Minerals and Soil Remediation Lectures PDF

Minerals & Soil remediation Presented by Dr. Ahmed Ouda Assoc. Prof. of Applied Inorganic Chemistry Housing & Building National Research Center Introduction on minerals  Minerals Minerals are the building blocks of rocks Minerals record t...

Minerals & Soil remediation Presented by Dr. Ahmed Ouda Assoc. Prof. of Applied Inorganic Chemistry Housing & Building National Research Center Introduction on minerals  Minerals Minerals are the building blocks of rocks Minerals record the formation and history of a rock and determine it,s physical and chemical characteristics Each mineral is characterized by:  A specific composition  A specific crystal structure  A specific stability range (Pressure and Temperature( ‫الماس‬  There are thousands of minerals They are separated into groups based on their: 1. Crystal structure 2. Chemistry Mica mineral ‫هندسة الشبكة البلورية‬  Covalent bonds Some minerals are made up of covalent bonds characterized by shared.electrons between different atoms. Diamond is a good example  Ionic bonding Most minerals, however, are composed of ionic bonds, in which cations.and anions attract each other. A simple example is Halite (NaCl) ‫دفعت جزئيا‬ ‫يتناسب الكاتيون مع المساحة‬  Systematic Mineralogy Separation of Minerals in Groups 1. Silicates Silicates are the most comon & important rock forming minerals on Earth Silicates are composed of a combination of SiO4 tetrahedrons and Cations: K+, Na+, Ca2+, Mg2+, Fe2+ or Al3+ The basic compositional unit of all silicate minerals is the silicon-oxygen tetrahedron (often. abbreviated Si-O tetrahedron). It consists of one silicon cation (Si-4) surrounded by 4 oxygen.  The principal building block of rock forming minerals The SiO4 Tetrahedrons  Silicates are the most important rock forming minerals.  They are composed of a very stable molecule made up of Silicon and Oxygen atoms. Those form through covalent bonds a SiO4 tetrahedron.  These tetrahedra can be combined in multiple ways. For example, they can be arranged by sharing an oxygen atom or through adding different cations.  Lecture 2 Soil & Mineral Resources  Soil ‫السائبة‬ Soil is the loose surface material that covers most land  It consists of inorganic particles and organic matter. Soil provides the structural support to plants used in agriculture and is also their source of water and nutrients  is formed when rocks and other materials near the Earth's surface are ‫التجوية‬ broken down by a number of processes collectively called "Weathering".  Weathering is the process by which rocks are chemically altered or physically broken down into fragments at or near Earth's surface. Two forms 1. Mechanical weathering, the process of physically breaking rock into smaller fragments 2. Chemical weathering, a process in which rock is broken down by chemical reactions  Physical characteristics of soil  Texture ‫نَسِيج‬ Colour Depth Structure Porosity (the space between the particles) Stone content  ‫تصريف المياه‬ Soil texture, structure, drainage characteristics ‫الطمي‬  Types of soils Soil is classified into four types: 1. Sandy Soil  It consists of small particles of weathered rock ‫جزيئات صغيرة من الصخور المتعرضة للعوامل الجوية‬  Sandy soils are one of the poorest types of soil for growing plants because it has ‫ضعف القدرة على االحتفاظ بالمياه‬ very low nutrients and poor water holding capacity, which makes it hard for the plant’s roots to absorb water. ‫تفريغ‬  is very good for the drainage system  ‫التجزئة‬  is usually formed by the break down or fragmentation of rocks like granite, limestone and quartz 2. Silt Soil  is known to have much smaller particles compared to sandy soil  is made up of rock and other mineral particles, which are smaller than sand and larger than clay  It is the smooth and fine quality of the soil that holds water better than sand  is easily transported by moving currents and it is mainly found near the river, lakes and other water bodies ‫المسطحات المائية‬  The silt soil is more fertile compared to the other three types of soil. Therefore, it is also used in agricultural practices to improve soil fertility 3. Clay Soil  is the smallest particle among the other two types of soil  The particles in this soil are tightly packed together with each other with very little or no airspace ‫خصائص تخزين المياه‬  This soil has very good water storage qualities and makes it hard for moisture and air to penetrate into it  It is very sticky to the touch when wet but smooth when dried  Clay is the densest and heaviest type of soil which does not drain well or provide space for plant roots to flourish 4. Loamy Soil ‫التربة الطينية‬  It is a combination of sand, silt and clay  It has the ability to retain moisture and nutrients; hence, it is more suitable for farming  This soil is also referred to as agricultural soil as it includes an equilibrium of all three types of soil materials ‫أصولها غير العضوية‬  It also has higher calcium and pH levels because of its inorganic origins  Factors acting together on rocks to form soil 1. Weathering is the process of breaking down rocks, soil, minerals and even wood through contact with the atmosphere, water and biological organisms. Long exposure to that air allows for the materials to be broken down into smaller pieces. The change can be physical, chemical or biological in nature. a. Chemical Weathering This happens when the break down of rocks is due to a change in their chemical makeup. This is usually because of the rock's reaction with water, air or other chemicals it comes in contact with. b. Biological Weathering Refers to the break down of rocks by bacteria and other living organisms 2. Temperature Both high and low temperatures can affect the break down of rocks. When rocks are exposed to heat, the molecules expand. When they are exposed to low temperatures, they shrink. This process eventually results in the breaking down of rocks as the bond between the molecules weaken 3. Rainfall ‫هطول األمطار الغزيرة‬ ‫فيضانات مفاجئة‬ Extreme rainfall would usually bring about flash floods which subject rocks to extreme amount of water pressure. This in turn can break them down into smaller pieces Mineral Resources  Minerals are naturally occurring, non-living, solid with a definite structure and composition  Properties of minerals ‫بريق‬ 1. Luster, is the way in which its surface reflects light ‫المع‬ ‫معتم‬ a. Metallic, generally opaque and exhibit a resplendent shine similar to a polished metal ‫المعدن المصقول‬ ‫زجاجي‬ b. Non-metallic, vitreous (glassy), adamantine ‫مشرق‬ ‫حريري‬ ‫لؤلؤي‬ ‫باهت‬ ‫صمغي‬ (brilliant/diamond like), resinous, silky, pearly, dull (earthy) and greasy ‫دهني‬Adamant or adamantine a generic name for a very hard material  ‫خدش‬ ‫مقياس موس‬ ‫تفتت‬ ‫قرش النحاس‬ ‫األزرق الالزوردي‬ ‫كسر‬ ‫الحواف الخشنة‬ ‫انشقاق‬ 7. DENSITY  Depends on its chemical composition  Minerals made up of elements with higher atomic masses have higher densities 8. MAGNETISM  Minerals containing iron are magnetic 9. ACID TEST  Use to find out if the minerals contain CO3 Relationship between mineral and soil Lecture 3 What is the relationship between minerals and soil? Elements form minerals, and minerals form rocks. Different rock types— igneous, sedimentary, and metamorphic—can transform through the rock cycle. Through the processes of weathering and erosion, rocks change, break, and move. Minerals mix with organic material to form the soil on which plants and animals rely.  Soil Minerals  Soil minerals play a vital role in soil fertility since mineral surfaces serve as potential sites for nutrient storage. ‫المواقع المحتملة لتخزين المواد الغذائية‬  Different types of soil minerals hold and retain differing amounts of nutrients.  There are numerous types of minerals found in the soil. These minerals vary greatly in size and chemical composition.  Soil Mineral Particle Size  Particle size is an important property that allows us to make distinctions among the different soil minerals. ‫صخور كبيرة‬  Soils contain particles that range from very large boulders to minute particles which are invisible to the naked eye.  To further distinguish particles based upon size, particles are separated into the two categories: (1) the coarse fraction and (2) the fine earth fraction. 1. FINE EARTH FRACTION  The fine earth fraction includes any particle less than 2.0 mm (0.078 inches) and is divided into three classes of size: (1) Sand, (2) Silt, or (3) Clay Table. Description of sand, silt, and clay classes ‫يسمح بالصرف الزائد‬ ‫قدرة التربة على االحتفاظ بالماء‬  2. COARSE FRACTION  The coarse fraction of soil includes any soil particles greater than 2 mm.  The coarse fraction includes boulders, stones, gravels, and coarse sands.  These are rocky fragments and are generally a combination of more than one type of mineral.  Types of Minerals in Soil  The largest component in the soil are minerals and it makes up 40-45 per cent of the total components.  The types of soil minerals are divided into two categories, which are as follows:  1. Primary Minerals in the Soil  It is one of the types of minerals in the soil and falls into that category of ‫الترسيب‬ soil which have not been chemically transformed since the deposition.  It is similar to their parent materials and is larger with irregular shapes  These minerals are usually present in sand and silt.  Examples of the primary minerals in soil include silica minerals and silicate, titanomagnetite, apatite, iron minerals, volcanic gases and non- crystalline inorganic constituents.  2. Secondary Minerals in the Soil  is formed after the weathering of primary soil minerals.  It is mainly found in fine silt or clay minerals.  The particle size of secondary minerals is much smaller as compared to the primary minerals since these are formed as a result of the weathering process.  Having a large surface area, these minerals help in retaining moisture.  Some examples of secondary minerals in the soil are hydroxides, phyllosilicates, oxides, carbonates, phosphates, sulfates and halides.  Functions of the Soil Minerals  Soil plays an important role in various functions including food and other biomass ‫تجميعة الجينات‬ production, biological habitat, gene pool, environmental interaction, physical and cultural ‫تراث‬ heritage, and acts as a platform for man-made structures.  The soil-forming rocks and minerals are very helpful for plant growth as it’s a great assistance to plant life.  Several minerals are absorbed from the soil via the roots of the trees and plants.  Most of the important minerals are magnesium and nitrate where the former helps in the production of chlorophyll allowing photosynthesis and the latter mineral is the major source of amino acids required to synthesis proteins.  Formation of Soil  Its formation involves the breakdown of rocks in the rock cycle.  Soil being a mixture of geological and organic materials, is highly beneficial for the growth of plants. In contrast, sand is purely rocky ‫خالية‬ material devoid of living organisms and therefore, sand is not great for plant growth.  Rock Cycle ‫الرواسب‬ Sediment ‫الرسوبية‬ ‫نارية‬ Erosion ‫التعرية‬ Compaction ‫الدمك‬ Cooling Heat/Pressure Magma Heating ‫متحولة‬  How are rocks broken to form soil? ‫التحلل‬  Soil formation starts with the disintegration of rocks under the influence of climate.  Sun, water and wind play important roles in weathering the rocks. ‫التقلبات‬  Rainwater dissolves rock elements; temperature fluctuations may cause differential weathering i.e. expansion and contraction of rock-forming crystals ‫التجميد والذوبان‬  Also, the freezing and thawing of water in rocks widen the cracks and the ‫األشنات‬ lichens, generally, cyanobacteria or algae growing on the rocks release substances that help in powdering down the rocks.  ‫نباتات حزازية‬  In addition, mosses help in further breaking down the rocks  Minerals Present in the Soil  Soil forming minerals are the major components of soil and are mostly found are Sodium, Potassium and Nitrogen. Some of the other minerals of soil are as follows: 1. Hematite:  It is red to blackish red in appearance and it swells up when it absorbs water forming hydrated iron oxide. 2. Limonite: ‫تدعيم‬  It is yellow to brown and it is hydrated ferric oxide and acts as a cementing and colouring agent for soil. 3. Goethite:  Goethite is formed when limonite adsorbs water. 4. Gibbsite: [Al(OH)3]  It is the most common Aluminium compound present in the soil. It is present in highly weathered soil. 5. Carbonate Group:  Calcium hydroxide and Magnesium hydroxide combine with carbon dioxide to form carbonates. a. Calcite:  Calcite is white or colourless and the major constituent of sedimentary rocks, consisting of calcium carbonate. b. Dolomite:  It is the chief source of magnesium found in the soil. c.Siderite: (FeCO3) ‫التربة المشبعة بالمياه‬  It is an important mineral present in the water-logged soil. It is generated by the alteration of other iron-bearing minerals. Sulphate Group:  It is formed by the combination of oxygen and sulphur ions. It further reacts to form calcium sulphate by reacting with calcium ions. Gypsum:  It is found in sedimentary rocks as well as desert soils. It is water-soluble and can be leached easily.  Uses of minerals present in the soil  Minerals present in the soils are important in the growth and development of ‫الغطاء النباتي‬ different vegetation and agriculture. These minerals are also needed for many industries to function.  Some of the uses of minerals present in the soil are 1. The element of Nitrogen present in the soil is an essential part of different kinds of proteins, nucleic acids, vitamins, and various hormones, which are absorbed by the plants and then spread to the animal kingdom. 2. Phosphorus is the element used in the creation of plasma membranes of plant cells, some proteins, nucleic acids, and nucleotides. 3. In plants ,potassium is a crucial element as it is needed for the process of photosynthesis. All three of these elements decide the fertility of the soil and these elements are added in the fields in the name of fertilisers.. 4. Calcium is the main constituent of our teeth and bones in animals while in ‫ألياف المغزل‬ plants they are used in the formation of the spindle fibres. 5. Magnesium present in the soil is needed in the functioning of various enzymes of the body.  ‫كمية ضئيلة‬ 6. Sulphur is required by the plants in a minuscule quantity for the root ‫العقدة‬ development and nodule functions. 7. Iron is also present in the soils and one does not specify the use of iron in the animals. Certain proteins and blood all require the presence of iron in the body. 8. Calcite is also used for the production of cement and also in agricultural soil treatment. ‫يسمى هرمون األوكسين كيميائيا ً حمض األندول الخلي‬ 9. For the synthesis of auxin, the trace element named Zinc is needed, which is again available in the soil.  Lecture 4 Causes of soil pollution and spread of chemicals hazards in soils of Egypt  What is soil contamination?  Soil contamination or soil pollution as part of land degradation is caused by the presence of human-made chemicals or other alteration in the natural soil environment.  It is typically caused by industrial activity, agricultural chemicals or improper disposal of waste.  ‫)‪Soil can be caused by the following (non-exhaustive list‬‬ ‫الذخائر‬ ‫صهاريج‬ ‫تفريغ‬ ‫المكثفة‬ ‫الكيماويات الزراعية‬ ‫مكب النفايات والتخلص غير القانوني‬ ‫حطام‬ Heavy metal concentration in lithosphere, soils and plants (µg/gm dry matter) Lithosphere ‫الغالف الصخري ويشمل في األرض القشرة والجزء األعلى من الوشاح‬  Heavy metal content of fertilizers (µg/gm) Calcium ammonium nitrate or CAN Soil remediation plan and treatment technologies  Soil Remediation Plan Successful soil remediation plan depends on: 1. Soil sampling 2. Monitoring 3. Model construction ‫بناء النموذج‬ 4. Soil remediation will be the final step in soil conservation plan  Soil Remediation Strategies Three primary strategies used separately or in conjunction to remediate most sites are: 1. Elimination or alteration of contaminants. 2. Extraction or separation of contaminants from environmental media. 3. Immobilization of contaminants. ‫معالجة في الموقع‬ Immobilization is an in-situ remediation technique that uses cost-effective soil amendments to reduce Pb and Cd availability in the contaminated soils Before selecting the treatment technique followed in the work we need to define  What is the type of pollutants (chemical composition)? Are it organic or inorganic? ‫تحديد الموقع‬  What are the dimensions and degree of pollution? Localize? ‫النوع المنتشر‬ - Is the diffuse type dispersed ?Also, How far the urgent treatment plan needed?  What is the level of risk of this pollution? - Low – Medium –High level  What is the technically measurements that are believed as the most appropriate for the implementation of the treatment project?  Define?  What is the technically measurements that are believed as the most appropriate for the implementation of the treatment project? - Address in place in situ ) or out of place , and if so , Is the soil will be transferred to a place of special quality? - Is the treatment of contaminated soil will in place prepared for that (prepared beds or tank). ‫قيود مالية‬  Are there any financial constraints when determining and selecting the required treatment method?  What is the most appropriate technically and financially to be the treatment project economically?  Lecture 5 Soils Remediation Technologies ‫‪Remediation methods‬‬ ‫غطاء‬ ‫في علوم التربة هو‬ ‫تحويل المركبات‬ ‫غير العضوية إلى‬ ‫مركبات عضوية عن‬ ‫طريق الكائنات الحية‬ ‫الدقيقة‬ ‫‪isolating the‬‬ ‫‪contaminants to‬‬ ‫‪keep them from‬‬ ‫‪spreading‬‬ ‫معالجة نباتية أو المعالجة النباتية للملوثات ‪ ،‬هي استخدام النبات في إزالة بعض‬ ‫الملوثات سوا ًء كانت عضوية أو غير عضوية من األماكن الملوثة كالتربة الزراعية‬ ‫والمياه‬ Treatment technologies capable of contaminant elimination by altering their chemical /physical structure are: 1. Chemical and physical treatment (ion exchange, oxidation, reduction, sedimentation, photolysis (the breakdown of any particular substance in presence of light), carbon uptake (the process by which the oceans (or plants and forests) absorb carbon), de-chlorination, steam extraction, soil ‫التجريف‬ dumping (soil removed during the dredging operations). 2. Thermal treatment (burning - heat removal –treatment of high temperature plasma (The core of plasma ranges in temperature from 11,000° – 14,500° Fahrenheit). 3. Biological treatment (Aerobic biological treatment: a biological process that uses oxygen to break down organic contaminants and other pollutants like nitrogen and phosphorous – Non aerobic biological treatment: uses anaerobic bacteria to convert organic pollutants into biogas in an oxygen- free environment - Biological treatment by plants(  ‫تصلب‬ 4. Solidification and stabilization (cement sclerosis - limestone sclerosis - thermoplastic groove - thermoplastic glass transformation)  Physico-Chemical Techniques of Soil Remediation 1. Oxidation Ex: Trichloroethylene (TCE) TCE breaks down more slowly in surface water and soil than in air, and it can pass through the soil into underground water  ISCO ‫األكسدة الكيميائية في الموقع‬ Subsurface:Underground is an environmental remediation technique used for soil and/or groundwater remediation to lower the concentrations of targeted environmental contaminants to acceptable levels. ‫الناشئة‬  ‫االلتزام باإلنفاق‬ ‫التعامل مع المواد المؤكسدة القوية‬ ‫مرافق مؤقته‬ ‫فعال على بعض المركبات التي يصعب عالجها‬ ‫كاشف فنتون هو محلول بيروكسيد الهيدروجين ومحفز حديد‪.‬يتم استخدامه ألكسدة‬ ‫الملوثات أو مياه الصرف‬ ‫انتشار‬  ‫الناشئة‬ ‫فوق كبريتات‬  Vadose zone The vadose zone, also termed the unsaturated zone, is the part of Earth between the land surface and the top of the phreatic zone, the position at which the groundwater (the water in the soil's pores) is at atmospheric pressure. Hence, the vadose zone extends from the top of the ground surface to the water table ‫ هي ذلك الجزء من األرض الذي يتوسط‬،‫ضا مصطلح المنطقة غير المشبعة‬ ً ‫ يطلق عليها أي‬,‫منطقة فادوز‬ ‫بين سطح األرض وأعلى المنطقة الجوفية أي المكان الذي تكون عنده المياه الجوفية عند مستوى الضغط‬ ‫ ومن ثم فإن منطقة فادوز تمتد من أعلى سطح األرض حتى مستوى المياه الجوفية‬.‫الجوي‬ ‫اآلثار الضارة المحتملة‬ is a measure of the carbonate and bicarbonate anions in a solution. ‫ثبات‬ minerals and organic material in soil The amount of oxidant consumed by the soil ‫‪Manganate ions‬‬ ‫أكسيد المنغنيز الرباعي‬  Lecture 6 ENVIRONMENTAL REMEDIATION  Definition Environmental remediation: providing a remedy for an environmental problem This can include removing contaminants from groundwater or cleaning up after an oil spill Environmental remediation is the removal of pollution or contaminants from water (both ground water and surface water) and soil.  Purpose ‫إعادة‬ 1. is to restore contaminated sites or resources to a level that is safe for humans and animals Depending on the type of damage that is done, this can be a complex and expensive process  Classification Environmental remediation technologies are divided into groups called 1. ex-situ ‫حفر‬ Processes that involve excavation of soil 2. in-situ are those that attempt to treat contamination without removing soil  Remediation Once a soil has to be remediated the key issue is which is the most appropriate technology to be used? ‫خطة الطوارئ الوطنية األمريكية‬ Nine possible criteria to select a remedy (The US National Contingency Plan (NCP) 1. The overall protection of human health and the environment ‫االمتثال‬ 2. Compliance with applicable or relevant and appropriate requirements ‫االستمرارية‬ 3. Long-term effectiveness and permanence ‫إمكانية التنقل‬ 4. Reduction of toxicity, mobility, and volume through treatment 5. Short-term effectiveness 6. Implementability ‫قابلية التنفيذ‬ 7. Cost 8. State acceptance 9. Community acceptance In the UK, three criteria that influence the choice of remediation techniques are considered (Beckett and Cairney 1993) ‫استصالح‬ 1. Cost-effectiveness 2. Speed of reclamation 3. Flexibility  Remediation Technologies These processes can be classified according to in situ and ex situ technologies Smith et al. (1995) Three Major categories or types of remedial actions: 1. Containment Restriction of contaminants to a specific domain to prevent further spreading 2. Removal A contaminant is transferred from an open to a controlled environment 3. Treatment A contaminant is rendered innocuous ‫غير ضار‬  Containment means of keeping something within limits Accomplished by controlling the flow of the fluid that carries the contaminant ‫تثبيت‬ OR by directly immobilizing the contaminant 1. PHYSICAL BARRIERS ‫عوائق هيكلية‬ are structural obstacles in natural or man made environments that prevent or block mobility (moving around in the environment) Operation Principle - To control flow of water, thus preventing the spread of contaminant - Usually, barrier installed downgradient of contaminated site ‫يتم تثبيت الحاجز أسفل الموقع الملوث‬  ‫غير المجمعة‬ - Used in primarily unconsolidated materials e.g. soil or sand - May be placed to a depth of 50 m Important Considerations 1. Presence of the zone of low permeability, into which the physical barriers ‫تثبيت‬ can be seated to prevent flow underneath the barrier 2. Permeability of the barrier itself (to be as low as practically possible) 3. Types of Physical Barriers 2. HYDRAULIC BARRIERS: - Similar principle of operation as physical barrier - Based on fluid potentials - Generated by the pressure differential arising from the extraction or injection of water Key performance Factor ‫عمود التلوث‬ 1. Capacity to capture the contaminant plume, in order to limit the spread of the zone of contamination A contaminant plume is the body of groundwater that has been affected by the presence of pollutants in the soil 2. Plum capture is a function of number, placement, and flow rate of the wells or drains ‫يعتمد اإللتقاط على عدد اآلبار أو المصارف وموضعها ومعدل تدفقها‬  Removal ‫حفر وتفريغ‬ 1. Excavation (Dig and Dump) - Excavation of the soil where contaminants reside - Used at many sites and is highly successful Disadvantages - Exposure of workers to hazardous compounds ‫التخلص‬ - Excavated soil require treatment and/or disposal, which can be expensive ‫ضحل‬ - Limited to relatively small areas (shallow, highly contaminated source zones)  ‫ضخ‬ 2. Pump and Treat - Currently the most widely used technology for contaminated groundwater ‫باطن األرض‬ - Removes contaminated water from the sub surface by using one or more wells to pump it out - Clean water brought into the contaminated region by the pumping ‫تحفيز االمتزاز‬ ‫تطرد‬ action-removes/flushes additional contamination by inducing desorption from the solid phase - The contaminated water pumped from the subsurface is directed to some type of treatment operation (e.g. carbon adsorption, biological treatment systems) - Usually used for saturated sub surfaces, can also be used to remove contaminants from the vadose zone  Performance Criteria - Contaminant Plume Capture - Effectiveness of contaminant removal Factors limiting the effectiveness of P&T - Presence of low permeability zones - Rate limited desorption ‫معدل االمتزاز محدود‬ - Presence of immiscible liquids ‫غير قابلة لالمتزاج‬  Enhancement of Removal Contaminant removal can be difficult due to such factors as 1. Low solubility 2. High degree of sorption 3. Presence of immiscible liquid phases  Enhancement of Removal Approach: ‫النهج‬ Enhancement of removal of low solubility, high sorption contaminants ‫طبقة المياه الجوفية‬ Inject a chemical into the aquifer (such as surfactant /detergent) that will promote dissolution and desorption of the contaminant, thus enhancing removal effectiveness  Soil Vapor Extraction (SVE) is a physical treatment process for in situ remediation of volatile contaminants in vadose zone (unsaturated) soils  Lecture 7 Soil vapor extraction (SVE)  SVE Systems ‫تنفيس التربة‬ SVE (soil vapor extraction), also known as “soil venting” or “soil vacuum extraction”, is used for contaminated soil remediation. Contaminants are removed by pulling air through soil which has previously been contaminated with volatile organic compounds, hydrocarbons or other organic compounds During the process of soil remediation, the extracted soil vapors and moisture/water are separated into two phases: 1. Vapor phase There are three common methods of treatment; Condensing vapors into NAPL [Non-Aqueous Phase Liquids] Running the vapors through an granulated activated carbon emission control system where the vapors adsorb onto the activated carbon Burning the vapors in a thermal and/or catalytic oxidizer [known as thermal destruction] 2. Liquid phase The liquid phase is generally treated through an activated carbon system and ‫المجاري‬ thereafter discharged to the storm drain, sewer or off site Important Considerations ‫قابلية اختراق التربة‬ The penetrability of the soil affects the rate in which the vapors and air can move through the soil. The higher the penetrability, the faster the air and vapors will pass through, meaning a higher amount of vapors can be extracted from the soil High soil moisture can reduce soil penetrability and also lower the effectiveness by restricting the air flow through soil pores  Soil venting: Similar to P&T ‫عازلة‬ The vadose (unsaturated) zone acts as a “buffer zone” for protecting the quality of the underlying groundwater When contaminated, however, it acts as a source zone for ground water pollutants and gaseous emissions A fluid is pumped through the contaminated domain to enhance removal by injecting a chemical into the aquifer (such as surfactant /detergent) that will promote dissolution and desorption of the contaminant, thus enhancing removal effectiveness  Effectiveness of SVE Depends on:  The permeability of the soil  Soil moisture  Depth to groundwater  Soil structure Soil vapor extraction of chlorinated solvents at an industrial site in Brazil  Advantages of SVE  Targets the removals of volatile organic compounds (VOCs) from the vadose zone by volatilization  Shown to be effective at removing NAPL, aqueous, and sorbed phases  Encourages aerobic biodegradation  Proven technology  ‫الظواهر‬ The components to be sealed must be free from ‫إغالق‬ contaminants such as oil films, dirt, paint or other ‫منسوب‬ coating materials. ‫تقليل مسامية التربة المملوءة بالهواء‬  ‫رذاذ‬ Air Sparging also known as in situ air stripping and/or in situ volatilization is an in situ remediation technique, used for the treatment of saturated groundwater by volatile organic compounds (VOCs), such as crude oil hydrocarbon derivatives which is a widespread problem for the ground water health. In situ air sparging is a means by which to enhance the rate of mass removal from contaminated saturated-zone systems. Air sparging involves injecting air into the target contaminated zone, with the expectation that volatile and semi volatile contaminants will undergo mass transfer (volatilization) from the groundwater to the air bubbles  Air Sparging  Related to SVE:  Involve injection of clean air into the saturated or aquifer  Purpose: to volatilize contaminants from the soil into air bubles  Air bubles make their way into the vadose zone where they are captured using SVE system  Can SERVE another purpose: for in situ bioremediation, air sparging can be used for oxygen supply https://www.scribd.com/presentation/78926370/Lecture-on-Remediation  Lecture 8 Bioremediation Bioremediation broadly refers to any process wherein a biological ‫معالجة فطرية‬ system (typically bacteria, microalgae, fungi in mycoremediation, and plants in phytoremediation), living or dead, is employed for ‫غازات المداخن‬ removing environmental pollutants from air, water, soil, flue gasses, ‫النفايات السائلة‬ industrial effluents etc., in natural or artificial settings Bioremediation is the use of microorganisms to destroy or immobilize waste materials Microorganisms include : 1. Bacteria (aerobic and anaerobic( 2. Fungi ‫شعاويات‬ ‫البكتيريا الخيطية‬ 3. Actinomycetes (filamentous bacteria) In comparison to conventional physicochemical treatment methods bioremediation may offer considerable advantages as it aims to be : (1) Sustainable, (2) Eco-friendly, (3) Cheap, and (4) Scalable ‫قابلة للتطوير‬  Bioremediation mechanism  Microorganisms destroy organic contaminants in the course of using the chemicals for their own growth and reproduction Organic chemicals provide : I. Carbon, source of cell building material II. Electrons, source of energy  Cells catalyze oxidation of organic chemicals (electron donors), causing transfer of electrons from organic chemicals to some electron acceptor  Limitations to biodegradation 1) Adequate bacterial concentrations (although populations generally increase if there is food present( 2) Electron acceptors 3) Nutrients (e.g., nitrogen and phosphorus) 4) Non-toxic conditions (NAPL pools are likely to be toxic) 5) Minimum carbon source (which may exceed regulatory limits for toxic chemicals  Bacterial growth 1) Typically very rapid if food (carbon source) is present: population doubles every 45 minutes ‫النقية‬ 2) Pristine soils contain 100 to 1000 aerobic bacteria per gram of soil 3) Increases to 105 within one week if carbon source is introduced (Polychlorinated biphenyls)  Bioremediation technologies for soil Bioremediation techniques can be classified as: (i) in situ techniques, which treats polluted sites directly ‫المحفورة‬ (ii) ex situ techniques which are applied to excavated materials  In both these approaches, additional nutrients, vitamins, minerals, and pH buffers are added to enhance the growth and metabolism of the microorganisms ‫التحفيز الحيوي‬  In some cases, specialized microbial cultures are added (biostimulation) Some examples of bioremediation related technologies are : ‫التسميد‬ 1. Composting – A controlled, aerobic (oxygen-required) process that converts organic materials into a nutrient-rich, biologically-stable soil 2. Biopiles – is an ex situ treatment technology that leverages biological processes to convert contaminants to low-toxicity by-products ‫أصلي‬ 3. Bioventing is an in-situ remediation technology that uses indigenous microorganisms to biodegrade organic constituents adsorbed to soils in the unsaturated zone  4. Land treatment – application of organic materials to natural soils followed by ‫ الري‬irrigation and tilling ‫الحرث‬  ‫القدرة على االحتفاظ بالمياه‬ ‫‪Dissolved oxygen‬‬  ‫يزيح‬ ‫الميثانوتروف هي‬ ‫بدائيات النوى التي‬ ‫تعمل على استقالب‬ ‫الميثان كمصدر‬ ‫التحلل الكيميائي‬ ‫للكربون والطاقة‬ ‫الكيميائية‬  ‫األيض أو االستقالب‬ ‫هو مجموعة من‬ ‫التفاعالت الكيميائية في‬ ‫خاليا الكائن تحافظ‬ ‫على الحياة‬ ‫إزالة السموم‬ ‫بالصدفة‬ ‫ميكروبات متحالفة‬ ‫الهدم‬ ‫هي اثنان أو أكثر من‬ ‫المجموعات‬ ‫الميكروبية التي‬ ‫تعيش معا ً بطريقة‬ ‫تكافلية‬ - Anaerobic biodegradation The degradation of compounds by microorganisms in the absence of oxygen is termed as anaerobic biodegradation. The process whereby microorganisms use a chemical other than oxygen as an electron acceptor ‫يعيد‬ ‫متأصل‬ ‫المنزلية‬ ‫غير ذاتي التَغذية َ‬ ‫وهو الكائن الحي الذي ال يستطيع تثبيت الكربون من المصادر‬ ‫غير العضوية ولكن يستخدم المركبات العضوية للنمو‬ ‫الجاني‬ ‫التوافر الحيوي‬