Solid Waste Exam 1 Lecture 3 Flashcards
(33 cards)
What is integrated solid waste management?
Hierarchical approach to waste management to manage increasing volumes of MSW
- source Reduction
- recycling / composting
- combustion / incineration
- landfill
What is source Reduction?
Altering products or materials to reduce amount of toxicity of what gets thrown away
- requires manufactures and consumers to take active role in reducing amount of waste produced
- increases the useful life of manufactured products
- pollution prevention and not producing waste in the beginning
Examples of Source Reduction
- Decrease packaging
- decrease toxicity by use of alternative materials (heavy metals : Cd, Pb, Hg)
- design products to last longer
- reduce paper waste via e-communication
- purchase selectively
Definition of recycling
A resource recovery method
- involves the collection and treatment of waste product for use as raw material in the manufacture of the same or another product
Benefits of recycling?
- Conserve natural resources
- Decrease toxicity
- Less dependence on landfill
- Use less energy (90-95%)
- Community / consumer pride
- Job development : 5 times more jobs than taking straight to landfill
Barriers to recycling ?
- convince factor
- price : plastics, cheaper to buy chemicals and make it new
- labor intensive (who is going to sort it out)
- consumer attitude (quality of recycled goods product)
Recycling collection methods
- drop off : voluntary, least amount of involvement
- buy back : take it there, get dollars for it
- curbside : pick up, they come to you
Three phases to recycling
- collecting secondary materials
- preparing materials for market : crushing cans, break glass, plastics shredded, paper baled, etc. very labor intensive / expensive
- Remanufacturing new products with recycled materials : selling , post consumer products
Recyclable markets
- Paper / cardboard ( 30% of MSW) : grade of paper and color, price fluctuates
- Glass (5% of MSW) : process driven, heavy , breaks, different colors, require separation
- Aluminum (9% of MSW)
- Plastics (12% of MSW) : difficult to crush, degrades and breaks down easily, cheaper to make new plastic, 1% gets recycled
What is composting?
Controlled biological decomposition of organic solid waste under aerobic conditions
- organic waste materials are transformed into soil amendments/ mulch
- decrease volume by 75%
Environmental conditions for composting
- control the environment, right mixture for odor free compost
- Biological
- Chemical
- Physical
Composting - Biological properties
Bacteria , fungi, insects : produce CO2 , heat, water
- Pathogen Reduction : Density of fecal coliform LESS than 1,000 MPN (most probable number) . Density of Salmonella LESS than 3 MPN
- MPN is a technique used to estimate microbial populations in soil water and agriculture products
Composting - Pathogen reduction
Enclosed or within- vessel composting : temp of 131F or higher for pathogen reduction period of THREE days.
Windrow composting : aerobic conditions, 131F or higher for a parthenogenesis Reduction period of FIFTEEN days or longer, minimum of FIVE turnings
Composting - Chemical properties
N, P, K are nutrients that must be managed
-Heavy metal content must not exceed the maximum acceptable concentrations
- Gardeners use a lot of nutrients on a square foot basis for fertilizers, composts, and organic materials. So they must be managed.
Composting - physical properties
- Water
- Oxygen level
- pH 6-8 (neutral )
- particle size
- temp of 130F for optimal temp. Too high = fire possibility, too low = support bacterial growth
- Eliminate toxics and pesticide
- Pile size : conserve energy, mixing
3 steps in composting
- Process waste : shred it, uniform size
- Compost using a technology : Windrow (long piles) , Static pile (uses pipes to control air supply, no turning necessary, control temp) , In vessel : container ,throw everything into it , drums, silos, tunnels
- Post processing : cured, screened, sold
Operational issues with composting?
Permitting Inspections Odors Leachates Pathogens
Properties of Waste Disposal?
- Resource Recovery
2. Incineration
Properties of a Transfer Station
- Receive , handle, separate, convert, process materials
- Transfer solid waste directly from one container to another or from one vehicle to another for transport
- Store solid waste
- Contain a material recovery facility where recyclables are sorted out and recovered
Minimum standards of Transfer Stations
No Off site of litter
Load checking program
Dust and odor control
Permit compliance : daily tonnage maximum, record keeping requirements
What is a material recovery facility?
Mechanical and manual separation of recyclables from MSW and Source Separated Recyclables
( were developed and implemented in order to help meet AB 939 landfill diversion goals)
Benefits of (MRF) Material Recovery Facility?
Reduces overall community truck traffic by consolidating
Reduces air pollution , fuel consumption, and road wear
Allows for screening of waste for special handling
Reduces traffic at the disposal facility
Concerns of a Material Recovery Facility (MRF?)
Vector control : rodents and birds
Air emissions: unloading dry dust waste, driving over unpaved surfaces, loaders and other equipment
Litter
Traffic
Noise : heavy truck traffic and operation of heavy duty facility equipment
Odor
MRF Process
Collection : mixed refuse collection (no separation) , recyclables collection ( co-mingled or separated)
Tipping : unloading of the materials from the collection vehicles , move the deposited material onto conveyors to the separation systems
Processing : sorting , baling
