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International Journal of Applied Engineering Research ISSN 0973-4562 Volume 13, Number 24 (2018) pp. 16825-16832 © Research India Publications. http://www.ripublication.com of Groundwater: An Overview

Shivam Mani Tripathi 1, Shri Ram2 1 ,2 Civil Engineering Department, MMMUT Gorakhpur, India

Abstract can be treated on site, thus reducing exposure risks for clean- In past, we have large open area and abundant land resources up personnel, or potentially wider exposure as a result of and groundwater. But after the industrialization the use of transportation accidents. Methodology of this process is not hazardous chemicals increased due to unmanageable technically difficult, considerable experience and knowledge conditions. The chemical disposed on the ground surface & may require implementing this process, by thoroughly many other anthropogenic activities by humans like use of investigating the site and to know required condition to and oil spillage contaminated the and achieve. groundwater. The different type of contaminant by percolation The usual technique of remediation is to plow up through the ground reach to the aquifer and get affected which contaminated soil and take away to the site, or to cover or cap causes serious problem. We spend lot of money and use many the contaminated area. There are some drawbacks. The first technologies to extract and remediate the . In method simply the contaminated materials which spite of different methods, bioremediation is a technology create major risks is excavation, handling, and transport of which is cost efficient and effective by using natural microbes hazardous material. It is very difficult to find the new and degrades the contaminants the conditions and different sites for disposal. The cover or cap method is only temporary bioremediation technologies like in-situ, ex-situ, solution whereas contaminants remain on site which requires technology are described. Some monitoring and maintaining the engineered barrier for a long contaminates like LNAPLS, DNAPLS, BTEX, TCE, time which increase the cost and the liabilities. The superior etc. also briefly described. The different sources, & and advanced methods than those previous methods which condition & technologies of remediation are also discussed. completely eliminate the or least transformation to innocuous substances. Some technologies that have been used INTRODUCTION are high-temperature and various types of chemical decomposition (e.g., base-catalyzed de-chlorination, Water beneath the ground which saturates the pores of UV oxidation). They can be very effective at reducing levels subsurface is known as groundwater. Huge populations of of a range of contaminants, but have several drawbacks, world depend upon the groundwater as the source of their principally their technological complexity, the cost for small- livelihood. About 1.69 percent of total water present in ground scale application, and the lack of public acceptance, especially are highly mineralized groundwater they don’t require much for incineration that may increase the exposure to treatment before use. They get filtered and mineralized by contaminants for both the workers at the site and nearby their movement in ground. But after industrialization and residents. increase in anthropogenic activity of human, many industrial effluents percolate the ground and reach to the water table which contaminates the groundwater some chemicals like FACTORS OF BIO-REMEDIATION Methyl Tert-Butyl Ether (MTBE), Benzene, , and the three xylene isomers (BTEX),etc. percolates to the Bio-remediation is a complex method to optimize this method groundwater and causes serious problem there are some heavy it requires several factors to work in appropriate manner metals like chromium, environmental factors such as pH, temperature, type of soil, presence of etc. These conditions required to , , cobalt, , can cause various biological growth of micro-organism which treat the disease such as cancer, cardiovascular and neurological contamination is control manner. Some of the factors and diseases etc. for extraction or treatment of these contamination acceptable condition on which bioremediation work are world are using different techniques and investing million shown below in Table1: billions of money. Bioremediation is the one of the technique by which we can easily and feasibly extract or treat such type Table 1: Factors of Bioremediation of contamination. It is a process by which organic wastes are biologically degraded under controlled conditions to a mild Factors Required Condition state, or to levels below concentration limits established by Micro-organism Aerobic and Anaerobic regulatory authorities for bioremediation to be effective; Biological Process Catabolism and Anabolism must enzymatically attack the pollutants and alter them to harmless products. Bioremediation can be Environmental Temperature, pH, Oxygen content, successful only where environmental conditions allow Factor or donor microbial growth and activity, its purpose often includes the Nutrient Carbon, Nitrogen, Oxygen etc changes in environmental parameters to allow microbial Soil Moisture 25-28% of water holding capacity growth and degradation to proceed at a faster rate. Type of Soil Clay and silty soil Bioremediation techniques are typically more economical than other methods such as incineration, and some pollutants

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Micro-organism can be grown in almost in all environmental Low concentration of contaminants can be directly treated by conditions. Microbes will accumulates and grow at sub zero bioremediation. It is time taking process & it takes about 6 temperature as well as at very high temperature or in water month to a 1 year or more to purify soil containing 2 % of medium or in presence or in absence of oxygen it can be oils, but if the concentration is 0.8 or less percentage of heavy grown in presence of any hazardous compound or is waste oil present it purify within 1 to 2 months. These methods help stream. The presence of carbon source as the energy of in recycling and reuse the soil with some efforts it is a enzyme that can be used to remediate or degrade the environmentally friendly process. contaminants are required for microbial growth. We can subdivide these micro-organisms into following groups: Table 2: Environmental Condition Aerobic like , Alcaligenes, , , and Mycobacterium. These Environmental Optimum Condition required microbes remediate the hydrocarbon and pesticides, both Factors Concentration for microbial alkanes and compounds. Lots of these are the main Activity source of energy and carbon it accumulate in presence of Soil Moisture Water holding 25-28% water oxygen. capacity 25-85% holding capacity Anaerobic are not much use as the aerobic bacteria. pH 6.5-8.0 5.5-8.5 It can be used to bio-remediate the polychlorinated biphenyls (PCBs) in river sediments, dechlorination of the solvent Nutrient C:N:P 120:10:1 N and P for growth (TCE), and chromium. It works in the of microbes absence of oxygen. Temperature 20-30°C 15-45°C Ligninolytic fungi they are use to degrade the Oxygen >0.2 mg/l DO, 10% Aerobic, minimum extremely unlike range of importunate or toxic environmental air-filled pore for air-filled pore pollutants. Common substrates used include straw, saw dust, aerobic degradation space of 10% or corn cobs. Example white rot potential Eh > 50 mill volts Methylotrophs bacteria that utilized methane for 700ppm Total content carbon and energy as their growth source it is an aerobic 2000ppm bacteria. The initial enzyme in the pathway for aerobic Contaminants Hydrocarbon 5-10% Not too toxic degradation, methane mono-oxygenase, has a broad substrate of dry weight of soil range and is active against a wide range of compounds, including the chlorinated aliphatics trichloroethylene and 1,2- dichloroethane Groundwater When the pollutants released on the ground it percolates through different interfaces of ground layer which comes in ENVIRONMENTAL FACTORS contact or mixed with the groundwater table. These substance 1. Nutrient: changes their physical and chemical properties like temperature, pH, color, total dissolve solids (TDS), dissolve The most important element which require in large quantity is oxygen (DO) etc. more than the tolerance limits causes due to Carbon that helps in the growth of microbes. Other than this anthropogenic activity of human or due to release of oxygen, hydrogen and nitrogen and is constituent about 95% chemicals by industries and use different chemicals like of the weight are required. Type of soil and its contamination pesticides in practice. can also helps to decide the type of bioremediation required the occur due to presence of unwanted substance or the impurity concentration of sulfur and phosphorous helps to remediate in the groundwater. the 70% of the contaminants. The nutritional requirement of carbon to nitrogen ratio is 10:1, and carbon to phosphorous is It affects the plume within an aquifer. Dispersion and 30:1 movement of water within the aquifer pollute the large area of the ground. Its advancing boundary, often called plume edge, 2. Soil: which get contacts with groundwater well or springs river etc Concentration of 5% contaminants or more highly into surface water which make water toxic for humans and contaminated water can be treated by passing water to wildlife. Plume front i.e. movement of plume can be analyzed different interface of the soil strata. Interface having active by groundwater model. Soil properties, hydrology, geology agents that partially separate contaminates from the oils. After and nature of contaminants help to analyze the groundwater passing to this, we can set up bioremediation to clean up the pollution. soil. At the experimental stage, this process is only one which Toxicity of groundwater can be illustrated as foreign material turns the contaminated soil into suitable soil for site & present in the groundwater which may have risk to the human landscaping. Many other modifications are applying for or wildlife health. These can be chronicle neurological making this process more effective. disorder or other health issue or psychologically not acceptable by human, it can be further sub divided into two toxicity i.e. acute toxicity and chronic toxicity. Acute toxicity

16826 International Journal of Applied Engineering Research ISSN 0973-4562 Volume 13, Number 24 (2018) pp. 16825-16832 © Research India Publications. http://www.ripublication.com is the toxicity as a result of short term exposure to a toxicant ground and return the treated water to the aquifer. Extraction quantified by LD50. The LD50 is defined as the lethal dose at is done by pumping groundwater from the well or trench and which 50% of the population if killed in a given period of treat them. time; an LC50 is the lethal concentration required to kill 50% of the population. There can be a wide range of tolerance to toxic agents among different populations of a species which should be taken into account. Whereas chronic toxicity is that toxicity as a result of long term exposures to a toxicant which can cause serious issues like carcinogenicity, mutagenicity, teratogenicity problem which can cause death by bio- accumulation. Bioaccumulation is the accumulation of substances, such as pesticides, or other chemicals in an organism. Bioaccumulation occurs when an organism absorbs a substance at a rate faster than that at which the substance is lost by catabolism and excretion. No Observed Effect Level (NOEL), Lowest Observed Effect Level (LOEL) and other are Figure1: Ex-situ Remediation the examples of this. The NOEL (no observable effect level) is the highest dose or exposure level of a substance or material that produces no noticeable (observable) toxic effect on tested In-situ Technology animals. The LOAEL is the lowest dosage level at which chronic exposure to the substance shows adverse effects on In-Situ Technology involves treatment of groundwater within tested animals. the aquifer (in the sub-surface) by using thermal, chemical and biological treatment technology. Involve treatment of It is more difficult to stop groundwater as the surface water groundwater (in-place) without extracting the water from because of movement of groundwater through unseen aquifer aquifer. through a large area. Clayey are non-porous aquifer which partially purifies the water by filtration (adsorption and Some contaminants like DNAPL (Dense Non Aqueous Phase absorption), dilution, and in some cases chemical reaction and Liquids), LNAPL (Light Non Aqueous Phase Liquids), biological activity; some pollutants changes to soil Inorganic Chemicals (Ammonia, Cyanide, and Fluoride), contaminants. Contaminants which percolate through Metals, Bacteria and Virus fractures cannot be filtered and can be easily contact with the DNAPL: Dense Non Aqueous Phase Liquids are organic surface water. compounds heavier than water and having less absolute By using different techniques we can remove the pollutants or solubility. These compounds include chlorinated solvents contaminants. Ground water remediation by using physical, (EDC) and halogenated aromatics (TCB) DNAPLs migrate biological and chemical or the combination of technologies very fast through the soil formation and reach water table we can apply and change the property of contaminated because of their high density and low viscosity. They sink groundwater. Some of the biological treatment techniques steeply to the bottom of the aquifer till they reach the include bio-augumentation, bioventing, biosparging, impermeable bed rock. bioslurping, and phytoremediation. Some chemical treatment LNAPL: Light Non Aqueous Phase Liquids are organic techniques include and oxygen gas injection, chemical compounds lighter than water and having low solubility. precipitation, membrane separation, ion exchange, carbon These liquids include Gasoline, fuel oil and other absorption, aqueous chemical oxidation, and surfactant products. Remediation may require the use of more than one enhanced recovery. Some chemical techniques may be technology. It is likely that several remediation techniques, implemented using nano-material. used in series and/or parallel applications, will be required for maximum contaminant removal. This collaborative effort may be referred to as a treatment train approach.

Pollutant removes or remediates by using physical, chemical and biological or combination of these processes helps to Treatment of DNAPL remediate the water, is said to be groundwater remediation. It The following types of technologies are increasingly being can be sub-divided into two categories ex-situ and in-situ. used to treat DNAPLs: •

• In situ chemical oxidation Ex-Situ Technology • Surfactant/co-solvent flushing Ex-Situ Technology involves treatment of groundwater by • In situ bioremediation dewatering the polluted aquifer (pumping out), then treating • Ground water extraction (P&T or recirculation) the water on surface by Physical, chemical or biological • Excavation containment (Engineered caps and slurry technology and finally re-injecting the treated water to the walls aquifer. Extraction of groundwater from aquifer, treat above

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Figure 2: In-situ Remediation

Table 3: Some DNAPL sources and Treatment Technology Contaminants Main Source Treatment Technology Trichloroethylene Degreasing of Metal and Electronic parts, Pump and Treat (TCE) Extract for oil and waxes, fumigant, carries in Activated Carbon paints and adhesives Thermal and Biological Ammonia Ammonia Storage Tanks, Landfill leaks, Pump and Treat Waste stockpile, etc. Combination of Air Stripping, Nitrification, Ion Exchange.

Bioremediation strategies Bio-venting In-Situ Bioremediation: It is a new in-situ technology which degrades the NAPL aerobically by providing oxygen to the microbes To eliminate the toxic chemicals or substance from the within the soil. By comparing the soil-vapor extraction and subsurface of the ground we setup the biological treatment. To bioventing we get this technology require low air-flow rates to give the appropriate conditions required for the growth of provide only enough oxygen to sustain microbial activity. By microbes and convert the organic matters into toxic less supplying air we can easily provide oxygen to the lasting matter we require the combination of many scientific and contamination in soil through the wells. Adsorbed fuel engineering disciplines. residuals are biodegraded, and volatile compounds also are biodegraded as vapors move slowly through biologically active soil [13]. Biosparging.

Increase the rate of biodegradation of contaminants by naturally occurring microbes. We oxidize the aquifer by Bio-augmentation injecting air under pressure below the water table which The introduction of a group of natural microbial strains or a increase the oxygen concentration and enhance the rate of genetically engineered variant to treat contaminated soil or reaction. It increases the assimilation in the zone of saturation water. It is use to restart the activated sludge process of and thus increases the contact between the groundwater and bioreactor to treat the municipal wastewater. Most cultures soil. The simplicity and optimal cost of setup of small- available contain a research based consortium of Microbial diameter air injection points allow significant elasticity in cultures, containing all necessary microorganisms At sites designing and construction of system.

16828 International Journal of Applied Engineering Research ISSN 0973-4562 Volume 13, Number 24 (2018) pp. 16825-16832 © Research India Publications. http://www.ripublication.com where soil and groundwater are contaminated with chlorinated organic matters degrade by micro-organisms at very high ethenes, such as tetra-chloro- and trichloroethylene, temperature is known as composting. On average bio-augmentation is used to ensure that the in situ temperature is in between 55° to 65°C. The degradation of microorganisms can completely degrade these contaminants organic matter to the waste increases by increasing in to ethylene and chloride, which are non-toxic [9]. Monitoring temperature. Windrow composting has been demonstrated of this system is difficult. using the following basic steps. First, contaminated soils are excavated and screened to remove large rocks and debris [2,

3]. Bio-piling

Biopile treatment is a complete technology in which aeration Bio-reactors is done by under pressure injecting air and excavated soils are mixed with improved soil. The contaminants are turns to It is an ex-situ process treatment is done by pumped up and water. The basic biopile system includes a contaminated water or soil it is also known as slurry reactors treatment bed, an aeration system, an irrigation/nutrient or aqueous reactors. By engineered contaminated system it system and a leach ate collection system. Physical parameter bio-remediate the contaminated water or material (soil, like heat, moisture, nutrient, pH and oxygen are controlled to sediment, sludge) by reactors. A containment vessel and optimize the biodegradation. By applying positive pressure or apparatus used to establish three phase i.e. solid, liquid and vacuum from passing air and nutrients the irrigation/nutrient gas combined condition to enhance the rate of bioremediation system is covered. It can be high up to 20 feet and caped with of soil bound and water soluble pollutants as water slurry of to control evaporation, runoff, and volatilization, and the biomass and contaminated soil and capable of eliminating encourage solar heating. . If Volatile Organic compounds the particular contaminated from it is known as slurry (VOCs) in the soil volatilize into the air stream, the air leaving bioreactors. As the physical environment is easily controlled the soil may be treated to remove or destroy the VOCs before and manageable the bioremediation rate is more as compare to they are discharged into the atmosphere. Treatment time is in situ or solid-phase system. In spite of advantage there are typically 3 to 6 months [25]. some disadvantages. Pre treatment o contaminated soil is required (excavation) or instead of this we exposed the

contaminant from the soil from soil washing or physical Ex-Situ Bio-remediation extraction (vacuum extraction) prior to place in a bioreactor. It is a type of bioremediation in which contaminates are treated on other location from the contaminated site. When the

Table 4: Methods Develop in Bio-remediation [24, 12] Technique Examples Benefits Applications References In Situ Biosparging; Most efficient, Non insidious; Biodegradative abilities of [4, 9, 19] Bioventing; Relative passive; indigenous microorganisms. Naturally attenuated process, Presence of metals and inorganic treat soil and water compounds Environmental parameters Biodegradability of pollutants Chemical solubility Geological factors Distribution of pollutants Ex situ Land farming (Solid- Cost efficient ,Simple, Surface application, aerobic [2,3] phase treatment Inexpensive ,self-heating. process, application of organic system). Low cost Rapid reaction rate, materials to natural soils followed Composting Inexpensive, self heating. by irrigation and tilling (Anaerobic, converts Can be done on site. To make plants healthier good solid organic wastes alternative to land filling or into humus-like incinerating practical and material) convenient. Surface application, Biopiles agricultural to municipal waste Bioreactors Slurry reactors Rapid degradation kinetic Bioaugmentat Toxicity of [20] Optimized environmental amendments Aqueous reactors parameters. Enhances mass transfer Effective use of inoculants and Toxic concentrations of surfactant contaminants

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Technique Examples Benefits Applications References Precipitation Non-directed physico- Cost-effective Removal of heavy Metals [16] or chemical complex - Flocculation ation reaction between dissolved contaminants and charged cellular components (dead Biomass) Micro- Microfiltration Remove dissolved solids Waste water treatment; recovery - filtration membranes are used at a rapidly and reuse of more than 90% of constant pressure original waste water Electro Uses cataion and anion Withstand high temperature Efficiently remove the dissolved - dialysis exchange membra-ne and can be reused solid pairs

Advantages of Bio-remediation Drawbacks of Bio-remediation  It takes less time comparing to other techniques to accept  Bioremediation is applicable only on those compounds the waste treatment process for contaminate material or which are bio-degradable. All compounds cannot be soil it is a naturally process. Micro-organisms are capable degraded completely. to eliminate the contaminants, when contaminants  There are some anxieties that the products of degrades it decrease the biomass population. The final biodegradation may be more continual or toxic than the parts of the treatment are typically harmless product. parent compound. Biological processes are often highly  Bioremediation can be practice without causing explicit. Important site factors required for success interference in natural activities it can be easily include the presence of metabolically capable microbial performed with very less efforts. Transportation of wastes populations, suitable environmental growth conditions, from the site to off-sites is eliminated from this there is and appropriate levels of nutrients and contaminants. no risk to the human health which can be arises due to the  It is difficult to extrapolate from bench and pilot-scale transportation. studies to full-scale field operations.  It requires optimal cost to degrade the hazardous wastes  There are needs of improvement and developments and compare to the other traditional methods. engineer bioremediation technologies are required to  Bioremediation completely eliminate the matter, develop for appropriate sites with typical combinations of many toxic compounds changes to harmless products. contamination that are not evenly detached in the This process also make free from future liabilities of the environment. Contaminants may be present as solids, sites and disposal of contaminated materials. liquids, and gases.  It uses the natural microbes which is harmless to  Bioremediation habitually takes long period of time than environment compare to the use of hazardous chemicals. other traditional treatment options, such as excavation It changes toxic chemicals into harmless gases or into and removal of soil or incineration. water toxicity of chemical completely eliminated.  Regulatory uncertainty remains regarding acceptable performance criteria for bioremediation

Table 5: Some Contaminants Source and Process of Bio-remediation [9] Class of Contaminants Example Source Process of Bio-remediation Chlorinated solvents Trichloroethylene Drycleaners Anaerobic Polychlorinated biphenyls 4-Chlorobiphenyl Electrical manufacturing Anaerobic “BTEX” Benzene, Toluene, Ethylbenzene Oil production and storage Both Aerobic and Anaerobic and Xylene Gas work sites Airports Paint manufacture Polyaromatic Naphthlene,Anthracen Oil production and Aerobic hydrocarbons e,Pyrene Storage, Engine works Pesticides , 2 4 D , Agriculture. Pesticides Both Aerobic and Anaerobic Parathon manufacture

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Table 6: Some other Contaminants Sources and Treatment Technology

Contaminants Sources Treatment Technology

1,2 Dichloroethene EDC From EDC and VCM Plants, storage tanks, In-situ Bioremediation (DNAPL) pipelines etc

Gasoline (LNAPL) Gasoline and other petroleum fuels tanks, petrol In-situ Bioremediation; Vapor extraction stations, storage tanks and pipelines

Ammonia Ammonia Storage Tanks, Landfill leaks, Waste Pump and Treat; Combination of Air Stripping, stockpile, etc. Nitrification, Ion Exchange

Phyto-remediation Overview of Phyto-remediation applications Microorganisms are not the only species that can be improved  Cost of phytoremediation is very minimal as compare to by genetic alteration for bio-remediatory purposes. Plants the other typical methods like in-situ and en-situ process have also been used and studied. Bioremediation by plants is of bioremediation called phytoremediation. Phytoremediation is a rising  Monitoring of plants is very easy. technology that uses a variety of plants to degrade, extract, contain, or immobilize contaminants from soil and water. This  There is chance to re-use and recycle the compound. technology has been receiving noticeable lately as a modern  It uses naturally occurring organisms and preserves the technology, cost-effective alternative to the more established treatment methods used at sites. natural state of the environment.  The low cost of phytoremediation (up to 1000 times

cheaper than excavation and reburial) is the main advantage of phytoremediation.

Table 7: Types of Phytoremediation:

Process Function Pollutant Medium Plants References

Phytoextraction Remove metals pollutants that Cd, Pb, Zn, Soil & Viola baoshanensis, [14, 26] accumulate in plants. Remove As, Petroleum, Groundwater Sedum alfredii, Rumex organics from soil by Hydrocarbos crispus concentrating them in plant parts and Radionuclies

Phytotranformation Plant uptake and degradation of Soil Cannas [15] organic Compounds substances

Phytodegradation Plants and associated DDT, Groundwater Elodea [8, 17] microorganisms degrade organic Explosives, Canadensis,Pueraria pollutants waste and

Rhizofiltration Roots absorb and Zn, Pb, Cd, As Zn, Pb, Cd, As Groundwater Brassica juncea [6, 22] Groundwateradsorb pollutants, mainly metals, from water and aqueous waste streams

Phytostabilization Use of plants to reduce the Cu, Cd, Cr, Soil Anthyllis vulneraria, [21] (Immobilization) bioavailability of pollutants in the Ni,Pb, Zn Festuca arvernensis Environment

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