This document discusses converting organic food waste and cow manure into methane gas through anaerobic digestion to provide energy for rural homes in developing nations. It describes the multi-step anaerobic digestion process of hydrolysis, acidogenesis, acetogenesis, and methanogenesis carried out by obligate anaerobes. An experiment is proposed to test different ratios of food waste and cow manure to determine the optimal ratio for highest methane production. The methane gas could then be captured and combusted to provide energy for heating or cooking, addressing both energy scarcity and waste pollution issues in a sustainable way.
This document discusses converting cow dung into methanol through a two-step process of anaerobic digestion followed by acid treatment. The quantities and qualities of methane gas and methanol produced depend on factors like slurry concentration and temperature. Gas chromatography analysis found the biogas contained 57.23% methane. Refining the biogas enhanced the carbon-to-nitrogen ratio, making the organic components more available for the acid reaction. Spectroscopic analysis indicated methanol was formed, with a purity of 92.5%. The process also generates fertilizer from the leftover sludge.
IRJET- Enhancement of Biogas Production by Co-Digestion of Fruit and Vegetabl...IRJET Journal
This document discusses a study on enhancing biogas production through co-digestion of fruit and vegetable waste with cow dung. Four mixtures of fruit, vegetable, and cow waste were prepared in different ratios and subjected to anaerobic digestion. The biogas production from each mixture was measured and modeled using logistic and modified Gompertz kinetic models. The results showed that a ratio of 0.5 parts fruit waste, 1.5 parts vegetable waste, and 1 part cow waste produced the highest amount of biogas and fit best to the modified Gompertz model. Characterization of the waste mixtures found total solid and volatile solid contents ranged from 74-75% with C/N ratios between 5-9.
Biogas Production Enhancement from Mixed Animal Wastes at Mesophilic Anaerobi...IJERA Editor
In this work, the effect of mixing ratio of cattle dung (CD) and poultry droppings (PD) on biogas generation was
determined. Mixtures of various CD: PD ratios (100% : 0%; 50% : 50%; 60% : 40%; 80% : 20% and 0% :
100%) were prepared, analyzed and then aerobically digested for a period of 40 days. For each mixture,
fermentation was carried out in a 20 L capacity digester. Results showed that biogas was obtained from the
digestion of CD and PD alone, showing the biogas from CD was several times larger than that from PD.
Furthermore, the resulted biogas yields from mixtures were found a function of the CD : PD ratio, the yield from
the ratio 80 : 20 was the maximum. Biogas yields from the prepared mixtures were found and arranged from
larger to lower in the form of (CD : PD) ratios as follow: 80% : 20%; 100% : 0.0%; 60% : 40%; 0.0% :
100%;50% : 50%. Addition of CD to PD enhances the PD production of biogas, while addition of a small
portion of PD to CD gave the maximum yield, a result not determined in literature. In other hand, larger
additions of PD to CD reduced the biogas yield. The effect of pH was also determined and found better around
7.0. These results are in agreement with research work in literature.
Comparative study of products of pyrolysis of cowAlexander Decker
This study compared the products of pyrolysis of cow dung and poultry litter. A pyrolysis assembly was used to pyrolyze samples of each residue at 450°C for 30 minutes. The main products collected were char, tar oil/pyroligneous acid, and pyrogas. For cow dung, the yields were 42% char, 35.66% tar oil, and 17.34% pyrogas. For poultry litter, the yields were 47.33% char, 28.33% tar oil, and 24.34% pyrogas. Analysis showed the pyrogas from cow dung contained 56.67% methane and 54.33% propane, while p
Evaluation of Biogas Production from the Digestion of Swine Dung, Plantain Pe...IJCMESJOURNAL
This study centered on biogas production from locally available animal and kitchen wastes: swine dung (SD), plantain peel (PP) and fluted pumpkin stem (PS) using five 32-Litres metallic prototype digesters. The anaerobic digestion was in the ratio of 3:1 of water to waste for all the samples as follows: Sample A was 100%SD, Sample B; 100% PP, Sample C; 100% PS, Sample D; 50%SD+50%PP and Sample E; 40% SD+30% PP+30% PS. The retention time was 30 days and parameters like pH, pressure, daily biogas production, ambient and slurry temperatures alongside the physico-chemical properties of wastes were monitored. The cumulative gas production yield was 11.5L, 35.1L, 39.5L, 46.9L, 59.3L for Sample A, Sample B, Sample C, Sample D and Sample E respectively. The flammable time was 15th, 5th, 25th, 26th, 2nd day for sample A, sample B, sample C, sample D and sample E respectively. The result revealed that the blend of the 3 substrates i.e. sample E: 40% SD+30% PP+30% PS gave the highest yield of biogas and flamed earlier than the other samples while sample A: 100%SD had the lowest yield of biogas. The results also showed that the sample that had the highest composition of methane in the biogas produced was Sample D: 50%SD+50%PP with 85.6989% while the lowest composition of methane was found in Sample C to be 79.0996%. The TS, TVS, BOD and VS were seen to be consistently reducing showing the level of waste treatment achieved during the digestion period of 30 days.
This document proposes a study to investigate the utilization of donkey dung for biogas production in Lamu County, Kenya. Donkey dung is readily available but currently a nuisance, littering towns. The study aims to assess biogas production from different mixtures of donkey dung and cow dung in flexi bag digesters. Five treatments mixing donkey and cow dung at ratios of 25-75%, 50-50%, 75-25%, 100% donkey dung, and 100% cow dung (control) will be evaluated. The volume of biogas produced daily will be measured to determine if co-digesting donkey and cow dung can improve biogas yields for energy needs in Lamu
In this slide i was include some information from the class lecture in my graduation class.I hope it will be useful for the students in other academics.
This document summarizes an experimental study on generating biogas from kitchen waste and cow dung. The study found that (1) Kitchen waste produced 150.69% more biogas than cow dung alone, showing it is a more efficient substrate. (2) Biogas production initially increased for 3 days then decreased as acid concentration rose, lowering the pH. Adding water increased the pH and biogas production. (3) The pH decreased more rapidly for the kitchen waste setup, indicating it underwent hydrolysis and acidogenesis faster than the cow dung setup. In conclusion, the study found that kitchen waste is a better alternative substrate than cow dung alone for generating more biogas and producing a useful byproduct with better anaer
This document discusses converting cow dung into methanol through a two-step process of anaerobic digestion followed by acid treatment. The quantities and qualities of methane gas and methanol produced depend on factors like slurry concentration and temperature. Gas chromatography analysis found the biogas contained 57.23% methane. Refining the biogas enhanced the carbon-to-nitrogen ratio, making the organic components more available for the acid reaction. Spectroscopic analysis indicated methanol was formed, with a purity of 92.5%. The process also generates fertilizer from the leftover sludge.
IRJET- Enhancement of Biogas Production by Co-Digestion of Fruit and Vegetabl...IRJET Journal
This document discusses a study on enhancing biogas production through co-digestion of fruit and vegetable waste with cow dung. Four mixtures of fruit, vegetable, and cow waste were prepared in different ratios and subjected to anaerobic digestion. The biogas production from each mixture was measured and modeled using logistic and modified Gompertz kinetic models. The results showed that a ratio of 0.5 parts fruit waste, 1.5 parts vegetable waste, and 1 part cow waste produced the highest amount of biogas and fit best to the modified Gompertz model. Characterization of the waste mixtures found total solid and volatile solid contents ranged from 74-75% with C/N ratios between 5-9.
Biogas Production Enhancement from Mixed Animal Wastes at Mesophilic Anaerobi...IJERA Editor
In this work, the effect of mixing ratio of cattle dung (CD) and poultry droppings (PD) on biogas generation was
determined. Mixtures of various CD: PD ratios (100% : 0%; 50% : 50%; 60% : 40%; 80% : 20% and 0% :
100%) were prepared, analyzed and then aerobically digested for a period of 40 days. For each mixture,
fermentation was carried out in a 20 L capacity digester. Results showed that biogas was obtained from the
digestion of CD and PD alone, showing the biogas from CD was several times larger than that from PD.
Furthermore, the resulted biogas yields from mixtures were found a function of the CD : PD ratio, the yield from
the ratio 80 : 20 was the maximum. Biogas yields from the prepared mixtures were found and arranged from
larger to lower in the form of (CD : PD) ratios as follow: 80% : 20%; 100% : 0.0%; 60% : 40%; 0.0% :
100%;50% : 50%. Addition of CD to PD enhances the PD production of biogas, while addition of a small
portion of PD to CD gave the maximum yield, a result not determined in literature. In other hand, larger
additions of PD to CD reduced the biogas yield. The effect of pH was also determined and found better around
7.0. These results are in agreement with research work in literature.
Comparative study of products of pyrolysis of cowAlexander Decker
This study compared the products of pyrolysis of cow dung and poultry litter. A pyrolysis assembly was used to pyrolyze samples of each residue at 450°C for 30 minutes. The main products collected were char, tar oil/pyroligneous acid, and pyrogas. For cow dung, the yields were 42% char, 35.66% tar oil, and 17.34% pyrogas. For poultry litter, the yields were 47.33% char, 28.33% tar oil, and 24.34% pyrogas. Analysis showed the pyrogas from cow dung contained 56.67% methane and 54.33% propane, while p
Evaluation of Biogas Production from the Digestion of Swine Dung, Plantain Pe...IJCMESJOURNAL
This study centered on biogas production from locally available animal and kitchen wastes: swine dung (SD), plantain peel (PP) and fluted pumpkin stem (PS) using five 32-Litres metallic prototype digesters. The anaerobic digestion was in the ratio of 3:1 of water to waste for all the samples as follows: Sample A was 100%SD, Sample B; 100% PP, Sample C; 100% PS, Sample D; 50%SD+50%PP and Sample E; 40% SD+30% PP+30% PS. The retention time was 30 days and parameters like pH, pressure, daily biogas production, ambient and slurry temperatures alongside the physico-chemical properties of wastes were monitored. The cumulative gas production yield was 11.5L, 35.1L, 39.5L, 46.9L, 59.3L for Sample A, Sample B, Sample C, Sample D and Sample E respectively. The flammable time was 15th, 5th, 25th, 26th, 2nd day for sample A, sample B, sample C, sample D and sample E respectively. The result revealed that the blend of the 3 substrates i.e. sample E: 40% SD+30% PP+30% PS gave the highest yield of biogas and flamed earlier than the other samples while sample A: 100%SD had the lowest yield of biogas. The results also showed that the sample that had the highest composition of methane in the biogas produced was Sample D: 50%SD+50%PP with 85.6989% while the lowest composition of methane was found in Sample C to be 79.0996%. The TS, TVS, BOD and VS were seen to be consistently reducing showing the level of waste treatment achieved during the digestion period of 30 days.
This document proposes a study to investigate the utilization of donkey dung for biogas production in Lamu County, Kenya. Donkey dung is readily available but currently a nuisance, littering towns. The study aims to assess biogas production from different mixtures of donkey dung and cow dung in flexi bag digesters. Five treatments mixing donkey and cow dung at ratios of 25-75%, 50-50%, 75-25%, 100% donkey dung, and 100% cow dung (control) will be evaluated. The volume of biogas produced daily will be measured to determine if co-digesting donkey and cow dung can improve biogas yields for energy needs in Lamu
In this slide i was include some information from the class lecture in my graduation class.I hope it will be useful for the students in other academics.
This document summarizes an experimental study on generating biogas from kitchen waste and cow dung. The study found that (1) Kitchen waste produced 150.69% more biogas than cow dung alone, showing it is a more efficient substrate. (2) Biogas production initially increased for 3 days then decreased as acid concentration rose, lowering the pH. Adding water increased the pH and biogas production. (3) The pH decreased more rapidly for the kitchen waste setup, indicating it underwent hydrolysis and acidogenesis faster than the cow dung setup. In conclusion, the study found that kitchen waste is a better alternative substrate than cow dung alone for generating more biogas and producing a useful byproduct with better anaer
This review article summarizes approaches for managing food waste through anaerobic digestion to produce energy and recycle nutrients. Anaerobic digestion is a multi-step process where microorganisms break down biodegradable material in the absence of oxygen and produce methane gas and digestate. Food waste is a suitable substrate for anaerobic digestion due to its biodegradable composition. The article reviews studies on producing methane from food waste via anaerobic digestion and discusses the microbial populations involved in the digestion process and factors that affect efficiency.
This document presents a cost-benefit analysis of installing a 5m3 capacity tubular polyethylene digester for small-scale hog farmers in the Philippines. The analysis finds that the projected costs of installation and maintenance over 10 years are outweighed by the projected financial benefits of fuel supply, manure maximization, and savings from reduced medical expenses. A sensitivity analysis shows the project remains economically viable even with a 10% reduction in total benefits but becomes unviable with a 45% reduction. The analysis concludes the digester installation project has a positive net present value and is a worthwhile economic investment.
Changes in energy sources and forest utilization in NepalKASUMIITO1
The document summarizes research on changes in energy sources and forest resource utilization in two villages in Nepal following the devastating 2015 earthquake. It finds that: (1) Villagers who lost biogas plants shifted temporarily to LP gas but intend to rebuild biogas, which they see as most suitable. (2) Forest usage did not change due to the quake but decreased previously due to biogas adoption, raising concerns about inappropriate forest management if people no longer depend on or visit forests. The study implies community forestry systems may need to review participation and forest health given changing resource dependence.
Environmental Engineering for Enhancing the Suitability of a Microalga for En...IRJET Journal
This document discusses research conducted on the microalga Chlorella vulgaris to study the effects of varying pH and salinity on its growth, biomass production, and lipid content. The researchers found that growth and biomass were highest at pH 7, while lipid content increased with higher salinity up to 0.25M, beyond which growth decreased. The goal was to optimize environmental conditions to enhance the suitability of C. vulgaris for renewable energy production through biomass and lipid accumulation.
Livestock farmers’ perception on generation of cattle waste Alexander Decker
This document discusses a study on livestock farmers' perceptions of cattle waste-based biogas methane generation in Embu West District, Kenya. The study surveyed 156 livestock farmers, most of whom practiced zero-grazing and had multiple cows. Only 14% had installed biogas digesters. The study found that farmers had a positive perception of biogas technology and knowledge of how it works, despite the low adoption rate. Statistical analysis showed no significant relationship between perception and adoption level. However, there was a significant relationship between perception and knowledge. The research concluded that other factors beyond perception, like installation costs, contributed more to the low uptake of biogas technology.
At present our country is facing various problems, among that energy crisis has become more serious in next coming years. Both energy crisis and pollution problems could be controlled by adopting an alternative method of biogas production form waste products. Food waste is the best alternative for biogas production in a community level biogas plant. Hence in the present study, an attempt has been made to study the rate of biogas production in a lab scale biogas digester model for the efficient conversion of the food waste (starch –rich materials) generated from PRIST University Campus. The biogas production depends on the maximum biogas yield, the concentration of volatile solids of the input, the density of the effluent, the density of the biogas and the reaction rate constant, which are all substrate - or process - specific. The experiments were carried out for 40 days and the rate of gas production was measured by water displacement method. The pH value of the cow dung and food waste was initially measured and adjusted to nearer to neutral and gradually increased to acidic and again it got stabilised to the neutral pH which favoured the production of biogas. The percentage of total solids was 69.86, 93.56 and 25.67 for cow dung, food waste and digested slurry respectively. The percentage of volatile solids was 52.5, 86.3 and 18.9 for cow dung, food waste and digested slurry respectively. The percentage of volatile fatty acid was 285, 356 and 365 for cow dung, food waste and digested slurry respectively. Observations on daily basis were made on the constituent of biogas, pH, volume and rate of biogas production. The rate of biogas production continuously increased as days progressed and there was maximum yield in biogas after 20 days. Thus continuous feeding helps in daily biogas production and can be used at a small as well as larger scale to manage the organic waste and energy production for various applications.
Ecosystem services provided by pollinatorsmogiliramaiah
Pollination is a vital ecological service provided by a wide range of insect species including bees, wasps, flies, butterflies, beetles and moths. ... Willow flowers contain pollen and nectar, both valuable resources for a wide variety of bee species and other pollinators
The document summarizes a study that investigated the effect of inoculum to substrate ratio on biogas production from anaerobically digested goat paunch manure. Goat paunch manure was digested at different inoculum to substrate ratios of 1.45, 2.2, and 4.3 in biodigesters labeled R15, R10, and R5, respectively, under mesophilic conditions. Results showed that biogas production rate peaked earliest in R10 and latest in R15, but inoculum to substrate ratio did not significantly affect production rate. However, biogas production accumulation increased from 0.44273 to 1.00783 Nm3/kg VS with increasing inoculum to substrate ratio
STUDY ON BIO-METHANATION USING POULTRY DROPPING-Abdullah Nasir PulakAbdullah Pulak
This study examined biogas production from poultry droppings through anaerobic digestion with cow dung. Four laboratory reactors were tested with varying ratios of poultry droppings and cow dung. Reactor D2, with 75% poultry droppings and 25% cow dung, produced the highest volatile solid reduction (53%), specific gas yield (0.72 l/g), and methane content (73.2%). Poultry droppings alone were found to be unsuitable due to a low carbon-nitrogen ratio, but mixing with cow dung increased the ratio and improved biogas production. The study suggests anaerobic digestion of poultry droppings mixed with cow dung can effectively produce
Biomass from sources like trees, crops, and waste can be used for energy through technologies like thermo and bio conversion. India aims to promote bioenergy to meet sustainability goals and increase energy security by reducing oil imports. Key challenges include overcoming economic, social, and technical barriers to increase adoption of bioenergy technologies on a larger scale. Developing reliable biomass supply and providing cost competitive energy services will be important for the growth of the bioenergy sector in India.
This document outlines the course materials and assignments for an environmental science course (SCI 256). It includes weekly discussion questions, individual and team assignments, and a final exam guide. The assignments cover topics such as ecosystems, biogeochemical cycles, natural resources, energy, climate change, and sustainability. Students are asked to apply course concepts to analyze environmental issues and decisions in their own communities. The goal is for students to understand human impacts on the environment and approaches to environmental management and conservation.
Influence Of Different Nitrogen And Organic Carbon Sources On Microalgae Grow...iosrjce
Microalgae based biofuels are getting attention due to energy crisis and enviromental protection. In
the present study, the Chlorella sp. was cultivated in BG-11 medium at batch mode. The effect of different
nitrogen (sodium nitrate, potassium nitrate and urea) and organic carbon (glucose, glycerol and sucrose)
sources were analyzed on growth and lipid accumulation on this species. The highest biomass growth and
biomass productivity of chlorella sp. was found 1.29±0.04 g/l, 76.96±4.5mgl-1
d
-
1 in urea. However in case of
organic sources, the biomass growth and productivity was found maximum in glucose (1.43±0.075 g/l 86.04±3.2
mgl-1
d
-1
). The lipid content was examined using folch method and found better in potassium nitrate nitrogen
source (11.84%) . Among organic carbon sources, the maximum lipid content (13.22% and lipid yield 189.94
mg/l were found in case of glucose, followed by glycerol and sucrose. Various properties of biodiesel obtained
from chlorella sp. such as Cetane number, Saponification value, Iodine value and Degree of unsaturation were
followed standerds set by the national petroleum agency (ANP255), ASTMD6751 and EN14214.
This thesis examines the energy return and economics of producing pellets from steam pretreated biomass. Chapter 1 introduces the background and objectives of assessing pellet production techniques. Chapter 2 develops process models for producing pellets from forest residues, agricultural residues, and switchgrass, and determines the net energy ratio (NER) of regular and steam pretreated pellet processes. Steam pretreated pellets have a lower NER than regular pellets. Chapter 3 provides a comparative NER analysis of pellets from steam pretreated agricultural residues and switchgrass. Pellets from steam pretreated straw have the highest NER. Chapter 4 develops a techno-economic model to evaluate production costs and determines the minimum cost plant size is 190
1) The document describes a study on the anaerobic co-digestion of water hyacinth and poultry litter.
2) Batch experiments were conducted in 300ml digesters at mesophilic temperatures to determine biogas production, total solids, volatile solids, and pH over retention periods of 0-56 days.
3) Kinetic modeling using an integral method revealed that the co-digestion process followed first-order reaction kinetics with a rate constant of 0.026 day-1.
Green chemistry is the synthesis of substance in such a way that is proper, non-polluting and protected and which requires lowest amounts of resources and energy but generating slight or no waste material. The green chemistry is required to minimize the harm of the nature by anthropogenic materials and the processes applied to generate them.Green chemistry indicates research emerges from scientific discoveries about effluence responsiveness. Green chemistry involves 12 set of values which minimize or eliminates the use or production of unsafe substances. Scientists and Chemists can significantly minimize the risk to environment and health of human by the help of all the valuable ideology of green chemistry.The principles of green chemistry can be achieved by the use environmental friendly, harmless, reproducible and solvents and catalysts during production of medicine, and in researches. The use of UV-energy Microwave irradiation in is also significant way to achieve the goal of green chemistry.This paper explain ideology, certain examples and application of green chemistry in everyday life, in industry, the laboratory and in education.
Impact of Improved Aeration on Decomposition Rate of Enriched Compostijtsrd
Agricultural activities tend to generate a substantial volume of animal and crop residues. Composting is the most economical and ecologically sustainable option to manage farmyard waste. However, it takes approximately three months to complete decomposition and contains lower plant nutrient percentages than inorganic fertilisers. This study aimed to reduce the decomposition time and improve the nutrient content of compost. Aerobic decomposition was enhanced by aeration inside the pile using a blower with 0.5 l min kg airflow. Paddy straw, poultry manure, goat manure, cattle manure and paddy husk ash were mixed in 3 1 1 1 1 ratio respectively as the raw materials and 3 of Eppawala Rock Phosphate was added to the mixture in weight basis. Six piles 150 X 100 X 80 cm were prepared, and three piles were aerated for six hours per day while other three piles were left to decompose under the ambient condition as the control. According to the results, aerated and control piles took 35 days and 65 days to complete the decomposition. Total N, available P, exchangeable K, C N ratio, pH, EC and CEC were analysed in compost samples from aerated after 35 days and controls, and the results were, 20.5 g kg 1, 1.8 g kg 1, 10.4 g kg 1, 7, 8.8, 4.3 mS cm 1, 19.3 cmol kg 1 and 17.8 g kg 1, 1.5 g kg 1, 9.9 g kg 1, 8.5, 8.8, 3.64 mS cm 1, 21.3 cmol kg 1 respectively. Data were analysed using SAS 9.0 software with a 95 confidence interval. The results revealed a significant increment in total N, exchangeable K, C N ratio, EC and CEC in aerated piles compared to controls. And the nutrient composition of both methods was significantly higher than the commercial compost. Therefore, it can be concluded that decomposition time can be effectively reduced and the nutrient level can be increased by artificial aeration and nutrient enrichment, respectively. However, further studies are recommended to study the economic feasibility. D. M. S. H. Dissanayaka | V. P. T. Dhananjaya | E. J. Kosgollegedara | S. Karthigayini "Impact of Improved Aeration on Decomposition Rate of Enriched Compost" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-2 , February 2021, URL: https://www.ijtsrd.com/papers/ijtsrd38557.pdf Paper Url: https://www.ijtsrd.com/engineering/agricultural-engineering/38557/impact-of-improved-aeration-on-decomposition-rate-of-enriched-compost/d-m-s-h-dissanayaka
Biogas Handbook by Biogas Developement and Training Centre.pdfRaj kumar
This document contains frequently asked questions about biogas technology. It discusses what biogas is, how it is produced through the anaerobic digestion of organic waste, and its applications. Key points covered include:
- Biogas is a mixture of methane and carbon dioxide produced by bacteria breaking down organic matter in oxygen-free conditions.
- Sources of organic matter include animal manure, food waste, and sewage. The decomposition occurs in three phases.
- Biogas can be used for cooking, lighting, electricity generation, and as a vehicle fuel as it is a renewable alternative to fossil fuels.
- India has a biogas program to promote family-sized biogas plants, with the goals of providing energy,
This document discusses producing biogas energy from different waste sources and creating awareness among humans. It describes several types of waste that can be used to produce biogas through anaerobic digestion, including municipal solid waste, agricultural waste, industrial waste, household waste, hazardous waste, hospital waste, and kitchen waste. It then explains the biogas production process, which involves three stages: hydrolysis, acetogenesis, and methanogenesis. Finally, it discusses a fixed dome type biogas plant as an economical and easy to construct option for converting waste into biogas as a renewable energy source, especially in rural areas.
To make a biogas energy from different sources & creating awareness between h...IJMER
Biogas from biomass appears as an alternative source of energy, which is potentially enriched in biomass resources. This article gives an overview of present and future use of biomass as an industrial feedstock for production of fuels, chemicals and other materials. However, to be truly competitive in an open market situation, higher value products are required. Results suggest that biogas technology must be encouraged, promoted, invested, implemented, and demonstrated, but especially in remote rural areas. Different types of wastes are used for production of biogas .these wastes are found very easy and an every palace. This article helps to make biogas form different wastes. From this study, it can be concluded that this method not only contributed to renewable biogas production but also improved the effluent quality
— Municipal Solid Waste (MSW), mainly Kitchen Waste
(K) with Cow Dung (C) and Fungi Culture (F) can be used to
generate energy which could save on the fossil fuels conventionally
used as source of energy. In this study, the possibility was
explored to mix Cow Dung with Fungi Culture for anaerobic
digestion, so that energy can be generated as biogas and at the
same time digested sludge can be used as fertilizer for agricultural
applications. Pre-treatment of Kitchen Waste was done by alkali
method. Anaerobic digestion (AD) was carried out in mesophilic
temperature range of 30°C to 37°C with different fermentation
slurries of 8 % total solids. Digestion was carried for a retention
period of 60 days. The gas produced was collected by the
downward displacement of water and was subsequently measured
and analyzed. The overall results showed that blending of Kitchen
waste with cow dung and fungi culture (Aspergillus flavus) had
significant improvement on the biogas yield.
This review article summarizes approaches for managing food waste through anaerobic digestion to produce energy and recycle nutrients. Anaerobic digestion is a multi-step process where microorganisms break down biodegradable material in the absence of oxygen and produce methane gas and digestate. Food waste is a suitable substrate for anaerobic digestion due to its biodegradable composition. The article reviews studies on producing methane from food waste via anaerobic digestion and discusses the microbial populations involved in the digestion process and factors that affect efficiency.
This document presents a cost-benefit analysis of installing a 5m3 capacity tubular polyethylene digester for small-scale hog farmers in the Philippines. The analysis finds that the projected costs of installation and maintenance over 10 years are outweighed by the projected financial benefits of fuel supply, manure maximization, and savings from reduced medical expenses. A sensitivity analysis shows the project remains economically viable even with a 10% reduction in total benefits but becomes unviable with a 45% reduction. The analysis concludes the digester installation project has a positive net present value and is a worthwhile economic investment.
Changes in energy sources and forest utilization in NepalKASUMIITO1
The document summarizes research on changes in energy sources and forest resource utilization in two villages in Nepal following the devastating 2015 earthquake. It finds that: (1) Villagers who lost biogas plants shifted temporarily to LP gas but intend to rebuild biogas, which they see as most suitable. (2) Forest usage did not change due to the quake but decreased previously due to biogas adoption, raising concerns about inappropriate forest management if people no longer depend on or visit forests. The study implies community forestry systems may need to review participation and forest health given changing resource dependence.
Environmental Engineering for Enhancing the Suitability of a Microalga for En...IRJET Journal
This document discusses research conducted on the microalga Chlorella vulgaris to study the effects of varying pH and salinity on its growth, biomass production, and lipid content. The researchers found that growth and biomass were highest at pH 7, while lipid content increased with higher salinity up to 0.25M, beyond which growth decreased. The goal was to optimize environmental conditions to enhance the suitability of C. vulgaris for renewable energy production through biomass and lipid accumulation.
Livestock farmers’ perception on generation of cattle waste Alexander Decker
This document discusses a study on livestock farmers' perceptions of cattle waste-based biogas methane generation in Embu West District, Kenya. The study surveyed 156 livestock farmers, most of whom practiced zero-grazing and had multiple cows. Only 14% had installed biogas digesters. The study found that farmers had a positive perception of biogas technology and knowledge of how it works, despite the low adoption rate. Statistical analysis showed no significant relationship between perception and adoption level. However, there was a significant relationship between perception and knowledge. The research concluded that other factors beyond perception, like installation costs, contributed more to the low uptake of biogas technology.
At present our country is facing various problems, among that energy crisis has become more serious in next coming years. Both energy crisis and pollution problems could be controlled by adopting an alternative method of biogas production form waste products. Food waste is the best alternative for biogas production in a community level biogas plant. Hence in the present study, an attempt has been made to study the rate of biogas production in a lab scale biogas digester model for the efficient conversion of the food waste (starch –rich materials) generated from PRIST University Campus. The biogas production depends on the maximum biogas yield, the concentration of volatile solids of the input, the density of the effluent, the density of the biogas and the reaction rate constant, which are all substrate - or process - specific. The experiments were carried out for 40 days and the rate of gas production was measured by water displacement method. The pH value of the cow dung and food waste was initially measured and adjusted to nearer to neutral and gradually increased to acidic and again it got stabilised to the neutral pH which favoured the production of biogas. The percentage of total solids was 69.86, 93.56 and 25.67 for cow dung, food waste and digested slurry respectively. The percentage of volatile solids was 52.5, 86.3 and 18.9 for cow dung, food waste and digested slurry respectively. The percentage of volatile fatty acid was 285, 356 and 365 for cow dung, food waste and digested slurry respectively. Observations on daily basis were made on the constituent of biogas, pH, volume and rate of biogas production. The rate of biogas production continuously increased as days progressed and there was maximum yield in biogas after 20 days. Thus continuous feeding helps in daily biogas production and can be used at a small as well as larger scale to manage the organic waste and energy production for various applications.
Ecosystem services provided by pollinatorsmogiliramaiah
Pollination is a vital ecological service provided by a wide range of insect species including bees, wasps, flies, butterflies, beetles and moths. ... Willow flowers contain pollen and nectar, both valuable resources for a wide variety of bee species and other pollinators
The document summarizes a study that investigated the effect of inoculum to substrate ratio on biogas production from anaerobically digested goat paunch manure. Goat paunch manure was digested at different inoculum to substrate ratios of 1.45, 2.2, and 4.3 in biodigesters labeled R15, R10, and R5, respectively, under mesophilic conditions. Results showed that biogas production rate peaked earliest in R10 and latest in R15, but inoculum to substrate ratio did not significantly affect production rate. However, biogas production accumulation increased from 0.44273 to 1.00783 Nm3/kg VS with increasing inoculum to substrate ratio
STUDY ON BIO-METHANATION USING POULTRY DROPPING-Abdullah Nasir PulakAbdullah Pulak
This study examined biogas production from poultry droppings through anaerobic digestion with cow dung. Four laboratory reactors were tested with varying ratios of poultry droppings and cow dung. Reactor D2, with 75% poultry droppings and 25% cow dung, produced the highest volatile solid reduction (53%), specific gas yield (0.72 l/g), and methane content (73.2%). Poultry droppings alone were found to be unsuitable due to a low carbon-nitrogen ratio, but mixing with cow dung increased the ratio and improved biogas production. The study suggests anaerobic digestion of poultry droppings mixed with cow dung can effectively produce
Biomass from sources like trees, crops, and waste can be used for energy through technologies like thermo and bio conversion. India aims to promote bioenergy to meet sustainability goals and increase energy security by reducing oil imports. Key challenges include overcoming economic, social, and technical barriers to increase adoption of bioenergy technologies on a larger scale. Developing reliable biomass supply and providing cost competitive energy services will be important for the growth of the bioenergy sector in India.
This document outlines the course materials and assignments for an environmental science course (SCI 256). It includes weekly discussion questions, individual and team assignments, and a final exam guide. The assignments cover topics such as ecosystems, biogeochemical cycles, natural resources, energy, climate change, and sustainability. Students are asked to apply course concepts to analyze environmental issues and decisions in their own communities. The goal is for students to understand human impacts on the environment and approaches to environmental management and conservation.
Influence Of Different Nitrogen And Organic Carbon Sources On Microalgae Grow...iosrjce
Microalgae based biofuels are getting attention due to energy crisis and enviromental protection. In
the present study, the Chlorella sp. was cultivated in BG-11 medium at batch mode. The effect of different
nitrogen (sodium nitrate, potassium nitrate and urea) and organic carbon (glucose, glycerol and sucrose)
sources were analyzed on growth and lipid accumulation on this species. The highest biomass growth and
biomass productivity of chlorella sp. was found 1.29±0.04 g/l, 76.96±4.5mgl-1
d
-
1 in urea. However in case of
organic sources, the biomass growth and productivity was found maximum in glucose (1.43±0.075 g/l 86.04±3.2
mgl-1
d
-1
). The lipid content was examined using folch method and found better in potassium nitrate nitrogen
source (11.84%) . Among organic carbon sources, the maximum lipid content (13.22% and lipid yield 189.94
mg/l were found in case of glucose, followed by glycerol and sucrose. Various properties of biodiesel obtained
from chlorella sp. such as Cetane number, Saponification value, Iodine value and Degree of unsaturation were
followed standerds set by the national petroleum agency (ANP255), ASTMD6751 and EN14214.
This thesis examines the energy return and economics of producing pellets from steam pretreated biomass. Chapter 1 introduces the background and objectives of assessing pellet production techniques. Chapter 2 develops process models for producing pellets from forest residues, agricultural residues, and switchgrass, and determines the net energy ratio (NER) of regular and steam pretreated pellet processes. Steam pretreated pellets have a lower NER than regular pellets. Chapter 3 provides a comparative NER analysis of pellets from steam pretreated agricultural residues and switchgrass. Pellets from steam pretreated straw have the highest NER. Chapter 4 develops a techno-economic model to evaluate production costs and determines the minimum cost plant size is 190
1) The document describes a study on the anaerobic co-digestion of water hyacinth and poultry litter.
2) Batch experiments were conducted in 300ml digesters at mesophilic temperatures to determine biogas production, total solids, volatile solids, and pH over retention periods of 0-56 days.
3) Kinetic modeling using an integral method revealed that the co-digestion process followed first-order reaction kinetics with a rate constant of 0.026 day-1.
Green chemistry is the synthesis of substance in such a way that is proper, non-polluting and protected and which requires lowest amounts of resources and energy but generating slight or no waste material. The green chemistry is required to minimize the harm of the nature by anthropogenic materials and the processes applied to generate them.Green chemistry indicates research emerges from scientific discoveries about effluence responsiveness. Green chemistry involves 12 set of values which minimize or eliminates the use or production of unsafe substances. Scientists and Chemists can significantly minimize the risk to environment and health of human by the help of all the valuable ideology of green chemistry.The principles of green chemistry can be achieved by the use environmental friendly, harmless, reproducible and solvents and catalysts during production of medicine, and in researches. The use of UV-energy Microwave irradiation in is also significant way to achieve the goal of green chemistry.This paper explain ideology, certain examples and application of green chemistry in everyday life, in industry, the laboratory and in education.
Impact of Improved Aeration on Decomposition Rate of Enriched Compostijtsrd
Agricultural activities tend to generate a substantial volume of animal and crop residues. Composting is the most economical and ecologically sustainable option to manage farmyard waste. However, it takes approximately three months to complete decomposition and contains lower plant nutrient percentages than inorganic fertilisers. This study aimed to reduce the decomposition time and improve the nutrient content of compost. Aerobic decomposition was enhanced by aeration inside the pile using a blower with 0.5 l min kg airflow. Paddy straw, poultry manure, goat manure, cattle manure and paddy husk ash were mixed in 3 1 1 1 1 ratio respectively as the raw materials and 3 of Eppawala Rock Phosphate was added to the mixture in weight basis. Six piles 150 X 100 X 80 cm were prepared, and three piles were aerated for six hours per day while other three piles were left to decompose under the ambient condition as the control. According to the results, aerated and control piles took 35 days and 65 days to complete the decomposition. Total N, available P, exchangeable K, C N ratio, pH, EC and CEC were analysed in compost samples from aerated after 35 days and controls, and the results were, 20.5 g kg 1, 1.8 g kg 1, 10.4 g kg 1, 7, 8.8, 4.3 mS cm 1, 19.3 cmol kg 1 and 17.8 g kg 1, 1.5 g kg 1, 9.9 g kg 1, 8.5, 8.8, 3.64 mS cm 1, 21.3 cmol kg 1 respectively. Data were analysed using SAS 9.0 software with a 95 confidence interval. The results revealed a significant increment in total N, exchangeable K, C N ratio, EC and CEC in aerated piles compared to controls. And the nutrient composition of both methods was significantly higher than the commercial compost. Therefore, it can be concluded that decomposition time can be effectively reduced and the nutrient level can be increased by artificial aeration and nutrient enrichment, respectively. However, further studies are recommended to study the economic feasibility. D. M. S. H. Dissanayaka | V. P. T. Dhananjaya | E. J. Kosgollegedara | S. Karthigayini "Impact of Improved Aeration on Decomposition Rate of Enriched Compost" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-2 , February 2021, URL: https://www.ijtsrd.com/papers/ijtsrd38557.pdf Paper Url: https://www.ijtsrd.com/engineering/agricultural-engineering/38557/impact-of-improved-aeration-on-decomposition-rate-of-enriched-compost/d-m-s-h-dissanayaka
Biogas Handbook by Biogas Developement and Training Centre.pdfRaj kumar
This document contains frequently asked questions about biogas technology. It discusses what biogas is, how it is produced through the anaerobic digestion of organic waste, and its applications. Key points covered include:
- Biogas is a mixture of methane and carbon dioxide produced by bacteria breaking down organic matter in oxygen-free conditions.
- Sources of organic matter include animal manure, food waste, and sewage. The decomposition occurs in three phases.
- Biogas can be used for cooking, lighting, electricity generation, and as a vehicle fuel as it is a renewable alternative to fossil fuels.
- India has a biogas program to promote family-sized biogas plants, with the goals of providing energy,
This document discusses producing biogas energy from different waste sources and creating awareness among humans. It describes several types of waste that can be used to produce biogas through anaerobic digestion, including municipal solid waste, agricultural waste, industrial waste, household waste, hazardous waste, hospital waste, and kitchen waste. It then explains the biogas production process, which involves three stages: hydrolysis, acetogenesis, and methanogenesis. Finally, it discusses a fixed dome type biogas plant as an economical and easy to construct option for converting waste into biogas as a renewable energy source, especially in rural areas.
To make a biogas energy from different sources & creating awareness between h...IJMER
Biogas from biomass appears as an alternative source of energy, which is potentially enriched in biomass resources. This article gives an overview of present and future use of biomass as an industrial feedstock for production of fuels, chemicals and other materials. However, to be truly competitive in an open market situation, higher value products are required. Results suggest that biogas technology must be encouraged, promoted, invested, implemented, and demonstrated, but especially in remote rural areas. Different types of wastes are used for production of biogas .these wastes are found very easy and an every palace. This article helps to make biogas form different wastes. From this study, it can be concluded that this method not only contributed to renewable biogas production but also improved the effluent quality
— Municipal Solid Waste (MSW), mainly Kitchen Waste
(K) with Cow Dung (C) and Fungi Culture (F) can be used to
generate energy which could save on the fossil fuels conventionally
used as source of energy. In this study, the possibility was
explored to mix Cow Dung with Fungi Culture for anaerobic
digestion, so that energy can be generated as biogas and at the
same time digested sludge can be used as fertilizer for agricultural
applications. Pre-treatment of Kitchen Waste was done by alkali
method. Anaerobic digestion (AD) was carried out in mesophilic
temperature range of 30°C to 37°C with different fermentation
slurries of 8 % total solids. Digestion was carried for a retention
period of 60 days. The gas produced was collected by the
downward displacement of water and was subsequently measured
and analyzed. The overall results showed that blending of Kitchen
waste with cow dung and fungi culture (Aspergillus flavus) had
significant improvement on the biogas yield.
Utilization of Food Waste to Produce BiodieselIRJET Journal
This document discusses utilizing food waste to produce biodiesel. Food waste was collected from a university campus and analyzed. It had moisture contents ranging from 5.2-7.2% depending on drying method. Lipid extraction yielded 15.8% lipids. Gas chromatography identified various fatty acids present including lauric, mystric, palmitic, stearic and oleic acids, indicating potential for biodiesel production. Transesterification of the lipids produced 31.9% biodiesel. Testing found the biodiesel met various standards for density, viscosity and other properties, suggesting food waste is a viable feedstock for biodiesel production.
Submission Report - Exploratory Project: Model for Rice Husk UtilizationAvnish Singh
The project aimed at finding the possible ways in which the abundant amount of rice husk produced each year (around 21 million tons) can be used. After doing a lot of research and experiments it can be concluded that it can be used as a source of electricity as well as a fuel in industry after increasing its carbon content by pyrolysing rice husk at elevated temperatures.
Microbial application for biofuel productionSAIMA BARKI
Microbial application for biofuel production-Third generation of the biofuels-emerging trend to accomplish with decreasing energy resources of the world-twenty-first century- a clean and green environment to decrease the greenhouse gases and to protect the third world countriess and also the food insecurities.
Technologies Involved in Biomass to Energy Conversion and its Utilization in ...IRJET Journal
This document discusses biomass conversion technologies used in India to generate energy from biomass. It begins with an introduction to biomass as a renewable energy source and India's growing installed capacity of renewable energy. It then describes the various types of biomass resources available in India, including wood/agricultural waste, solid waste, landfill gas, and biofuels. The major technologies currently used at large scale in India are discussed - co-firing of biomass with coal, gasification of biomass, and anaerobic fermentation to produce biogas. While biomass energy has benefits, issues associated with large-scale usage include potential environmental impacts if forest resources are overexploited and public health impacts if biomass
The document provides an overview of anaerobic digestion as an approach for managing food waste and recycling nutrients in a sustainable way. It discusses how anaerobic digestion breaks down food waste into biogas through four phases - hydrolysis, acidogenesis, acetogenesis, and methanogenesis carried out by different microorganisms. This process generates methane which can contribute to energy needs while reducing environmental pollution from food waste. The document also summarizes worldwide and regional data on food waste generation and its potential for energy production through anaerobic digestion.
Development of integrated bioremediation and anaerobic digestion process usingIAEME Publication
This document discusses a study on the development of an integrated bioremediation and anaerobic digestion process using microalgae. Specifically, it examines using the microalgae Chlorella pyrenoidosa to treat biogas digester wastewater. The study finds that C. pyrenoidosa is able to grow well in biogas wastewater, removing up to 92.8% of nitrate nitrogen. The treated wastewater can then be used to support anaerobic digestion of the algal biomass to produce biogas. Co-digesting the microalgae with cow dung achieved higher biogas yields than digesting cow dung alone. Overall, the integrated process effectively treats biogas
IRJET- Design of Biogas Plant for Food Waste and Evaluation of Biogas Generat...IRJET Journal
This document summarizes a study that designed a biogas plant for food waste generated at a college in India and evaluated the efficiency of biogas production from various co-digester mixtures added to the food waste. The researchers conducted a survey that found the college generates an average of 100kg of food waste per day. They designed a fixed dome biogas plant based on this amount of waste with a gas production rate of 24 cubic meters per day. Experiments tested co-digesters of water hyacinth, algae, cow dung, and sugar cane added to food waste in a 1:1 ratio, finding water hyacinth improved overall biogas plant efficiency the most. The study concluded a biogas plant using a
Study of Biomass Briquettes, Factors Affecting Its Performance and Technologi...iosrjce
IOSR Journal of Environmental Science, Toxicology and Food Technology (IOSR-JESTFT) multidisciplinary peer-reviewed Journal with reputable academics and experts as board member. IOSR-JESTFT is designed for the prompt publication of peer-reviewed articles in all areas of subject. The journal articles will be accessed freely online
This document discusses food waste management and recycling strategies. It begins with an abstract stating that the project focuses on converting food waste into value-added by-products through recycling, as most food waste currently ends up in landfills releasing greenhouse gases. The document then provides details on three food waste recycling methods - producing biofuel through microbial conversion of food waste carbohydrates and lipids, producing biodiesel from waste cooking oil through trans-esterification, and composting food waste into fertilizer through microbial breakdown in the presence of air.
This document summarizes a study on a biomethanation plant that converts vegetable waste into biogas. Some key points:
- The plant uses a BIMA digester to break down vegetable waste from markets into biogas through anaerobic digestion.
- The process involves shredding the waste, digestion in the BIMA digester to produce biogas, collection of biogas, power generation from the biogas, dewatering of the digested substrate, and odor control.
- The byproduct of digestion (biodigested slurry) is a valuable organic manure high in nutrients that can be used to enrich soils or as fertilizer.
This document describes the design and fabrication of a mini biogas plant using kitchen waste. The researchers in India created a small-scale biogas reactor using kitchen waste collected from their university's hostel mess halls. The reactor operated via anaerobic digestion to produce biogas, a renewable energy source. The biogas produced was found to contain 55-65% methane and could effectively be used as fuel after processing. Additionally, the leftover slurry provided valuable organic fertilizer for farming. The researchers concluded that kitchen waste is well-suited for small-scale biogas production and that such mini biogas plants can help reduce waste and emissions while generating renewable fuel at the community level.
This document describes the design and fabrication of a mini biogas plant using kitchen waste. The researchers in India created a small-scale biogas reactor using kitchen waste collected from their university's hostel mess halls. The reactor operated via anaerobic digestion to produce biogas, which is a renewable energy source. The biogas produced was found to contain 55-65% methane and could effectively be used as fuel after processing. Additionally, the leftover slurry provided valuable organic fertilizer for farming. The researchers concluded that kitchen waste is well-suited for small-scale biogas production and that such mini biogas plants can help reduce waste and emissions while generating renewable fuel at the community level.
This document describes the design and fabrication of a mini biogas plant using kitchen waste. The researchers in India created a small-scale biogas reactor using kitchen waste collected from their university's hostel mess halls. The reactor operated via anaerobic digestion to produce biogas, which is a renewable energy source. The biogas produced was found to contain 55-65% methane and could effectively be used as fuel after processing. Additionally, the leftover slurry provided valuable organic fertilizer for farming. The researchers concluded that kitchen waste is well-suited for small-scale biogas production and that such mini biogas plants can help reduce waste and emissions while generating renewable fuel at the community level.
1) The document describes a study on designing and fabricating a mini biogas plant using kitchen waste.
2) The goals of the study were to produce alternative energy from biogas in an effective and cost-efficient manner, while also generating high-quality fertilizer.
3) Kitchen waste was collected from hostel mess halls at a university to use as feedstock for a 20L laboratory-scale biogas reactor to produce biogas through anaerobic digestion.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Bio Gas Generation from Biodegradable Kitchen WasteIJEAB
Generation of Solid wastes in general and biodegradable waste in particular is increasing at house hold level over the last two decades. Per capita generation of the waste has been increasing steadily due to population growth and changing socio-economic characteristics and cultural habits and varies from 250g to 600g. Any material which can be decomposable by the action of microorganisms in a short period of time is called biodegradable Mostly food waste; vegetable peels and fruit pulp are biodegradable. These materials readily mix with the soil by the action of bacteria. During decomposition, these materials release carbon dioxide, methane, ammonia and hydrogen sulphide into the environment thereby contributes to air pollution and odour pollution. The gases that are released during the decay of biodegradable wastes can be captured for the economic utility and as well as to save the environment. An attempt is being made in this technical research paper to demonstrate the possibilities energy recovery from biodegradable kitchen waste that is collected from residential societies which can be utilized for the benefits of the society. Kitchen and food waste collected from a high end residential community of 300 families in Mumbai city suburbs is analyzed for the quantification of bio gas. Bio gas is captured through a fabricated anaerobic digester. Experimentation and results are discussed. The results are encouraging.
Bio Gas Generation from Biodegradable Kitchen Waste
EE Final
1. 0
How can we convertorganicfoodwaste intomethane gasthroughanaerobicdigestiontopowerhouses
in developing nations?
Adhitya Jayasinghe
CHEMISTRY KILLING TWO BIRDS WITH ONE STONE
2. ABSTRACT
The paper seeks to investigate the proposed conversion of organic food waste into
sustainable energy, CH4, methane to power houses in developing nations. The pressing issue of
energy scarcity has filled the minds of politicians, engineers, and scientists across the world.
There have been numerous proposed solutions from tidal power to geothermal, but most of
these alternatives require a rather large initial fee, making it difficult for developing nations to
adopt. Therefore, the researcher looked to find an alternative source of energy that developing
countries would be able to adopt; biogas. Biogas and biofuels have been used for thousands of
years, but the researcher chose to approach the idea of biogases from a different perspective.
How can we kill two birds with one stone and solve the issue of energy scarcity and waste
pollution?
To answer this question, the researcher used an age-old method of using cow manure
as an initial fuel source. The researcher tested different ratios of cow manure and food waste in
order to find the optimal ratio of methane production, because the structure of pure food
waste would be far too rigid for the anaerobic methanogens to digest. The solution of Basal
Carbonate Yeast Trypticase and different ratios of food waste and cow manure went through
the process of Hydrolysis, Acidogenesis, Acetogenesis, and Methanogenesis. The researcher
withdrew gas from each sample daily and put it through a gas chromatographer and recorded
the yield of Hydrogen H2, Methane CH4, and Carbon Dioxide CO2. In the preliminary stages of
the experiment, the researcher saw the highest yield of methane gas coming from the solution
of pure cow manure. After three to four days, the researcher recorded an exponential yield
increase from the solution that contained 75% food waste and 25% cow manure.
3. Tables of Contents
Introduction……………………………………………………………………………………......
Research Question………………………………………………………………………………...3
Background Information…………………………………………………………………………..3
3.1 Hydrolysis……..……………………………………………………………...……….3
3.2 Acidogenesis………..………………………………………………...…………….…4
3.3 Acetogensis…...…………………………………......………………...………………5
3.4 Methanogenesis………………………..……………………………...……………….5
3.5 Obligate Anaerobe ……………………...…………………...…….………………...6
Method…………………………………………………………………………………………….7
4.1 Synthesizing Basal Carbonate Yeast Trypticase………….………………...……........7
4.2 Dilution of Substrates…………………………..…………………………………......8
4.3 Food Waste and Cow Manure Substrate Inoculation……..………………………......9
4.4 Gas Chromatography……………………...…………………..……………………..10
Results……………………………………………………………………………………………11
Interpretations of Results…...........................................................................................................13
Conclusion……………………………………………………………………………………….15
Bibliography..........……………………………………………………………………………....16
Appendix I ………………………………………………………………………………………19
4. 1
INTRODUCTION
Indiaisone of the fastestdevelopingnationsinthe worldtodayatan average growthof 7.02%
GDP overthe pastfour years.1
Today,Indiaisdelvingthroughastage of industrialization,ahighlyenergy
intensivestage of growthforany country.CountriessuchasUnitedKingdom, the UnitedStates,Japan,
Germany,and France wentthroughthisstage of developmentdecadesago.A commonsocial stigma
createdby these countriesis thatthere is a positive correlationbetweendevelopmentandpollution,
and the drop of standardof livinginexpectancyof arapidincrease of standardof livinginthe near
future.Currentexamplesof unsustainable industrializationcanbe observedinChinaandSaudi Arabiain
the past twodecades.Waste pollution,increasingsocial-incomegaps,andincreasingfrequency of
terminal diseaseare justdropsof waterin a seaof side-effectsof unsustainablegrowth.2
The question
has beenthrownaroundnumeroustimes: how candevelopingnationsprogresswithoutresultingina
depressionof standardof living?There are multiple alternativesoutthere;solarpower,nuclearpower,
windpower,hydroelectricpower,ethanolbiofuels,andthe listgoeson.All these sourceshave the
abilitytoyieldenormousamountsof energy,buttheyall come withone draw-back;price.For
developednations,these are logical investments,butfordevelopingnationssuchasIndiaor Rwanda,it
isimprobable thatindividualswillhave the moneytoinvestintothesetypesof technologies.
Overthe past decade there hasbeena surge inresearchintoalternative energysourcesthatare
feasible atthe micro-scale. One of these manyalternativesisbiogas. Driedcow manure hasbeenused
as a source of fuel since 3200-2700 BCE, and isstill beingusedtodaytopowercooking,water-heating,
and fertilizingfields3
.In1995, manure accountedfor almost21 percentof netenergyexpenditure in
rural India.4
The Ministryof NewandRenewable Energyinitiatedthe National BiogasandManure
1 “GDP Growth (annual %)” See India for GDP statistics.
2 Effects of unsustainablegrowth in India.See Pandey and Khanjan 113-115.
3 The uses of cow manure in history.See Miller 71-73.
4 Rural India’s Energy Expenditures. See Sampat 1.
5. 2
ManagementProgramme in1981 in orderto provide cleanenergytovillagesthathave beenstruggling
withenergydeficits.In March 2014, the MNRE revisitedthe programme and,withthe helpof State
Nodal Agencies,KhadiandVillageIndustriesCommission,BiogasDevelopmentandTrainingcenters,
and the IndianInsitute of Technology,hasbolsteredthe programme,recordingabout82,700 villager-
initiatedbiogasplants.5
However,thisisnota sustainable solutionforthe comingyears,andfailsto
meetIndia’svastenergydemands. Inaddition,itfailstoaddressthe problemof waste pollutioninIndia,
one of the largest sourcesof disease andgreenhouse gasemissions.6
Accordingto the 2010 MNRE annual report,Indiaproducesapproximately55milliontonsof
municipal solidwaste eachyear,andthatamountisincreasingata rate of 1% annually.7
The diverse
cultural boundariesof India’spopulace make itdifficultforgovernmenttotake authoritative actionon
the micro scale,thusrelyingonstate governmentsto assume the responsibility of cleaningthe streets
and rivers.The lackof importance placedonwaste-pollutionhasledIndiatobe visiblyone of the most
pollutedcountriesintermsof surface waste.The vastdepositof surface municipal solidwaste isthe
root of a wide varietyof diseases.8
A pile of waste isanideal habitatformosquitoestobreed,which
leadstothe spreadof Chikungunya,Malaria, andDengue fever.9
Waste pollutionisalsoabreeding
habitatfor flies,whichare carriersof deadlydiseasessuchastyphoid,tuberculosis,leprosy,and
cholera.10
Insteadof scramblingtocreate a cure fora new strandof these diseases,we mustfocuson
tacklingthe source of the disease andpreventthe birthof new pathogens.Bylookingatbothproblems,
the energycrisisandpollutioncrisis,fromthe perspective of sustainabledevelopment,we seethat
we’re able tokill twobirdswithone stone.
5 Ministry of New and Renewable Energy biogas progamme. See 67.
6 Waste pollution in Indiaand the repercussions of this topic.See Sachs.
7 Measurements of waste pollution in India and projected growth of waste. See 5.38.
8 The diseases caused by waste pollution in India.See6.
9 The variety of diseases thatmosquitoes carry.See links for depth.
10 The various diseases flies carry becauseof solid wastepollution.See 35.
6. 3
RESEARCH QUESTION
How can we convertorganicfoodwaste and cow manure intosustainable energyinordertopower
rural village houseswhile alsosolvingthe issue of waste pollutioninIndia?
BACKGROUNDINFORMATION
Biogasis a mixture of carbondioxide (CO2),hydrogen(H2),andmethane (CH4).Itisa clean
source of energythatisproducedthroughthe breakdownof biodegradable materialsby obligate
anaerobesinthe absence of oxygen. Thisprocessisknownasanaerobicdigestion. Foodwaste andcow
manure,whichare composedof cellulose(large polymers),starch(carbohydrates),casein(proteins),
and triglycerides(fats),are the productsusedforthe firststage of the anaerobicdigestionprocess.
3.1 Hydrolysis
The firststage of this process iscalledhydrolysis.Hydrolysis,insimple terms,isthe stage in
whichfoodwaste andcow manure isbrokendownintoliquefiedmonomersandpolymers.Inthisstage
a molecule issplitintotwopartsbyaddinga watermolecule.The cationof the parentmolecule gains
the hydroxyl group(OH-
) while the anionof the parentmolecule gainsthe hydrogenion(H+
). Cellulose
are convertedintoglucose withthe presence of cellulases,anenzyme thatcatalysesthe hydrolysisof
cellulose,andwater(H2O).Caseinsare convertedinto aminoacids,specificallyLysine andHistidine,in
the presence of proteases,anenzyme thatcatalysesthe hydrolysisof caseins,andwater(H2O).
Triglyceridesare brokendownintofattyacidsinthe presence of lipases,anenzyme thatactsas a
catalystfor the hydrolysisof triglycerides.11
Forcarbohydratesthe equationis:
ExampleHydrolysisof Carbohydrates: C6H10O4 + 2H2O <--> C6H12O6 + 2H2
11 Presentation on biogas with breakdown of cellulose,starch,casein,and triglycerides.See 10.
7. 4
The hydrolysistakesplace inthe presence of alpha-amylaseswhichhelps breakdownthe
carbohydrate intosimple sugars,suchasmaltose orglucose.12
The carbohydrate ismade up of a string
of monosaccharides.Whentwoof the monosaccharidescombine,ahydroxyl ionisremovedfromone of
the monosaccharidesanda hydrogenionisremovedfromthe other.Whenthe bondsare broken,they
mustbe replaced. The watermoleculeissplitintotwoandthe monosaccharide whichlostthe hydroxyl
iongainsthe OH-
anionfrom the watermolecule,whilethe monosaccharidewhichlostthe hydrogenion
gainsthe H+
cation,thus,producingglucose (C6H12O6) andhydrogengas(H2).13
Byhydrolyzingthe
carbohydrate,we are breakingitdownintoa simple sugarwhichcan be usedinthe nextphase,
acidogenesis.
3.2 Acidogenesis
Acidogenesis,the fasteststep, isthe processinwhichacidogenicbacteriadigestthe productsof
hydrolysis,creatingketones,alcohols,hydrogen,carbondioxide,andvolatile fatty acids.The most
commonproductsof thisstage are: aceticacid (CH3COOH) butyricacid(CH3CH2CH2COOH),propionic
acid (CH3CH2COOH),lacticacid(C3H6O3),formicacid(HCOOH),ethanol (C2H5OH),andmethanol (CH3OH).
The byproducts hydrogengas, carbon dioxide,andgaseousammoniagostraighttothe last stage,
methanogenesis,tobe digestedbythe methanogenicbacteria. The volatile fattyacids,alcohols,and
ketonesare thenbrokendownfurtherinthe nextstage,acetogenesis.
Example breakdown of glucose into acetic acid: C6H12O6 <--> 3CH3COOH
12 The function of alpha-amylasein hydrolysis.See 1.
13 Hydrolysis of Carbohydrates,Fats,and Proteins.See Carbohydrates.
8. 5
3.3 Acetogenesis
Acetogenesis,the intermediate step, isthe stage inwhichthe productsof acetogenesisare
brokendownintohydrogen,carbondioxide andaceticacidbyacetogenicbacteria.14
Hydrogenplaysa
veryimportantrole inthisstage.The reactionwill occurand acetogenesiswillonlyproceedif the partial
pressure is“lowenoughtothermodynamicallyallow the conversionof all the acids.” The partial
pressure isloweredbybacteriathatare seeking hydrogen;therefore,awayto testthe healthof the
acetogenicbacteriaistomeasure itshydrogenconcentration.
Examplebreakdown ofpropionateto acetate: CH3CH2COO-
+3H2O <--> CH3COO-
+ H+
+ HCO3- + 3H2
3.4 Methanogenesis
The last stage ismethanogenesis.Thisisthe stage inwhichthe productsof acetogenesis:
hydrogen,carbondioxide,andaceticacid,are convertedtohydrogengas,methane gas,andcarbon
dioxide bymicro-organisms.The bacteriathatcarry out thisstepare calledmethanogens.Theseare
strict obligate anaerobeswhichwill becometoxicinthe presenceof oxygen. Methanogensare
chemoautotrophs. The stabilizationof waste isreachedwhenmethane gasandcarbondioxide are
produced.15
Examplebreakdown ofCarbonDioxide andHydrogen Gas: CO2 + 4H2 <--> CH4 + 2H2O
14 Description of the acidogenesis and acetogenesis.See 377-378.
15 Equations for all of the mechanisms with explanations of each one in simpleterms. See all.
9. 6
3.5 ObligateAnaerobes
Obligate anaerobesproducesuperoxide dismutaseandcatalase insmall quantitiesinorderto
remove invasivemolecularoxygenthatwill reduce tohydrogenperoxide (H2O2) andsuperoxide(O2
-
)
inside the cell.
Superoxide Dismutase reaction with O2-: 2O2- + 2H+----> O2 +H2O2
16
Catalase reaction with H2O2: 2H2O----> 2H2O + O2
17
Obligate anaerobesbydefinitionare anaerobesthatare notable to grow inaerobicconditions,
but the productionof these twoenzymesare evidence forthe slight the tolerance (0.2% to8%) of
oxygenthatobligate anaerobesare able tohandle.Thisallowsforminimalerrorinthe labwhen
growingthese anaerobes,butwill deterthe resultsasthe anaerobeswillhave beenexposedtotoxic
conditions.18
Afterthe anaerobesproduce carbondioxide,hydrogen,andmethane,the gasesare
harnessedandsealedwithinanair-tightcontainer.Theycanthenbe combustedwithoxygen,releasing
energywhichcanbe usedforheatingwater,oras a source of fuel forcooking.
Methane combustion with Oxygen: CH4 + O2 ----> CO2 + H2O + energy 19
The byproductof thiscombustionisminimal amountsof carbondioxide andhydrogengas,whichis
equivalenttothe amountof carbon dioxide aplantabsorbsduringitsgrowthcycle,makingthe
combustionof biogasclimate-neutral.20
16 Reaction f superoxidedismutasewith an oxygen radical.See 1.
17Catalasereaction with Hydrogen Peroxide. See 1.
18 Explanation of ObligateAnaerobes and their preferred conditions.See 67-68
19 The combustion of methane with oxygen to produce energy. See 1.
20 Byproducts of the combustion of methane and oxygen. See 1.
10. 7
METHOD
4.1 Synthesizing BasalCarbonateYeastTrypticase
The Basal Carbonate YeastTrypticase isthe culture whichwill be combinedwiththe different
batch digestionsinfivedifferentgas-tightbottles.To make the Basal Carbonate YeastTrypticase we
usedthe followingchemicals:NH4Cl,KH2PO4,K2HPO4,CaCl2 ·2H2O,KCl,MgCl · 6H2O, NaCl,C6H12O6,and
yeastextract[See Appendix 1forChemical Measurements].
The firststepwas to take a 1000mL Erlenmeyerflaskandfill itwith600mL of distilledwater. The
nextstepisto boil the 500mL of water,place the flaskona hot plate,andmaintainaninternal
temperature of 105̊C. Combine the chemicalspreviouslylistedandmix themintothe boilingwater. Stir
the flaskuntil youare able to see a consistentmedium-browncolor.Next, recordthe pHof the solution.
The solution shouldhave apH of 6.8 (±0.1). At thispoint,take a volumetricpipette anddrop0.5 mL of
Rosazurinintothe solution. Place the flaskbackonthe hot-plate andletitreachan internal
temperature of 105̊C. Boil for one minute,until youare able tosee bubblesformingonthe surface of
the solution.Next,cool the mediainthe presence of nitrogengas(N2) fortwotothree minutes.After
the mediaiscooled,fill one of the five bottleswith20mLof mediawhile spargingthe mediawith
Nitrogengas(N2). Next,addthe L-Cysteine hydrochloride tothe media,continue sparging.Quickly
remove the tube andplace a rubberstopperinthe mouthof the glass bottle.Place analuminumcap
aroundthe mouthof the bottle andcut outa three centimeterhole ontopinorderto provide accessto
the mediawheninoculatinginthe future.Repeatuntilall five bottlesare filled.Store the bottles
containingthe Basal Carbonate YeastTrypticase inan ovenforthree days at 65̊C.
11. 8
4.2 Dilution of Substrates
While the culture iscooking,prepare yoursubstrateswiththe differentratiosof dilutedfood
waste and dilutedcowmanure.Take five glassunsterilizedglassvialsandplace theminanautoclave.
Sterilize the glassvialsat121̊C for fifteenminutes.Next,removethe glassesandplace theminan oven
at 100̊C fortwentyminutes. Whilethe glassvialsare inthe oven,startto dilute the cow manure andthe
foodwaste. The target Molarityforeach solution is0.5M, and a volume of 250mL of eachdiluted
solution. Forthe cowmanure calculation,we need250mL of dilutedsubstrate inordertofill all five jars,
the equationwouldbe: 0.5M =
𝒎𝒐𝒍
𝟎.𝟐𝟓𝟎 𝑳
= 0.125 mol. For the foodwaste calculation,we need250mLof
dilutedsubstrate inordertofill all five jars,the equationwouldbe: 0.5M =
𝒎𝒐𝒍
𝟎.𝟐𝟓𝟎 𝑳
= 𝟎. 𝟏𝟐𝟓 𝒎𝒐𝒍. Thus,
we require 0.125 molesof cowmanure in orderto dilute eachsample toa constant0.5M, and 0.125
molesof foodwaste inorderto dilute eachsample toa constant0.5M.
Afterdilutingboththe foodwaste andcow manure to 0.5M, separate the twosubstratesinto
the bottlesaccordingto the presetratios.The firstbottle will be filledwith100mLof dilutedcow
manure,shutwitha rubberstopper,sealedwithanaluminumcap,andlabeled B1C100F0. The second
bottle will be filled with90mLof dilutedcow manure and10mL of dilutedfoodwaste,shutwitha
rubberstopper,sealedwithanaluminumcap,andlabeled B2C90F10. Thiscontinuesasshownin Table
1.
B1C100F0 B2C75F25 B3C50F50 B4C25F75 B5C0F100
DilutedCow
Manure(mL)
100 75 50 25 0
DilutedFood
Waste (mL)
0 25 50 75 100
Table 121
21 – Ratios of cow manure (mL) to food waste (mL) in each bottle.
12. 9
By doingthiswe create a wide varietyof substrateswhilekeepingthe control of dilutedcow
manure,andcomparingit to the methane productionof pure dilutedfoodwaste. Aftersplittingupthe
differentsubstratesintothe ratiosprovidedabove,andsealingeachbottle,we place the glassvialsin
the ovenat 65̊C, alongwiththe bottlesof Basal Carbonate YeastTrypticase forthree days.
4.3 Food Wasteand CowManureSubstrateInoculation
After72 hours,remove the six glassvialsfilledwiththe substrate,andthe six glassvialsfilled
withthe Basal Carbonate YeastTrypticase media.The stage of inoculation orthe introductionof micro-
organismsintoa mediumthatwill supportgrowth, will take place inthe BactronIV 900 SHEL LAB, an
anaerobicchamberusedtoprevent the samplesfromthe invasiveoxygenradicals.Place all five of the
substrate filledsamples,all fiveof the Basal Carbonate YeastTrypticase media,andthree 14-gauge 5mL
syringesintothe anaerobicchamberdoor.Toensure thatthe anaerobicchamberiscleanedof gases,
openthe valve onthe nitrogengastank to twentyPascals,lettingthe N2 gasflow intothe anaerobic
chamber.Next,clickthe vacuumbuttonforthirtyseconds,removinganygasesinthe chamber. Next,
release more nitrogengasintothe chamber.Repeatthe lasttwostepsthree timesinorder tofilterout
all of the toxicgases.Whenopeningthe doorstoplace yourhands inside the chamber,pressdownon
the foot-pedal labeledvacuumtomake sure that notoxicgasesare allowedtoenterthe chamber, and
thenpressdownon the foot-pedal labeledgas torerelease the storednitrogengasintothe chamber.
Now,we have achieved anaerobicconditions.Openthe internal doorandreceive the glass-ware and
syringes.Usingone syringe, pierce the rubberstopperwiththe needle,and carefullyextract5mL of
liquidsubstrate fromthe B1C100F0 glassvial.Release the liquidintoone of the Basal Carbonate Yeast
Trypticase media;label thisglassvial B1C100F0-S1.Repeatthese stepsusingacleansyringe eachtime
and transferring5mLof liquidsubstrate fromeachvial containingsubstrate intothe corresponding
mediaandlabelingitaccordingtoits correspondingsubstrate;e.g.B3C50F50-S3. Afterinoculatingall
13. 10
the samples,remove all the samples,turnoff the machine,andclose the valve of the gastank to cease
the release of the nitrogengas. Next,place the tenglassvialsbackintothe ovenat65̊C, ideal conditions
for the anaerobe growth,for24 hours.
4.4 Gas Chromatography
The last stage of thisexperimentistomeasure the concentrationof methanegaswithinthe
biogasproducedbythe varioussamples.Todothis,we must use gas chromatographyandcomputed
integralsinordertomeasure the separationof concentrationsof H2, CH4,andCO2 gases. To start, turn
on the computerlinkedtothe gaschromatographer,inthiscase the ChemitoGasChromatographGC
7610, andopenPeakSimpleV1.47and opena blanktest.Asthe computeris startingup,retrieve your
five inoculatedmediaandthe 5mL thinlayerchromatographysyringe.Openthe valve tostartthe flow
of the carriergas, N2.Nitrogenisthe ideal carriergasbecause ithas a highthermal conductivitywhich
will keepthe tungsten-rheniumfilamentcool and turnon the Main switchandthe Bridge switch and
waittill itthe apparatus reads60̊C. Switchthe machine tomethod8 for the Thermal Conductivity
Detector. Waitfive minutes.Next,withdraw 5mLof gas from yourfirstsample,B1C100F0-S1 and
release itintothe hole atthe top of the ChemitoGasChromatographGC 7610. ClickCtrl+Rto start the
teston the program PeakSimple. The biogasisevaporatedinaninjectorwhichisheatedto200-300̊C.
The evaporatedgasis thenputthroughthe column,PolarpakQ,where itisseparatedintoCH4,H2, and
CO2 as itmovesalongthe N2 carriergas. Overthe course of eightminutesall the data will be recorded
and a graph similartothe one in Figure 1 will be displayedonthe screen. Alongwiththisfigure,the
program will give youthe concentrationsof CO2, CH4, and H2 by computingthe areaunderthe peakusing
integration.The exactequationtofindthe concentrationis: 𝑪𝒐𝒏𝒄𝒆𝒏𝒕𝒓𝒂𝒕𝒊𝒐𝒏 =
𝑨𝒓𝒆𝒂 𝒖𝒏𝒅𝒆𝒓 𝑷𝒆𝒂𝒌
𝑺𝒕𝒅 𝒐𝒇 𝑪𝑯𝟒
𝒙 𝟏𝟎𝟎.
Recordthe data,and repeatthe previousstepsforall five inoculatedmediaeachdayforfive days.
14. 11
RESULTS
Figure 122
Table 2: Separation of the Concentration of gases first 24 hours23
Concentration ofMethane Gas
(%)
Concentration ofHydrogen Gas
(%)
Concentration ofCarbon Dioxide
B1C100F0 12.05 1.28 86.67
B2C75F25 8.13 1.51 90.36
B3C50F50 6.37 2.53 91.1
B4C25F75 5.16 2.66 92.18
B5C0F100 2.47 3.21 94.32
Table 324
Concentration ofMethane Gas
(%)
Concentration ofHydrogen Gas
(%)
Concentration ofCarbon Dioxide
B1C100F0 16.51 2.21 81.28
B2C75F25 11.37 2.56 86.06
B3C50F50 9.72 2.48 91.14
B4C25F75 6.76 2.13 91.11
B5C0F100 2.50 3.94 93.56
22 Graph that shows the abundanceof each gas relativeto its specific retention time standard for B1C100F0
23 Recordings of the concentrations of methane gas, hydrogen gas,and carbon dioxideof each sampleon day one.
24 Recordings of the concentrations of methane gas, hydrogen gas,and carbon dioxideof each sampleon day two.
15. 12
Table 425
Concentration ofMethane Gas
(%)
Concentration ofHydrogen Gas
(%)
Concentration ofCarbon Dioxide
B1C100F0 21.88 2.36 75.76
B2C75F25 16.81 2.78 80.41
B3C50F50 10.99 2.13 86.88
B4C25F75 9.45 2.46 88.90
B5C0F100 2.51 2.42 95.07
Table 526
Concentration ofMethane Gas
(%)
Concentration ofHydrogen Gas
(%)
Concentration ofCarbon Dioxide
B1C100F0 34.39 2.22 63.39
B2C75F25 24.72 2.94 72.34
B3C50F50 18.43 2.57 79.0
B4C25F75 16.07 2.29 81.64
B5C0F100 2.54 2.51 95.07
Table 627
Concentration ofMethane Gas
(%)
Concentration ofHydrogen Gas
(%)
Concentration ofCarbon Dioxide
B1C100F0 46.03 2.31 51.66
B2C75F25 36.14 2.1 61.76
B3C50F50 27.66 2.58 69.76
B4C25F75 37.25 2.79 59.95
B5C0F100 6.97 2.85 90.18
25 Recordings of the concentrations of methane gas, hydrogen gas,and carbon dioxideof each sampleon day
three.
26 Recordings of the concentrations of methane gas, hydrogen gas,and carbon dioxideof each sampleon day four.
27 Recordings of the concentrations of methane gas, hydrogen gas,and carbon dioxideof each sampleon day five.
16. 13
INTERPRETATION OF RESULS
The data displayedinthe tablesabove show thatthe yieldof methanegasconcentrationgrows
exponentiallyinamatterof days for eachsample exceptforB5C0F100. The reasonis because the
methanogensrefusedtodigestthe pure foodwaste substrate because itwasafar more complex
structure than the easy-to-break-downcow manure.The foodwaste contained complex polymersand
proteinsthattookmuch longertobreakdownthan the carbohydrates,proteins,fats,andlarge
polymersin cowmanure.Thisisevidentbythe ratherlinearincrease of the yieldof methane gas
concentrationforthissample forthe firstthree tofour dayswhichare consideredthe lag-phase inthe
growthof the micro-bacteria.28
Afterthe firstfourdayswe are able tosee the concentrationof methane
gas inthe B5C0F100 sample increase bythree hundredpercent.Ratherthanchoosingtodigestthe
complex polymersinordertogrow at an exponential rate,the methanogenschoose to onlydigestthe
polymerswhenthere isanecessitytosurvive.
On the fourthday of data collection,we see anexponential increase inthe concentrationof
methane gasinalmosteverysample.Thisisbecause of the lag-phase inmicrobial growthexhibited by
methanogens.Insteadof the cellsgrowing,theyspendthe lagphase replicatingvariousproteinsand
DNA in orderto prepare itself forthe nextphase whichisthe logphase.29
Inthe logphase the bacteria
will begintoconsume the productsof acetogenesisandstartto produce methane gas(CH4).Thisisseen
inthe equationstatedearlierCO2 +4H2 <--> CH4 + 2H2O. Inthe logphase of microbial growth,the
bacteriastart to replicate atan exponential rate,dividingandconsumingmore andmore products of
acetogenesis,thusincreasingthe concentrationof methanegas.
28 The lagphaseof the bacteria lasts three days then goes onto the log phase.See 170-171.
29 Explains replication of DNA rather than the growth of Bacteria in the lagphase. See 1.
17. 14
Aside fromthe methane gas,we can see thatthe hydrogengasstays almostconstantfor all of
the results,withafractional jumpor dropfrom dayto day. Thisisbecause the methanogens donot
produce an abundantamountof hydrogengas.Most of the hydrogencationsfromthe firstand second
stage,hydrolysisandacidogenesis,wereattachedtothe carbon atomsto produce methane,andmethyl
whichisconvertedintomethane viaademethylationreactioncarriedoutbythe methanogens.30
Thisis
the reasonwhymethane gasand carbon dioxide appeartobe soabundant.The carbon dioxide startsoff
havingthe highestconcentrationthenslowlymovingtowardszeroasthe concentrationof methane gas
increasesdue tothe digestionof productsfromacetogenesisandexpulsionof methanegas.When
lookingatthe data, it looksalmostasthoughthe carbon dioxide concentrationandthe concentrationof
methane gasare inverselycorrelated,andthiswouldapplyforeverysample.
Whenlookingatthe fourthsample,B4C25F75 we notice a consistenttrendwiththe other
samplesforthe firstfourdays,but thenthere isapproximatelyatwohundredpercentjumpbetween
day fourand five.Thisjumpputsthe substrate whichcontains25% cow manure substrate and75% food
waste substrate exceedsthe B2C75F50 sample aswell asthe B3C50F50 sample.Thiscouldbe the effect
of twothings:erroror the methanogenicbacteriagettingusedtothe largerpolymersandefficiently
breakingdownthe more complex structures,thusyieldinghigherconcentrationsof methanegas.If
there wasto be an errorthenthe most logical eventthatwouldoccurwouldbe a steeprise incarbon
dioxide.Thisisthe mostlogical because otherthananapparatus malfunction,the secondmostprobable
error isfor the aluminumcasingtobreakand have atmospherictoxinspollutethe sample.A verysmall
percentage of the atmosphere’sgaseouscompositionismethane gas.There isamuch higher
percentage of atmosphericcarbondioxide thatcouldhave leakedintothe glassbottle.If thiswastrue
we wouldhave seenadrastic rise inthe carbon dioxide levels,almosttoa pointof one hundredpercent.
Insteadwe see anincrease inmethane gasconcentration,thusprovidingevidence thatthe
30 The demethylation reaction and relation to methanogens. See 2385.
18. 15
methanogenslearnedtoefficientlydigestthe more complex structuresof foodwaste andinturn,yielda
higherconcentrationof methane gas.
Conclusion
The foodwaste and cow manure whichisbrokendownthroughhydrolysis,acidogenesis,
acetogenesisandmethanogenesis,producessignificantamountsof methane gaswhichcanbe usedfor
heatingwater,cooking,orevenheatingthe village housesduringthe night.Aswe have seeninhistory,
cow manure hasbeenusedas fuel ina wide range of forms, fromburningdriedcow manure totoday’s
anaerobicdigestionof cowmanure toproduce methane gaswhichiscombustedwithoxygentocreate
heat. Our goal wasto substitute foodwaste forthe cow manure inorderto solve boththe problemof
waste pollutionaswell asthe energydeficitinIndia. Fromthe results,we seethatinthe primarystages
of methanogenicbacterial digestion,cow manure isthe mostefficientsubstratesource touse interms
of the yieldof methane gas.Butas evidentinsample B4C25F75,whichconsistedof 25% cow manure
substrate and75% foodwaste substrate,once the methanogenslearnedtodigestmore complex
polymers,the digestionof foodwaste yieldedthe highestconcentrationof methanegas.If we were able
to continue the experimentformore days,we couldextrapolatethe dataandsee that the samples
whichcontainedsome amountof a foodwaste substrate wouldyieldthe highestamountsof methane
gas.
19. 16
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22. 19
Appendix: BCYT (Basal Carbonate Yeast Trypticase) media
g/L
Dipotassiumhydrogenphosphate 0.3
AmmoniumChloride 1.0
SodiumChloride.
6H2O 0.6
Calcium chloride anhydrous 0.1
Yeast extract 0.08
Trypticase 0.5
Trace elements* 0.5
Trace Vitamins** 1.0mL
Resarzurin 1.0mL
ReducingAgent (CYS-HCl)*** 1.0mL
pH 6.8
Gas Phase N2: CO2 orH2:CO
*Trace Elements
g/100mL
Nitrilotriacetic acid 4.5
Ferric Chloride .
4H2O 0.1
Maganese Chloride.
4H2O 0.1
Calcium Chloride 0.02
Cobalt Chloride.
6H2O 0.17
Zinc Chloride 0.1
Boric Acid 0.019
SodiumMolybdate 0.01
(Nitrolotriacetic acid was dissolved with potassiumhydroxide to pH6.5 and then the othersalts were added).
**Trace Vitamins
23. 20
mg/100mL
Biotin 2.0
Folic Acid 2.0
Vitamin B12 0.1
Pyridoxine HCl 10.0
Thiamine 5.0
Riboflavin 5.0
Nicotinic acid 5.0
DL-Calcium Pantothenate 5.0
P-Amino Benzoic Acid 5.0
Lipoic Acid 5.0
**Trace Vitamins
mg/100mL
Cysteine hydrochloride 2.5
pH 9.0
Sodiumsulphide .
9H2O 1.0
(Added afteradjustingpH)
Preparation of Pre-Reduced Media
The distilled water was taken in a one liter conical flask and boiled till boiling point to displace
the dissolved oxygen. All the chemical ingredients were added to the boiled water and the same was made
up to one liter. One ml each of Resarzurin and trace elements were added to the above solution and mixed
well. The media was precooled under passage of oxygen free nitrogen (to saturate the media with
nitrogen). Gassing was continued till the media temperature dropped to 40°C and then the pH was
adjusted to 6.8 with sodium bicarbonate. The serum bottles of 130 ml were pregassed with Nitrogen to
displace the air and 36 ml of media was dispensed under continuous gassing. Even after pouring the
media, the gassing in the container was continued for a few minutes to avoid post transfer oxygen
contamination. After dispensing the media, the bottles were immediately sealed with butyl rubber stopper
and capped with aluminum crimps. The media was autoclaved at 121°C for 15 minutes. The change of
media colour from royal blue to pink after autoclaving was observed. The reducing agent and vitamin
solution were then added to the media (sodium sulphide in reducing agent and vitamin solution are heat
labile compounds so they are added after sterilization). After half an hour to one hour, the media was
reduced as indicated by decolorization of resarzurin.