Test1 Flashcards
what act defines waste material in NL?
Environmental Protection Act
What is waste material?
– A material or thing that may be a danger to the health
of human beings, animals, wildlife or fish, or is of
unsightly appearance, and
– A substance designated as waste material in the
regulations.
- items that are dumped, discarded, abandoned or
otherwise disposed of
EX. Refuse, garbage, rubbish, litter, scrap and discarded
material, including tailings, effluent, sludge, sewage
What is Solid Waste Management
Collection, transportation, handling, storage,
treatment, utilization, diversion, recycling,
reuse, recovery, reduction and disposal of
waste material
What are the issues with Improper disposal of solid waste? (5)
- serious environmental damage:
– Air pollution
– Soil contamination
– Surface and groundwater contamination - diseases in humans that would threaten the public
health - Municipal solid waste is not considered hazardous
- Vectors of infection
– Rodents
– Insects
– Birds - Open dumps can be a nuisance
– Odors
– Fire hazards
– Windblown debris
What is NIMBY syndrome?
Not in my backyard’
Technical challenges must be met
- Social problems
- Economic problems
- Must involve the public in the decision
making process before final plans and
designs are completed.
Main causes of complaints with landfills
odors and visual displeasure
What is SWM?
Solid Waste Management
Solid Waste Management factors include:
– Types
– Waste generation rates
– Sources
– Quantities
In Canada, there are three waste
generation sectors:
– Residential (MSW)
– Institutional, Commercial and Industrial (IC&I)
– Construction and Demolition (C&D)
What is IC&I
Institutional, Commercial and Industrial
What is C&D
Construction and Demolition
types of residential waste (3)
Garbage -food wastes, organic materials
Rubbish/Trash - paper products, plastics, cans, bottles, glass, etc
Ashes - residue from fireplaces and wood stoves
Non-hazardous solid waste from residential
structures
Institutional, Commercial and Industrial (IC&I) come from?
offices, banks, retail stores, restaurants, schools, hospitals
Institutional, Commercial and Industrial (IC&I) does not include
Biomedical wastes from hospitals
Institutional, Commercial and Industrial (IC&I) includes
- Garbage
- Rubbish
- Ashes
- Construction and Demolition
wastes from renovations
Construction and Demolition (C&D) includes
- Lumber and drywall
- Bricks
- Concrete
- Plumbing
- Electrical and wiring
- Asphalt products
what is the highest MSW composition % of
Paper and paper products 39
what is the highest Construction and Demolition (C&D)
Composition (%)
*Wood 27
An Integrated Waste Management Strategy has 3 main components
– Source reduction
– Recycling
– Disposal
What are the 5 Rs?
– Reject (safe disposal)
– Recover (recover energy from waste, reclaim useful portion of waste and remove contaminants)
– Reduce (lower the amount of waste produced)
– Reuse (reuse without breaking down)
– Recycle (use waste materials to produce new materials)
what is Source Reduction? what are examples
Means waste prevention
- Reuse of products on-site
- Redesigning products and packaging making them easier to reuse
- Lengthening the useful lives of products
- On-site composting of yard trimmings
Recycling does source separation of:
glass, organics, metal, paper, and plastic
Disposal Methods include
- Incineration (with energy recovery)
- Land disposal
- Ocean dumping
- Infilling abandoned mines
Approximately ___ % of cost associated with MSW is for collection
60
Compaction in collection vehicle reduces the
volume by approx. ___%
80
benefits of MSW Processing
The most effective way to reduce the volume and weight of MSW
- Reduce the total volume and weight
- Improve its handling characteristics
- Energy recovery from MSW
- Reuse and recycle waste
MSW Proceses include
- Incineration
- Shredding and Pulverizing
- Baling
- Composting
Recycling is?
separating and converting waste materials
into new materials
Advantages of recycling
- Saves on natural resources
- Saves on energy
– To make new products
– Extracting the heat content - Cuts down on space in landfill sites
Source Separation means
that the homeowner or business
keeps the recyclable materials separate
recyclable Metals include
- Ferrous (Contains iron (magnetic))
- Non-ferrous (Aluminum) is a small component
of MSW
Ferrous MSW is
metal that contains iron (magnetic)
Non-ferrous MSW is
Aluminum
* Very high value
* Separated magnetically
* Shredded
Scrap steel and car wrecks are NOT part of MSW (T/F)
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how many trees does it take to make 1 tonne of paper?
19 trees
Recycled paper is never as good as new because it is
– Weaker
– Colour is off
what is cullet?
crushed glass
issues with recycling glass
heavy; expensive to transport
What is the benefit of glass?
Glass is inert and nonpolluting
can be re-melted to produce new glass
plastic is a
Non-biodegradable, petroleum derived substance
How is the following Construction & Demolition Debris recycled?
– Concrete and asphalt
– Wood
– Asphalt roofing
– Drywall
– Concrete and asphalt > > > >road bedding
– Wood > > > >chipped as mulch
– Asphalt roofing > > > >cold mix products
– Drywall > > > >new drywall
What are Tailings
Materials left over after valuable ore is removed
Common minerals found in tailings:
- Arsenic (associated with gold ores)
- Barite
- Calcite
- Fluorite
- Radioactive materials
- Mercury
- Sulfur
- Cadmium
Common additives found in tailing: (4)
- Sodium Ethyl Xanthate (flotation agent)
- Sulfamic acid (cleaning agent)
- Sulfuric acid (leaching agent)
- Calcium (found in lime for pH control)
Environmental Considerations for tailings
- Minerals uncovered and additives used in processing have the
potential detrimental effects on the receiving environment - Mining wastes contain sulfides
- These breakdown to form acid drainage
- Disposal of mine tailing is the most important environmental issue
in a mine’s life - Many projects in developing nations don’t consider these issues
the most important environmental issue in a mine’s life
Disposal of mine tailing
Tailings Waste from Mine Activities depends on
-size of mine
-production rate
- productions
- Tailings storage strategies
-Climate
Tailings Storage Methods include (6)
- Pond storage
- Paste tailings
- Dry stacking
- Underground works
- Submarine disposal
- Phytoremediation
Pond Storage / tailings ponds include
- Impoundment ponds (dam or embankment used to impound
tailings) - Constructed tailing ponds were introduced instead of using
natural ponds - Tailings slurry (dilute tailings with water) were sent to a
tailings storage area (pond)
disadvantages of Pond storage
- can be very toxic
- May be harmful to the environment
- These attract wildlife and waterfowl
-potential seepage or dam failure
can lead to groundwater contamination
source of acid drainage
advantages of Pond storage
reduction of wind transport of finer tailings (water traps tailings)
- Tailings pumped to the pond and allowed to settle
Solid settling: helps contain the tailings pond, they also attract and accumulate the mineral content that exists in tailings water.
Overtime, as these minerals stabilize in the tailings solids, their risk to people and the environment is minimized.
Valley ponds and Earthen dams
Natural topographical ground depressions
Earthen dams - constructed to increase storage
can lead to groundwater contamination
Dewatering of tailings is important -> water can be reused in mining process
Dam failure (breaches) is a major problem
Paste Tailings
Removing water and using thickeners to produce a toothpaste like tailings
Advantages of Paste Tailings
– more water recycled
– Reduced land footprint
– less seepage potential
Disadvantages of Paste Tailings
– much higher production cost
– higher pumping costs
Dry Stacking
Tailings are first dewatered using vacuum or pressure filters
Advantages of Dry Stacking
– Great water savings: potentially
less environmental impacts
– Reduced land footprint
– Delivers more dense and stable
tailings
– Allow better recovery of dissolved
metals and process chemicals
Dry Stacking Disadvantages:
– Very high capital costs
– higher operating costs (consumables and electricity)
– dust generation with high contaminant concentrations
– Tailing are exposed to the air
– Oxidation of sulphides in tailings can create high
concentrations (but low volume) of seepage water
– When wet (periods of rain) will create acid drainage
Underground Works/Backfilling
Backfilling tailings into open pit or underground mines
Underground Works/Backfilling are More expensive than pond storage (T/F)
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Underground Works/Backfilling Benefits:
– reduced need of above
ground storage
– reduced risk of surface
water contamination
– adds significant stability
to underground mines
Submarine Disposal
Tailings conveyed using a pipeline
then discharged in the ocean
issues with Submarine Disposal
Extensive damage to the seafloor
Density and temperature
controls of the tailings are critical
to reduce tailings travel and
floating
Phytoremediation of tailings
hyperaccumulator plants for long term stability and containment of tailings
- Contaminates confined in soil and near the roots of the plants
- Metals precipitate and are stabilized
- Works bests in dry environments
Phytovolatization:
Phytovolatization:
Uptake and transpiration of a contaminant
Phytoexraction:
Uptake of metals from soil by roots into above ground portion of plant
Phytostabilization:
Plant roots bind soils in place – immobilizing contaminants
Phytostimulation:
Plant roots contain organic carbons which microbes use as food (stimulate growth)
Rhizofiltration:
Absorption or precipitation onto roots or absorption into roots (later the plant is removed to remove the contaminants)
MSW Processing includes
- Incineration
- Shredding and Pulverizing
- Baling
- Composting
Most effective way to reduce volume and weight of MSW
Incineration
Incineration reduces MSW volume and weight by
– Volume 90%
– Weight 75%
what makes incineration an expensive option
– Air pollution equipment
– Highly skilled workforce
most economical option for long-haul distances of MSW
Incineration
Resource recovery of incineration
– Waste-to-energy units
– Steam generation
Incineration Does not destroy all MSW, the following solid material remains
Bottom Ash - solid residue remaining in
the furnace after combustion
Fly Ash - carried along in the combustion flue gas
Fine particulate matter
What metals are Concentrated in the ashe?
Lead and cadmium
____ ash generally has higher concentrations of
toxic substances than the _____ ash
Fly ash generally has higher concentrations of
toxic substances than the bottom ash
Air pollution devices: (3)
– Fabric filters
– Acid gas scrubbers
– Electrostatic precipitators
Air Pollution Devices in depth (5)
- Gravity settling chamber
- Cyclone Separators
- Wet Collectors
- Filtration
- Electrostatic Precipitators
What makes incineration an efficient operation
– High combustion temperatures
– Adequate burning times
– Sufficient air supply
– Frequent stack testing
Incineration: Design & Operation
- Continuous feed operation
– Uniform furnace temperature
– Efficient combustion
– Reduces potential thermal shock damage - Batch feed
– Intermittent burns
– Not very efficient
Two phase burning Incineration
– Primary – moisture is driven off while volatile waste is burning
– Secondary – remaining unburned gases and particulates are oxidized
* Eliminate odors
* Reduces the amount of unburned particulates
Energy Recovery Incineration by 2 types
– Boilers are used to convert the heat from combustion into steam
– Water tube wall
* Steel tubes are arranged vertically
* Heat absorbed and circulated through tubes
Advantages of baling
– Significant decreases in waste volume
– Increase the life of MSWLF
– Ease of handling
– Reduction in litter and nuisance potential
– Waste is able to be stacked
– Eliminates on-site compaction
Baling is
Compacting MSW into rectangular blocks
Volume reduction of baling can be as much as
90%
Shredding and Pulverizing is
Size reduction by shredding and pulverizing
Shredding and Pulverizing Volume reduction can be up to
40%
benefit of shredding and Pulverizing
Increases capacity of MSWLF
Sanitary Landfills
most widely used methods for ultimate disposal of SW
Not a dump
Planned and engineered facility for MSW disposal
Constructed and operated in an environmentally sound manner that does not threaten public health and minimizes public nuisances
what is a Open Dumps
MSW placed in a heap on top of the ground was called a dump
disadvantages of open dumps
- Uncontrolled
- Breeding ground for many vectors of disease
- Smelly and unsightly
- Polluted surface and groundwater
- Open fires
Characteristics of MSWLF
- MSW is placed in a suitably selected and prepared landfill site
- Waste is spread out and compacted
- Waste is covered each day with a layer of soil
Sanitary Landfills (MSWLF)
- Technologies are available to prevent groundwater pollution
- Leachate is now collected and treated
- Monitoring systems are used to detect groundwater pollution
Natural attenuation sites
Allowing the Leachate from MSW to percolate
down to the groundwater
benefits of Sanitary Landfills (MSWLF)
Land reclamation – improves poor quality land
allowing it to be used for (in the future):
– Municipal parks
– Playgrounds
– Golf courses
the most economical MSW option
Landfilling
continuous problem with incinerators
bottom ash
layers of a Lined Landfill (8)
- cushion layer
- leachate collecyion layer
- flexible membrane liner
- Compacted soil
4.leak detection - geomembrane
- base layer
- subbase
Most important technical factors for MSWLF Site Selection
– Volume capacity
– Accessibility
– Hydrogeology
– Climate
– Socioeconomic conditions
– Political (public perceptions)
Daily soil cover will account for ___ of the
overall fill volume
20%
Design life for MSWLF usually
25 years
Hydrogeology for MSWLF
- Important to minimize the contamination from a MSWLF to the surrounding environment
- Study the subsurface geology (soil bore holes)
- Rock types and soil gradation
- Permeability
how far must a MSWLF be from an airport
8 km
how far must a MSWLF be from active fault lines
100 m
Leachate must be (3)
– Controlled
– Contained
– Treated
to Control surface water
- 6-12 % slopes on daily cover
- Drainage ditches around perimeter of site
- Use cap on top of final MSWLF
- Use proper grading to divert surface water
Leachate must be intercepted and contained by the
bottom liner
Leachate characteristics
wastewater
high BOD,
low pH,
toxic substances
4 Elements for Successful Composting
- Carbon - for energy and growth
- Nitrogen - for protein and reproduction
- Oxygen - >5% , air has 21%, water <0.2%
- Moisture - 40% to 65%
