ENVIRONMENTAL IMPACT OF DOMESTIC ANAEROBIC DIGESTION IN BANGLADESH

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• ENVIRONMENTAL IMPACT OF DOMESTIC ANAEROBIC
  DIGESTION IN BANGLADESH
• Khondokar Mizanur Rahman
• SUPERVISORY TEAM
• Prof Marie Harder
• Dr. Ryan Woodard
• Dr Elizabeth Manzanares

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Diagram Showing Research Outline
Duration
Course
Activities

• Adding food waste / Household waste with
  slurry
• More study on other impacts of AD like Social
  impact

PhD
Sep 09- Sep 10

Transfer to PhD

• Assess the Environmental Impact of AD plant
• Energy calculation of AD plant

April 09-July 09

• More detailed information of AD with
  different feedstock
• Study on different process of Environmental
  Impact Assessment
• Current practices of Carbon Counting
• Additional
• Improving the language and Research Skills
• Improving writing skill in proper academic
  form

Oct 08-March 09
MPhil

• Background study on waste management
• E.g. Anaerobic Digestion(AD), Pyrolysis,
  Composting, Incineration, Gasification,
  Combustion etc.
• Current AD practices and project planning

July 08-Sep 08
General knowledge of waste management,
Development of skills, organizing ideas about
research project, Reading scientific papers.
Oct 07-June 08
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• The key work I have done since the last PRP
  meeting (Sept 2008)
• 1. October 2008- December 2008
• Study domestic AD system, review of literature
• Study LCA, review of literature
• Learned Simapro- The LCA software
• 2. January 2009
• Visited Bangladesh11 AD plant from 4 districts
  of Bangladesh
• Collected Environmental, Social and Economic
  data
• Participated in workshop in Bangladesh on
  Promotion of renewable
• energy technologies to rural stakeholders
• 3. February 2009- present
• Analyse the data and assess the impact through
  Life Cycle Assessment. Write up the project
  report
• Invited to Brussels for workshop on
  Micro-financing of Renewable
• Energy gave presentation
• Attended UK national conference for post
  graduates in Waste
• Management in the University of Nottingham

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Why this project ?
ENVIRONMENTAL IMPACT OF DOMESTIC ANAEROBIC
DIGESTION IN BANGLADESH

• To help develop an alternative to traditional
  biomass
• - Biomass share of energy usage is 55
• - 8 million HHs cook in traditional
  stove using biomass (40 M tonnes use in 2006)
• - Traditional biomass has problems like
• Deforestation and Natural
  disaster
• Soil erosion
• Soil nutrient reduction
• Health problems
• Anaerobic Digestion is the alternative to
  traditional biomass
• - Solves all the problems associated with
  traditional biomass
• - Potential for 3 million domestic AD biogas
  plants
• Life Cycle Analysis of small-medium AD systems to
  assess the environmental impact of potentially
  millions of AD plants.

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PROBLEMS WITH USING BIOMASS

• Deforestation and natural disasters
• More than 55 energy from traditional fuel
• It the last 15 year the deforestation rate is gt
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• Need 25 forest for a balance environment
• Deforestation increase propensity of
• environmental disaster like flood, cyclones etc.

• Soil Fertility
• A fertile soil should contain at least 3.5
  organic matter. Bangladeshi soil contains 1.7
  organic matter.
• Excess use of chemical fertilizer causes
  depletion of soil natural nutrient, increase
  production cost and causes environmental
  pollution specially the aquatic environment.
• There is a need for organic fertilizer to
  replenish the soil

• Health issues
• Eye infection
• Respiratory diseases
• Coughing
• Dizziness
• Headache
• Children are affected by smoke particles

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What is Anaerobic Digestion (AD)?

• Biological process that happens naturally when
  bacteria breaks down organic
• matter in environments with little or no
  oxygen,
• Produce biogas (60 methane and 40 CO2 by
  volume) and digestate

- Biogas - fuel used for cooking and lighting -
Digestate a fertilizer with higher nutrient
value than fertilizer from composting and
chemical fertilizer.
Anaerobic digestion process
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Waste Cow dung Poultry litter
CH4 rich
Digestate
Bricks, Cement, Sand
Schematic of a fixed dome anaerobic digester
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Prospect of Domestic Anaerobic digestion in
Bangladesh

• 8.44 million of households in Bangladesh
• 22.29 million of Cattle/ buffalo and
• 116,000 poultry farms (BCAS, 2005)

Potential for more than 3 millions of domestic
biogas plants from dung only Bangladesh has
about 30,000 biogas plants Ref SNV, 2005
Construction of a domestic biogas
plant of Bangladesh
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Impact Assessment and Life Cycle Assessment

• Compilation and evaluation of inputs, outputs
  and potential environmental
• impacts of a product system throughout its
  life cycle (extraction to end-of-life)
• UK PAS 2050 is consistent method for assessing
  the life cycle Greenhouse Gas (GHG ) emissions of
  goods and services.

• PAS 2050 can provide
• A standard method for assessing a product carbon
  footprint
• Internal assessment of product life cycle GHG
  emissions
• Evaluation of alternative product
  configurations, operational and sourcing options
• A benchmark for measuring and communicating
  emission reductions
• Support for corporate responsibility reporting
  social and economic impacts

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From SimaPro CML 2000 there are 10 impact
units
Abiotic depletion - extraction of minerals and
fossil fuels. Global warming potential (GWP) -
the greenhouse effect, equivalent to carbon
footprint. Ozone layer depletion (ODP) - causes
UV-B radiation reaching the earth surface. Human
toxicity - effects of toxic substances on the
human environment Fresh water aquatic ecotoxicity
- impact on fresh water ecosystems, Marine
aquatic ecotoxicity - impacts of toxic substances
on marine ecosystems. Terrestrial ecotoxicity -
impacts of toxic substances on terrestrial
ecosystems. Photochemical oxidation - potential
capacity of a volatile organic substance to
produce ozone. Acidification - acidifying effect
of SO2. Eutrophication (nutrification) - impacts
due to excessive levels of macro-nutrients in the
environment.
http//www.brighton.ac.uk/werg/pdf/factsheets/LCA
20factsheet.pdf
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Methodology of research/PAS 2050 Methodology
For industrial inputs there is embedded energy in
the raw materials to consider.
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The process map for AD biogas production
For farm feedstock there is no embedded energy to
consider.
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Data from Bangladesh

• Visited January, 2009
• Data from 11 biogas plants from 4 districts of
  Bangladesh
• Sizes were 2.4 m3, 3 m3, 3.2 m3 and 14 m3
• 9 of those were domestic/family sized plant and
  2 medium sized (14 m3)
• Only one of those was a poultry based plant
• A 3.2 m3 plant was considered as a standard
  domestic biogas plant and
• was compared between same sized dung and
  poultry based plant.

Biogas production rate 0.037 m3/kg
dung 0.071 m3/kg poultry litter (Data is
provided from Grameen Shakti, Bangladesh)
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Some Secondary data collected
Impacts determined using SimaPro per kg gas
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IMPACT OF BIOGAS Life time (10 year) impact
assessment of a 3.2 m3 dung based biogas plant
from the main output gas (before combustion
methane) using SimaPro.
Global warming saving through methane combustion
CH4 2O2 CO2 2H2O
For 3.2 m3 daily charge is 87 kg dung is
required from GS manual
65/- 15 kg from my farm data visits
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IMPACT OF DIGESTATE Life time (10 year) Impact of
digestate of a 3.2 m3 dung based biogas plant in
soil and water
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IMPACT OF INFRASTRUCTURE
A 3.2 m3 biogas digester building materials are
predominantly clay bricks and cement Number of
Bricks - 1747 or 4368 kg Cement - 1050
kg Few other materials like sand, Rod, Polythene,
PVC pipe etc are used to build up digester.
Impact of infrastructure of a 3.2 m3 biogas plant
(Cement-1050 kg and Bricks-4368 kg)-Cement and
brick data according to Bangladesh industries and
energy distribution
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Ten year lifetime impact (in GWP) of 3.2 m3
biogas plant biogas digestate
infrastructure
A loaf of bread has GWP of 1.3kgCO2
GWP biogas for a year 2100 kgCO2 eq
How significant is 2100 KgCO2? A family
consumes about a loaf a week or 50 loafs a year

• So 2100 kgCO2 represents 1615 loafs a year
• consumption of only 32 families a year !!

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Biogas is used for Lighting - Replacing
kerosene Cooking - Replacing wood biomass

• Replacing kerosene with biogas (by comparing GWP)
• Used 4 hours/day a kerosene lamp emits 100kg of
  CO2 annually
• 100 kg CO2 produce from 28.9 kg kerosene (CDM
  report on pacific island)
• Caloric value of kerosene is 47.5 MJ/kg
• Kerosene use for light, GWP per MJ is - 0.072 kg
  CO2 equivalent
• Biogas use for light, GWP per MJ is - 0.074
  kg CO2 equivalent THIS WORK
• GWP of kerosene and biogas are similar per energy

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Replacing biomass with biogas Biomass fuel
stoves have a significant portion of the
pollution in the form of products of incomplete
combustion (PIC), i.e., much fuel carbon is
diverted into non-CO2 airborne emissions such as
CO, CH4, NMHC, and particles.
GWC of different house hold fuels in China
CO2CH4COTNMHCNO
Source Edward, 2002
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Biogas is FuelEnergy Calculations
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Conclusions For 10 years life time of a 3.2 m3
biogas plant

• The GWP is about 21 tonnes CO2 eq after
  combustion
• Combustion of methane reduces GWP by 109 tonnes
  CO2 eq
• Use of biogas replaces more than 15 tonnes of
  wood
• Digestate is a nutrient rich fertilizer causing
  zero GWP

• Future Work Plan
• More critical investigation of Socio economic
  impact of biogas plant
• Compare with other feedstock like House hold
  waste
• Primary data for use of biogas in stoves

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Thanks a lot for your attention