Presentation on theme: "Overall CEL795 Term Paper Summary Slides November 15 th 2012."— Presentation transcript:
Overall CEL795 Term Paper Summary Slides November 15 th 2012
Karishma Bhatnagar2012CEV2274 (Group Leader) Megha Kanoje2012CEV2283 Shailvee2012CEV2273 SreelakshmiBabu2012CEV2267 MeenakshiKayesth2011CET3585 Group members :
The main objective of this study is to investigate the removal of pesticides by NF and RO membranes and to study the effect of Membrane characteristics, Pesticide properties, Feed water and Membrane fouling. The presentation includes : Basic information about Nano Filtration and Reverse Osmosis. Factors affecting the performance of NF/RO system. Benefits of using NF/RO system over other conventional methods Nano filtration is a process in which membranes with Nano size pores are used to separate solutes or salts based on size/and or charge. It can effectively remove multivalent ions, pesticides, pathogens, hardness and nitrates. RO membranes are effectively non-porous and thus are very effective in removal of particles with low molar mass species.
NF/RO System Membrane Properties Feed water composition Pesticide Properties MWCO Water pH Molecular weight Membrane Porosity Solute Concentration Molecular Size Membrane material Ionic Strength Chemical property Organic matter Polarity Summary of factors to be considered while designing a NF/RO system Study on three different membranes NF90, NF270 and NTR7250 for removal of Atrazine ParametersEffects on all three membrane Feed ConcentrationNegligible effect PressureRetention increased with increased pressure pHBest retention at 7; reduces at 4 and 10 Humic AcidRejection increased Flux decreased TiO 2 Rejection increased Flux decreased
Property Comments WATER pH Higher pH values - reduced removal rates. Reason-ion adsorption on membrane surface. SOLUTE CONCENTRATION No significant effect on removal. IONIC ENVIRONMENT High ionic concentrations - Better removal. Reason - reduction in electrostatic forces inside membrane. PRESENCE OF ORGANIC MATTER(OM) Presence of natural OM - Increased removal. Reason - Binding between pesticides and humic substances. PropertyComments Membrane molecular weight cut-off Most effective membranes are in range of 200 to 400 Da Membrane porosityMicro-porous membranes are most effective Membrane materialSynthetic organic polymers are more efficient than ceramic and metallic membranes. Composite Polyamide (PA) are more effective than Cellulose Acetate (CA) Poly Vinyl Alcohol membranes are more effective than SulfonatedPolyehtesulfone Poly Vinyl Alcohol membranes.
PropertyComments Physical Properties of Pesticides Molecular size Higher the molecular size, higher will be the rejection Molecular Length works in positive direction for removal of organic compound Molecular Width Better indicators for removal of alcohols and carbohydrates Mean molecular Size Pesticides chemical properties Sorption Capacity Higher the sorpotion capacity, higher will be the rejection Hydrogen Bonding Hydrogen bonding between hydrogen component of pesticide and hydrogen component of membranes works in positive direction for removal of pesticides Hydrophobic interactions hydrophobic interactions are mostly responsible for pesticides adsorption on membrane Pesticide polarityDipole momentSolute rejection decreases
TANNERY WASTEWATER TREATMENT THROUGH DIFFERENT TECHNOLOGIES UNDER THE INFLUENCE OF TOXICOLOGICAL EXPOSURE TO THE ENVIRONMENT Submitted by: Nidhi Gera 2011CEV3063 Varsha Singh 2011CEV3064 Swati Sharma 2011CEV3065 Vikas Agrawal 2009TT10835
introduction A significant number of operations within a tannery are wet operations consuming large amounts of water, chemicals and energy and leading to large amounts of polluted water. The uncontrolled release of tannery effluents to natural water bodies increases health risks for human beings and environmental pollution. Effluents from raw hide processing tanneries produce wet blue, finished leather, contain compounds of trivalent chromium (Cr3+),sulphides (S2-) and colour. Organic and other ingredients are responsible for high BOD (Biological Oxygen Demand), COD (Chemical Oxygen Demand)and TSS values and represent an immense pollution load, causing technical problems, sophisticated technologies and high costs in concern with effluent treatment. Through this term paper we will demonstrate that by means of a combination of biological and physico-chemical treatment technologies, complex tannery wastewater can be effectively and efficiently treated with high reduction rates.
methodology Sr. No. Different Treatment Process Treatment Technologies 1 Primary treatment ( involves Metal grating, shortening the retention time). Primary settling tank is used for removing almost half of suspended solids. 2 Secondary treatment Aerobic Treatment Anaerobic Treatment activated sludge trickling filter - for biological Treatment oxidation ponds Chlorination - applied for disinfection UASB- for Anaerobic treatment of wastewater converts the organic pollutants into a small amount of sludge and large amount of biogas as methane and carbon dioxide 3 Tertiary treatment (involves a series of additional steps to further reduce organics, turbidity, N, P, metals, colour and pathogens) - Coagulation - Filtration - Activated carbon adsorption of organics Physiochemical Process - Disinfection 4Sludge Treatment-Thickening - Digestion - Dewatering -Incineration -Final Disposal
Results : Different Technologies for effective removal of pollutants Sr No. TechnologiesEfficiency/ Effectiveness (on the basis of data available through experiments) 1 Electro coagulation and Electro-Fenton methods EF Process is much efficient than the EC process in terms of COD and sulfide removal. 2Catalytic oxidation Aeration is required in Catalytic Oxidation of almost 7 n half with 98% removal efficiency of sulfide to maintain the optimum concentrations of the catalysts. With no catalyst used in the process, the sulfide removal was found to be 80% effective with an 8-hour aeration period. 3 Chemical oxidation using manganese oxide (IV) The amount of sulphides and the pH of solution have an influence on oxidation process duration; it is longer when the sulphide amount and pH in WW is higher. 4Wet Oxidation The pre-treatment is favoured by the fact in wet oxidation that it contains high amounts of NaCI: %.which reduces the phenolic compound/ ammonium Nitrogen/ oxidation of sulfides. 5Galvanostatic electrolysis Higher current densities resulted in a faster COD removal due to a greater electro generation of active chlorine. 6Batch SettlingEffective in removal of Suspended solids and Total solids and helps in removal of MLSS. 7 Constructed wetland system This study is carried out with Pilot units which is vegetated with plants like Canna indica, Typha latifolia for surface water/ ground water in which it was shown that horizontal subsurface flow can be a viable alternative for reducing the organic matter content from tannery wastewater. 8 Removal of Chromium from Tannery Effluents. By Adsorption/Biological/ Chemical techniques -Cr 3+ around 98-99% get precipitated as cr (0H) 3. Cr (VI) can be removed by biological treatment. Cr(VI) concentration decreases until reach nil after 96hr in all isolates except (S46).- - In Adsorption, chromium removal is controlled by degree of stirring. As rate of stirring increased the removal. 9Electrodialysis Dimensional stability of membrane (MTS,MCS) is used which increases as the polymer affinity for water decreases.The membranes had higher resistance due to the residual organic matter present in the effluent, which might have caused the membranes fouling, hindering the transport, and consequently increasing electric resistance thus helping in removal of color.
summary The extent of pollution created by tanneries required different biological/chemical /Physical treatment and disposal of effluent wastewater for effective removal of unwanted toxicological exposure to plants and living beings. Biological treatment methods is a better choice for removal of organic and certain inorganic content yet the process efficiency is questioned. It is generally accepted that anaerobic treatment is less energy intensive and superior in most respect for the tannery wastewater treatment than the aerobic treatment. The application of combined process of physical or chemical with biological process to treat tannery wastewater would give satisfactory results compared to individual treatment processes.
INTRODUCTION Nanotechnology manipulates matter at the nanoscale (1–100 nm) producing nanoproducts and nanomaterials -physicochemical properties The Woodrow Wilson Database lists consumer products in market incorporating NPs -259 containing silver nanoparticles (AgNPs)- largest and fastest growing class of NMs in product applications Sources of Silver Nanoparticles present in sludge: Silver is used as an antimicrobial agent in ointments and creams. Manufacturers add silver nanoparticles to hundreds of consumer products, including food storage containers, computer keyboards, cosmetics, pillows, cell phones, and medical appliances. Manufacturers of clothing articles exploit its antimicrobial property to produce novel items like ‘No stink socks’.
Effect of Silver nanoparticles (AgNPs): Silver is water soluble, unwanted AgNPs are formed in the sludge produce by sewage treatment plants. These antimicrobial nanoparticles could adversely impact desirable microorganisms that decompose waste in sewage treatment plants. For instance, they affect many nitrifying bacteria responsible for biological oxidation of ammonia with oxygen into nitrite followed by the oxidation of these nitrite into nitrates. Nanosized silver sulphide applied to agricultural land could oxidize in soils and release toxic silver ions that kill beneficial soil microorganisms. Occurrence of bio magnification of silver nanoparticles along the food chain. High exposures to silver compounds can cause Argyria, an irreversible condition in which the deposition of Ag in the body tissue results in the skin turning bluish in colour.
OBJECTIVE To find the different types of microorganisms which biosynthesize Silver nanoparticles under controlled laboratory conditions. To analyse different factors affecting Silver nanoparticle synthesis. To quantify field study and lab studies done on Silver nanoparticles in the past 5 years. METHODOLOGY: The term paper was prepared by referring to journals available on published scientific research sites like ScienceDirect.published scientific research Research papers were thoroughly studied -detailed analysis was done on our understanding.
Sl. No. Name of micro organisms which reduce silver nano particles Amount of AgNO ₃ added Incubation Conditions pH Absorbtion (nm) Size of NPs synthesis ed (nm) Referenc e Temp (˚C) Time (Hr) 1Shewanella oneidensis1mM ±3.51 2Fusarium oxysporum1mM to 504 3Escherichia coli1mM to to 456 4Bacillus subtilis1mM to 507 & 23 5Penicillium fellutanum1mM to Pseudomonas aeruginosa 0 to 30 mg/l Micrococcus luteus 0 to 30 mg/l Bacillus barbaricus 0 to 30 mg/l Klebsiella pneumoniae. 0 to 30 mg/l Microorganisms which biosynthesize Silver nanoparticles under controlled laboratory conditions DATA INTERPRETATION:
Various factors affecting the biosorption and toxicity of silver nanoparticles ◦pH ◦salt concentration Maximum adsorption and toxicity of AgNPs on bacterial species was observed at pH 5, and NaCl concentration of <0.5 M but, very less adsorption was observed at pH 9 and NaCl concentration >0.5 M, resulting in less toxicity. It was also seen that Zeta potential plays an important role in adsorption of nanoparticles by microorganisms. In our research on the types of study done on silver nanoparticles it was found that the laboratory work on concentration of nanoparticles have been widely done in the past 5 years but the field study on environmental concerns over harmful effects of AgNPs in the wastewaters has paced in last three years.
CEL 795 TERM PAPER M.Tech ENVIRONMENT Ist Sem
TOPIC REMOVAL OF ARSENIC FROM WATER USING ADSORPTION AND OXIDATION TECHNIQUES
Group Members SWAGAT DAS 2012CEV2275 GOVIND NARAIN 2012CEV2280 DHEERAJ CHAUDHARY 2012CEV2284 ARNAV KUMAR GUHA 2012CEV2268 NANDAN 2011CEZ8473 FATEMEH ZAHER 2012CE19042
Methodology studied 1) REMOVAL OF ARSENIC BY SOLAR OXIDATION AND ADSORPTION- The removal of arsenic by solar oxidation in individual units (SORAS) is currently being explored as a possible economic and simple technology to treat groundwater in Bangladesh and India. Light plays the role of accelerating the oxidation of As(III) to As(V), and also affects the nature of the solid and, hence, its sorptive properties. The efficiency of As removal depends on- the mechanism of formation of the solid iron (hydr)oxide, the rate of As(III) oxidation, and the possibility to include As(V) in the growing solid. Given enough Fe and alkalinity, As may be removed by the simple dark flocculation. 2) REMOVAL OF ARSENIC BY OFF-LINE COUPLED ELECTROCAT OXIDATION AND LIQUID PHASE POLYALYTIC MER BASED RETENTION (EO-LPR)- Electrochemistry and membrane ultrafiltration methods (electro-oxidation and liquid phase polymer based retention technique, LPR, respectively) were off-line coupled to remove As(III) inorganic species from aqueous solutions to achieve an efficient extraction of arsenic species by associating a polymer-assisted liquid phase retention procedure, based on the As(V) adsorption properties of cationic water-soluble polymers,with an electrocatalytic oxidation process of As(III) into its more easily removable analogue As(V) Treatment by the liquid phase polymer based retention technique of aqueous arsenic solutions previously submitted to an electrocatalytic oxidation to convert arsenic(III) to arsenic (V) species quantitatively removes hazardous arsenic from these aqueous solutions.
3) REMOVAL OF ARSENIC BY SAND-ADSORPTION AND ULTRA-FILTRATION- in situ precipitated ferric and manganese binary oxides (FMBO) adsorption, sand filtration, and ultra-filtration (UF) for arsenic removal FMBO shows higher capability of removing arsenic than hydrous ferric precipitate (HFO) and hydrous manganese oxide (HMO) This is ascribed to the combined effects of oxidizing As(III) and adsorbing As(V) for FMBO. The continuous experiments indicate that this process is effective for arsenic removal. The rate of arsenic adsorbing onto FMBO is fast, and most arsenic is removed by the sand filter. UF increases the arsenic removal to a certain extent. 4) REMOVAL OF ARSENIC FROM DRINKING WATER USING ADSORPTION BY MODIFIED NATURAL ZEOLITE- The structure of modified and unmodified clinoptilolite samples from the Gördes–Manisa deposit was studied. The elemental composition and specific surface areas of zeolitic samples were also determined. Iron concentrations in the solution to modify clinoptilolite play important role in the arsenate adsorption. However arsenate adsorption kinetics was slightly affected by them. At lower initial arsenate concentration, arsenate exhibited greater removal rates and best removed when the Fe1-GC was used for adsorbent. Thus, iron modified zeolite can be used as an efficient and economic adsorbent for arsenate removal.
5)REMOVAL OF ARSENIC FROM WATER USING PINE LEAVES use of Chir pine leaves (Pinus roxburghii) to remove As(V) ions from aqueous solutions. Maximum adsorption has taken place at pH 4.0 while equilibrium was achieved in 35 min. Langmuir, Freundlich, Temkin, Elovich, Dubinin–Radushkevich and Flory– Huggins isotherm models were used to explain the phenomenon. Maximum adsorption capacity of P. roxburghii was 3.27 mg/g that was compared with the capacities of some previous adsorbents used for arsenic removal. Adsorption mechanism was explored by Pseudo first- and second-order kinetic models, and it was found that the process followed second order kinetics. The study concluded that the Chir pine leaves can be a good adsorbent for removing As(V) from water owing to the fine adsorption capacity. 6)ARSENIC ADSORPTION PERFORMANCE OF HYDROUS OXIDE NANOPARTICLES: exceptional arsenic removal performance on both As(III) and As(V)species. At near neutral pH environment, the maximum adsorption capacity of HCO nanoparticles is over 170 mg/g on As(III), and 107 mg/g on As(V). Under very low equilibrium arsenic concentrations, the amount of arsenic adsorbed by HCO nanoparticles is over 13 mg/g (Ce at 10 ~g/L) and over 40 mg/g (Ce at 50 ~g/L). Over awide pH range from 3 to 11, HCO nanoparticles demonstrated an unique capability to readily remove As(III), which was not observed previously and is beneficial to their applications for water bodies with various conditions. HCO nanoparticles demonstrated fast arsenic removal rate and high adsorption capability without the need of pre-oxidation and/or pH adjustment, which is very attractive for their real application.
BIOREMEDIATION FOR THE REMOVAL OF URANIUM FROM GROUND WATER Submiteed to –Dr. Arun Kumar Neha Mehta-2012 cev2271 Neeraj Golhani-2012cev2281 Samarpreet Singh- 2012cev 2270 Swati Srivastava- 2012cev3043
Introduction bioremediation is the use of living organisms, primarily microorganisms, to degrade the environmental contaminants into less toxic forms. Bioremediation techniques prove to be more ecofriendly, low cost and easy technique as it uses naturally occurring bacteria and fungi or plants to degrade or detoxify substances hazardous to human health and/or the environment. The bioremediation techniques prove to be much better in comparison to conventional remediation methods especially at low concentrations i.e. high efficiency in detoxifying very dilute effluent and also generate less sludge at the end of the treatment (minimum ratio of disposable chemical and/or biological sludge volume). OBJECTIVE Reduction of uranium present in ground water into less harmful by- products by using bio-remediation techniques. If possible complete removal of uranium from affected water by using microbes. Converting soluble uranium compounds to insoluble forms to treat water containing uranium. PATHWAYS OF URANIUM TO WATER- Uranium can enter ground water because of its presence in earth’s crust. Due to radioactive wastes from nuclear industry. Due to institutional use of radioisotopes(medicine, industry, agriculture, research reactors and test facilities)
Methods used Bioremediation of uranium through reduction of the metal- Microbial reduction of soluble U (VI) to insoluble U (IV) plays an important role in the geochemical cycle of uranium and also serves as a mechanism for the bioremediation of uranium-contaminated waters. Enzymatic U (VI) reduction converts dissolved U (VI) to an extracellular precipitate of the U (IV) mineral uraninite (UO). Thus this has provided a possible mechanism for the removal of contaminating uranium from groundwaters. Bioremediation through rhizofiltration- Rhizofiltration is a type of phytoremediation, which refers to the method of using cultivated plant roots to remediate contaminated water through absorption, concentration, and precipitation of pollutants. In this, suitable plants with stable root systems are supplied with contaminated water to acclimate the plants. These plants are then transferred to the contaminated site to collect the contaminants, and once the roots are saturated, they are harvested. Biomineralization- The term biomineralization refers to the process of production of minerals by biological organisms. The complex mineral produced not only includes metallic or mineral part but also organic part of organism.
Bioaccumulation refers to the accumulation of substances, such as pesticides, or other organic chemicals in an organism. Bioaccumulation occurs when an organism absorbs a toxic substance at a rate greater than that at which the substance is lost. Bioremediation of uranium through biosorption- Biosorption is a physiochemical process that occurs naturally in certain biomass which allows it to passively concentrate and bind contaminants onto its cellular structure. The chemical tolerance of microbes to radionuclides/heavy metals rather than radiation tolerance is therefore preferable for remediation of metal contamination.
Results Reduction of uranium from U (VI) to less toxic, insoluble U (VI) has been the method of choice for many scientists. Since this reaction is performed by bacteria, the results are obtained generally at a fast rate and with more efficiency. Handling bacteria both at lab scale and in fields is easier as their growth rate is high and short if optimum conditions are provided. Bacteria and few algae are able to use a number of metals as electron acceptors e.g. Uranium. Many a times the change in the redox state alters the toxicity or solubility of the metals. Bioaccumulation processes are under study, for removal of uranium, and researches show that bioaccumulation processes are used In acidic medium only. application of biosorption by the brown alga in purification of wastewater for the removal of uranium ions from industrial wastewaters can be suitable for large-scale exploitation. More studies are needed to optimize the system from the regeneration point of view and economic variance Adsorption of uranium ions was quite sensitive to pH of the medium and the maximum biosorption was obtained at acidic pH between 4.5 and 5.5. Temperature has not a favourable effect on biosorption capacity of fungal biomass in the range of 5–35 ◦C.
Rhizofiltration allows in-situ treatment, minimizing disturbance to the environment. Various plant species have been found to effectively remove toxic metals such as cadmium, zinc, uranium etc. Bioremediation can provide final treatment to the contaminated water by reducing uranium levels upto 20 µg/L which is even lower than the US EPA guideline. Limitations- cases include where the metal removal by means of algae was not feasible in practice even though it showed satisfactory results under lab study. Sometimes the living organism is able to intake or tolerates uranium upto a certain concentration only. Beyond which uranium proves toxic to the organism as well. If substantial portion of the U(VI) is strongly associated with the sediments then it cannot be reduced microbially.. In all the methods, efficiency of processes is highly dependent on pH of the system, and efficiency may drasticlly reduce in basic or alkaline mediums. Considering the abundance and diversity of microorganisms in the natural domain, it is of immense importance to identify and characterize microbial strains with high metal accumulation capacity and specificity, Understanding and exploring potential of microbe–metal interaction.
A potential of Biosorption derived for removal of Arsenic from contaminated water
INTRODUCTION The experiment was conducted for banana peel due to its natural, renewable, abundance and thus cost effective biomass. Maximum efficiency found to be 82% at pH 7, contact time 90 minute, dosage 8g, temperature 35 degree and 10 mg/L ion concentration of arsenic.
Effect of pH % removal of As increased with pH of solution and reached optimum value of 86% at pH 7. If pH value is lowered below 7, electrostatic repulsion between metal ions and H + increased and removal of As was seen. If pH is above then 7, electrostatic repulsion decreases and metal adsorption process enhances and it is found to be maximum at a range of 6-8 i.e. at neutral condition.
Effect of temperature % removal increases with the increase in temperature but upto 35 degree and then decreases due to breaking down of bond on the surface of biomass at higher temperature.
Effect of dosage Maximum removal is observed at 8 g/L. It is observed that increase in biosorbent dose results in increase in the number of active sites, which lead to increase in the percentage removal of As ion. However no significant increase in the percentage removal was observed with the increase in biosorbent concentration beyond 8g/L.
Effect of contact time At initial stage of removal there is rapid removal of As ion and later on removal becomes slow and reaches optimum stage at 90 minutes. Further time won’t significantly effect %removal due to the accumulation arsenic species.