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  1. 1. Civil Engineering IV Year - II Semester Academic Year 2020-2021 Course: Solid and Hazardous Waste Management (Course Code: R164201C)
  2. 2. 2 UNIT-5 U6M1 Hazardous Waste Management- sources, collection, U6M2 transport, treatment and disposal methods U6M3 transport, treatment and disposal methods U6M4 Biomedical waste Management U6M5 Biomedical waste Management U6M6 Electronic waste Management; U6M7 Electronic waste Management; U6M8 Environmental law related to waste Management; U6M9 Environmental law related to waste Management; U6M10 Case studies U6M11 Case studies
  3. 3. Hazardous Waste Management- sources, collection  A waste is classified as a hazardous waste if it exhibits any of the four primary characteristics based on the physical or chemical properties of toxicity, reactivity, ignitability and corrosivity.  Toxic wastes are those substances that are poisonous even in very small or trace amounts.  Reactive wastes are those that have a tendency to react vigorously with air or water.  Ignitable wastes are those that burn at relatively low temperatures (less than 60°C) and are capable of spontaneous combustion during storage, transport or disposal.
  4. 4. Hazardous Waste Management- sources, collection  A waste is classified as a hazardous waste if it exhibits any of the four primary characteristics based on the physical or chemical properties of toxicity, reactivity, ignitability and corrosivity.  Corrosive wastes are those that destroy materials and living tissue by chemical reaction.  Infectious wastes include human tissue from surgery, used bandages and hypodermic needles, microbiological materials, etc.  Radioactive waste is basically an output from the nuclear power plants and can persist in the environment for thousands of years before it decays appreciably.
  5. 5. List of Hazardous Chemicals The following hazardous chemicals selected as require priority consideration: 1. Arsenic and its compounds 2) Mercury and its compounds; 3) Cadmium and its compounds; 4) Thallium and its compounds 5) Beryllium and its compounds 6) Chromium (VI) compounds; 7) Lead and its compounds; 8) Phenolic compounds; 9) Antimony and its compounds; 10) Cyanide compounds; 11) Isocyanates; 12) Organo-halogenated compounds except inert polymeric materials; 13) Chlorinated solvents; 14) Organic solvents; 15) Biocides and phytopharmaceutical substances; 16) Tarry materials from refining and tar residues from distilling; 17) Pharmaceutical compounds; 18) Peroxides, chlorates, perchlorates, and azides 19) Ethers; 20) Chemical laboratory materials, not identifiable and/or new, with unknown effects on the environment;
  6. 6. 21) Asbestos 22) Selenium and compounds 23) Tellurium and compounds 24) Polycyclic aromatic hydrocarbons 25) Metal carbonyls 26) Soluble copper compounds 27) Acids and/or basic substances used in the surface treatment and finishing of metals.
  7. 7. Sources of Hazardous Waste  The term hazardous waste often includes by-products of industrial, domestic, commercial, and health care activities. Rapid development and improvement of various industrial technologies, products and practices may increase hazardous waste generation.  Most hazardous wastes are produced in the manufacturing of products for consumption or further industrial application. Hazardous waste sources include industry, institutional establishments, research laboratories, mining sites, mineral processing sites, agricultural facilities and the natural environment. All sources that discharge liquid, gaseous or solid wastes that fit the above definition can be regarded as sources of hazardous wastes.  Some major sources are agricultural land and agroindusty, households, mines and mineral processing sites, health care facilities, commercial facilities, institutional facilities, industrial sites, solid waste disposal sites, contaminated sites and building materials. Major hazardous waste sources and their pollution routes in the environment are listed below.
  8. 8. Agricultural land and agro-industry: Hazardous wastes from agricultural land and agro- industry can expose people to pesticides, fertilizers and hazardous veterinary product wastes. Farms are a major source of these wastes, and agrochemicals can leach into the environment while in storage or can cause damage after their application. Domestic: Households stock various hazardous substances such as batteries and dry cells, furniture polishes, wood preservatives, stain removers, paint thinners, rat poisons, herbicides and pesticides, mosquito repellents, paints, disinfectants, and fuels (i.e. kerosene) and other automotive products. These can present a variety of dangers during storage, use and disposal. Mines and mineral processing sites: Mining and mineral processing sites handle hazardous products that are present in the additives, the products and the wastes.
  9. 9. Health care facilities: Health care facilities are sources of pathological waste, human blood and contaminated needles. Specific sources of these wastes include dentists, morticians, veterinary clinics, home health care, blood banks, hospitals, clinics and medical laboratories. Commercial wastes: Commercial waste sources include gasoline stations, dry cleaners and automobile repair shops (workshops). The types of hazardous wastes generated by these sources depend on the services provided. Institutional hazardous waste sources: Institutional hazardous waste sources are mainly research laboratories, research centers and military installations. Some military installations are used for the manufacture and storage of ammunition, and they are also used as testing grounds for military hardware. Military establishments also carry out activities that generate other types of hazardous wastes of household, commercial and industrial nature.
  10. 10. Industrial hazardous waste sources: Hazardous wastes are created by many industrial activities. For example, the hazardous wastes from the petroleum fuel industry include the refinery products (fuels and tar), impurities like phenol and cyanides in the waste stream, and sludge flushed from the storage tanks. Solid waste disposal sites: These are mainly disposal sites for municipal solid waste, but hazardous wastes that have not been properly separated from other wastes are also at these sites. In developing countries, solid waste disposal sites are a major source of pollutant-laden leachate to surrounding areas, as well as recyclable materials for scavengers, who can collect and resell waste materials that have been exposed to or that contain hazardous substances. Contaminated sites: These are sites that are contaminated with hazardous wastes due to activities that use or produce hazardous substances or due to accidental spills. Former sites of industries that used or produced hazardous materials belong to this group. Building materials: Roofs and pipes made of materials incorporating asbestos, copper, or other materials may present a source of hazardous waste.
  11. 11. Generation of Hazardous Waste The major generators of hazardous waste among 15 industries studied by the environmental protection agency (EPA) are as follows, more or less in order of the quantities produced: • primary metals, • organic chemicals, • electroplating, • inorganic chemicals, • textiles, • petroleum refining, and • rubber and plastics.
  12. 12. The elements of hazardous waste management that must be dealt with include (1) source reduction at the point of generation; (2) recycling both on- and off-site; (3) transportation to processing and/or disposal facilities; (4) treatment and processing to reduce or eliminate toxicity, to reduce the volume, and to immobilize contaminants; and (5) secure long-term storage and disposal.
  13. 13. Waste Collection and Transportation Waste collection agents appear to be generally private companies and are essentially local enterprises rather than national organisations. Most of the existing collectors in Romania are municipal waste collection and transportation contractors and these largely only collect municipal wastes. Some of these collectors also collect refuse- type wastes from commercial and industrial sources, park wastes and construction and demolition wastes. These contractors claim not to collect any hazardous wastes. There are waste recycling organisations that collect wastes from generators, some of these collect hazardous wastes, most notably waste oils, car batteries and, to a lesser extent, solvents.
  14. 14. Hazardous Waste Reduction: In plant waste, reduction measures can be most effective in reducing the air, liquid, and solid waste contaminants generated, and hence the treatment needed to meet disposal standards, with resultant cost savings. Hazardous Waste Recycling: Often it may not be possible to reduce the volume or toxicity of some hazardous wastes. However, it may be possible to reuse the waste material in other processes within the same facility or other related facilities. Hazardous wastes that may be recycled either directly or after processing include water, solvents, spent oils, and selected solids. Hazardous Waste Transportation: The transportation of hazardous wastes always introduces the possibility of accidental spills.
  15. 15. Transportation and Disposal of Hazardous Waste The transportation of hazardous waste can pose a threat to the public. To promote safety and protect the public's health, companies follow four basic control measures for the movement of hazardous waste from a source to disposal site; 1. Hazardous waste manifest: The concept of a cradle-to-grave tracking system is considered key to proper management of hazardous waste. Manifest copies accompany each barrel of waste that leaves the site where it is generated, and are signed and mailed to the receiving sites to indicate the transfer of waste from one location to another. 2. Labeling: Each container is labeled and marked. The transporting vehicle is labelled before waste is transported from the generating site. Companies post warning labels such as: explosive, strong oxidizer, compressed gas, flammable liquid, corrosive material, and poisonous or toxic substances.
  16. 16. 3. Haulers: Because of the dangers involved, haulers of hazardous waste are subject to operator training, insurance coverage, and special registration of vehicles transporting hazardous waste. Handling precautions include restrictive use of the transport trucks and the use of gloves, face masks, and coveralls for the workers' protection. 4. Incident and accident reporting: Accidents involving hazardous waste must be reported immediately to the state regulatory agency, as well as local health departments. Necessary information that will help responders contains the material that should be made available.
  17. 17. Treatment, Storage and Disposal Facilities (TSDF) TSDF is a facility that is permitted to treat, store and dispose hazardous wastes in special hazardous waste management units. TSDFs can be commercial or private – i.e., they may accept hazardous waste from outside generators for a fee, or they may be set up for a manufacturing facility (in which case they do not accept waste from other generators). Definitions:  Treatment – Incineration or oxidation are commonly used to alter the chemical properties of the incoming hazardous waste. Other chemical processes seen in Module 6 may be applied here too. Incineration is detailed in the sections below.  Storage – Storage units are used for temporary storage of hazardous wastes until they are completely treated or disposed of.  Disposal – Hazardous waste landfills or deep underground injection wells are used for this purpose.
  18. 18. Hazardous Waste Processing Technologies: The principal objectives of hazardous waste treatment are (1) toxicity reduction, (2) conversion to forms that can subsequently be processed by other technologies, (3) total elimination (e.g., complete destruction), (4) volume reduction, and (5) immobilization. Treatment technologies used to process hazardous wastes may be classified as (1) biological methods, (2) physicochemical processes, (3) stabilization and solidification, and (4) thermal destruction.
  19. 19. Biological methods (1) Suspended growth processes (aerobic, anoxic, and anaerobic); (2) attached growth processes (aerobic, anoxic, and anaerobic); (3) combined suspended and attached growth processes (aerobic, anoxic, and anaerobic) Physical methods: drying, screening, grinding, evaporation, sedimentation, filtration, fixation, etc. Chemical methods: Oxidation, reduction, neutralization, hydrolysis, etc. Physicochemical processes: (1) Carbon adsorption; (2) chemical oxidation; (3) gas stripping; (4) steam stripping; (5) membrane separation; (6) supercritical fluids extraction and supercritical water oxidation
  20. 20. Stabilization and solidification: (1) Cement-based solidification; (2) pozzolan-based aggregate; (3) thermoplastic; (4) organic polymers These are the processes designed to improve waste handling and physical characteristics, decrease surface area across which pollutants can transfer or leach, or limit the solubility, toxicity of the hazardous constituents. Solidification/Stabilization can be simply classified in to two types a) In situ S/S b) Ex situ S/S
  21. 21.  Solidification/stabilization (S/S) reduces the mobility of hazardous substances and contaminants in the environment through both physical and chemical means.  Unlike other remedial technologies, S/S seeks to trap or immobilize contaminants within their "host" medium (i.e., the soil, sand, and/or building materials that contain them) instead of removing them through chemical or physical treatment.  Leachability testing is typically performed to measure the immobilization of contaminants. S/S techniques can be used alone or combined with other treatment and disposal methods to yield a product or material suitable for land disposal or, in other cases, that can be applied to beneficial use. These techniques have been used as both final and interim remedial measures.
  22. 22. In Situ Vitrification (ISV) In situ vitrification (ISV) is another in situ S/S process which uses an electric current to melt soil or other earthen materials at extremely high temperatures (1,600 to 2,000 °C or 2,900 to 3,650 °F) and thereby immobilize most inorganics and destroy organic pollutants by pyrolysis. Inorganic pollutants are incorporated within the vitrified glass and crystalline mass. Water vapor and organic pyrolysis combustion products are captured in a hood, which draws the contaminants into an off-gas treatment system that removes particulates and other pollutants from the gas. The vitrification product is a chemically stable, leach-resistant, glass and crystalline material similar to obsidian or basalt rock. The process destroys and/or removes organic materials. Radionuclides and heavy metals are retained within the molten soil.
  23. 23. Ex Situ Physical/Chemical Treatment (assuming excavation) Ex situ S/S contaminants are physically bound or enclosed within a stabilized mass (solidification), or chemical reactions are induced between the stabilizing agent and contaminants to reduce their mobility (stabilization). Nine distinct innovative processes or groups of processes include: (1) bituminization, (2) emulsified asphalt, (3) modified sulfur cement, (4) polyethylene extrusion, (5) pozzolan/Portland cement, (6) radioactive waste solidification, (7) sludge stabilization, (8) soluble phosphates, and (9) vitrification/molten glass.
  24. 24. Encapsulation Is the process where the wastes are enclosed within a stable water resistance material. The encapsulated wastes must then be placed in a land fill or similar disposal site. Stabilization/solidification relies upon mobility reduction resulting from a combination of chemical reaction (e.g., precipitation) and physical entrapment (e.g., porosity reduction). Hazardous waste materials can be encapsulated in two ways: microencapsulation macroencapsulation. Microencapsulation involves mixing the waste together with the encasing material before solidification occurs. Macroencapsulation involves pouring the encasing material over and around a larger mass of waste, thereby enclosing it in a solidified block. Sometimes these processes are combined.
  25. 25. Thermal methods: (1) Vapor, liquid, and solid combustion; (2) catalytic volatile organic chemical (VOC) combustion; (3) fluidized-bed incinerators; (4) pyrolysis reactors Land disposal: (1) Municipal landfills; (2) monofill landfills; (3) land farming; (4) impoundment and storage facilities; (5) deep-well injection
  26. 26. I. Waste Analysis  The incoming waste is first analyzed in order to verify the composition – the hazardous components are characterized. This is done by thorough physical and chemical analysis in a laboratory. The waste analysis must have rules for the following:  Parameters to be analyzed  Safe sampling methods  Labelling  Repeatability of tests  Standardized tests for physical and chemical properties  Trained personnel to handle equipment and hazardous substances
  27. 27. II. Hazardous Waste Landfills  A hazardous waste landfill must fulfill the following design requirements:  Double liner  Double leachate collection removal systems  Leak detection system  Monitoring storm water run-on and run-off  Monitoring wind dispersal  Absence of liquid wastes  Cover system in place
  28. 28. III. Incineration of hazardous wastes The definition of an incinerator is “any enclosed device that uses controlled flame combustion and does not meet the criteria for classification as a boiler, sludge dryer, carbon regeneration unit, or industrial furnace”. Typical incinerators include rotary kilns, liquid injectors, controlled air incinerators, and fluidized-bed incinerators. There are three factors which ensure the completeness of combustion in an incinerator: 1. Temperature of combustion chamber 2. Length of time wastes are maintained at high temperatures 3. Turbulence (degree of mixing)
  29. 29. Hazardous Waste Disposal The sound treatment and disposal of industrial waste and industrial hazardous waste is an essential element of an effective overall waste management system. In general terms, treatment at source is most appropriate for low-capital cost treatment processes or for generators of very large volumes of waste whilst centralised facilities are most appropriate for management of wastes requiring larger capital investments and wastes generated by smaller enterprises. It is generally accepted that centralised, strategic, facilities for environmentally sound management of hazardous wastes are a necessary element of the overall hazardous waste management system. The availability of suitable facilities is a critical element in that the legislation cannot be complied with unless the facilities exist.
  30. 30. The hazardous waste, after treatment, can be ultimately disposed using the following methods: a) Land farming: the treated waste can be used as a fertilizer or soil conditioner with the approval of concerned regulatory entities; b) Deep well injection: a special kind of drilled well is prepared for such purposes. Brine (40% salt solution) is usually disposed in this manner. Precautions for water pollution need to be a concern. c) Surface impediment: encapsulation, fixation, or containment of the waste. This method involves arresting or demobilizing the movement or migration of the waste by containing it in a hard core: clay soil, thermoplastics polymers, non- corrosive metallic containers (carbon-steel tanks), cement, lime, fire glass, rocks. d) Ocean dumping: was mostly practiced from 1945 to the 1970s. Despite the existing public protest, this method continuous to be an alternative for the waste generators.
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