinventy
A major treat to the comfort of human life has been imposed by the unintentional and great increased industrialization and urbanization. Their generations and land disposals of huge amounts of toxic materials and pollutants have contributed in contaminating our environment frighteningly. Synthetic dyes (SD) and heavy metals (HM) are becoming increasingly prevalent in soil and surface water environments, as the most dangerous pollutants. They are present a great concern worldwide, due to their toxicity to many life forms. Environment-friendly utilization of agricultural by-products/waste materials either as raw materials or in production of the so-called activated carbons (AC) is an important issue. Because, it is apparent from our literature review that the main factors characterizing these materials are the inexpensiveness, the local availability and their efficiencies in removal of heavy metals and dyes from contaminated water. A number of different agricultural by-product/wastes as renewable and potential sources for green adsorbent production has been listed in this review. Additionally, the paper has provided the reader with an overview of a number of case studies which were conducted by scientists and researchers. These case studies have pointed out to the efficient removal of SD/HM ions from aqueous solutions by the agricultural by-products/wastes in the form of a raw material, spent tea leaves (STL), spent coffee ground(SCG), and rice husk (RH) wastes were selected as a good examples. Besides, the efficient removal of such ions by AC produced from the same raw materials has been also reviewed. Both kinds are widely used adsorbents in the treatment of wastewaters. High adsorption capacity, cost effectiveness, and environmentally friendly, and their abundance in nature are the important factors which explain why the adsorbent materials derived from an agricultural by-product/wastes is economical for the removal of dye and metal ions from contaminated water. Comparison of different technologies of wastewater treatment especially heavy metals and dyes were also listed in this review
This ppt covers sources, natural and anthropogenic processes, and impacts of heavy metals pollution on environment with Mechanisms of Remediating Heavy Metals.
18 Volume 78 • Number 8A D V A N C E M E N T O F T H E .docxfelicidaddinwoodie
18 Volume 78 • Number 8
A D V A N C E M E N T O F T H E SCIENCEA D V A N C E M E N T O F T H E SCIENCE
I N T E R N A T I O N A L P E R S P E C T I V E S / S P E C I A L R E P O R T
Introduction
Hazardous Substances in E-Waste
The composition of e-waste is incredibly
miscellaneous. E-waste contains complex
mixtures of potential environmental con-
taminants that are distinct from other forms
of waste (Robinson, 2009). It contains more
than 1,000 different substances that fall
under “hazardous” and “nonhazardous” cat-
egories (Ministry of Environment and For-
ests, 2008). Due to the presence of a large
number of hazardous substances including
heavy metals (e.g., mercury, cadmium, lead,
etc.), flame retardants (e.g., pentabromo-
phenol, polybrominated diphenyl ethers
[PBDEs], tetrabromobisphenol-A, etc.), and
other substances, e-waste is generally con-
sidered hazardous, and if improperly man-
aged, may pose significant environmental
and health risks (Tsydenova & Bengtsson,
2011). Some potential contaminants in
e-waste are so uncommon that little research
has been conducted on their disposal conse-
quences. Further, chemical composition of
e-waste varies depending on the age and type
of the discarded item as some new chemicals
are introduced into electrical and electronic
equipment (EEE) from time to time while
other chemicals are restricted. For instance,
e-waste composition is changing with tech-
nological development and pressure on
manufacturers from regulators and nongov-
ernmental organizations (NGOs) (Robin-
son, 2009). The replacement of cathode ray
tube (CRT) monitors with liquid crystal dis-
plays (LCD) is a constructive advancement
in this context as it reduces the concentra-
tion of lead in e-waste. LCD displays, how-
ever, contain the heavy metal mercury.
Furthermore, e-waste contains certain pre-
cious metals such as gold, silver, and copper.
This provides incentives for recycling and
makes e-waste economically significant. For
instance, precious metal concentrations in
printed circuit boards are more than tenfold
higher than commercially mined minerals
(Robinson, 2009). Platinum group metals are
included in EEEs due to their high chemical
stability and conductance of electricity (Rob-
inson, 2009). Thus, a hidden treasure lies
beneath the ever-growing mountain of e-waste.
Some 820,000 tons of copper are included in
the annual flow of e-waste (Robinson, 2009).
Health Hazards Related to E-Waste
Treatment
E-waste treatment including simple recycling,
burning, chemical digestion, and disposal
practices exposes the workers and area resi-
dents to high levels of toxicity through mech-
anisms such as inhalation, contact with soil
and dust, dermal exposure, and oral intake
of contaminated locally produced food and
drinking water. Unregulated recycling activi-
ties generate workplace and environmental
contamination by a wide range of chemi-
cals. Methods used for recycling of e-w ...
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
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It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
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Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
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Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
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Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
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Removal of lead and oil hydrocarbon from oil refining contaminated wastewater using pseudomonas spp
1. Journal of Natural Sciences Research
ISSN 2224-3186 (Paper) ISSN 2225-0921 (Online)
Vol.3, No.11, 2013
www.iiste.org
Removal of Lead and Oil Hydrocarbon from Oil RefiningContaminated Wastewater Using Pseudomonas spp
2.
Ebtesam El.Bestawy1 & 2* , Majdah Abu Rass2, Mervat Amin Abdel-Kawi1
1. Department of Environmental Studies, Institute of Graduate Studies and Research, Alexandria
University, 163 Horria Ave. El-Shatby, P.O. Box 832, Alexandria, Egypt
Department of Life Sciences, Faculty of Science, King Abdul Aziz University. P.O. Box 42805 Jeddah
21551, Kingdom of Saudi Arabia
* E-mail of the corresponding author: ebtesamelbestawy@yahoo.com
Abstract
The main objective of this study is to investigate the potentiality of using three bacterial species {Pseudomonas
florescence (PF), Pseudomonas paucimobilis (PP) and Pseudomonas sp. (PQ)} for the removal of lead and crude
oil from oil-contaminated wastewater of an oil refining company, Alexandria, Egypt before discharging into
open environments. Bacterial candidates were employed in a batch mode as free-living individuals or mixture.
Bioremediation assays were run with three different oily wastewater/bacteria ratios (1:1, 1:2 and 2:1). At each
batch, residual concentration (RC) of the selected parameters (Pb+2, oil content, BOD and COD) were
determined and their removal efficiencies (RE %) were calculated. Results revealed high removal efficiency for
Pb (90.97% from initial concentrations 307.9 mg/l) and oil (56.8 and 68.8% from initial oil concentrations 25
and 500 mg/l respectively) from physically treated oil refinery wastewater. In addition, partial removal of COD
(30.98% from 720 mg/l) and BOD (18.98% from 590 mg/l) was achieved. Pseudomonas florescence (PF) was
the most active reaching the highest removal of most of the tested parameters and wastewater/bacteria ratio of
1:2 was the most convenient while the ratio 2:1 was the least suitable and was inhibitory in most cases for the
contaminants removal. Results highly recommend using Pseudomonas spp especially Pseudomonas florescence
(PF) as efficient, low cost remediation method in oil refineries and similar industries where metallic and organic
contaminants are included. It is also suggested treating wastewater using fixed Pseudomonas florescence in a
continuous system, which can greatly enhance bacterial performance for biodegradation of organic and
accumulation of inorganic contaminants.
Key Words: Accumulation, Biodegradation, Industrial Wastewater, Lead, Organic Matter, Petroleum Oil,
Pseudomonas spp.
1. Introduction
Because of the severity of heavy metal contamination and potential adverse health impact on the public,
tremendous efforts have been made to purify waters containing toxic metal ions. Many industries such as coating,
automotive, aeronautical, oil refining and steel generate large quantities of wastewater containing various
concentrations of lead and other heavy metals (Stellman et al. 2008). Lead (Pb+2) is widely used in applications
such as storage battery manufacturing, printing, pigments, fuels, photographic materials and explosive
manufacturing. Permissible limits for lead in drinking water given by the U.S. Environmental Protection Agency
(USEPA) is 0.015 mg/l and for wastewaters is 0.1 mg/l, given by both USEPA and Bureau of Indian Standards
(BIS). According to the World Health Organization (WHO), the accepted range of Pb+2 in water is 0.01 ppm
(Sharma 2009).
Lead is present in natural deposits and may enter soil through (leaded) gasoline leaks from underground
storage tanks or through a waste stream of lead paint or lead grindings from certain industrial operations.
Emitted lead into the atmosphere can be inhaled, or ingested after it settles out of the air. It is rapidly absorbed
into the bloodstream and is believed to have adverse effects on the central nervous system, the cardiovascular
system, kidneys, and the immune system (Lane et al. 2005). Petroleum refineries discharge large volumes of
water including cooling, surface water runoff and sanitary wastewaters. The quantity of wastewaters
generated and their characteristics depend on the process configuration, which is approximately 3.5–5.0 m3 of
wastewater per ton of crude generated when cooling water is recycled. Polluted wastewaters generated from
oil refineries containing approximately 150–250 biochemical oxygen demand (BOD), 300–600 mg/l chemical
oxygen demand (COD), phenol (20–200 mg/l), oil (100–300 mg/l) in desalted water and up to 5,000 mg/l in
tank bottoms, benzene (1–100 mg/l), benzo(α)pyrene (less than 1 to 100 mg/l), heavy metal (0.1–100 mg/l for
chrome and 0.2–10 mg/l for lead) and other pollutants. Refineries also generate solid wastes and sludges
(ranging from 3 to 5 kg per ton of crude processed), 80% of which may be considered hazardous because of
the presence of toxic organics and heavy metals. Accidental discharges of large quantities of pollutants can
occur because of abnormal operations in a refinery and potentially pose a major local environmental hazard
(Sharma 2009).
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2. Journal of Natural Sciences Research
ISSN 2224-3186 (Paper) ISSN 2225-0921 (Online)
Vol.3, No.11, 2013
www.iiste.org
Lead poisoning in humans, documented ages ago in ancient Rome, Greece, and China (Goyer & Chisolon
1972), can affect almost every organ and system in the body. It may cause severe damage to the kidneys,
reproductive system, liver, and brain. Severe exposure to lead is also associated with sterility, abortion, stillbirth,
and neonatal deaths. Like mercury, Pb is a potent neurotoxin that accumulates in soft tissues and bone over
time. It can damage nervous connections (especially in young children) and associated with delayed puberty
in girls (John et al. 1998). Lead exposure has been linked to learning disabilities (Singh & Stapleton 2002) and
has been shown many times to permanently reduce the cognitive capacity of children at extremely low levels
of exposure and there no detectable lower limit, below which lead has no effect on cognition (Sharma 2009).
Lead exposure causes blood and brain disorders, weakness in fingers, wrists, or ankles, small increases in
blood pressure, particularly in middle-aged and older people as well as anemia. Exposure to high lead levels
can severely damage the brain and kidneys in adults or children and ultimately cause death. In pregnant
women, high levels of lead exposure may cause miscarriage. Chronic, high-level exposure in men can damage
the organs responsible for sperm production (Sharma 2009). Most cases of adult elevated blood lead levels are
workplace-related (Subijoy 2002). In the human body, lead inhibits porphobilinogen synthase and
ferrochelatase, preventing both porphobilinogen formation and the incorporation of iron into protoporphyrin
IX, the final step in heme synthesis. This causes ineffective heme synthesis and subsequent microcytic anemia.
At lower levels, it acts as a calcium analog, interfering with ion channels during nerve conduction, a
mechanism by which it interferes with cognition (Shree & Tripathi 2007; Stellman et al. 2008). Not only
humans, but also microorganisms are subjected to metals toxicity due to displacement of essential metals from
their native binding sites. Metals can bind to functional groups of biological molecules with varying affinities,
and can be classified as either hard or soft (Gadd 2007). Pb (soft metal) is a large cation, very polarizable due
to their large number of electrons (Hughesm & Pooler 1989) and preferentially bind to legends containing
sulfur such as sulfhydryl (-SH2) groups found in protein. Toxicity of Pb is a consequence of its ability to
interfere with several enzymes. Lead has been reported to inhibit acidogenisis, nitrogen transformation or
litter decomposition but have stimulatory effects on methanogenisis in anoxic salts sediments (Capone et al.
1997).
Thus, it becomes mandatory to remove lead from drinking and wastewaters. However, the conventional methods
have some disadvantages such as incomplete removal, high reagent and energy requirements, and generation of
toxic sludge or other waste products that require disposal. A variety of methods, e.g. precipitation, coagulation,
ion-exchange membrane processing, and electrolytic technologies are used to remove these toxic substances
from effluents and industrial wastewater. The search for alternative and innovative treatment techniques has
focused attention on the use of biological materials such as algae, fungi, yeast, and bacteria for the removal and
recovery technologies. This has gained importance during the recent years because of the better performance and
low cost of such biological materials. Bio-sorption presents an alternative to traditional physicochemical means
for removing toxic metals from ground waters and wastewaters.
Remediation of metals often involves five general approaches: isolation, immobilization, mobilization,
physical separation, and extraction. A combination of more than one approach may be used to properly treat
metal-contaminated sites. This combination can be cost-effective (Evanko & Dzombak 1997; Raskin & Ensley
2000; NABIR 2003; Gadd 2007). Microorganisms reduce metals when utilizing them as terminal electron
acceptors for anaerobic respiration. Microbial methylation such as transformation of lead to dimethyl lead
observed in various contaminated environment especially soil plays an important role in the biological cycle
of the metal because methylated compounds are often volatile (Pongratz & Heumann 1999). The ability of
bacteria to degrade, accumulate or transform a variety of organic and inorganic compounds is remarkable and
has been used in waste processing and bioremediation (Singh & Ward 2004; Atlas & Philip 2005). Many
microorganisms are capable of adsorbing metal ions from aqueous solution even with dead cells (Brady &
Duncan 1994). Microorganism may uptake metals through either fast, unspecific route (driven by chemoosmotic gradient across the cytoplasmic membrane of bacteria) or slow, highly specific route that often uses
ATP hydrolysis as an energy source and is only produced by cell in time of need. Pb is uptaken through
specific slow route to inside the cell (Fagan & Saier 1994). The outer membrane of Gram-negative bacteria
such as Pseudomonas effectively complexes metals including calcium, nickel and lead (Beveridge & Doyle
1989).
It was documented that some members of the genus Pseudomonas are able to metabolize chemical pollutants,
therefore, can be used for bioremediation. Biodegradation abilities were shown for polycyclic aromatic
hydrocarbons by P. alcaligenes (Riis et al. 1998), toluene by P. mendocina and P. putida (Diane & Katherine
1994; Wild et al. 1996), carbazole by P. resinovorans (Atlas & Philip 2005), a variety of simple aromatic
organic compounds by P. veronii (Singh & Ward 2004) and carbon tetrachloride by P. stutzeri strain KC.
Moreover, P. pseudoalcaligenes was found able to use cyanide as a nitrogen source (Juana & Edward 1998).
In the present study three Pseudomonas spp. were investigated on individual and mixed cultures basis for
113
3. Journal of Natural Sciences Research
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Vol.3, No.11, 2013
www.iiste.org
biosorption of lead from contaminated wastewater of an oil refinery, Alexandria, Egypt before discharging
into open environments.
2. Materials & Methods
2.1 Microorganisms
Three different bacterial species of Pseudomonas {Pseudomonas florescence (PF), Pseudomonas
paucimobilis (PP), Pseudomonas sp (PQ)} were kindly provided by IGSR (Institute of Graduate Studies &
Research, Alexandria University) collection. They were originally isolated from heavily polluted wastewater
and environments and exhibited superior ability for organic matter and heavy metals remediation (El-Bestawy
2005; El-Bestawy & Ibrahim 2005). In the present study, they were used as individual and mixed culture
(Pmix) for batch bioremediation of Pb-contaminated wastewater from an oil refinery, Alexandria-Egypt.
2.2 Samples
Samples were collected from water-oil separator (physical treatment unit) of an oil refinery located in
Alexandria, Egypt before entering any biological treatment.
2.3 Media and Incubation Conditions
Dehydrated nutrient broth (NB) and agar (NA) used during the present study were supplied by HIMEDIA. NB
medium contained (g/l) peptic digest of animal tissue, 5.0; sodium chloride, 5.0; yeast extract, 1.50 and beef
extract, 1.50 with 15.0 g/l agar in case of NA medium. They were prepared by dissolving 13.0 and 28.0 g/l
from NB and NA dehydrated media respectively. Media pH was adjusted to 7.4, sterilized by autoclaving at
121ºC for 20 min and freshly used for growth experiments as well as bioremediation assays.
2.4 Lead Bioaccumulation
For each species one loop-full of cells were transferred from a fresh slant culture into 50-ml NB placed in a
100-ml conical flask, three replicates each. After inoculation, flasks were incubated under 30°C ± 1 and 120
rpm for 48 hours to allow entering the log phase and getting enough bacterial growth. Nine 250-ml
Erlenmeyer flasks containing 50 ml distilled water each with 50 mg/l Pb (II) ion was inoculated with 5% (v/v)
of each of the bacterial inocula and incubated under the same conditions. Samples were collected at 24 h
interval for 7 days. After collection, samples were centrifuged at 4000 rpm for 20 minutes where bacterial
pellets were discarded. Residual concentration of lead present in the clear supernatant was determined using
Atomic Absorption Spectrophotometer (Varian spectraAA200). The percent metal accumulated was taken to
be the difference between the control and the final concentration of metal in the supernatant.
2.5 Bioremediation Bioassay
Selected bacterial candidates (PP, PF and PQ) were employed in a final volume of 500 ml and run with
different ratios of the bacterial inocula (B) and the contaminated wastewater (W) in the following
arrangements:
1- 1:1 Oily Wastewater : Bacteria {250 ml (W) + 250 ml (B)}
2- 2:1 Oily Wastewater : Bacteria {333.3 ml (W) + 166.7 ml (B)}
3- 1:2 Oily Wastewater : Bacteria {166.7 ml (B) + 333.3 ml (W)}
For each flask, 5% (v/v) inoculum from 24 h old culture was used. Thus, in case of 250 ml bacterial
suspension, 12.5 ml from the pre-grown culture was taken and completed with 237.5 ml nutrient broth (NB).
Similarly, with the other ratios when 166.7 ml bacterial suspension is needed 8.3 ml from 24-h culture is
added to 158.4 ml NB and in case 333.3 ml bacterial suspension 16.66 ml from pre-grown culture was
inoculated in 316.6 ml NB. In addition a 500 ml-bottle was used as a control sample (blank) and run along
with other cultures. It contains 250 ml oily-wastewater and 250 ml nutrient broth (NB) free of bacteria.
Treated effluent was sampled for 7 days (24 h interval), then residuals of Pb and organic matter (BOD and
COD) were determined at each exposure time and their removal efficiency were calculated to determine the
effectiveness of the remediation process.
2.6 Analysis of the Raw and Treated Industrial Effluent
2.6.1 Determination of Lead
Concentration of lead in the raw as well as treated samples was determined using an atomic absorption
spectrophotometer (Varian Spectra AA200). Sometimes raw concentrated samples had to be diluted and other
times synthetic wastewater was prepared when oil samples were not available.
2.6.2 Determination of Petroleum Oil
Oil contents in wastewater samples were extracted using trichloroethane and determined by colorimetric
method using Hack spectrophotometer (Hack DR 2000) at 450 nm wavelength.
2.6.3 Biochemical Oxygen Demand (BOD5)
Method 5210 B was used for BOD5 determination as described in the Standard Methods for Examination of
Water and Wastewater (Clesceri et al. 1999). BOD5 can be calculated as follows:
114
4. Journal of Natural Sciences Research
ISSN 2224-3186 (Paper) ISSN 2225-0921 (Online)
Vol.3, No.11, 2013
www.iiste.org
BOD5 (mg/l) =
D1− D 2
P
Where D1 = DO of diluted sample immediately after preparation in mg/l,
D2 = DO of diluted sample after 5- day incubation at 20 °C in mg/l,
P = Decimal volumetric fraction of sample (300 ml).
2.6.4 Chemical Oxygen Demand (COD)
Closed Reflux Colorimetric Method 5220 D was used for COD determination using potassium dichromate as
chemical oxidant as described in the Standard Methods for Examination of Water and Wastewater (Clesceri et
al. 1999). Colour developed in the samples as well as blank and standards was measured at 620 nm using
DR/5000 HACH spectrophotometer and the concentration was calculated from the slope of the standard curve.
3. Results
Bioremediation assays were run with three different oily wastewater/bacteria ratios (1:1, 2:1 and 1:2). At each
batch, residual concentration (RC) of the selected parameters (Pb, oil content, BOD and COD) were
determined and their removal efficiencies (REs %) were calculated. Since time of sampling was different at
the different applying wastewater/bacteria ratios, the initial concentrations (Zero Time) of the tested
parameters were different. Regardless bacterial strains, there was a general trend where REs % of all the
tested parameters were proportionally correlated with exposure time reaching the highest removals at the end
of experiment duration (7 days). Also, at each wastewater: bacteria ratio, clear variation was achieved among
the tested species.
3.1 Removal of Lead
Oil wastewater samples were drawn from the API separator (oil-water separation basin) and were tested for the
presence of Pb ion that showed varied concentrations according to the production and operational scheme. Only
samples with high Pb concentration were collected and subjected to bioremediation using the tested bacteria,
otherwise, synthetic wastewater with the required Pb content was prepared and used. Initial lead concentrations
in the contaminated effluent ranged between 94 and 307.9 mg/l during sampling time, which considered quite
high levels if reached any water source. Comparison of lead removal among the tested Pseudomonas spp.
either as individual or mixed cultures during the experiment duration at the tested wastewater/bacteria ratios
(Table 1 and Fig. 1) revealed the following points:
1. As individuals, PF considered the most efficient (90.3%) followed by PP (74.7%) and finally PQ (45.0%)
with the lowest efficiency.
2. The individual cultures of the tested bacteria were most efficient at wastewater/bacteria ratios of 1:1 for
strain PF, 1:2 for strain PQ and at 2:1 for strain PP.
3. However, according to the maximum permissible limit (MPL) of Pb stated by the Egyptian Environmental
Law (48/1982), none of the cultures reached safe limit (0.05 mg/l) for discharging the effluent. A range of
13.7-25.5 mg/l was recorded as the lowest RC of the Pb after seven treatment days, which is equivalent to
274-510 folds higher than MPL of Pb.
4. Using a mixed culture of the 3 tested species remarkably enhanced Pb removal especially at the highest
investigated Pb concentration (307.9 mg/l) reaching 90.97% RE (27.8 mg/l). Such result highly
recommends using of the mixed culture especially when handling highly contaminated effluents in
addition to either increasing the exposure time or doubling the inoculum size to reach acceptable limits for
safe discharge
3.2 Removal of COD
COD values ranged between 700 and 720 mg/l in the raw wastewater samples. COD removal using the
selected bacteria concluded the following points: the least efficiency (19.4%) all after 7 exposure days.
1. At 1:1 wastewater/bacteria ratio (Fig. 2A), PP showed the highest COD removal (30.55%) followed by PQ
(22.22%) and finally PF with the least efficiency (19.4%) all after 7 exposure days.
2. At 1:2 wastewater/bacteria ratio (Fig. 2B), PF showed the highest COD removal (30.98%) with almost no
significant difference with PP (30.28%) and finally strain PQ (23.94%) after seven
115
5. Journal of Natural Sciences Research
ISSN 2224-3186 (Paper) ISSN 2225-0921 (Online)
0921
Vol.3, No.11, 2013
www.iiste.org
Table 1. Comparison of Residual Concentrations (RC) of Pb (mg/l) and the Highest Removal Efficiency
(RE %) Using Pseudomonas spp. Cultures at Different Wastewater/Bacteria Ratios
Exposure
Time
(Days)
0
1
2
3
4
5
6
7
RE%
3.
4.
5.
6.
7.
1 :1
141
121
9 2 .8
7 2 .3
6 0 .4
5 3 .7
4 8 .2
4 6 .3
6 7 .2
PP
1 :2
9 4 .0
8 7 .1
6 4 .5
4 1 .7
3 6 .4
3 3 .1
2 8 .6
2 5 .5
7 2 .9
2 :1
188
181
140
8 4 .6
7 1 .4
6 3 .2
5 1 .3
4 7 .5
7 4 .7
1 :1
141
129
9 2 .6
6 9 .1
3 4 .6
2 6 .1
2 0 .3
1 3 .7
9 0 .3
PF
1 :2
94
8 7 .3
6 2 .6
5 8 .4
3 6 .8
3 2 .8
2 6 .7
2 5 .5
7 2 .9
Bacterial Culture
PQ
2 :1
1 :1
1 :2
1 8 8 1 4 1 .0 9 4 .0
1 6 8 1 3 0 .0 8 3 .0
1 2 8 1 2 0 .0 6 4 .0
6 4 .7 1 0 9 .0 5 6 .0
5 2 .0 1 0 5 .0 5 5 .6
3 4 .8 1 0 4 .2 5 4 .3
2 6 .7 1 0 1 .0 5 4 .0
2 5 .5 1 0 0 .7 5 1 .7
8 6 .4 2 8 .5 8 4 5 .0
2 :1
188
1 6 9 .0
1 5 1 .0
1 4 5 .3
1 3 1 .2
1 2 8 .2
1 2 3 .7
1 2 0 .3
3 6 .0 1
1 :1
2 3 0 .9
2 2 8 .1
2 1 5 .6
1 5 6 .4
1 3 4 .1
1 2 7 .3
1 2 0 .5
117
4 9 .3 3
P Mix
1 :2
154
153
152
143
134
113
106
103
3 3 .1
2 :1
3 0 7 .9
3 0 4 .3
2 5 9 .7
8 6 .8
7 3 .5
5 6 .7
3 3 .9
2 7 .8
9 0 .9 7
Blank
1 :1
2 3 0 .9
1 8 0 .6
1 6 8 .4
1 3 1 .6
43%
Figure 1. Comparison of Biological Lead Removal among Pseudomonas Cultures
exposure days. At this ratio although PP had no efficiency change compared to the first
wastewater/bacteria ratio (1:1) but the other 2 (strains PF in particular) exhibited significant increase in
COD RE%. These results confirmed the influence of the inoculum size of those strains where higher
bacterial densities have led to enhancement in their biodegradation capabilities.
e
At 2:1 wastewater/bacteria ratio (Fig.2C), COD removal by all the tested strains was significantly reduced
io
,
recording 19.72% as the highest RE by PQ after 7 days followed by 16.90 and 14.08% by PP and PF
respectively at the same exposure. This is mainly attributed to the toxicity of the wastewater components
when the amount was doubled.
Using the mixed Pseudomonas spp. culture (PMix) (Fig. 3) achieved COD removal ranged between a
maximum of 26.39% and a minimum of 19.72% at wastewater/bacteria ratios of 1:2 and 2:1 respectively.
PP was the most active for COD degradation at all the tested wastewater/bacteria ratios while PMix
he
culture showed relatively lower REs% compared to individual cultures especially at 1:1 and 1:2 ratios.
Wastewater/bacteria ratio of 1:2 considered the best choice for COD removal by individual or mixed
cultures due to the presence of enough bacterial cells performing the degradation process.
o
The lowest recorded RC of COD recorded 490 and 495 mg/l achieved by PF and PP respectively after 7
mg/l
days at 1:2 wastewater/bacteria ratio. These values are almost 5 fold higher than MPL of COD (100 mg/l).
bacteria
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Figure 2. Removal Efficiency (RE %) of COD Using the Selected Pseudomonas spp.
at (A) 1:1; (B) 1:2 and (C) 2:1 Wastewater/Bacteria Ratios
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Figure 3. Removal Efficiency (RE) of COD Using the Mixed Culture of
Pseudomonas spp. (PMix) at Different Wastewater/Bacteria Ratios
3.3 Removal of BOD
BOD levels in the raw contaminated effluent ranged between 482 and 887 mg/l. BOD removal using
D
Pseudomonas spp. (Fig. 4) revealed the following:
1. Generally, low removals for BOD were recorded. Moreover, due to the high toxicity of wastewater on the
tested bacteria, BOD was increased occasionally compared to that recorded in the raw wastewater (zero
time). These increases are attributed mainly to the death of the involved bacteria, which in turn increased
the organic load (BOD).
2. RE of the BOD ranged between a minimum of 0.18% and a maximum of 18.98% both recorded by Pmix
after 5 days at 1:1 and 1:2 wastewater/bacteria ratios respectively. PQ also achieved as high as 18.82% RE
wastewater/bacteria
of BOD after 5 days at 2:1 wastewater/bacteria ratio.
3. Wastewater/bacteria ratio of 1:2 stills the best ratio for organic matter (BOD & COD) removal due to the
highest bacterial density at this ratio to overcome wastewater toxicity. This was confirmed by the very low
s
removal and even BOD increases at the 1:1 and 2:1 wastewater/bacteria ratio.
In conclusion and in addition of being highly promising candidates for Pb removal, Pseudomonas spp. could
remove almost one third of the organic load (BOD & COD) which is definitely an additional advantage.
Figure 4. Removal Efficiency (RE) of BOD Using the Selected Pseudomonas spp.
at Different Wastewater/Bacteria Ratios
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3.4 Removal of Oil
Removal of oil by the tested bacteria was investigated at two concentrations 25 and 500 mg/l at different
wastewater/bacteria ratios and exposure time.
3.4.1
At Low Oil Concentration (25 mg/l)
Oil content in the wastewater was adjusted at 25 mg/l that was modified to 12.5, 8.33 and 16.7 mg/l due to the
dilution in 1:1, 1:2 and 1:3 wastewater/bacteria ratio respectively. Comparison among the tested bacteria in
the removal of crude oil at its lowest (25 mg/l) applied concentration (Table 2 and Fig. 5A) revealed the
following points:
1. PF showed the highest oil RE (56.8%) followed by PP (53.6%), Pmix (43.2%) and finally PQ (35.0%) all
after 7 exposure days.
2. Again, the highest RE of oil took place at 1:2 followed by 1:1 wastewater/bacteria ratio while the lowest
oil RE by all the tested bacteria was recorded at 2:1 wastewater/bacteria. This is mainly attributed to the
toxicity of the wastewater, which is magnified when small bacterial inoculums size is used (2:1).
3. However, control sample (bacteria-free wastewater) showed extremely low oil removal (4.0%) after seven
exposure days confirming the efficiency of the augmented species for oil biodegradation.
4. According to MPL of the crude oil (5 and 10 mg/l) in wastewater discharged into fresh/ground water and
fresh surface water respectively stated by law, the treated wastewater had lower recorded RC (3.6 mg/l)
and can be safely discharged.
3.4.2. At High Oil Concentration (500 mg/l)
Oil content in the wastewater was adjusted at 500 mg/l that was modified to 250, 166.7 and 333 mg/l due to
the dilution in 1:1, 1:2 and 1:3 wastewater/bacteria ratios respectively. Comparison among the tested bacteria
in the removal of crude oil at its highest applied concentration (Table 3 and Fig. 5B) revealed the following
points:
1. Increasing oil concentration 20 folds significantly enhanced oil RE due to the induction of the required
enzymes. Again PF showed the highest RE of oil (68.8%), followed by PP (64.1%), Pmix (56.8%) and
finally PQ (55.3%) all after 7 days.
2. At this oil concentration, all the highest removals were achieved at 1:2 wastewater/bacteria ratio
confirming the importance of bacterial size or density during the treatment process.
3. Control wastewater also showed enhancement in oil removal (32.0%) after seven exposure days.
4. The lowest recorded RC (52.0 mg/l) is slightly (5.2-10.4 fold) higher than the MPL. To reach acceptable
discharging limits, wastewater can be treated using fixed bacteria in a continuous system, which can
greatly enhance bacterial performance for either biodegradation and/or accumulation of organic and
inorganic contaminants.
Table 2. Residual Concentration (mg/l) and Removal Efficiency of Crude Oil in the Raw and Treated
Wastewater at Different Wastewater/Bacteria Ratios at the Lowest Tested Oil Level
Exposure
PP
PF
PQ
Pmix
Blank
Time
1 :1
1 :2
2 :1
1 :1
1 :2
2 :1
1 :1
1 :2
2 :1
1 :1
1 :2
2 :1
1 :1
(Days)
0
1 2 .5 8 .3 3 1 6 .7 1 2 .5 8 .3 1 6 .7 1 2 .5
8 .3 1 6 .7 1 2 .5
8 .3 1 6 .7
1 2 .5
1
1 2 .2 8 .1 1 6 .1 1 2 .3 7 .1 1 6 .2 1 2 .5
7 .9 1 6 .4 1 2 .4
8
1 6 .2
1 2 .5
3
5
1 1 .6
8 .6
7 .8
7 .1
1 4 .9
1 3 .8
1 1 .9
9 .7
6 .3
5
15
1 3 .9
1 2 .3
1 2 .1
7 .1
6 .2
1 5 .9
1 5 .4
1 1 .9
9 .8
7 .5
6 .8
1 5 .3
1 4 .2
1 2 .5
1 2 .2
7
RE%
5 .8
5 3 .6
6 .4
2 3 .2
1 2 .6
2 4 .4
7 .1
4 3 .2
3 .6
5 6 .8
1 2 .7
2 3 .8
12
4 .0
5 .4
3 5 .0
1 4 .8
1 1 .2
7 .1
4 3 .2
6 .2
2 5 .6
1 3 .2
2 0 .8
1 2 .0
4 .0
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and domestic wastewater into aquatic ecosystems. Metal as well as oil pollution in aquatic ecosystems is well
known as a serious environmental and public problem. Conventional methods for the removal of heavy metals
from wastewaters are often costly and less efficient, therefore, biological removal considered as a cheap
treatment method, which proved high capability for pollutants removal.
The three promising Pseudomonas bacterial candidates (PP, PF and PQ) used in the present study were selected
according to their high ability for the removal of organic and inorganic pollutants (El-Bestawy et al. 2005).
Genus Pseudomonas includes the opportunistic human pathogen P. aeruginosa, plant pathogenic bacteria,
plant beneficial bacteria, ubiquitous soil bacteria with bioremediation capabilities and other species that cause
spoilage of milk and dairy products. P. fluorescens (PF), one of the present bacterial selections has multiple
flagella indicating high motility. It has an extremely versatile metabolism, and can be found in the soil and in
water. It is an obligate aerobe, but certain strains are capable of using nitrate instead of oxygen as a final
electron acceptor during cellular respiration. Optimal temperatures for growth of P. fluorescens are 25-30 ºC.
It tests positive for the oxidase test. P. fluorescens is also a non-saccharolytic bacterium. Heat-stable lipases
and proteases are produced by P. fluorescens and other similar pseudomonades (Riis et al. 1998). During the
present study, the selected Pseudomonas spp. showed superior ability to bioaccumulate Pb and biodegrade crude
oil from the contaminated effluent and use it as a source of carbon and energy. In addition, they could remove
one third of the organic load (BOD & COD) which considered lower efficiency compared to the removal of Pb
and oil but it is definitely an additional advantage in the present case. The rate of their metabolism for
contaminants removal from contaminated media either synthetic or raw industrial effluent was found to be a
function of bacterial species, contaminants concentration, and ratio of wastewater: bacteria used and finally
exposure time. The marvelous resistance and superior potentiality of Pseudomonas for biodegradation of toxic
organic pollutants and biosorption of heavy metals have been extensively proved by many authors (Aislabie &
Lloyd 1995; De Souza et al. 1998; El-Bestawy & Ibrahim 2005; El-Bestawy & Albrechtsen 2007).
Considerable variations were detected in Pb removal by the individual cultures of the tested bacteria according to
bacterial species and wastewater/bacteria ratios but they all showed their maximum removal at the last exposure
day. In that respect, PF considered the most efficient followed by PP and finally PQ with the lowest efficiency.
They were most efficient at wastewater/bacteria ratios of 1:1 and 2:1 (strain PF) and at 1:2 (PP and PQ). Using a
mixed culture (3 tested species) remarkably enhanced Pb removal especially at the highest investigated Pb
concentration (307.9 mg/l) reaching 90.97% RE (27.8 mg/l). A range of 13.7-25.5 mg/l was recorded as the
lowest RC of the Pb after seven treatment days using the tested bacteria, which is 274-510 fold increase in the Pb
content allowed for safe discharge (0.05 mg/l).
These results are in agreement with other workers (Srivastava & Majumder 2008) where growth of three
freshwater microalgae {Phormidium ambiguum (Cyanobacteria), Pseudochlorococcum typicum and
Scenedesmus quadricauda var quadrispina (Chlorophyta)} was enhanced (chlorophyll a and protein) at lower
concentrations of Pb2+ and Cd2+ (5–20 mg/l) while elevated concentrations (40–100 mg/l) were inhibitory. The
highest bioremoval of Pb2+ (70%) was achieved by P. typicum within the first 30 min exposure (Foster 1982).
Comparing with the present results showed that the selected Pseudomonas spp. exhibited much higher
bioremoval efficiency especially at much higher Pb concentration (307.9 mg/l) which is more than three folds
the highest tested concentration in Foster's study.
The Neem tree leaves, known for its drought metals resistance could remove 76.8, 67.5, 58.4 and 41.45% for
Cu2+, Ni2+, Zn2+ and Pb2+ ions respectively from synthetic wastewater after 120 minutes (Emmanuel & Thomas
2009). Again, Pseudomonas spp. in the present showed higher Pb removal in addition to minimizing organic
content of the effluent. These results confirmed that biosorption is an effective and versatile method and can be
easily adopted at low cost to remove heavy metals from industrial wastewaters.
Among the tested strains applied as individuals, Pseudomonas paucimobilis (PP) was the most active for COD
degradation (30.55%) at all the tested wastewater/bacteria ratios. On the other hand, mixed Pseudomonas culture
showed relatively lower REs% compared to individual cultures especially at 1:1 and 1:2 ratios. These results
confirmed the influence of the inoculum size of those strains where higher bacterial densities have led to
enhancement in their biodegradation capabilities. The lower COD efficiency is mainly attributed to two factors;
first, most of the metabolic energy was directed towards Pb removal. Second, Pseudomonas spp. showed high
efficiency for crude oil even at its very high concentration tested where they used crude oil as the main carbon
and energy source while using other organic content in the effluent as secondary source in a co-metabolic
metabolism. Dincer et al. (2008) reported that batch oxidation reactions using H2O2/Fe+2 could achieve 86%
COD reduction (from 21000 to 2980 mg/l) in 60 minutes. To achieve this removal 200.52 g/l H2O2 and 23.16
g/l Fe+2 concentrations were used to reach an optimal mass ratio of 8.658 g. Using UV/H2O2 recorded lower
(39%) COD reduction (from 21000 to 12730 mg/l). Although higher COD removal could be achieved using
chemical oxidation, huge amount of chemicals (H2O2 and Fe+2) are required especially for the treatment of
highly contaminated oil recovery industrial wastewater.
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Generally, low removals for BOD were recorded and may even increase compared to the initial raw wastewater
value due to death of the tested bacteria because of the high toxicity of wastewater, which in turn increased the
organic load. RE of BOD ranged between a minimum of 0.18% and a maximum of 18.98%. Wastewater/bacteria
ratio of 1:2 still the best ratio for organic matter (BOD & COD) removal due to the highest bacterial density at
this ratio which is partially overcome wastewater toxicity. Although the cost of removing BOD/COD through
chemical oxidation with hydrogen peroxide is typically greater than that through physical or biological means, it
has an advantage of high efficiency of BOD and COD removal. However, H2O2 considered high cost treatment.
In addition, the residual hydrogen peroxide in the sample will liberate oxygen over the test period, resulting in a
"false low" BOD value (1 mg/l H2O2= 0.5 mg/l DO). In the standard COD test, residual hydrogen peroxide will
react with the potassium dichromate reagent, resulting in a "false high" COD value (Steiner 1992). Although
high organic matter (BOD & COD) removal can be achieved through chemical oxidation, such reactions
considered costly and add huge amount of chemicals into the environment, a character that must be avoided to
keep the ecosystem balance. Biological treatment overcomes such disadvantages since no chemicals are used;
instead, naturally occurring microorganisms are employed that possess high metabolic activity to deal efficiently
with the included contaminants.
Pseudomonas florescence (PF) considered the most active in oil removal at the lowest and highest tested
concentration (25 and 500 mg/l respectively). Significantly, higher removals were recorded at the highest tested
oil concentration, which is mainly attributed to the active induction of more enzymes upon increasing oil
concentration 20 folds, which in turn enabled the tested bacteria to degrade and remove more oil achieving
higher efficiencies. At both concentrations, the highest REs of oil took place at 1:2 wastewater/bacteria ratio due
to the high bacterial density while the lowest REs were achieved at 2:1 wastewater/bacteria ratio due to the
toxicity of the wastewater. Augmented species showed significantly higher oil removal at the tested oil levels
compared to bacteria-free wastewater. Such bacteria were able to bring oil content in the wastewater at both
concentrations tested to levels below its MPL. In a similar study, bulked soil with indigenous or augmented
microbial flora showed more rapid degradation of oil compared to all other amendments. During the
experimental period (90 day), wheat bran-amended soil showed 76% hydrocarbon removal compared to 66% in
the case of inorganic nutrients-amended soil associated with increase in the number of bacterial populations was
also noticed. Addition of the bacterial consortium in different amendments significantly enhanced the removal of
oil from the petroleum sludge at the different treatment units (Rajaram & Vasudevan 2001). Although good
removal efficiency for oil from soil was obtained, a very long duration (90 day) of time was required compared
to the 7 days required in present study to achieve similar results.
Microorganisms are capable of degrading different types of hydrocarbons. Each organism has a preference kind
of hydrocarbon and may have a spectrum of optimal degradation activity among related hydrocarbons. Generally,
the aerobic degradation of simple aromatic compounds follows different metabolic pathways based on the
enzyme system present in the microorganisms. Biodegradation of phenol, for example, is initiated by the
formation of catechol, which later undergoes ring cleavage via either meta fission (Hermann et al. 1995) or ortho
fission (Ahamad & Kunhi 1996) to intermediates of the central metabolism. On the other hand, five different
biochemical pathways have been characterized for BTEX degradation by aerobic bacteria (Cerniglia 1992).
Among microorganisms, bacteria are usually the choice for bioremediation technology because they have more
rapid metabolic rates and numerous metabolic pathways of various organic pollutants have been determined in
bacteria. Bacterial genera including Pseudomonas, Aeromonas, Bacillus, Flavobacterium, Corynebacterium,
Micrococcus etc. were reported for their ability to degrade oil hydrocarbon. Previous observations have
identified the Pseudomonas genus as most efficient among hydrocarbon degrading microorganisms.
Pseudomonas aeruginosa was the most active hydrocarbon utilizer in crude oil and tolerating high
concentrations (up to 50% v/v) of crude oil. It was able to utilize compounds such as aliphatic and monoaromatic hydrocarbons as well as alcohols as substrates (Das & Chandran 2011). In a recent study, Pseudomonas
stutzeri was the most efficient and cost-less in the degradation of petroleum hydrocarbons (ALGodah 2012).
Enhanced oil degradation, particularly high-molecular-weight n-alkanes and alkylated PAHs, suggesting an
increase in the microbial bioavailability of these compounds (Kasunga & Aitken 2000).
5. Conclusion
The selected Pseudomonas spp. exhibited high efficiency for removing Pb (90.97%) and oil (56.8 and 68.8%
from initial oil concentrations 25 and 500 mg/l respectively) during remediation of oil refinery wastewater. In
addition, partial removal of COD (30.98%) and BOD (18.98%) was achieved. Pseudomonas florescence (PF)
was the most active reaching the highest removal of Pb, oil and COD during the experimental period while Pmix
and PQ showed the highest BOD removal. Wastewater: bacteria ratio of 1:2 was the most convenient where
amount and density of bacteria was doubled compared to the wastewater helping to efficiently handle the
treatment and increasing removal efficiency. On the other hand, using 2:1 wastewater/bacteria ratio was the
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least suitable and was inhibitory in most cases due to high toxicity exerted on the augmented bacteria, which
is magnified when small bacterial inoculums size is used. In addition, the short period of the treatment (7 days)
considered behind the unacceptable limits of the tested parameters for safe discharge. Therefore, results highly
recommend using Pseudomonas spp, especially Pseudomonas florescence (PF) can be manipulated as efficient,
low cost remediation method in oil refineries and similar industries where metallic and organic contaminants are
available. To overcome being not compile with law and to reach acceptable discharging limits wastewater can be
treated using fixed Pseudomonas florescence in a continuous system, which can greatly enhance bacterial
performance for biodegradation of organic and accumulation of inorganic contaminants.
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