epc_fa2011_lecture_11

epc_fa2011_lecture_11 - Solid Waste Management -- Any...

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Unformatted text preview: Solid Waste Management -- Any material generated by human activity and is considered a waste product (i.e., materials to be discarded).. -- The general term "Solid Waste" (sometimes also called " Refuse") can be defined as waste not transported by water and that has been rejected for future use. -- Type of Solid Wastes by general classification; Municipal Solid Waste (MSW) Industrial Wastes Hazardous Wastes -- Total solid waste produced in US is approximately 75 lb/person/day if we combine all three types of solid wastes. 1 Solid Waste Management Municipal Solid Waste (MSW) -- 1 -- Approximately 5 lb/person/day -- Consist of; Rubbish - nonputrescible (= non-biodegradable) solid wastes include combustible (paper, plastic, textiles, etc.) and noncombustible (glass, metal, etc.) wastes. Garbage - putrescible (=biodegradable) food wastes. -- Main sources of MSW are; Residential (=domestic) wastes Commercial business wastes Water and wastewater treatment sludges 2 Solid Waste Management Municipal Solid Waste (MSW) -- 2 -- Percentage breakdown of MSW; Paper - approximately 35% of MSW Yard Waste - approximately 20% of MSW yearly Glass Waste - approximately 7% of MSW yearly Metal Waste - approximately 8% of MSW yearly Plastic Waste - approximately 10% of MSW yearly Food Waste - approximately 12% of MSW yearly 3 Solid Waste Management Municipal Solid Waste (MSW) -- 3 -- Starting 1960s, amount of MSW has been drastically increased due to two root causes -- Industrialization and Urbanization -- that created a "throwaway" society. Cans, bottles, plastic containers, appliances, tires and many other items were considered to be cheaper to throw away than to reclaim/recycle. Recovery of material has become more difficult because of the use of numerous synthetic materials, bonded plastics, and nonferrous alloys. Packaging for convenience foods, hardware, household items and other goods has created a vast array of material that is easy to discard. The growth of the food-processing industry and the increase in packing associated with convenience foods are the reason for the growing per capita waste production. 4 Solid Waste Management Municipal Solid Waste (MSW) -- 4 -- In addition to the variations in quantity, wide differences in MSW composition exist due to several factors; Frequency of collection - More frequent collections tend to increase the annual amount collected. Per capita income - Low-income areas produce less total waste but with a higher food content in their wastes. Social customs - Some ethnic areas use few convenience foods, and results in less paper materials and more raw food wastes. Climate - in wet areas such as Miami, FL, the moisture content of solid waste is typically 50%. Prevalence of home garbage grinders - Grinders reduce, but do not eliminate food wastes. 5 Solid Waste Management Industrial Wastes -- Wastes associated with industrial processes. -- Approximately 66 lb/person/day. -- Very process-specific. -- Vary greatly among industries. For example, wastes generated by office activities at the plant differ significantly from wastes associated with manufacturing operation at the plant. 6 Solid Waste Management Disposal of Solid Wastes -- 1 -- All solid wastes have to be either disposed of or to be recycled for reuse in one form or another. -- Typical disposal practices include Landfilling Incineration/Energy Recovery Recycling Ocean Dumping -- Percentage-wise, landfill consists 80% and recycling and incineration make up the remaining 20% of all solid wastes. -- Recent trend is heavily geared toward "Source reduction" such as reuse of products and backyard composting of yard wastes. (USEPA’s Zero Landfill and Resource Recycling) 7 Solid Waste Management/Disposal of Solid Wastes Landfilling -- 1 -- Burying solid waste below the land surface. -- On-going municipal problem since many municipally operated landfills are filling to capacity. -- Environmental problems Vector control (mosquitoes and flies) Obnoxious odors Rodents and scavenger birds (e.g., gulls) Water passing through buried solid waste can contaminate groundwater (Leachate) Accidental burning can cause air pollution problems 8 Solid Waste Management/Disposal of Solid Wastes Landfilling -- 2 -- Tremendous difficulties in siting new landfills due to new environmental regulations that strictly govern where landfills can be located, and cannot be located such as Can not be located near wetlands Can not be located near old gravel beds or sandy soils (permeable soil where groundwater contamination could occur) Can not be located near land supporting endangered/rare animals or plants -- Only few large, undeveloped land tracts remain near urban areas where a landfill could be located without being near populated areas. 9 Solid Waste Management/Disposal of Solid Wastes Landfilling -- 3 -- Whenever a municipality attempts to locate a new landfill, considerable opposition is raised by people living near the populated site, including Pressuring local politicians Filing lawsuits NIMBY (Not In My Back Yard) syndrome - almost everyplace is someone’s backyard these actions have recently caused many municipalities to consider other alternatives. cf) PIMBY (Please In My Back Yard) phenomena 10 Solid Waste Management/Disposal of Solid Wastes Incineration/Energy Recover -- Heat generated by solid waste combustion is used to produce steam for heating or electricity generation. -- Steadily gaining popularity from industry side, yet steadily loosing popularity from the resident side. (=NIMBY) Recent renewable energy plant deal in former Navy shipyard site in Portsmouth, VA -- Still has persisting environmental problems such as release of contaminants to the atmosphere due to the incomplete combustion. -- New technologies such as Plasma Arc Incineration. 11 Solid Waste Management/Disposal of Solid Wastes Recycling -- Not a disposal method but can be as effective as a disposal unit. Many materials can be recycled include Metals Paper and cardboard Glass Plastics -- Any materials recycled reduces the amount of waste that needs to be disposed of. -- It can extend the operating life span of a landfill. -- Plastic and metal (especially Aluminum) recycling is most promising due to low overhead of collection and pre-sorting requirements. 12 Solid Waste Management/Disposal of Solid Wastes Plastic Recycling -- 1 -- Recyclable plastics have a Plastic Recycling Codes (PRC) mark specifying their pre-sorting requirement. -- Plastics collected for recycling must first be sorted and separated into polymer types. PRC codes help recycling contractors to do this. -- Most plastics can be recycled, but due to the difficulty in collecting, sorting, cleaning and reprocessing, at present it is only economically viable to recycle three types of plastic from domestic sources; Code 1, PETE (e.g., soft drink bottles) Code 2, HDPE (e.g., milk and juice bottles) Code 3, V (e.g., juice and cordial bottles) 13 Solid Waste Management/Disposal of Solid Wastes Plastic Recycling -- 2 -- Bales of different types of plastic are then returned to factories for reprocessing. -- The steps in the reprocessing process are: a) Large contaminants are removed manually. b) Plastics are either shredded, chopped or ground and then washed to remove further contaminants. c) Material is dried and formed into pellets or powder, ready for remaking into new plastic products. 14 Solid Waste Management/Disposal of Solid Wastes/Plastic Recycling Plastic Recycling Codes (PRC) -- 1 1) Polyethylene terephthalate, PETE -- Often referred to as No. 1 Plastic. -- PETE has the properties of clarity, toughness, and barrier (the ability to maintain carbon dioxide). PETE is the fastest growing plastic used in household applications. PETE represents about 25% of the plastic bottle market. -- A type of plastic that is clear or colored transparent with high gloss; Soft drinks and mineral water bottles, edible-oil bottles, liquor bottles, peanut butter jars, clear film for packaging, filling for sleeping bags and pillows, carpet fibers, fleecy jackets and textile fibers. 15 Solid Waste Management/Disposal of Solid Wastes/Plastic Recycling Plastic Recycling Codes (PRC) -- 2 2) High-density polyethylene, HDPE -- Often referred to as No. 2 Plastic. -- HDPE is characterized by its stiffness, low cost, ease of forming and resistance to breakage. It represents over 50% of the plastic bottle market. -- It produces toxic fumes when burned. Milk jugs, detergent and bleach containers, shampoo and cleaning product bottles, freezer bags, toys, milk crates, crinkly shopping bags. -- Plastics made from recycled waste PETE plastic include; (curbside) Trash bins, crates, rubbish bins, agricultural pipes and pallets. 16 Solid Waste Management/Disposal of Solid Wastes/Plastic Recycling Plastic Recycling Codes (PRC) -- 3 3) Polyvinyl chloride, PVC -- Often referred to as V-3 or No. 3 Plastic. -- PVC is the most versatile of all plastics because of its blending capability. PVC has the properties of good clarity and chemical resistance. -- PVC bottles make up less than 6% of plastic bottles typically found in the household. -- PVC is environmentally indestructible plastic that releases toxic hydrochloric acid when burned. Clear cordial and juice bottles, food wraps, clear plastic bags, automotive parts, garden hose, plumbing pipes and fittings shoe soles, medical bags and tubing. 17 Solid Waste Management/Disposal of Solid Wastes/Plastic Recycling Plastic Recycling Codes (PRC) -- 4 4) Low-density polyethylene, LDPE -- LDPE is widely used in applications requiring clarity, inertness, processing ease, and moisture barrier. -- Its largest end use is as film for plastic bags - garbage bags and garment bags, etc. -- Plastics made from recycled waste LDPE plastic include film for builders/constructions, packaging and plant nurseries, i.e., black plastic sheet. 18 Solid Waste Management/Disposal of Solid Wastes/Plastic Recycling Plastic Recycling Codes (PRC) -- 5 5) Polypropelyne, PP -- Plastic with a smooth surface that cracks easily when bent and is difficult to scratch. -- Typical uses are potato crisp bag, drinking straws, hinged clear lunch boxes, battery cases, ice cream containers, yogurt and margarine containers and syrup bottles. -- It is hard to collect in marketable quantities for recycling and has limited uses in its recycled form. 19 Solid Waste Management/Disposal of Solid Wastes/Plastic Recycling Plastic Recycling Codes (PRC) -- 6 6) Polystyrene, PS -- Plastic with a smooth surface, rigid, brittle plastic that cracks easily when bent such as yogurt containers, plastic cutlery, imitation crystal glasswares. -- Plastics made from recycled waste PS plastic include coat hangers, office accessories, rulers, DVD/CD boxes. -- Another type of PS is called EPS (Expanded PS) -foamed, lightweight, energy absorbing, thermal insulation. EPS is used for fast food packaging such as hot drink cups, takeaway food containers, and styrofoam cups and packing peanuts, egg cartons and meat trays. -- it takes up a large part of landfill space because of its bulk. 20 Solid Waste Management/Disposal of Solid Wastes/Plastic Recycling Plastic Recycling Codes (PRC) -- 7 7) “Other” -- Includes all other plastics, including acrylic and nylon, made with a resin other than the six plastics listed previously, or is made of more than one plastic listed above in a multi-layer combination. -- Some recyclable, depending on what it is. -- Examples are some squeezable syrup and catsup bottles and some microwave food trays. 21 Quick Recap on Plastic Recycling -- Recyclable plastics have a Plastic Recycling Codes (PRC) mark specifying their pre-sorting requirement. -- Most economically viable plastics to recycle from domestic sources; Code 1, PETE (e.g., soft drink bottles) Code 2, HDPE (e.g., milk and juice bottles) Code 3, V (e.g., juice and cordial bottles) 22 Solid Waste Management/Disposal of Solid Wastes Ocean Dumping -- A disposal option to previously available to coastal communities -- barge sold wastes, sail off and dump. -- All ocean dumpings are prohibited as of 1972 (Marine Protection Research and Sanctuaries Act/MPRSA). -- MPRSA has General Permits clauses for - Burial at sea - Transportation and disposal of vessels 23 Quick Recap on Disposal Practices of Solid Wastes Landfilling Incineration/Energy Recovery Recycling Ocean Dumping 24 Solid Waste Management/Disposal of Solid Wastes Solid Waste Landfills -- 1 -- Landfill is the most utilized method of solid waste disposal. -- About 1 ha/yr for every 25,000 people (= 1 acre/10,000 people) is needed for landfilling of solid wastes. -- Sanitary landfill is the most widely used municipal landfill type -- by compacting the waste in layers and covering it with earth at the end of each day's operation. -- For sanitary landfill, compacting and covering are still the basic operations applied today. -- However, considerable improvements have been made recently in developing better compaction and leachate collection methods and systematic site monitoring in junction with more careful site selection approach. 25 Solid Waste Management/Disposal of Solid Wastes Solid Waste Landfills -- 2 Important Considerations for a Landfill Siting Geological setting - Permeability of soils - Location of groundwater - Located near recharge area for a aquifer that is currently in use (for water source) - Located near surface water Area Availability - Primary factor determining the location of the landfill and its operating life. Distance from Waste Source - Greater the distance, the higher the transportation costs. 26 Solid Waste Management/Disposal of Solid Wastes Solid Waste Landfills -- 3 Important Considerations for a Landfill Siting –Cont.d Surrounding Environment - Would residential homes be on major transport route to landfill? - Does surrounding area support threatened & endangered species of plants or animals? Cover Material - Does sufficient cover material exist on or near proposed site? Siting Regulation Issues - Nowhere near an airport (i.e., scavenger birds are considered as airport operational hazard). - Outside of 100-year floodplain. - Nowhere near wetlands. - Nowhere within 200 ft of an earthquake fault. 27 Solid Waste Management/Disposal of Solid Wastes Methods of Landfilling -- 1 Area Method Trench Method Pit Method 1) Area Method -- Solid waste is deposited on the land surface inside an earthen wall. -- Used in regions with high water tables where aboveground filling is necessary to prevent groundwater contamination. -- Sanitary landfill, i.e., by compacting the waste in layers and covering it with earth at the end of each day's operation. 28 Solid Waste Management/Disposal of Solid Wastes Methods of Landfilling -- 2 2) Trench Method -- Solid waste is deposited in a ditch dug below the land surface. -- Used in areas where the groundwater table is far below the land surface. -- Sanitary landfill, i.e., by compacting the waste in layers and covering it with earth at the end of each day's operation. 29 Solid Waste Management/Disposal of Solid Wastes Methods of Landfilling -- 3 3) Pit Method -- Use of an existing, natural depression in the land to deposit solid waste (i.e., depression landfill). -- Equivalent of throwing solid wastes out to a valley. 30 Solid Waste Management/Disposal of Solid Wastes Landfill Concerns (Leachate) -- Gas and leachate productions are the major landfill concerns, both short- and long-term basis. -- Leachate is the contaminated liquid draining from a sanitary landfill that has extracted dissolved and suspended matters from a landfill. -- Leachate varies widely in its composition, depending on the age of the landfill and the type of waste it contains. Could cause a major groundwater contamination if it is not managed properly. 31 Solid Waste Management/Disposal of Solid Wastes Leachate Composition -- Leachate is influenced by solid waste composition in landfill and their biochemical reactions. -- Microbiological decay of organic solid wastes, e.g., from food wastes, vegetation, etc. will occur in the landfill. This results in a high BOD leachate. -- Transformation of organic solid wastes into a high BOD leachate would go through; Complex organics Simple organics Acetic acid (CH3COOH) Methane (CH4) and carbon dioxide (CO2) -- Other waste liquids (solvents, oils, pesticides) are also easily leach through solid wastes, usually become a part of the leachate composition. 32 Solid Waste Management/Disposal of Solid Wastes Measures to Prevent Leachate Movement -- 1 Preventive Measures a) Site Selection - Soils with low permeability - In regions with deep groundwater table b) Low - permeability bottom liner Installed before landfill begins the operation Clay material Synthetic materials (Geomembrane, Geotextile, Geofabric, etc.) c) Leachate Collection System - Installed prior to the operation - Designed to collect leachate and treat in-situ d) Low Permeability Cap (=Closure of landfill by using) - Clay, Synthetic liner and Asphalt or concrete 33 Solid Waste Management/Disposal of Solid Wastes Measures to Prevent Leachate Movement -- 2 Remedial Actions for Leachates -- After groundwater contamination by leachate has occurred - Intercepting Trenches - Well pumping (where leachate plume is deep below the surface can not be intercepted by trenches) 34 Solid Waste Management/Disposal of Solid Wastes Determining the Presence of a Leachate Plume -- Leachate plumes follow the direction of groundwater movement. -- Groundwater movement generally follows land surface topography and slope gradient. -- Monitoring wells serve to allow sampling of groundwater that can be analyzed for detecting the presence of leachate plume and components. (Expensive!) 35 Solid Waste Management/Disposal of Solid Wastes Detecting Volatile Leachate Plumes Soil Gas Survey (SGS) -- Advantages of the Soil Gas Survey over the monitoring well are; It is quicker. It is less costly compared to monitoring well approach so that more locations in a site can be analyzed to detect plume boundaries. -- Soil Gas Survey analyzes volatile organic carbon that diffuses through the soil to the atmosphere for a presence of the plume if it exists (i.e., gasoline plume). 36 Solid Waste Management/Disposal of Solid Wastes Landfill Gas Generation and Management -- 1 Largely resulting from anaerobic microbial decomposition of organic matters. Major gases produced are CH4 (methene gas) and CO2. Nuisance (odor problem) gases include NH3, H2S. Gas Movement -- Gas will move laterally through soil if not vented to atmosphere. -- Lateral gas movement can be prevented by putting gravel packed trenches around soil boundary. Gas will be vented to atmosphere vertically through gravel packed trench. 37 Solid Waste Management/Disposal of Solid Wastes Landfill Gas Generation and Management -- 2 Energy Recovery -- Gas may also be collected for energy recovery (after landfill has closed). -- Pipe inlets are inserted deep into closed landfill to collect gases (CH4). -- Collected gases will be sent to combustion and electricity generation. -- In some landfills, CH4 gas is collected and burned without any energy recovery. 38 Solid Waste Management/Disposal of Solid Wastes Solid Waste Disposal in Southeastern Virginia Southeastern Public Service Authority (SPSA) -- SPSA is a governmental entity established in 1973 to address and manage solid waste problems in Southeastern Virginia. -- Local areas serviced by SPSA include; - Chesapeake - Franklin - Norfolk - Portsmouth - Suffolk - Virginia Beach - Isle of Wright - Southampton -- SPSA is governed by a board of directors with one director from each city and county, and goals of SPSA are; a) Replace numerous municipal sanitary landfills b) Develop long-term plans for solid waste management 39 Solid Waste Management/Disposal of Solid Wastes Composition of Solid Waste -- Important composition characteristics of solid waste for energy recovery (as fuel) are; Moisture Content Volatile matter Ash - residue after combustion Fixed carbon - remaining after combustion Elemental analysis of C, H, O, N, S Heating value (energy that may be released) 40 Solid Waste Management/Disposal of Solid Wastes Solid Waste Energy Recovery -- 1 -- Total Energy content of the solid waste can be determined by assessing the energy content of individual components, and add them up. Step 1 Collect a representative sample (100-200 kg) of solid waste and sort through it, identify the components and measure their weights 41 Solid Waste Management/Disposal of Solid Wastes Solid Waste Energy Recovery -- 2 Step 2 Use available data to compute the energy content of each component. For example, a municipal solid waste was found to contain the following components with corresponding energy values. 42 Solid Waste Management/Disposal of Solid Wastes Solid Waste Energy Recovery -- 3 Step 2 – Cont.d When using energy values, make sure the component basis is consistent, e.g., if energy values are on a dry weight basis, convert solid waste composition to a dry weight basis ⎛ 100 - %Moisture ⎞ kg Dry Solid Waste = kg " Wet" Solid Waste × ⎜ ⎟ 100 ⎝ ⎠ 43 Solid Waste Management/Disposal of Solid Wastes Solid Waste Energy Recovery -- 4 Step 3 Calculate a KJ/kg unit energy content for the solid waste 44 Solid Waste Management/Disposal of Solid Wastes Energy Content Computation Using Modified Dulong Formula -- 1 -- Alternatively, energy content of a solid waste can be computed by using Modified Dulong Formula which is based on chemical composition of waste. O⎞ ⎛ Kj/kg = 337 ⋅ C + 1428 ⎜ H - ⎟ + 9 ⋅ S 8⎠ ⎝ where C, H, O, S represent % of mass of each element in the solid waste 45 Solid Waste Management/Disposal of Solid Wastes Energy Content Computation Using Modified Dulong Formula -- 2 Example) A solid waste sample was analyzed for its chemical composition as shown below. Calculate energy content of the solid waste by using Modified Dulong Formula. 46 Solid Waste Management/Disposal of Solid Wastes Energy Content Computation Using Modified Dulong Formula -- 3 Step 1 First, need to convert the moisture (H2O) portion of the waste to H and O; Moisture = Wet Mass - Dry Mass = 88 -70 = 18 kg of H2O 2 H (H2 O) = (18) = 2 kg H 18 H2 O O 16 O= (H2 O) = (18) = 16 kg H H2 O 18 H= H content = 8.3 + 2 = 10.3 kg O content = 23.7 + 16 = 39.7 kg 47 Solid Waste Management/Disposal of Solid Wastes Energy Content Computation Using Modified Dulong Formula -- 4 Step 2 Since the moisture portion of waste was incorporated into H and O in Step 1, find the percentages by mass of C, H, O, S and ash+N components corresponding to total wet mass. 48 Solid Waste Management/Disposal of Solid Wastes Energy Content Computation Using Modified Dulong Formula -- 5 Step 3 With tallied % of mass of C, H, O, S in the solid waste, calculate energy content using Modified Dulong Formula. O⎞ ⎛ Kj/kg = 337 ⋅ C + 1428 ⎜ H - ⎟ + 9 ⋅ S 8⎠ ⎝ 45.1 ⎞ ⎛ = 337 (32.4) + 1428 ⎜ 11.7 ⎟ + 9 (2.7) 8⎠ ⎝ = 10 ,919 + 8,657 = 19,600 Kj/kg 49 Quick Recap Landfill siting criteria Area, Trench and Pit methods of Landfill Leachate!! Monitoring Wells vs. Soil Gas Survey (SGS) Southeastern Public Service Authority (SPSA) Modified Dulong Formula for calculating the energy content of a solid waste 50 Hazardous Waste Management -- Hazardous waste is most often a by-product of a manufacturing process, i.e., hazardous materials left or thrown away after products are made, they become hazardous wastes. -- Some hazardous wastes also come from the domestic source; domestic garbage can include hazardous wastes such as old batteries, bug spray cans, and paint thinner. 51 Examples of Hazardous Wastes -- Many older exterior paints contained lead (Pb), a known neurotoxin. Local example includes EPA/Portsmouth lead contamination incident in soil in the residential area and playground (2000 to present). -- Synthetic organic chemicals (SOCs) such as DDT (Dichlorodiphenyl trichloroethane; C14H9Cl5). -- Toxic metals and cyanides in sludges from electroplating process and Leaded sludges from gasoline refinery process. -- A underground storage tank (UST) weaken over time and leak its hazardous contents. (i.e., become LUST Leaking Underground Storage Tank) -- Organic and chlorinated solvents from manufacturing processes. -- Acidic metal wastes from metal finishing process. 52 EPA Designation of Hazardous Wastes -- EPA designates hazardous wastes by following categories; a) Wastes from non-specific sources b) Wastes from specific sources -- Once designated, the hazardous wastes are further grouped into following categorization; a) Substances identified as acute hazardous waste b) Substances identified as hazardous waste c) Wastes that exhibit one or more of four characteristics; Ignitability Corrosivity Reactability Toxicity 53 EPA Designation of Hazardous Wastes a) Wastes from Non-specific sources -- 1 -- Generic wastes commonly produced in a variety of industrial processes. -- Includes common halogenated degreasing solvents, electroplating wastes, wastes from metal heat treating and recovery. (halogenated elements - F , Cl, Br, I, At). -- An example is TCE (Trichloroethylene) that is used in removing oils and other contaminants during many metal manufacturing operations. -- Electroplating wastewater typically contains cyanides, metals, and chromates (CrO42-), any sludge generated by treating such wastewaters is also defined as a waste from non-specific sources. 54 EPA Designation of Hazardous Wastes a) Wastes from Non-specific sources -- 2 -- Usually, an Industry and EPA Hazardous Waste Number will be designated to a waste from non-specific sources depending on its characteristic. Code of Federal Register, CFR Part 261.31 -- Each Industry and EPA Hazardous Waste Number has an associated EPA Hazard Code that represents the nature of the waste. 55 EPA Designation of Hazardous Wastes b) Wastes from Specific sources -- Wastes from specific industrial processes identified by EPA Code of Federal Register, CFR Part 261.31 -- These specific sources are divided into 12 categories; 1) 2) 3) 4) 5) 6) 7) 8) Wood preservation Production of inorganic pigments Organic chemicals Pesticides Explosives Petroleum refining Iron and steel manufacturing Primary copper, lead, zinc, aluminum, ferroalloys production 9) Secondary lead production 10) Veterinary pharmaceuticals 11) Ink formulation 12) Coking (with coal) 56 EPA Listed Hazardous Wastes Characteristics -- 1 -- Wastes that have one or more characteristic of following list are called EPA Listed Wastes. Ignitability Corrosivity Reactability Toxicity 57 EPA Listed Hazardous Wastes Characteristics -- 1 A) Ignitability -- It poses a fire hazard; can irritate the skin, eyes, and lungs; and may give off harmful vapors. (gasoline, paint, furniture polish, etc.) -- Characteristics of an ignitable hazardous waste defined by EPA are a) It is a liquid, other than an aqueous solution containing less than 24 percent alcohol by volume and has a flash point less than 60°C (140°F). b) It is not a liquid and is capable, under standard temperature and pressure, of causing fire through friction, absorption of moisture or spontaneous chemical changes and, when ignited, burns so vigorously and persistently that it creates a hazard. c) It is an ignitable compressed gas. 58 EPA Listed Hazardous Wastes Characteristics -- 2 B) Corrosivity -- A corrosive material can wear away (corrode) or destroy a substance. For example, most acids are corrosives that can eat through metal, burn skin on contact, and give off vapors that burn the eyes. -- Characteristics of a corrosive hazardous waste defined by EPA are a) It is aqueous and has a pH less than or equal to 2 (i.e., strong acid) or pH greater than or equal to 12.5 (i.e., strong base). Example includes highly acidic or basic metal cleaning solutions b) It is a liquid that corrodes steel (SAE 1020) at a rate greater than 6.35 mm (0.25 inch) per year at a test temperature of 55°C (130°F) as determined by the test method specified in NACE (National Association of 59 Corrosion Engineers) Standard EPA Listed Hazardous Wastes Characteristics -- 3 C) Reactability -- A reactive material can explode or create poisonous gas when combined with other chemicals. For example, chlorine bleach and ammonia are reactive and create a poisonous gas when they come into contact with each other. a) It is normally unstable and readily undergoes violent change without detonating. b) It reacts violently with water, and forms potentially explosive mixtures with water. When mixed with water, it generates toxic gases, vapors or fumes in a quantity sufficient to present a danger to human health or the environment. c) It is a cyanide or sulfide bearing waste, which, when exposed to pH conditions between 2 and 12.5, can generate toxic gases, vapors or fumes. 60 EPA Listed Hazardous Wastes Characteristics -- 4 D) Toxicity -- Toxic substances can cause illness and even death if swallowed or absorbed through the skin. Pesticides, weed killers, and many household cleaners are toxic. a) Have an oral LD50 toxicity (in rat test) of less than 50 mg/kg b) A dermal LD50 toxicity (in rabbit skin test) of less than 200 mg/kg c) An inhalation LC50 toxicity (in rat test) of less than 2 mg/L Lethal Dose (LD50) -- a measure of an exposure level under precisely described conditions that 50% of the exposed population will die. Lethal Concentration (LC50) -- a concentration that 50% of the exposed population will die. 61 EPA Listed Hazardous Wastes Characteristics -- 5 D) Toxicity – Cont.d -- Otherwise hazardous wastes that are capable of causing or significantly contributing to an increase in serious irreversible, or incapacitating reversible, illness. (Waste listed in accordance with these criteria will be designated Acute Hazardous Waste) 62 Screening Method -Toxicity Characteristic Leaching Procedure (TCLP) -- It simulates the leaching conditions found in landfills and identifies materials that will leach toxic materials if placed in a landfill. (= prescreening method for toxic leaching potential of hazardous wastes) -- In the procedure, a waste -- let's say, industrial process sludge -is extracted (or leached) for 24 hours with an acetic acid solution. This extraction dissolves any constituents that are soluble in acetic acid solution. -- The residual acidic liquid, or leachate is analyzed for several different EPA-listed substances. -- If the leachate contains any of the listed compounds in excess of the specified amounts, the waste is considered to be "TCLP toxic" -- toxic leaching potential when the waste is placed in a landfill. -- Maximum concentration of contaminants for the toxicity characteristic defined in the Code of Federal Register, CFR Part 261.24. 63 Fate of Hazardous Wastes Where does the hazardous waste go? -- Ideally, hazardous waste is reused or recycled. -- If this is not possible, hazardous waste is safely contained while it is stored, transported, and properly disposed of to prevent an accidental release into the environment. -- Typical methods of hazardous waste storage and disposal include; Surface impoundments (storing it in lined ponds) High temperature incineration (controlled burning) Municipal and hazardous waste landfills (burying it in the ground) Deep well injection (pumping it into underground wells) -- More promising methods focus on minimizing waste, reusing and recycling chemicals, finding less hazardous alternatives, and using innovative treatment technologies (EPA main strategy). 64 Exposure to Hazardous Wastes -- 1 How can hazardous waste affect us? -- When hazardous wastes are released in the air, water, or on the land they can spread, contaminating even more of the environment and posing greater threats to human health. -- For example, when rain falls on soil at a waste site, it can carry hazardous waste deeper into the ground and the underlying groundwater in form of leachate. -- A hazardous substance can cause injury or death to a person, plant, or animal if: A large amount is released at one time A small amount is released many times at the same place The substance does not become diluted The substance is very toxic (for example, arsenic). 65 Exposure to Hazardous Wastes Concept of Exposure -- 1 -- Coming into contact with a substance is called an exposure. -- The effects of exposure depend on: How the substance is used and disposed of Who is exposed to it The concentration, or dose, of exposure How someone is exposed How long or how often someone is exposed. -- Humans, plants, and animals can be exposed to hazardous substances through inhalation, ingestion, or dermal exposure. 66 Exposure to Hazardous Wastes Concept of Exposure -- 2 Inhalation (LC50) - we can breathe vapors from hazardous liquids or even from contaminated water while taking a shower. Ingestion (LD50) - we can eat fish, fruits and vegetables, or meat that has been contaminated through exposure to hazardous substances. Also, small children often eat soil or household materials that may be contaminated, such as paint chips containing lead and toy made with Cd. Most common type of exposure is drinking contaminated water. Dermal exposure (LD50) - a substance can come into direct contact with and be absorbed by our skin. 67 Exposure to Hazardous Wastes Concept of Exposure -- 3 -- Exposures can be either acute or chronic. Acute exposure A single exposure to a hazardous substance for a short time. Usually measured as LD50/LC50 Health symptoms may appear immediately after exposure; for example, the death of a fly when covered with bug spray or a burn on your arm when exposed to a strong acid such as from a leaking battery. Chronic exposure Occurs over a much longer period of time, usually with repeated exposures in smaller amounts. For example, people who lived near Love Canal, New York a leaking hazardous waste dump, did not notice the health effects of their chronic exposure for several years. 68 Exposure to Hazardous Wastes Concept of Exposure -- 4 Chronic exposure – Cont.d Chronic health effects are typically illnesses or injuries that take a long time to develop, such as cancer, liver failure, or slowed growth and development. Cancers caused by carcinogenic materials Birth defects caused by teratogenic materials Cell mutations caused by mutagenic materials Chronic exposure to even tiny amounts of hazardous substances can lead to bioaccumulation. Bioaccumulation Some substances are absorbed and stay in our bodies rather than being excreted. They accumulate and cause harm over time (carcinogenic/teratogenic/mutagenic). 69 Important Regulations on Hazardous Wastes -- There are “many many” Federal regulations directly deals with hazardous wastes, and following regulations are the major ones that you should know. (from Civil Engineering perspectives) 1) Resource Conservation and Recovery Act, RCRA (1976) 2) The Hazardous & Solid Waste Amendments (HSWA), 1984 3) Comprehensive Environmental Response, Compensation & Liability Act (CERCLA), 1980 4) Superfund Amendments & Reauthorization Act (SARA), 1986 5) Oil Pollution Act (OPA), 1990 6) Toxic Substances Control Act (TSCA), 1976 7) Emergency Planning and Community Right-to-Know Act (EPCRA), 1986 70 Important Regulations on Hazardous Wastes 1) Resource Conservation and Recovery Act, RCRA (1976) -- Pronounced "rek-ra". -- RCRA applies mainly to tracking and ensuring safe management of hazardous waste from creation to disposal. -- Requirements are enforced through permits that specify the practices and conditions that must be followed by hazardous waste handlers. -- RCRA works together with Superfund (=CERCLA), which addresses the serious problem of abandoned wastes and inactive hazardous waste facilities. -- Superfund handles the mistakes of the past, and RCRA tries to prevent the creation of new hazardous sites. 71 Important Regulations on Hazardous Wastes 1) Resource Conservation and Recovery Act, RCRA (1976) (part 2) -- RCRA also regulates solid waste management and the underground storage tank (UST) program. There are nearly two million USTs around the country. USTs can harm the environment through leaks or spills (=LUST). UST owners and operators must clean up any damage their tanks may have caused. New tanks must also meet stringent standards and be operated to minimize the chance of leaks or spills. -- Heart of RCRA legislation is to hold generators, transporters and owners and operators of waste treatment, storage, and disposal facilities (TSDFs) responsible for their wastes. “from Creation to Disposal” Concept 72 Important Regulations on Hazardous Wastes 1) Resource Conservation and Recovery Act, RCRA (1976) (part 3) a) Generators -- 1 -- Generators are responsible of determining whether the waste is hazardous. -- Generators are responsible of complying with the guidelines for storage of their hazardous waste, i.e., if the waste is stored more than 90 days, obtain permit as a storage facility. -- Generators are responsible of the waste they produce from "cradle-to-grave". The generator cannot avoid liability by contracting with a third party to dispose off the waste. -- Required to develop a manifest system to track hazardous waste, , i.e., "cradle-to-grave,“ upon leaving the facility and continues with it to its ultimate disposal. 73 Important Regulations on Hazardous Wastes 1) Resource Conservation and Recovery Act, RCRA (1976) (part 4) a) Generators -- 2 -- Generators are responsible of all records of hazardous waste activity including manifest for 3 years and submitting biennial reports. -- All generators are required to obtain an EPA identification number. No waste may be transported by or sent to any facility that does not also have an EPA generator ID number. 74 Important Regulations on Hazardous Wastes 1) Resource Conservation and Recovery Act, RCRA (1976) (part 5) a) Generators -- 3 -- Depending on the amount of hazardous wastes produced, generators can be categorized into three groups; Small Quantity Generator (SQG pronounced "squeegees“) 100-1000 kg of hazardous waste per month, and less than 1 kg of acute hazardous waste per month storage time limit is 180 to 270 days Large Quantity Generator more than 1000 kg of hazardous waste per month, or more than 1 kg of acute hazardous waste per month storage time limit is 90 days Conditionally Exempt less than 100 kg of hazardous waste per month, and less than 1 kg of acute hazardous waste per month 75 Important Regulations on Hazardous Wastes 1) Resource Conservation and Recovery Act, RCRA (1976) (part 6) b) Transporters -- Transporters are responsible of ; Comply with the manifest system. Must deliver waste only to the treatment facility listed on the manifest. 76 Important Regulations on Hazardous Wastes 1) Resource Conservation and Recovery Act, RCRA (1976) (part 7) c) Treatment, storage, and disposal facilities (TSDFs) -- Treatment Facilities (TSDF) are responsible of ; Must show good housekeeping activities. Comply with technical standards. 77 Important Regulations on Hazardous Wastes 2) The Hazardous & Solid Waste Amendments (HSWA) of 1984 (part 1) -- Major goal is the protection of groundwater. Land Disposal Prohibitions Minimum Technology Requirements Permitting, Exposure and Risk assessment prohibits bulk liquid hazardous waste in landfills prohibits specific chemicals (halogenated organics) make land disposal the last resort For land disposal facilities: double liners leachate collection systems groundwater monitoring leak detection systems For Incinerators: New standards for destruction and removal of principal hazardous constituents Mandates corrective actions for releases or spills 78 Important Regulations on Hazardous Wastes 2) The Hazardous & Solid Waste Amendments (HSWA) of 1984 (part 2) Inspection and Enforcement More stringent actions, fines and imprisonment Underground Storage Tanks (UST) New regulations for UST's that store liquid, petroleum and chemical products Small quantity generators New requirements for small quantities of hazardous waste generated by auto repair shops, dry cleaners, etc. 79 Important Regulations on Hazardous Wastes 3) Comprehensive Environmental Response, Compensation & Liability Act (CERCLA), 1980 -- Addresses the serious problem of abandoned wastes and inactive hazardous waste facilities. -- To control and clean up uncontrolled hazardous waste sites or poor disposal practices. -- This is also known as Superfund regulation. -- Superfund handles the mistakes of the past, and RCRA tries to prevent the creation of new hazardous sites. 80 Important Regulations on Hazardous Wastes 4) Superfund Amendments & Reauthorization Act (SARA), 1986 -- Extension of CERCLA program to clean up hazardous releases at abandoned hazardous waste sites. 5) Oil Pollution Act (OPA), 1990 -- OPA establishes liability and compensation rules related to oil spills, and creates a $1 billion supplemental compensation fund for oil spills. Exxon Valdez oil spill occurred in Prince William Sound, Alaska, 1989 -- OPA focuses on liability and compensation after a spill has occurred, and guides cleanup of contaminated areas. -- Like Superfund, OPA’s fund can be used for cleanups if responsible parties can’t or won’t do the work themselves. 81 Important Regulations on Hazardous Wastes 6) Toxic Substances Control Act (TSCA), 1976 -- Pronounced as "tos-ka". -- TSCA requires Tests of chemicals that may harm human health or the environment. Reviews of new chemical substances. Limits on the availability of some existing chemicals. Import certification standards to ensure that imported chemicals comply with domestic rules. -- TSCA bars the introduction of chemicals that may pose unreasonable risks to people or the environment, when the risks outweigh possible economic and social benefits. -- TSCA also regulates existing chemicals, particularly PCBs (polychlorinated biphenyls). For PCBs and a few other chemicals (mostly dioxins), TSCA prohibits or limits use and regulates handling, storage, and disposal. 82 Important Regulations on Hazardous Wastes 7) Emergency Planning and Community Right-to-Know Act (EPCRA), 1986 -- EPCRA makes sure people have an opportunity to find out what chemical hazards are in a community, and helps communities plan for chemical accidents or incidents. (i.e., via Freedom of Information Act/FOI). -- EPCRA requires States to develop plans to prepare for possible chemical accidents or emergencies. -- EPCRA It also makes businesses report annually on the chemicals they use and store and the amount of toxic chemicals they have released into the environment. This information will be made available to the public. 83 Treatment and Disposal Methods -- There are four major treatment and disposal methods widely used in practice for managing hazardous wastes ; 1) Physical and chemical treatment 2) Landfill disposal 3) Incineration 4) Chemical fixation 84 Treatment and Disposal Methods 1) Physical and Chemical Treatment -- 1 Primarily removing metals from wastewater Precipitation and coagulation Many metals are readily precipitated when pH is raised to 8 to 10 ranges, usually by addition of lime (calcium hydroxide) Coagulation is used simultaneously to agglomerate the material and remove it from suspension (Cu and Cr removal) Filtration Neutralization Filtration of residual solids after precipitation and coagulation Used to eliminate characteristic of corrosivity (bring pH inside 2 to 12.5 range) 85 Treatment and Disposal Methods 1) Physical and Chemical Treatment -- 2 Oxidation and Reduction (Redox process) Redox = Reduction-Oxidation reaction Electroplating wastes reduction -- Cr4+ is very soluble, but after oxidation, Cr3+ is precipitatable Hexavalent chromium [Cr(VI)] -- Erin Brockovich/Hinkley, CA CCL3 (2008) by EPA, CA considers limiting at 60 ng/L MCL (2009) Cyanide oxidation with CO2 and nitrogen gas Adsorption processes Carbon adsorption and ion exchange to concentrate a contaminant at the surface of a solid (usually on activated carbon) 86 Treatment and Disposal Methods 2) Landfill Disposal -- Suitability of a hazardous waste for landfill disposal is depending on ; Leachability State (solid or liquid) Toxicity Volatility -- Groundwater monitoring is an essential part of any landfill operation. Initial ambient groundwater assessment is conducted to establish the ambient or background level of groundwater quality as well as detect any contamination. -- Secure landfill is the term generally used to refer to a landfill specifically designed for handling hazardous wastes. 87 Treatment and Disposal Methods 3) Incineration -- It is the preferred option for disposal of many hazardous wastes because it reduces relatively large volumes of many waste to only a small amount of residual ash and scrubber sludges. (i.e., wet scrubber) -- Congress and EPA designated incineration as the only acceptable method of disposal for chlorinated organics. Combustion of most organic wastes results in end products of water, carbon dioxide and other inorganics. -- Many corporations are choosing incineration over other disposal methods even when burning costs are significantly greater because the process leaves no appreciable waste and no liability. -- Scrubber sludge can be dewatered and placed in a secured landfill if it is found to be hazardous. 88 Treatment and Disposal Methods 4) Chemical fixation -- A term for several different methods of chemically immobilizing hazardous materials into a cement, plastic, or other matrix. -- Also known as stabilization and solidification. -- The end product should be a solid that is resistant to natural and manufactured processes that could leach contaminants into the surrounding soil or groundwater. Portland cement Lime or Quick lime Thermoplastics Sludges, contaminated soil, metal salts, low-level radioactive wastes Sludges containing metals and oils, contaminated soils, flue gas desulfurization wastes, other inorganic wastes Strong oxidizers, inorganic salts, low-molecular weight volatiles, radioactive wastes 89 Treatment and Disposal Methods Micro- & Meso-Site Remediation Methods -- Depending on type, level and size of contamination, following three methods are most widely used in practice ; Containment Conventional cleanup methods In Situ cleanup methods 90 Micro- & Meso-Site Remediation Methods 1) Containment -- 1 -- To prevent further contamination migration and affecting other areas by wind, surface water, runoff, and groundwater flow. -- Containment is usually a temporary measure intended to "buy time" while other strategies are developed and implemented. -- Common containment techniques include: Pumped containment To intercept the contaminant plume and keep it from expanding. Wells are placed at or near the advancing edge of a plume, and pumped contaminants are removed for treatment. Disadvantage is that the collected groundwater must be treated prior to discharge to surface water or reinjection. 91 Micro- & Meso-Site Remediation Methods 1) Containment -- 2 Capping Leaking landfills and disposal sites can be given a protective cover to prevent additional surface water and precipitation from seeping into landfills/sites and producing more leachate. Capping is usually done by placing 1- to 3-foot thick clay layer or synthetic membrane over the area. By digging a trench, then filling it with a clay or grout mixture that has a very low permeability to block the plume. Slurry walls Usually implemented in junction with pumping to prevent water from building up adjacent to the wall and then flowing around it. 92 Micro- & Meso-Site Remediation Methods 2) Conventional cleanup methods -- Most expensive method, remediation cost will escalate exponentially as the size of contamination increases from micro- to meso-scale. -- Include removal and incineration of contaminated soil, direct pumping and treating of contaminated groundwater, chemical treatment, fixation, or solidification. -- Contaminated vegetation is often incinerated. -- Soils incineration can be accomplished by literally digging up all affected soil and combusting in a rotary kiln furnace. Every living creature in the soil will be completely decimated. 93 Micro- & Meso-Site Remediation Methods 3) In Situ cleanup methods -- 1 -- Removal or destruction of contaminants without removal of subsurface water or soil involved. -- Less expensive than removing/pumping/burning approaches. -- Many new “un-proven” yet expensive technologies come and go. -- Several demonstration projects of proven In Situ cleanup methods have been funded by EPA, DOE (Department of Energy) and DOD (Department of Defense) and producing better to excellent results in comparison to the conventional methods. Vacuum extraction Air stripping In situ biological treatment 94 Micro- & Meso-Site Remediation Methods 3) In Situ cleanup methods -- 2 Applicable when subsurface hazardous materials are sufficiently volatile. Vacuum extraction Air stripping Screened pipes are placed only in the contaminated area, and suction is applied. Normally coupled with air stripping technique. Using compressed air to volatilize subsurface organics. Air is injected below the contaminated zone, and augmented with vacuum extraction. Advantageous of being effective not only in the unsaturated zone, but also in the saturated or groundwater zone. 95 Micro- & Meso-Site Remediation Methods 3) In Situ cleanup methods -- 3 In Situ Biological Treatment -- Supplying nutrients and/or an electron acceptor (hydrogen peroxide or oxygen) to soil bacteria already present in the soil. -- A rich supply of nutrients is pumped into and re-circulated through the contaminated zone. This spurs bacterial growth and reproduction, which creates a demand for even more nutrients. -- With no further nutrient supplied, bacteria starts utilizing organic contaminants as substrate for energy or synthesis, effectively removing and destroying the contaminants. Similar to the biological nutrient removal technique in wastewater treatment plant. -- Special types of bacteria (i.e., designer bacteria targeting specific contaminants such as petroleum-based contaminants) can be also injected directly, but often difficult to obtain EPA approval for the application of such microorganisms due to the fear of introducing non-indigenous microorganisms. 96 ...
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