Electrical Energy From Solid Waste

Report
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Final project in M.Sc. Course for teachers, in •
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program of the Feinberg Grad School of the
Weizmann inst. of Science.
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Electrical energy
from solid waste
Solid waste
Waste is an inevitable product of modern society. Population growth and rising
standard of living with increased consumption rate, exact a heavy
environmental price in natural resource depletion and waste accumulation.
In Israel, the amount of waste has grown at a rate of about 5% annually.
Each resident generates an average of about two kg/day of garbage, which
adds up to a total amount of waste of more than five millions tons per year.
Composition of solid waste
in Israel
4.5%
4.0%4.5%
4.0%
3.0%
41.0%
15.0%
24.0%
Organic waste
Plastic
Textile
Miscellaneous
Paper
Metals
Glass
Dipers
• 75% of the waste is
dumped into landfills
• 25% of total waste
(household,
commercial and
industrial waste) is
recycled.
• 13% of household
waste is recycled
What is biogas?
Biogas consists mainly of methane (CH4) and carbon dioxide (CO2), in
addition to a small fraction of a variety of other gases.
Biogas is known to have a negative environmental impact for its contribution
to the "greenhouse effect“.
To minimize the global warming effects, associated with climate change, we
must reduce greenhouse gas emissions.
Another important global challenge is to secure energy supply, as most of
the conventional oil and gas reserves are located in politically unstable
regions.
Bio-Digestion process of organic waste
In the first
phase (1-5):
Requires
2 molecules
of ATP per
molecule of
glucose
:
In stages 6 to
10 four ATP
molecules
are formed
and two
molecules of
NADH
Properties of landfill gas
Value
Attribute
40-50
)oC(Temperature
1.02-1.06
Density
Saturation
Water content
100-140
Calorific Value (kcal)
0.11-0.16
)kilowatt-hour, kWh(
Major development of landfill gas formation
( IV) and break-down
Ratio of the gases that make up the biogas up till stage IV (Merz and Stone: 1970)
Average (percent by volume)
Methane
CH4
CO2
5
88
Nitrogen
N2
5.2
21
76
3.8
29
65
0.4
40
52
1.1
47
53
0.4
48
52
0.2
51
46
1.3
47
50
0.9
48
51
0.4
The time period from
closing the landfill
(month)
0-3
3-6
6-12
12-18
18-24
24-30
30-36
36-42
42-48
It is necessary to collect and treat the generated gas
because of the following reasons:
• Under certain conditions and concentrations, methane
and hydrogen form an explosive and flammable mixture.
• In low and closed spots, biogas results in suffocation
hazard for people.
• Biogas may leak out of the dump site and damage
agricultural crops and surrounding vegetation
• Biogas contains toxic gases which pose health hazards
• Gases cause odor nuisances
Sanitary landfill
 Waste disposal method.
 Considerably reduces environmental hazards and reduces public health
risks and safety.
 The method typically utilizes ground outlets such as valleys, dry rivers,
mines, and quarries.
Sanitation landfill method requires:
 Clay-like layer
 Spread sealed plastic sheets on top of the clay-like layer to prevent the
waste leachate to seep into the groundwater
‫תשתיות נדרשות ממטמנת פסולת‬
 Covering the sheet with sand to filter the leachates and protecting the plastic from
tearing damage
 Waste is spread in compacted layers with a maximum height of 60 cm
 Each layer of compacted waste is covered with 15 cm height of dirt, in order to
reduce the hazards of odors and so as not to attract birds.
 Once the stack reaches 10 meters height, it should be covered with soil and later
with plastic sheets, to prevent percolation of rain water that could cause leaching
of contaminants into groundwater.
 Cover with soil at a height of 60 cm, at least.
The site is divided into dump chambers of a size determined in accordance
with the topography of the area and the amount of waste intended for it.
Each chamber has different pipes:
Leachate collection pipe - runoff drainage and treatment to prevent
contamination of groundwater.
Groundwater sampling pipeline , designed to test the penetration of
pollutants into groundwater
Biogas collection pipeline - to prevent explosions and fires, in addition to
preventing leakage of biogas to the atmosphere. Moreover, the pipeline
transfers the biogas to the generator.
Leachates : the liquid found in organic substance waste. Its concentration
increases during compaction.
 Leachates are rich in organic particles, and have high acidity due to the
metals concentration.
Leachates are considered to be hazardous to groundwater.
 in order to insure groundwater quality, leachate collection pipe installed
to transfer it to a treatment facility (a process similar to wastewater
treatment), in addition to monitor tubes
Disadvantages of the
landfill:
Advantages of the landfill:
Waste of resources - many raw
Suitable for all types of waste.
materials are recyclable.
Inexpensive
Waste of sand.
No residues of waste requiring
further treatment
Waste of land.
Emissions polluting the air.
Simple to operate
Flexibility to absorb quantities of
waste.
 Does not cause severe
environmental hazards.
 Minimal damage to groundwater.
Time till degradation for various
materials
Tin can - 100 years
Banana peel - a few weeks
Disposable diapers - 500 years
Newspaper - Month
Plastic cup - 1000 year
Cotton trousers - 5 months
Glass bottle - 1 million years
Styrofoam packaging - NEVER!
Wool socks – a year
Wooden rolling pin - 10 years
Leather wallet - 50 years
Effect of ambient temperature on methane production:
:
Feasibility study for the establishment of electricity generation facility from
solid waste– for the city of Karmiel
The purpose of the project is to generate electricity from Municipal Solid Waste Karmiel.
 Amount of waste in Karmiel is 50 tons per day, but the feasibility limit to
establish a landfill is a minimum of 1,000 tons of waste per day.
 Additional feasibility problem, is the lack of place. This limits the landfill to30-40
dunam.
 Moreover, negative construction cost reimbursement, need a period of 4-7 years
to refund the cost of construction
Thanks to David Malka, Director of Environmental Quality Department , Karmiel
Evron waste disposal site
 Operates since 1971 in former limestone quarry. Rate at which
household waste is dumped ranges from 150,000-225,000 tons / year.
 Till 2013, ~ 6.5 million tons of waste dumped at the site.
 Landfill area estimated at ~ 30 hectare.
 ~ 80% is household waste
 Waste does not pass a screening process.
Evron gas management system design :
Gas management system - includes three basic components:
• gas production unit (wells): Location and depth of the wells was
determined according to waste composition, its thickness, moisture
content, coverage character. 25 wells were drilled and constructed to a
depth of between 14-30 meters from the ground in cell A.
• Gas transmission facilities (pipes ,valves ,condensation trap): gas
pipeline size was calculated to insure the gas flow for each cell and the
whole landfill .
• Vacuum system (gas compressors) and gas treatment facility (Torch): gas
production system includes three centrifuge compressors and a torch.
Each compressor has an output capacity of 500 to 2500 m³ / h in a
maximal sub pressure of at least 200 mbar, with a torch that has a similar
maximum flow rate.
Kibbutz Evron landfill Costs and payback:
Landfill construction cost
 5 million NIS for landfill construction working space.
excluding land cost and maintenance, taxes, and manpower.
 3.5 million NIS for generator, with 60,000 hr life span (~ 7 yr non-stop).
Transportation cost:
150 trucks per day
INCOME
Waste receipt rate:
Average travel distance:
Fuel consumption / km :
Fuel price \ lit:
20.6 km
3 km / lit
8 NIS/lit
Total Cost:74,160 NIS/day
158,000 NIS/day
Waste compressing cost :
Two tractors each day
Work Duration 10 hours \ day
Distance 400 km \ day
Fuel consumption 50 liters \ day
Fuel price \ lit:
8 NIS/lit
Total Cost : 800 NIS
The cost of purchasing and maintening 1000 kW generator 24 hr/day:
480 NIS/day
NIS 0.2 *hours 24 *kW 1000
Total Investment: 75,440 NIS/ day
27,535,600 NIS/ year
Payback:
82,560 NIS/ day
Process energy cost :
Power output (kWd)
31,200
methane volume m3 / d
107,500
Waste quantity (tonnes)
T/day 1000
note :
 The amount of methane emitted from waste digestion, calculated according
to northern Germany, is 100 kg of methane for one tonne of waste, .
 The impact of temperature on gas production was taken into consideration
(average temperature summer and winter).
 The difference in the output of methane between day and night was not
discussed.
The amount of electricity produced accounts for ~80% of the electricity
consumed in the Kibbutz, which is estimated ~1300 kWh.
20% of electricity supplied by national grid, which is estimated ~325 kWh.
kWh price determined for the process is taken from the link:
http://www.pua.gov.il/Sip_storage/FILES/5/3115.pdf
 Life span of the system up to overhaul : 60,000 - 80,000 hours
 Working time per year:
8760 hours
 Years of service:
30-40 years Work
 Payback time:
(3.5-4 years)
Sources:
Biogas production: current state and perspectives 2009, Peter Weiland,
Adani, F., Calcaterra, E., Malagutti, L., 2001. Preparation of a test for estimating biogas
production from pretreated urban waste. Proceeding Sardinia 2001 Eight International
Waste Management and Landfill Symposium. Cagliari, Italy.
By the MOTHER EARTH NEWS editors. May/June 1970, Convert Waste to
Energy with Methane Production
H.G.Bingemer and P.J.Crutzen 1987, The production of methane from solid wastes
Ann C .Wilkie, Ph.D. 2005, Anerobic digestion: Biology and benefits.
.Bullard, R. D. (1971). Solid Waste Sites and the Black Houston Community
.Sociological Inquiry, 53(2-3), 273-288
:‫קישורים‬
http://www.bayadaim.org.il/2012/12/%D7%91%D7%99%D7%95%D7%92%D7%96-%D7%90%D7%A6%D7%9C%D7%9A%D7%91%D7%91%D7%99%D7%AA%D7%97%D7%9C%D7%A7-%D7%90/#anc6
http://www.sviva.gov.il/subjectsEnv/BusinessLicensingIndustry/Int
Management/Documents/IntegratedGuidelinesIPPC092013.pd
f
http://www.motherearthnews.com/renewable-energy/waste-toenergy-methane-productionzmaz70mjzkin.aspx#axzz2pDxDvbqz
http://www.small-farm-permaculture-and-sustainableliving.com/methane_generator.html
http://environmentvictoria.org.au/content/organic-waste
http://www.doityourself.com/stry/how-to-convert-organic-waste-intoelectricity#.UsVCKNIW2VM
http://en.wikipedia.org/wiki/Waste-toenergyhttp://www.adamteva.org.il/_Uploads/dbsAttachedFiles/mis
s.pdf
http://en.wikipedia.org/wiki/Met

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