Hazardous and Industrial Waste Management
Hazardous and Industrial Waste Management CVEN 4474
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This 13 page Class Notes was uploaded by Lina Vandervort on Thursday October 29, 2015. The Class Notes belongs to CVEN 4474 at University of Colorado at Boulder taught by Angela Bielefeldt in Fall. Since its upload, it has received 33 views. For similar materials see /class/231885/cven-4474-university-of-colorado-at-boulder in Civil Engineering at University of Colorado at Boulder.
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Date Created: 10/29/15
CVEN 44745474 Haz Waste Outline Contaminantfate and transport Air dispersion Radioactive elements Typical Air Pollution Issues Emissions from a stack point source CO NOx SOx as related to smog acid r in and global warming regulated by Hazardous Air Pollutants HAPs At contaminated sites HAPs often originate from soil at ground level over an area Sometimes will also have a point source emissions from soil vapor extraction Remediation activities frequently disturb the can such as excavation and can increase HAP emissions Example of Air Contam from Site Contaminants must volatilize from the groundwater into the vadose zone air H AC Contaminants must diffuse through the air filled pores of the soil sorb dissolve in moisture Contaminants diffuse out of the ground surface Contaminants are dispersed and transported in bu k air ow Wind s eed solar radiation etc affect stabilityturbulence gt more variable on a daily basis and time of day basis than groundwater Height and distance from source affect concs Air Dispersion Example estimate the concentrations of TCE benzene and Cr6 in the air above a gw contaminant plume containing 10 15 and 20 mgL respectively similar to Lowry Air Force Base Advection dispersion diffusion still important More difficult to predict based on wind conditions temperature etc Diffusion through Soil Vapor J D dCdx J ux massareatime D diffusion coefficient ofthe cmpd in AIR cm2s Appendix B of text Estimate based on mol wt amp known cmpd dCdx concentration gradient massvollength Low conc at ground surface if windy 0 conservative Close to equilibrium near the source vapor pressure if NAPL or Henry s with GW conc Dispersion and Advection in the Atmosphere above ground Box model Wind gt Gaussian distribution AA 3D Model of Above Ground Contam Mvmt CXyz Qee1LJZ expliL ZJl exp lrU Vl 2noyozu 2K6y 2 oZ 2 oZ M Q emission of pollutant J A masstime 6y oz horizontal and vertical std dev based on disperion conditions temp turbulence x downwind on centerline wind direction y horizontal distance J to wind direction to pt of interest Z height above ground of point of interest H height of emissionsource 0 at ground 3D Model of Above Ground Contam Mvmt Txtbk eqn on previous page assumes No photoreactions No rain deposition washout Flat level ground ROUGH estimate only Superfund Air Pathway Analysis De ne APA objectives APA 1992 What are the goals amp needs Ex determine max fenceline shortterm cone of benz in air Collect info needed during RIFS to help answer s Design amp Conduct site scoping gtNo risk Potential for signif air contam either undisturbed or during potential remed L risk Screening Assessment Modeling and data collection L risk In Depth APA Modeling amp data collection Establish a baseline Also establish remediation impacted air concs Monitor during site activities Measuring Air Concs Tricky procedures dome on ground Pump air to carbon trap time averaged conc Analysis onsite vs send to offsite lab Concentrations highly variable Can be expensive Particulate Air Pollution RadioaCtiVes 39 baCkground Atoms are composed ofa nucleus with Particles themselves are regulated PM10 protons Pi 1 amu and neutrons Ni 1 amu orbited by electrons e Size matters smaller particles penetrate deeper into lungs Element determined by the of protons Hazardous compounds sorbed to small soil Atomic mass P N solids inha ed7 Isotopes same elementWIth different V nd entrained dust much more complex to atomic weight d l d t t d 39t39 tt mo e ue 0 cap ure epos39 Ion pa ems Radioisotopes have an unstable nucleus and spontaneously emit particles ampor energy aka radiation Types of Nuclear Decay Example Alpha 0 2 P 2 N 4He nucleus Spontaneously emitted from many heavy Carbon 123 stable MC radioactive nuclei with massgt150amu Both are naturally present in environment Very Shom range few mohes m an 39merad with matter only harmful if ingested Beta B fast electron D not change mass of the atom but 0 much more common in nature increases atomic by 1 Medium range in air stopped by glass or aluminum oil Gamma y high energy photon No change in atomic composition More penetrating than on or 3 Related Each isotope has a characteristic decay Xrays are high energy photons of non pattern particle time UCIear origin eleCtromaQnetiC 39 very Rate of decay is a first order reaction Penetrating dNdt A N N atoms A decay const Half life T12n2A 0693 Formation rate of daughter product decay rate of parent f stable daughter N2 NW 1 em Daughter products are often also unstable and decay 39 N2 7 Nlo 97M 39 97M W Example Decay of U238 Element Atomic Mass 121ife decay U 92 238 45E9 yr 0c Th 90 234 24 d 3 Pa 91 234 1 min 3 25E5 yr 0c 7 5E4 yr 0c BIOVENTING Histog When SVE was implemented progress of remediation was monitored by measuring the concentrations of contaminants in the extracted gas Ca and the depletion of contaminant mass in the subsurface There should have been a mass balance contaminant mass removed in SVE gas contaminant mass depleted in soil However it was found that the contaminant mass in the soil was decreasing faster than was accounted for by the mass extracted This was most common at gasoline spill sites under going SVE remediation Where was the mass of contaminant going The answer Bacterial degradation Natural bacteria present in the soil were degrading the contaminants The activity of the bacteria preSVE was limited by oxygen availability Usually oxygen got into the soil pore space simply by diffusion from the aboveground atmosphere This is slow and in contaminated areas bacteria quickly removed all of this oxygen as they biodegraded the contaminants in the background soil the carbon is usually at low concentrations and is poorly degradable therefore oxygen in uncontaminated vadose zone soil is usually ok at 5 18 After SVE was started air containing oxygen from uncontaminated regions or the atmosphere was pulled into the contaminated zone and now the bacteria had oxygen to respire so they could grow by eating the available food source the contaminant Thus the idea for Bioventing was bom Aerobic P39 J J quot of 39 For bioventing to work natural bacteria in the soil must have the capability to degrade the contaminants in the presence of oxygen Luckily aerobic bacteria those that breathe oxygen for survival able to degrade fuel spill compounds BTEX alkanes etc are common in almost ALL soils Bacteria are made primarily of COHNSP elements plus trace amounts of many other elements such as Fe Mn Mg Ca etc To survive aerobic bacteria must have oxygen To grow and reproduce aerobic bacteria must additionally have a source of carbon the food The generalized reaction representing this bacterial activity is Bacteria Organic compound 02 gt C02 H20 more bacteria For organic contaminants this has the potential to transform them from a harmful state into benign carbon dioxide water and more bacteria don t worry these bacteria are not the kind that cause illness in people How much oxygen is needed to degrade contaminants You can get an idea by writing the stoichiometry of the mineralization reaction ignore the new bacteria growth Ane sample for benzene is C6H6 02 gt C02 H20 Just balance the of C from benzene with CO2 therefore 6 CO2 formed then balance the H from benzene with H20 therefore 3 H2O formed Lastly determine how much 02 is required to supply the O in CO2 and H20 therefore 62 31 15 O needed75 O2 molecules With this balanced stoichiometry we have the approximate number of moles of oxygen needed per mole ofbenzene we want to biodegrade This can be converted to a mass of oxygen per mass of benzene benz using molecular weights 1 g benz 1 mol benz78 g benz 75 mol O2mol benz 32 g O2mol O2 31 g 02 Therefore 31 g oxygen will be consumed for every g of benzene biodegraded Of course other factors will in uence the survival of the bacteria and the RATE at which they degrade the contaminants Temperature moisture nutrients mostly NP pH absence of toxic conditions such as high metals or contaminant concentrations all in uence bacterial survival Bioventing Basics The general concept of bioventing is to supply oxygen to bacteria in contaminated vadose zone soil so that they can degrade the contaminants This is generally accomplished by INJECTING AIR 2021 oxygen into the contaminated soil using vertical or horizontal wells just like those used for SVE If this method is going to enhance the cleanup of the contaminated site 2 conditions must be met 1 the contaminant MUST be biodegradable by aerobic bacteria in the soil if not adding oxygen will have no effect 2 oxygen must currently be limited in the contaminated area if plenty of oxygen is already there adding more won t help The primary advantages of bioventing compared to SVE 1 under proper operation and site conditions no offgas treatment is needed this saves money 2 some contaminants that are not very volatile and cannot be efficiently removed by SVE are 39 39 quotJ 39 39 J J 39 39 and cant quot quotJ be removed by biodegradation When air is injected into the subsurface spreading the contamination into clean soil by moving the soil pore gas or forcing this contaminated soil gas to above the ground are concerns Therefore bioventing is not recommended if the contaminant is highly volatile Rule of thumb Vapor pressure gt1 atm then use SVE not bioventing unless the solubility is greater than 10 uMolar then can go up to 10 atm Intermediate volatility compounds can be remediated efficiently by bioventing assuming biodegradability OR SVE vapor pressure between 1 and 0001 atm At less than 0001 atm the compounds are not volatile enough to be efficiently removed by SVE but if they are aerobically biodegradable bioventing can be used Note some compounds are degraded faster by bacteria which function in the absence of oxygen An example are fully chlorinated compoundsthese CANNOT be degraded by aerobic bacteria at least no one has discovered these bacteria YET but can be degraded by bacteria that function without oxygen oxygen is actually toxic to these bacteria So in some cases it is better to let natural bacteria work under oxygendepleted conditions it is just typically a very slow process To help minimize spreading of the contaminants and exposing people by forcing the contaminants aboveground into the atmosphere the top of the well should be screened no closer than 3 to 5 ft below the ground Design of Bioventing l Characterize the site to determine what kinds of contaminants present using records or existing data The contaminants present will allow you to determine if they have appropriate volatility and aerobic biodegradability If ok then proceed 2 Soil gas survey Goal to determine the distribution of contaminants and oxygen in the vadose zone soil both areally and with depth Grid the site with monitoring points Start in the middle of the contaminated area and work out until uncontaminated soils are reached allowing you to bound the contaminated region Measure Total Volatile Petroleum Hydrocarbons TVPH using a field instrument Also measure oxygen and carbon dioxide If oxygen levels at the contaminated locations are gt 5 in the soil vapor then oxygen is not limiting biodegradation Therefore bioventing is not recommended Generally there will be higher oxygen concentrations in the soil vapor near the ground surface and depletion with depth Carbon dioxide should be elevated in areas with high bioactivity but cannot be used as a quantitative indicator due to the effects of soil type buffering and carbon dioxide involvement in carbonate cycle Oxygen and carbon dioxide should also be measured in uncontaminated background soil and are generally gt18 oxygen and lt05 C02 3 In Situ Respiration Test Measure the oxygen uptake rate during a eld pilot bioventing test which will indicate contaminant biodegradation rate Procedure a select or drill a vadose zone well in the contaminated region b inject AIR plus l3 unreactive tracer gas into the subsurface for about 24 hours goal replace existing soil vapor with the new injected gas that is 20 oxygen generally the tracer gas used is Helium c stop injection of gas d monitor the change in oxygen carbon dioxide and tracer gas in the soil vapor over time can measure at monitoring well near injection point OR the injection point itself measure about once per hour should observe a liner decline in oxygen plus increase in CO2 hopefully stable level of tracer continue monitoring for 24 hours or until lt5 oxygen in soil gas e calculate the oxygen uptake rate OUR the linearized oxygen depletion time OUR O2 removed d f IF the concentration of oxygen in the background soil was lt18 need to determine how much oxygen uptake observed in the contaminated region is attributable to biodegradation of natural soil organics Therefore repeat the above oxygen uptake rate procedure in uncontaminated soil Calculate the OURbkg O2d Then correct the OUR calculated in part e for bkg OURcontam OURe 7 OURbkg OR if background oxygen is gt18 assume OURbkg is negligible RULE OF THUMB If OURcontam is gt0 ld then bioventing is recommended If OURcontam lt0 1 look for factors limiting bioactivity such as moisture content or nutrient availability these could be modified in addition with air injection for insitu biodegradation of contaminants g From the OURcontam estimate contaminant biodegradation rates calculate stoichiometry of contaminant mineralization as discussed in the Aerobic Biodegradation of Contaminants section above convert OUR into a mass 02 consumed per mass of soil OUIUlOO mol O2mol aird mol 02mol aird mol air224 L MW02 nair pb mass OZkg soild where MW 02 molecular weight of oxygen nair airfilled porosity of soil pb bulk density of soil kgL g OZkg soil 41 g contamg 02 g contam kg soil 7 d 4 Conduct an InSitu Air Permeability Test same test procedure as for SVE can inject air instead of extract if preferred want ka gt 1 E9 cm2 estimate the radius of in uence of the well But the PRESSURE radius of in uence calculated from the SVE equations will be different from the distance at which enhanced oxygen levels are achieved For bioventing Ri Qa 21 5 05 K11 b OUR nair J b vadose zone thickness If pressure Ri lt bioventing Ri from above use limiting case of SVE Ri for well spacing RULES OF THUMB FOR BIOVENTING DESIGN Qa BV is approx 01 Qa SVE 01 to 1 air exchanges of pore volume d is generally sufficient Lecture 1 Historical Perspective When did hazardous wastes first become recognized as a problem What are some famous incidents which have in uenced regulations and public perception 1962 Rachel Carson s Silent Spring on the effects of the pesticide DDT on birds and the ecosystem 1978 Love Canal hits the news 19421953 site near Niagara Falls NY received 20000 metric tons of chemical wastes with gt80 different compounds disposed in claylined canal 20m x 1000m x 3m deep 1953 covered waste canal and sold property to Niagara Falls School Board school board had KNOWLEDGE of the chemical dumping activities 1955 school opened on site remaining property sold to housing developers by 1972 most homes on the site built 1976 heavy rain subsidence in land lled area ponded surface water contained toxic chemicals 1977 found that 21 of 188 homes adjacent to canal had chemical residues in basements 1978 state of emergency declared by state and federal governments 237 families evacuated 1989 over 140 million spent to relocate residents and clean up the site later review of data on health effects found no clear evidence of signi cant adverse human health impacts which could be related to the compounds present Times Beach Missouri 1970 application of waste oils containing dioxin to roads and farms for dust control animals diedfound 100 ppm dioxin TCDD in soil in town of Times Beach entire town eventually evacuated Bhopal India tragedy Dec 2 1984 methyl isocyanate leak from Union Carbide plant 200010000 deaths gt300000 suffered personal injuries Chernobyl nuclear disaster Soviet Union 26 April 1986 best estimates are some 2000 extra cancer deaths lifetime among almost 200000 liquidators from 1986 and 1987 and 4600 deaths among some 68 million residents of contaminated territories Increases of this magnitude would be extremely difficult to detect against an expected background of 41500 and 800000 cancer deaths respectively among the two groups The major radiological impact is leukemia particularly among liquidators Increases in thyroid cancer among those exposed as children were observed in the more heavily contaminated regions at rates much higher than predicted from previous studies Increases in thyroid cancer are also reported among liquidators and the general population It is important to recognize that current estimates of doses to exposed populations are uncertain in particular doses received early after the accident are not well known Exxon Valdez Oil Spill March 25 1989 several million gallons of crude oil contaminated almost 300 miles of shoreline in Prince William Sound Alaska the largest cleanup problem in US history Pritchard et a1 1991 Our Stolen Future by XX A book about the potential endocrinedisrupting effects of pollution One of the most controversial points was the evidence for decreasing sperm counts in men and feminization of male animals The Solid Waste World Solid waste is defined as any garbage refuse sludge or other waste material It includes solid liquid semisolid or contained gaseous material resulting from industrial commercial mining or agricultural operations or from community activities approximately 114 B tonsyr total of non hazardous solid waste is generated in the Us 7600 million tons industrial nonhazardous waste 2095 million tons oil and gas waste 1400 million tons mining waste 180 million tons municipal solid waste 85 million tons utility waste 32 million tons construction and demolition waste 18 million tons other approx 275 million tonsyr hazardous waste 24 of total solid waste 99 of all hazardous wastes produced by large generators large generators 2 of total number of hazardous waste generators 23 of hazardous wastes generated in 10 states where most manufacturing located 71 from chemical and petroleum industry 22 from metal industry 7 other Types cleanup residuals from hazardous waste spills and remedial activities paint production residuals organic solvents metalbased pigments adhesives organic and oily residuals thick sludges and solids inorganics and organics organic sludges and still bottoms from production of organic chemicals solvents and organic solutions from manufacturing pharmaceuticals plastics etc anion complexes from electrical machinery and metal coating production processes metals and inorganic solutions and sludges from metal nishing petroleum re ning pesticides oils and greases from vehicles and machinery dirty oil with solid contaminants solid inorganic residuals incineration ash air pollution control residuals spent catalysts The Contaminated Site Remediation World Total US environmental spending 1993 100134 billion hazardous waste remediation early 1990s 412 billion 512 of total env 1996 9 billion spent on remediation in Us MacDonald and Rao 1997 Super lnd Remedial Actions treatment technologies selected through scal year 1992 solidi cationstabilization 28 incineration on and off site 26 soil vapor extraction 18 bioremediation in situ and ex situ 10 thermal deso tion 5 rp more than one technology per site may be used bioremediation selected at an increasing number of Superfund sites 1984 gt1992 Average cost to cleanup a private sector Superfund site 25 million site Total estimated cost to cleanup National sites DOD DOE DOI DOA NASA 234 to 289 billion over next 75 years Total estimated cost to cleanup private sites 500 billion to 1 trillion Type of Site Pstimated of Sites Types of Contaminants Superfund 36800 chlorinated VOCs BTEX heavy metals RCRA 80000 chlorinated VOCs BTEX heavy metals LUST 1500000 BTEX petroleum hydrocarbons LUST leaking underground storage tanks DOD 24500 petroleum HC solvents heavy metals PCBs pesticides explosives DOE gt4000 radioactives others Currently there are approximately 1231 sites on the Superfund National Priorities List NPL The most frequently found compounds at NPL sites are lead trichloroethylene chromium benzene tetrachloroethylene arsenic and toluene detected at 43 42 35 34 28 28 and 27 percent of the NFL sites Of the NFL sites the Agency for Toxic Substances and Disease Registry classi ed 109 as public health concerns due to actual and highly probable exposures to toxic chemicals Public exposure is a concern to approximately 715000 people who live within a 1mile radius of these sites Watts 1997 Cleanup at Superfund sites is making progress Of the 1231 sites cleanup is completed or remediation is in full operation at 595 48 at another 424 sites 34 a minimum of 1 remedial strategy has been selected andor is underway and for 135 sites 11 immediate actions have been taken to address severe risks but longterm solutions have not been selected The average time reported to construct the selected remedial process at Superfund sites is on the order of 8 to 10 years so it takes awhile for sites to reach a completed stage It is predicted that by the year 2010 remedies should be completed at 87 of sites currently on the NPL On average about 40 sites year may be added to the NPL according to EPA Sept 27 1999 Chemical amp Engineering News For further information wwwgaogovRCED99245 U S Reglations solution to pollution is dilution gt regulation gt preventz39on 1955 Clean Air Act 1967 Air Quality Act 1970 1977 1990 Clean Air Act Amendments 1956 Water Pollution Control Act 1972 Federal Water Pollution Control Act Amendments 1977 Clean Water Act 1987 Water Quality Act 1965 Solid Waste Disposal Act 1992 Federal Facility Compliance Act 1970 Resource Recovery Act 1972 Federal Insecticide Fungicide and Rodenticide Act FIFRA 1976 Toxic Substances Control Act TSCA 1986 Asbestos Hazard Emergency Respone Act 1976 Resource Recovery and Conservation Act RCRA 1984 Hazardous and Solid Wastes Amendments 1977 Soil amp Water Resources Conservation Act Surface Mining Control amp Reclamation Act 1978 National Ocean Pollution Planning Act 1980 Comprehensive Environmental Response Compensation and Liability Act CERCLA 1986 Superfund Amendments and Reauthorization Act SARA 1986 Emergency Planning and Community Right To Know Act EPCRA Title III of SARA 1990 Pollution Prevention Act Oil Pollution Act Two primary regulatory arenas for hazardous industrial waste urrently generated wastes 2 Cleanup of contaminated sites aka site remediation What is the current outlook on site remediation Survey of consultants and contractors in Soil and Groundwater CleanUp Growth of industry 42 39 25 constant 33 growing larger companies Three issues at the forefront of the soil and roundwater cleanup industry 1 2 3 Source chlorinated solvents Risk Based Corrective reuse of remediated land President Golder Tech Action riskbased cleanup change liability standards nonre ulation of USTs Principal fr GEA Engrg changing costprofit rate of cleanup Info manager PW Grosser regulations enforcement of modifying regulations reg acceptance of natural President OnSite Tech regulations attenuation how clean is clean variable goals site by site technologies to address Manager Roy F Weston too many References American Chemical Society 1992 Hazardous Waste Management Information Pamphlet Devine K 1995 US Bioremediation Market Yesterday Today and Tomorrow 1n Applied Bioremediation of Petroleum Hydrocarbons Ed Hinchee Kittel and Reisinger Battelle Press Columbus OH Kissel J 1993 Course Notes from Haz Waste Management ENVH 446 Dept Environ Health Univ of WA MacDonald J and P Rao 1997 Shift needed to inprove market for innovative technologies Soil amp GW Cleanup AugSept p 1925 Nivissi A 1995 Radioactive and Chemical Wastes course notes from ENVH 524 Univ of Washington Ray BT 1995 Environmental Engineering PWS Publishing Company New York
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