ES 172 Waste Management (UCSB)

Waste Management Hierarchy
Source Reduction & Reuse, Recycling/Composting, Energy Recovery, Treatment & Disposal
engineered structure with controlled use and environmental control systems
Environmental Controls
-Landfill gas is collected and destroyed
-Gas migration monitoring system in place
The Law: Controlling Landfill Gas
Disposal site operators must ensure that methane and trace gas concentrations do not exceed: (§20921 Title 27, CCR):
-1.25% in any onsite structure;
-5% by volume in air at the facility boundary;
-Trace gases must be controlled to prevent acute exposure
Constituents of Landfill Gas:
45-60% Methane
40-60% Carbon Dioxide
Trace Gases
Organic compounds: trichloroethylene, benzene, vinyl chloride
Basics of Landfill Gas
Landfill gas is generated as organic waste (plant material & food material) decomposes
Amount generated depends upon:
Age of waste (5-7 years vs. 30-40 years)
Waste characterization: organic load
Moisture content of fill/introduced into fill
Temperature in fill and of landfill location (e.g. Alaska versus Southern California)
Landfill Gas Migration
Landfill Gas can migrate from its point of origin depending upon:
Cover Type
Impermeable (clay): migrate outward
Permeable: migrate upward
Barometric Pressure
Natural Geology
Natural and Manmade Pathways: pipelines and conduits
Why Care About Landfill Gas?
-Explosive Hazard: methane is explosive in air at concentrations between 5% – 15% in air
-Asphyxiant: Gases can displace oxygen (e.g. Hydrogen Sulfide)
-Toxins and Carcinogens: benzene, vinyl chloride
How Far Will Landfill Gas Travel?
Regulatory basis: 1,000 feet
Documented Cases: 1,500′ – 2,500′ (rare)
Documented Explosions
1999: An 8-year-old girl was burned on her arms and legs when playing in an Atlanta playground. The area was reportedly used as an illegal dumping ground many years ago. (Atlanta Journal-Constitution 1999)

1994: While playing soccer in a park built over an old landfill in Charlotte, North Carolina, a woman was seriously burned by a methane explosion. (Charlotte Observer 1994)

1987: Off-site gas migration is suspected to have caused a house to explode in Pittsburgh, Pennsylvania. (EPA 1991)

1983: An explosion destroyed a residence across the street from a landfill in Cincinnati, Ohio. (EPA 1991)

1975: Sheridan, Colorado: landfill gas accumulated in a storm drain pipe that ran through a landfill. An explosion occurred when several children playing in the pipe lit a candle. (USACE 1984)

Las Positas Landfill
1940’s – 1967: served as municipal landfill
1967: landfill ceased last waste shipment
~ 1975: City leased the site to the non-profit “Elings Park Foundation” for $1 per year
Elings Park Foundation established Elings Park on 92 acres (landfill occupies 26 acres)
Recreational Fields (soccer, lacrosse, baseball)
BMX track
Hiking trails
Administrative office and several restrooms
Picnic areas
Thermal Oxidizer
-Receives landfill gas
-Removes moisture
-Combusts at 1,5000 Fahrenheit
-Produces carbon dioxide and water vapor
Need for a Local Buffer Zone Ordinance (LBZO)
-Explosive hazard posed by landfill gas (LFG)
-Threat to groundwater
-Title 27 shortfall: 27 CCR §21190 requires facility owners to control LFG in onsite structures located within 1,000 feet of the disposal area
Regulation does not extend beyond the permitted boundary
-Encroaching Development: Ensure long-term availability of disposal sites by avoiding potential conflicts between disposal sites and adjacent land uses (e.g. Lewis Road Settlement Agreement, 2001)
Laguna Seca Landfill
-Located on private property
-Remainder parcel of subdivision
-Closed in 1966 (pre Subtitle D)
-Encroaching development throughout 1980’s and 1990’s left little buffer
-Incomplete waste characterization and LFG monitoring data
Recyclable Materials in Ca.
-2010 in California:
Total Generation: 73 million tons
Recycled: 36 million tons (42 million processed)
Landfilled: 37 million tons
Segregate and bundle similar material types for market or for further processing
-Incoming Material:
Single-Stream Recylables
Mixed Waste
Purpose of Materials Recovery Facility
Segregate and bundle similar material types for market or for further processing
What is a Materials Recovery Facility?
-Mechanical (sorters, magnets, air blowers) and some manual (hand-picking) to separate recyclable materials from trash
-Recyclables baled and sent to market
Types of Materials Recovery Facilities
-Clean: Segregate and bale source-separated Recyclables

-Dirty: Separate recyclable or organics materials from the trash stream for:
Traditional marketing; or,
As feedstock for another process: Anaerobic Digestion; Gasification; Refuse-Derived Fuel, etc.

MRF Components
-Separate Materials based on:
Size: small, medium, large
Density: light, medium and heavy
Magnets: attracts ferrous metal
Eddy Current: deflects non-ferrous in electrical current
Trommel Screens: separate by size
Air Separators: light from heavy
Ballistic Separators
Titech: material type, color, paper,
Material Grades
Mixed: catalogs, mail, magazines
High Grade de-Inked: letterhead, copier paper
Flint (clear)

Plastics: resin identification code (1-7)
PET: soda bottles
HDPE: milk jugs
LDPE: film plastic
PP: margarine tubs, bottles
Polystyrene: lids, cups, CD jewel cases

Aluminum: non-ferrous

Commodity Markets
California Exports:
Aluminum: 99% (Southeastern US)
Steel: 90% Pacific Rim; 10% California
Glass: 93% USA; 7% Mexico
HDPE: 46% Ca; 36% China; 18% USA
PET: 77% China; 14% Ca; 10% Southeastern USA
Cardboard and Paper: 64% USA; 36% China

Foreign Imports: from California
Mixed Paper – largest category: 51%
Top Countries: China, Taiwan, Korea
Paper: China, Korea
Plastics (PET, HDPE, LDPE): China, Hong Kong
Glass: India, Japan, Honduras
Tires: Vietnam, Korea, Hong Kong
Metals: Taiwan, Korea, China

Factors Influencing the Value of Commodities
-Contamination: see “Bale Specifications”
Single stream vs. Multi-Stream
Customer behavior and knowledge
Trash Contamination:
Other Organics
Paper Mold
-Economic Demand: 2008 Global Downturn: bales stockpiled at shipping ports as values plummeted.
Green Fence
Enacted February 2013
Ended November 2013
Purpose: Established 1.5% contamination limit on recyclable bales
US never segregated plastics 3-7 well:
Result: 55 scrap transactions and 7,600 tons of material rejected in 3 months
Shipping Cost
Port Fee
Return Shipping Cost
Landfill Disposal back in US
is the product resulting from the controlled biological decomposition of organic material. More specifically, compost is the stable, humus-like product resulting from the biological decomposition of organic matter under controlled conditions.

is the decomposition of plant remains and other once-living materials to make an earthy, dark, crumbly substance that is excellent for adding to houseplants or enriching garden soil.

5 reasons to compost
-Organics in Waste Stream
-Composting Controls GHG Emissions
Organic materials generate methane in landfill (greenhouse gas, 21x CO2 equivalent)
-Soil/Plant Benefits
-Renewable Energy Production
-Produce Marketable Commodities – $
Environmental Benefits of Compost
-Better environment for plant roots: improves soil structure and porosity;
-Increases infiltration and permeability of heavy soils, thus reducing erosion and runoff.
-Improves water holding capacity, thus reducing water loss and leaching in sandy soils.
-Supplies a variety of macro and micronutrients.
-May control or suppress certain soil-borne plant pathogens.
-Supplies significant quantities of organic matter.
-Improves cation exchange capacity (CEC) of soils and growing media, thus improving their ability to hold nutrients for plant use.
-Supplies beneficial microorganisms to soils and growing media.
-Improves and stabilizes soil pH. Can bind and degrade specific pollutants.
Science of Composting
-Composting is the natural process in which living organisms decompose organic matter into inorganic matter in the soil.
-The organisms feed on the organic material and through respiration generate the energy that they use for movement, growth, reproduction or stored energy.
-The organism excrete inorganic material that enriches the soil.
-When the organisms die, their bodies add to the organic matter in the compost pile.
Composting – All about Microbes
-Composting, whether Aerobic or Anaerobic, is all about making favorable conditions for microbes to digest and metabolize organic material.
Bacteria, Fungi
Physical Conditions: Moisture, pH, Nutrients (Carbon:Nitrogen), concentration of Oxygen (lots or little)
Temperature is indicative of microbial activity: Mesophilic, Thermophilic
Moisture Management (Compost)
=Critical to Moderating Biological Processes
Adding Moisture
Preventing Moisture
What do microbes do in Compost?
-Consume organic matter to grow
Stabilize organic matter
Aerobic oxidation produces CO2
Anaerobic produces reduced compounds organic acids, alcohols
-Mineralize nutrients
Organic to inorganic forms (protein to NH4)
-Transform nutrients
Nitrification – pH and temperature sensitive
Science of Composting (2nd part)
Composting goes through three distinct phases that can be characterized by temperatures.

1. Mesophilic Phase 1 (10-40 0 C)
Lasts only a few days
Explosive growth of bacteria and fungi
Rapid breakdown of soluble sugar and starches

2. Thermophilic Phase (>40 0 C)
Can last from several days to several months depending on size of system
Mixed population of heat loving organisms
High heat helps breakdown of proteins, fats, “tough” plant material like cellulose
High temperature (>55 0C) kill weeds and pathogen harmful to humans
Higher temperature (>600C) kill organism needed for decomposition

3.Mesophilic Phase 2 (10-40 0 C) “Curing Phase”
Can last several months
Bacteria, fungi, actinomycetes( mix between bacteria and fungus, give “earthy” smell) predominate. Invertebrates active.
Supply of organic material has decreased. Remaining organic material is slowly broken down.
Additional chemical reactions take place to make remaining organic material more stable

Composting Chemistry
Important factors in compost chemistry
Needed to oxidize carbon for energy
Without oxygen will produce rotten egg smell
-pH Level
Acids form as organisms digest organic material and lowers pH
Lower pH encourages fungi and the break down of “tough” matter
If pH too low (<4.5) limits microorganisms' activity
Main Players (composting)
Bacteria:major decomposers, breakdown simpler forms of organic material

Actinomycetes:degrade complex organics such as cellulose, lignin, chitin, and proteins -earthy” smell, long “spider webs” filaments

Fungi:Break down tough debris, too dry, too acidic or too low in nitrogen for bacteria to eat

Composting Process
1. Delivery of Feedstocks
2. Load Checking
3. Pre-Processing (e.g. grinding)
4. Blending: Carbon: Nitrogen Ratio
5. Compost Phase: Aerobic or Anaerobic
6. Curing
7. Contaminant Removal (Secondary Screening)
8. Bacterial and Metals Testing
9. Marketing
Composting Methods
-Two Ways of Classes Composting

1. Presence of Oxygen

Windrow Composting
Aerated Static Pile
Aerated Covered Windrow
Forced Air Windrow Composting

– Anaerobic
Other In-Vessel

2.Facility Type:


Aerobic Compost: Moisture level is critical
Optimum moisture content 40-60%
Feels moist to touch, but when squeezed only produces few drops
Aerobic Windrows
-Most common system for wasteof low odour generating potential
-Low capital costs
-High Operating costs
-Aeration by turning with front-end loader or specialized machine
-stable compost in 3-12months
-can be outdoors
Enclosed Aerated Static Piles
-Piles enclosed in a plastic bag, breathable fabric, ridged container or building
-Keep out moisture and control odors
-Use mechanical aeration to control compost conditions
-Not agitated
Aerated static pile
-medium capital costs
-medium operating costs
-forced aeration
-some control of temperature and aeration resulting in faster composting (6-12 weeks)
Static forced air
-Air forces heat outwards
-Some systems can switch direction to keep base core at high enough temperature
-Also helps control odor
Ag-Bag Composting Technology
-Material is pushed into the bag as perforated aeration pipes are laid on the bottom of the bag
-Monitored for temperature and oxygen to ensure proper conditions
-Material is composted in the bags for 60 days and then cured in open windrows for 30 days
-Composts 5,200 tons of food scraps from San Francisco and Oakland and 2,000 tons of yard trimmings from Dixon and Vacaville every month.
Aerated Covered Windrow
-medium capital costs
-medium operating costs
-cover for windrows reusable
-Space efficient
Delivery Feedstock (1.composting process)
Feedstock selection
-Quality of feedstock influences quality of finished compost products.
-Chemical and physical characteristics such as C:N ratio, moisture content and porosity are also important since they determine whether a feedstock can be safely composted by a given composting system at a specific site.
-Common Feedstocks: Materials such as garden organics, wood chips, bark, food organics, manure, biosoilds, grease trap waste
Receiving and Load Checking (2.composting process)
-All incoming raw feedstock material must be verified, weighed and documented, preferably at the main gate.
-Every raw material load must be inspected on arrival for contaminants such as glass, plastics and metals.
-Depending on putrescibility of material received, material may be stockpiled (e.g. woody garden organics) or processed immediately (e.g. food organics)
Blending: Carbon : Nitrogen Ratio (4. composting process)
Organisms use carbon as a source of energy and nitrogen to grow and reproduce.

C:N Ratio: 25:1 – 30:1 is optimal
Carbon: shredded newspaper, straw, wood chips, sawdust, leaves, paper towels, *Sansum table paper
Nitrogen: manure, foodscraps, grass clippings, coffee grounds, fish emulsion

Too little N:
there will be few microorganisms, and decomposition will be slow.
Too much N:
some will turn to ammonia that will volatilize, creating an odor.

Important factors in compost chemistry
Aerobic and Anaerobic
-Carbon-Nitrogen Mix (C/N Ratio)
Carbon provides energy source and building material for 50% of composting organisms’ cells
Nitrogen important in formation of proteins, nucleic acids, amino acids, enzymes etc. for organisms
30:1 Carbon to Nitrogen optimum mix (decreases in curing phase)
Brown and woody carbon
Green and moist nitrogen
Example C/N ratios for several waste types
Cow/Chicken Manure: 2/4
Vegetable Waste: 11/13
Blending (4.composting process)
Blending and size reduction: Careful feedstock preparation is crucial to successful composting in all types of composting systems

*Size Reduction increases surface area upon which microbes act.

C:N Ratio

Moisture Content

End Product Marketing Considerations

Aerobic Composting Phase (5. composting process)
1. Composting process management varies with type of composting technology
2. For outdoor turned windrows, key process management steps are:
Maintenance of thermophilic (55-60°C) conditions to ensure rapid decomposition
Turning to aerate mass, improve oxygen levels, alleviate compaction and avoid odor formation
Addition of water to ensure optimum moisture content for microbial decomposition, and to avoid dust and aerosol production
Curing (6. composting process)
Aging compost to create stable marketable product

1. A period of curing of between 3 and 6 weeks may be required for a stable and mature product suitable for unrestricted application
2. Immature composts can be toxic to plants (oxygen depletion; ammonia release):
3. Curing should be performed in a separate functional area of the composting facility

Cure compost with 40-50% moisture
to promote competitive microorganisms and
avoid salmonella regrowth

Benefits of Cured Compost
1. Increases soil’s structure and ability to hold water and nutrients
2. Can reduce the need for pesticides by increasing soil biological activity
3. Offsets use of natural resources (e.g., peat moss) for mulch
4. Diverts valuable organic materials from landfills
5. Adds organic matter and nutrients to soil, reducing the need for chemical fertilizers.
6. Encourages slow release of nitrogen and lowers the carbon to nitrogen ratio, making nitrogen more available to plants.
7. Kills pathogens and weed seeds
8. Prevents soil erosion.
Contaminant Removal
Post Compost Screening
1. Screening separates compost particles of different size and/or shapes.
2. Purpose of Screening:
removes a physical contaminants from the finished compost: rocks, metal, glass, plastic etc.;
recovers bulking agent from the compost for re-use; and
Quality Control of Marketable Product: particle size specifications for mulch, soil conditioner, top dressing, potting mix
Screened Material
-1/8th inch
Bacterial and Metals Testing (8. composting process)
-Title 14 – California Code of Regulations
Pathogen Reduction:
131 degrees F for 15 days
5 Turnings: maintain aerobic environment (aerobic windrow)
Sampling and Testing:
Biological: Salmonella, E. coli
Heavy Metals
Marketable Products
Final product preparation

1. Creation of specific products: After screening, the base compost product can be blended with a range of additives to form a range of value-added products – e.g. engineered soils, colored mulches, potting mixes, customized products etc.

2. Additives may include: fertilizer; wetting agents; sand; gravel; ash; rock dust; natural soil; dolomite; lime; gypsum etc.

3. Compost blends must have predictable and uniform characteristics to meet market demands

In-Vessel Composting
-Aerobic or Anerobic
-Improved Odor Control
-Greater Process Control
-Anaerobic Digestion allows for production of renewable power
What is In-Vessel Composting?
“a process in which compostable material is enclosed in a drum, silo, bin, tunnel, reactor, or other container for the purpose of producing compost, maintained under uniform conditions of temperature and moisture where air-borne emissions are controlled” – Title 14 CCR, Division 7, Chapter 3.1, Section 17852
Uses forced aeration and/or mechanical agitation to control conditions and promote rapid composting
Each system design is different, but there are some common elements.
Advantages of In-Vessel Composting
1. Composting can be more closely controlled, leading to faster decomposition and more consistent product quality.
2. Effects of weather are diminished
3. Less manpower is required to operate the system and staff is less exposed to composting material
4. Can often be done onsite, saving collection costs
5. Less land area is required
6. Process air and leachate can be more easily collected and treated
7. Public acceptance of facility may be better
8. Can accommodate various types and amounts of organic waste (e.g., odorous biosolids & food)
Two Types of Decomposition
Aerobic – Biological decomposition of organic substances in the presence of oxygen.

-oxygen in…water, heat and CO2 out

Anaerobic -Biological decomposition of organic substances in the absence of oxygen.

-No oxygen…water, heat, CO2, Intermediate Compounds, CH4 out

Intermediate Compounds (VOAs, H2S)

*H2S is what makes it smell like rotten eggs

Aerobic vs. Anaerobic Composting
-In general, aerobic composting is done in the U.S. because it:
Reaches optimal temperatures faster
Leads to faster decomposition
Moves material through the vessel quickly

-Degrades and prevents the formation/emission of odorous compounds which are produced under anaerobic conditions (e.g., hydrogen sulfide and short-chain fatty acids).

-Reasons one might do anaerobic composting
It does not require aeration or turning
It can retain more nitrogen and initial organic matter
Greenhouse gases can be trapped and harvested for energy

Important: Even in aerobic composting there will be pockets of anaerobic activity caused by excess moisture, inadequate porosity, rapid degradation and large pile size

Rotating Drums
-Cylindrical vessels that are automatically turned on a continuous basis, usually at speeds of 1 rpm or less.
Adapted from concrete or feed mixers and cement kilns
-Mix, grind and aerate materials to initiate composting
-Composting starts quickly – partly due to reduced particle size
-Usually have a very short residence time.
Can be said to be more physical than biological
-Can be partitioned for more controlled composting

-high capital costs
-medium operating costs
-Less preparation of starting materials required due to constant mixing and size reduction
-further decomposition required in windrows or aerated static piles

In-vessel (horizontal and vertical configuration)
-high capital cost
-automated system
-composting vessels can be housed in a building or outdoors
Renewable Energy Production
-Wet Digestion
East Bay MUD Sludge Composting
Dry: Dry Fermentation Composting
Anaerobic Digestion Process
1. Feedstock
-Organics separated from trash by MRF
2. Biological Process & Electricity Production
3. Screening & Curing
4. Soil Amendment
In Vessel: Liquid Fertilizer
-Feedstocks: fish waste: High Nitrogen
-Thermophilic Bacteria
Liquid Fertilizer
Solid Fertilizer
Facility Design Standards (In-vessel)
Groundwater Protection
Leachate Management
The site should be well-drained to prevent excess water accumulating at the base of piles after rainfall (if not under cover)
More stringent water management regulations forthcoming from State Water Board (e.g. impervious surfaces for all windrow composting – $$
-“the liquid that results when water comes in contact with a solid and extracts material, either dissolved or suspended, from the solid” [On-Farm Composting Handbook, ed. R. Rynk, 1992].
-The leachate produced in in-vessel systems can often be collected easily using options built into the system.
-It can then be used to:
Rewet active compost, returning nutrients to the next compost batch
Rewet the biofilter
Or is sometimes marketed as a separate fertilizer product
-It can also be disposed through:
The local waste water treatment system, either by truck or pipeline.
An engineered wetland designed to purify the leachate at the facility
Or, other engineered natural purification systems (e.g., filter fields).
State Minimum Standards (Windrow composting facility)
-Odor Control
-Record Keeping
-Pathogen Reduction (temperature and turning)
-Pathogen and Metals Testing
Odor Control
-Feedstock Delivery and Unloading
-Odor Mitigations:
Understand Prevailing Winds
Windrow Caps
Odor Masking
Maintaining Aerobic Conditions
C:N Ratio
-Odor Avoidance:
Maintain proper moisture and aeration to avoid anaerobic compounds (e.g. hydrogen sulfide, dimethyl sulfide, volatile fatty acids, etc.)

Generally there will be anaerobic pockets but as air comes in contact with aerobic organisms, odorants will be degraded.

Make sure incoming materials are stored properly and composted quickly to maintain aerobic conditions

Maintain near neutral pH or add extra carbon to avoid ammonia volatilization at higher pH’s
This can occur in both aerobic and anaerobic conditions

Schedule odor causing activities (e.g., moving raw materials) in early morning and when wind direction is favorable.

-When odors do occur they should be treated.

Odor Engineering Controls
-Air in entire enclosure is captured and treated or can be diluted and exhausted to the atmosphere

Want to design system so as little air as possible needs to be treated

-Depends on quality and quantity of air to be treated, results of air dispersion modeling and proximity to occupied dwellings.

-Odor Treatment Options:
Chemical scrubbing
Thermal oxidation
Non-thermal plasma oxidation
High-carbon wood ash incorporation

-Use moist organic materials (e.g., compost, soil, peat, wood chips, sometimes blended with inert materials such as gravel for porosity) to adsorb and then biologically degrade odorous compounds
Works similar to a compost pile

-Cooled and humidified compost process air is typically injected through a grid of perforated pipes into a bed of filtration media.

-They have been shown to be effective at treating essentially all odorous compounds from composting (e.g., ammonia and volatile organic compounds)

-However, it is important to recognize that
biofilters can be a source of odor
themselves, if not properly maintained

Why Pursue Energy Recovery
-Preserve landfill airspace
California: landfilling 37 million tons of material annually is unsustainable

-Meet diversion mandates
-Generate renewable energy
-Reduce Air Quality Impacts:
Generate less greenhouse gases (as compared to landfilling)
Create marketable products: (e.g. green fuels)

Types of Energy Recovery
1. Biochemical

2. Thermochemical

Biochemical Process Feedstocks
Biodegradable components of the landfill stream:

Food wastes
Leaves, grass, trimmings
Wood waste

Remember: % of US Waste Stream is Organic/Compostable

Anaerobic Digestion
Principle process occurring in landfills (anaerobic environment)

Many waste water treatment plants use AD

Extensive development and use of this technology in Europe
Policies; GHG reduction, Total Organic Carbon restrictions in Landfill stream.

Capital costs are high, but requires less manpower to operate

Microbial digestion of organic waste in the absence of Oxygen

Produces “biogas” (not syngas)

Biogas (~ 50-65% methane, balance CO2, + small amounts of impurities) can be used to generate electricity

AD in Europe
86 facilities larger than 3,300 ton per year capacity

Total installed capacity of 2.8 million tons waste per year

Spain treating 7% of biodegradable components of MSW (13 facilities, average 70,000 tons per year).

Future of Composting – in California
-Threats to Aerobic Windrow:
Encroaching Development
Odor Complaints
New Water Management Standards
Leafy Green Recalls (E.coli)

-Anaerobic Digestion will Rule (including co-digestion at WWTP)
Nuisance Mitigation
Renewable Energy and GHG Reduction

Why is Diversion a Priority?
Burying waste in a landfill is the most expensive disposal option – short-term and long-term

-Current tipping $82.00/ton
-Tipping fees will continue to increase until closure
-Every ton of waste buried carries long-term liability
The City will “own” every ton buried for many years
Case Study: Las Positas Landfill

In contrast…
Processing of source separated comingled recyclables generates revenue
No future or unknown liabilities
Composting of food scraps limits methane production at the landfill

Why Target Food scraps?
-Environmental impacts of organics in a landfill

-Financial benefits

-Greatest opportunity for recovery

-Single largest portion of waste stream

-Produces valuable agricultural commodity

City of Santa Barbara
Waste Characterization 2009

31% food and soiled paper
18% Trash/nondivertable
17% recycleable
7% greenwaste

Strong Candidates: Food-Serving Establishments
compostables 66%
recyclables 21%
trash 13%
Energy Recovery
Energy can be recovered from:

Biodegradable Organics (Anaerobic Digestion); AND,

All Other Organics

Therefore, Energy Recovery technologies have the greatest potential to process the whole MSW organic stream

Available Feedstocks
-Paper and Cardboard
Substantial portion of California’s MSW Energy value

2nd highest energy content
Substantial Volume of Waste (even though light weight)
Plastics fraction growing rapidly and recycling rates are relatively low
Only thermochemical can process

-Biochemical Feedstocks
Food waste
Green/paper waste

Chlorine containing materials (PVC)
metal contaminants

Key Design Consideration Matching Technology to Feedstock
Biochemical: (Anaerobic Digestion):
Wet Organic Material: Foodwaste, grass, leaves

Thermochemical: Dry Organic Material: Wood, Paper, Tires, plastics

Energy Recovery Processes
Biochemical; and,


Thermochemical Processes
Create energy in the form of electricity, fuel or heat from combustion or gasification of solid waste (“Waste to Energy”).
Emergence of Waste to Energy
First plant built in New York City – 1898

Large-Scale thermochemical processes used since the 1800s for commercial applications (e.g. coal processing)

TyssenKrupp Uhde has ~100 gasifiers most for coal

1970’s Oil Embargo led to more widespread development

No new plants have been brought online in the USA in the past 10 years
More stringent air quality standards (Clean Air Act)

Thermochemical processes more widely applied to MSW in Europe and Japan

Thermochemical – Advantages
-Volume and weight reduced (approx. 90%)

-Waste reduction is immediate, no long term residency required

-Destruction in seconds where LF requires 100s of years

-Incineration can be done at generation site

-Air discharges can be controlled

-Ash residue is usually non-putrescible, sterile, inert

-Small disposal area required

-Cost can be offset by heat recovery (heat buildings, etc. )/ sale of energy

Thermochemical – Disadvantages
High capital cost
Skilled operators are required (particularly for boiler operations)
Some materials are noncombustible
Some material require supplemental fuel

Air Emissions:
dioxin, mercury, etc.
Air Volume of gas from incineration is 10 x as great as other thermochemical conversion processes, greater cost for gas cleanup/pollution control

Public disapproval
Risk imposed rather than voluntary
Incineration will decrease property value (perceived not necessarily true)
Distrust of government/industry ability to regulate

Thermochemical Products
Fuel gases
Internal/external combustion engines
Fuel cells

Liquid Fuels
Fischer-Tropsch (FT) liquids
Synthetic ethanol

Ethylene (recycling of plastics)
Ammonia based fertilizers
Substitute petroleum products
Adhesives and resins
Food flavorings

Thermochemical Technology
1. Mass Burn (combustion)
90 facilities in USA; 3 in California
Unprocessed waste is burned (aerobic) with fire
Combustion gasses heat water to produce steam and power a turbine to produce electricity.
90% Volume Reduction
Waste Products: ash and heavy metals
Flame temp: 1500 – 3000ºF

2. Refuse Derived Fuel (combustion)
MSW is pre-processed before incineration:
Feedstock made homogeneous; dried or pelletized to improve combustion
(recyclables and non-combustibles removed)
Feedstock is burned (aerobic) with fire
Combustion gasses heat water to produce steam and power a turbine to produce electricity.
16 facilities in USA (as of 2011)
Waste Products: ash and heavy metals

Solid waste heated to high temperature (oxygen deficit environment) to produce:
“syngas”: electricity and heat
Fischer Tropsch Rxn: converts CO and H2 into liquid hydrocarbons (LNG)
Waste: char and ash
No MSW Gasification in USA:
Common in Japan and South Korea

4. Plasma Arc Gasification
MSW heated to extremely high temperatures (low or no Oxygen)
Resulting gas passes through electrical field where it is ionized into H2 “syngas”
Syngas used to generate electricity.
Waste: inorganic vitrified into glassy residue (road base)
Film on Plasma Arc

Thermally degrades solid waste without additional air or Oxygen.
Similar to gasification but optomized for production of fuel liquids or oils.
Liquids can be used directly or further refined for motor fuels and chemicals
Waste: waste carbon (char)
Temperature Range: 750-1,500o F

Pyrolysis vs. Combustion (Burning)
-Char-Coal: Indirect heating of wood chips in anaerobic environment; (pyrolysis)
bar-b-que charcoal invented by Henry Ford

-Using char-coal to grill a steak (combustion)

Pyrolysis – Historical Applications
Heat wood (indirectly) without fire to produce oil, tar and char. The tar, called “pitch” was used to waterproof the seams of ships.

Later, char mixed with metallic ores such as iron ore and copper ore and burned would produce pure metals. Led to the Bronze Age, Iron Age and metallurgy.

Coal Pyrolysis was popularized: Coal, heated in the absence of oxygen, drove off impurities and produced “coke.” Processing iron ore with coke resulted in a better grade of iron.

Pyrolysis Oils
– Complex mixtures of hydrocarbons
Alcohols, aldehydes, ketones, esters, water, etc

-Can be combusted on site in boilers and engines

-Chemical uses:
Phenol species, acetaldehyde, formaldehyde, aromatic chemicals
Wood waste – fragrances, adhesives, resins, food flavorings, pharmaceuticals

-Dioxins and Furans can concentrate in pyrolytic oils

Air Emissions – Gas Pollutants

-Acid Gases
From Cl, S, N, Fl in refuse (in plastics, textiles, rubber, yard waste, paper)

-Nox: source removal and high temp combustion


-Organic Hazardous Air Pollutants

-Metal Hazardous Air Pollutants

Combustion of chlorinated waste
Feedstocks with high levels of Cl and Cu (PVC)

Formed from Incomplete combustion
Removed by exclusion or with activated carbon

Health Effects:
Birth Defects

Air Pollution Control
Remove certain waste components – PVC
Good Combustion Practices: CO, NOx, SOx
Cold Quenching: dioxins/furans (rapid cooling of gases)
Emission Control Devices
Electrostatic Precipitator: particulates
Baghouse Filter: particulates
Acid Gas Scrubber
Activated Carbon: dioxin, VOCs
Air Emissions Reductions
Federal MACTA Regulations:
Dioxins: 99% Reduction
Mercury: 96%
Cadmium: 96%
Lead: 97%
Particulates: 96%
HCl: 94%
SO2: 88%
Nox: 24%
Thermochemical – Disposal of By-Products
-Ash is taken to a landfill

-Particulates are captured by high-efficiency baghouse filters where 99% of particulates are removed

-Fly Ash falls into hoppers and transported to an ash discharger where they are wetted to prevent dust. They are then mixed with bottom ash.

-Fly ash and bottom ash are then transported in covered containers to landfills.

-Ash can be further processed to remove recyclable heavy metals.

Environmental Impact Summary
-All waste disposal methods carry environmental risks

-Proper design of waste conversion processes must address air emissions, liquid and solid residues

-Characterization and pre-sorting of feedstocks can reduce emissions

-Process and pollution control technologies can minimize environmental impacts, but must be carefully designed and operated

-Overall environmental impacts of well-designed alternative waste conversion technologies are equal to or less than current practice of landfilling

Greenhouse Gas Reductions
According to EPA:

One ton of carbon dioxide equivalent is prevented for each ton of mixed MSW combusted rather than landfilled.

Life Cycle Assessment
-Waste to Energy results in higher reduction in emissions compared to landfill-to-energy per kWh production.

-City of Boulder, CO: electricity produced from MSW instead of combusting coal would result in fewer emissions of Sox, Nox and particulates

Challenges for WTE in USA
1. Financing
2. Huge start-up capital costs vs. typical landfill costs ($100 ton breakpoint)
3. Public Opposition
Bradley Angel
4. Risk: Many facilities have not transitioned from pilot to large-scale applications.

5. Statutory framework for alternative technologies such as gasification in California have not been fully developed
Regulatory framework is not well coordinated among agencies
California: Diversion credit not given for thermal gasification; only pyrolysis
Plasco Energy lost out on premium power sales and project collapsed in Monterey County.
Without a financial premium on power sales, sufficient revenue could not be generated to make economics work.

6. Siting and permitting processes are complex and time consuming
7. Limited information on emissions data including and greenhouse gases
8. Alternative technologies are not perceived as economically cost effective (landfilling is still less expensive)
9. Limited public awareness of the benefits of alt. technologies
10. Good News in US: Flow Control decisions by Supreme Court (Carbone, Oneida Herkimer)

Outlook in USA – Energy Recovery Council
1. Policymakers are looking for renewable energy sources that reduce greenhouse gas emissions and reduce dependence on fossil fuels.

2. Dependable and long-term solutions for municipal solid waste disposal remains a paramount concern for local governments.

3. Higher energy revenues, metals recovery, renewable incentives, and decades of operational efficiency have made waste-to-energy more cost-competitive.

4. High price of transportation fuel coupled with increased distance to new landfills makes landfilling more expensive.

Alternative Technologies in Europe
Many emerging technologies (gasification, plasma arc) are not operational

Composting and anaerobic digestion facilities are emerging

Many advanced Waste-to-Energy facilities employ front end recycling, have advanced pollution prevention technology, physically attractive buildings and are well integrated into their communities

“Feed in Tariffs” – requires utilities to pay market-rate for alternative sources of renewable power (Germany)

Examples of Source-Reduction and Reuse
Re-fillable bottles (“refilleries”)
Bring Your Own…

-Second Hand clothing, books

E-Bill Pay
E-Readers (might be trading paper for e-waste)
LED bulbs vs. incandescents

Production and Consumption
Company manufactures Product
Company Packages Product and Ships to Market
Consumer Purchases Product
Consumer Discards Packaging: Becomes responsibility of local Government and by extension, the waste service provider
Consumer uses Product until end of life
Consumer Discards Product: Waste Product becomes responsibility of local government and by extension, the waste service provider
Production and Consumption (Part 2)
What’s Wrong with this Picture?
Cost to collect and dispose of a product and its packaging are external to the price of its production.
In other words, the cost of dealing with our stuff falls to others rather than to the entity that produced it.

Further Problem with Toxics: Under “Cradle to Grave” provisions of RCRA, local government is liable for material indefinitely.
Liability and risk is shifts COMPLETELY from manufacturer and consumer to local government

Problem: Local governments, which had no input into the design or packaging decisions and did not make a dime from the sale, are saddled with the responsibility for every product that is sold and discarded in their geographical boundaries.
Lack of input on design is especially critical with hazardous wastes
Difficult and very costly to dispose

How Have Governments Responded? (production/consumption)
Enacted Landfill Bans: common with toxic material (batteries, electronics, mercury devices, paints, etc.)
Ban the material from landfill disposal (to protect the environment)
Establish specialized collection (household hazardous waste collection facilities
Failure to Solve Root Problem
The local government response of
1)Dealing with material; and, 2)Banning its disposal do nothing to send a message to the manufacturer to:
Stop producing over-packaged products;
Stop producing toxic products; and/or,
To curb the problem of Planned Obsolescence
Planned Obsolescence
Popularized in the 1950s by Brooks Stevens, an industrial designer who specialized in making new cars.
Briskly adopted by postwar companies to coax Americans to sell their 1955 Cadillacs for the 1956 Cadillacs (tail fins)
Continued trend with each new model year (’57, ’58, ’59)
Extended Producer Responsibility
Premise: You Produce it, You Deal With It

In other words, those who design and profit from a product should be required to take it back.

All parties involved in producing (design, production, sales and distribution) and consuming products must share the responsibility for minimizing the environmental impacts associated with the product throughout its life cycle.

Materials Targeted by EPR
EPR generally targets materials that:
Comprise a significant portion of the waste stream (containers and packaging); or,
That are Toxic

Examples of Common EPR Legislation:
Packaging: waste comp
Printed Materials: waste comp
Mercury-containing lamps: toxicity
Electronics: toxicity
Household hazardous wastes: toxicity
Automobile Products: toxicity

Production and Consumption – The EPR Way
Company manufactures Product
Company Packages Product and Ships to Market
Consumer Purchases Product
Consumer Discards Packaging
Manufacturer collects product and packaging directly or through third party.
End-of-Life costs are INTERNALIZED into cost of product and borne by manufacturer and consumer.
What Dominates Our Composition?
EPA Study – 2011
Containers and Packaging: 30%
EPA: approximately 75% of our waste stream is product waste and associated packaging
Bottle Bills:
Oregon: 1972
California: 1986
What is a “Bottle Bill”?
A bottle bill is a law that. . . .
Requires distributors and retailers to collect a minimum refundable deposit, usually 5-10 cents on certain beverage containers
Creates a privately-funded collection infrastructure for beverage containers
Makes producers and consumers responsible for their packaging waste
How do Container Deposits Work?
Distributor collects deposit when he/she delivers containers to retailer
Retailer collects deposit from consumer at point of purchase
Deposit is refunded to consumer when container is returned
Deposit is refunded to retailer when containers are returned to distributor
Need for laws and regulations (hazardous waste)
Flammables were commonly disposed of in rivers, via the sewer system
Surface and groundwater contaminated
1930-1950’s, Love Canal in Niagara Falls, NY
Common pastime kids set small fires on the water
1968, Cuyahoga River in Ohio, river fire destroyed 7 bridges
Until 1976, all chemical wastes were regulated at the end of pipe, after they have been dumped. RCRA sought to regulated at the point of generation…..
Love Canal
Canal excavated in 1892 by W.T. Love for commercial purposes, but never completed.
1930-1950’s Hooker Chemical Company used ditch to dump over 80 different chemical wastes, 20,000 tons
1953 Land sold to city for $1
City developed a residential community with homes, schools, playground, built on top of chemical wastes
Then….winter 1976-77 heavy rains, snow
Vegetation dies, dogs develop sores, claims of miscarriages, birth defects, blood/liver abnormalities
Regulating Hazardous Waste
1972: California Hazardous Waste Control Law
1976: Resource Conservation and Recovery Act
1979: Love Canal focused national attention on hazardous waste, but prior to this over 600 “Love Canals” prompting Congress to pass RCRA *
1982: EPA developed regulations to satisfy RCRA

* many on current U.S. National Priorities List in line for clean up under Superfund

Federal Laws
-Statute: Resource Conservation and Recovery Act or RCRA, Chapter 42, United States Code
-Regulations: Title 40, Code of Federal Regulations (40 CFR,Parts 260-279)
Hazardous Waste Laws and Regulations
Protect human health and the environment from the potential hazards of waste disposal
Conserve energy and natural resources
Reduce the amount of waste generated
Ensure that wastes are managed in an environmentally sound manner
Prevent future problems caused by irresponsible waste management and,
Clean up releases of hazardous waste in a timely, flexible, and protective manner

1. Tracking
EPA ID Number
Manifest from point of generation to point of disposal

2. Permitting
Agencies issue facility permits for storage, treatment, disposal
Management standards

EPA ID number
Number identifies each generator on manifests
Federal and California specific numbers
Track cradle-to-grave (origin to final disposal)
Site-Specific; one number at a single address
All Treatment, Storage and Disposal Facilities (TSDF)must have an identification number
Cradle-to-Grave Tracking: Documents shipments of hazardous waste from Cradle to Grave (generator to designated facility e.g. TSDFs)
• U.S. DOT Shipping Paper: Satisfies U.S. DOT shipping requirements
• Emergencies: Provides emergency responders and CHP critical shipment information on waste, quantities, and contact numbers
• Tracking/Revenue: Enables tracking and billing for waste generation, transportation, and disposal
• Enforcement/Compliance: Provides third party confirmation manifest is accurate and received
• Liability: Identifies Potential Responsible parties
Hazardous Waste Determination
It shall be the generator’s responsibility to determine if the waste is classified as a hazardous waste.
A generator who incorrectly determines that a hazardous waste is nonhazardous and mismanages the waste pursuant to the provisions of the law is in violation of the requirements and is subject to enforcement action.

The information a waste generator may use to classify their waste falls into two categories:

1. Analytical testing data:
Manufacturer Info: Material Safety Data Sheets

2. Generator knowledge of materials and processes used

Hazardous Waste Determination Procedure
Is the material a waste?
Is the material a hazardous waste?
Is the waste excluded or exempted?
Is the waste Listed?
Does the waste exhibit a characteristic of hazardous waste?
What is a Waste? Layperson’s definition
Some thing that someone has, but that they don’t have a use for
Probably going to get rid of
Labeling and Marking
Composition and physical state
Hazardous properties
Name and address of generator
Accumulation start date
“Hazardous Waste”
Common Violations
No EPA ID Number
Manifests or receipts not available for review
No business plan or contingency plan
No training records
Universal Waste
Universal wastes are hazardous wastes that are more common and pose a lower risk to people and the environment than other hazardous wastes
Regulations identify universal wastes and provide simple rules for handling, recycling and disposing of them
2010 Assembly Bill 341
it set a diversion goal of 75% by the year 2020

-targeted 2 generators of waste
1. Large Businesses ( 4 cubic yards of trash must have some level of recycling)

2. Apartments, CONDOS, units ( some level of recycling)

1989 AB 939
-helps to know how CA looked like
– CA disposed 38 millions ton of trash
-diversion rate = 10%
-each person was giving out more than a ton a year
-drastically reduce landfill disposal by increasing recycling

25% by 1995
50% by 2000

Total Generation
Diverted + Disposed
Diversion Percentage
Diversion/ Total Generated
State minimum standards for Landfill
-dust control
-litter control
-daily cover (6 inches of cover)
Its what makes it a sanitary landfill
Subtitle D 1992
brought any landfill to modern day standards
County Wide Integrated Waste Management Plan
1. County wide sighting element (location)
at least 15 years of disposal capacity

2. Source reduction and recycling element
-makes all jurisdiction analyze waste stream
-waste composition study
-looking in at our trash

3. Non-disposal facility element
everything else but landfills: transfer station, composting facilities

4. Household Hazardous Waste Element
-toxicity of trash

EPA (2011) Recycling Rates
Products – Rates
Auto Batteries=96.2%
Total MSW Gen. (material)

250million tons (before recycling)

paper- 28%
food waste-14.5%
Total MSW Gen. recovery (material)
87 million tons
yard trim- 22.2%
food waste-1.6%
Total generation, recovery + discards of materials
Paper-total material- total msw

Weight generated= 70.02-176.53-250.42
W. recovered= 45.90-66.20-86.90
Recovery 45% of gen= 65.6%-37.5%-34.7%
weight discarded=24.12-110.33-163.52

EPA Vs. Biocycle

Total gen. =249.6-389.5
total recovered= 82.9-93.8
energy recov.= 31.6-25.9
discards to landfill= 135.1-269.8

Composition is the same

EPA-characterizes the MSW stream for the whole nation and not on a state by state basis.
-bases its results on the aggregate of several source, including estimates of material/products generated and their lifespans, the media & industry
-estimates the tonnage landfilled as the difference between its estimate of MSW generated minus its estimate of what is sent to composting, recycling, or WTE plants.

Resource Conservation and Recovery
Act (RCRA) 1976
an amendment to the Solid Waste Disposal
Act, was enacted in 1976 to address the huge
volumes of municipal and industrial solid waste
generated nationwide.

The goals set by RCRA are:

To protect human health and the environment
from the potential hazards of waste disposal

To conserve energy and natural resources

To reduce the amount of waste generated

To ensure that wastes are managed in an
environmentally sound manner.

Subtitle C (the hazardous
waste management program) and Subtitle D (the
solid waste program).

There are several components of RCRA
-The Act
-The Regulation
-The Guidance
-The Policy

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