Mahmudul Haque, Roll No P), Session: October, 2005, was accepted as satisfactory in partial fulfillment of the requirement for the degree of Master of Civil Engineering (Environmental) on 7th March, 2009. Composting is a natural process in which organic material breaks down into a dark, nutrient-rich soil amendment. The stabilized end product (compost) is often used to improve soil structure, provide plant nutrients and facilitate re-vegetation of damaged or eroded soils.
INTRODUCTION
GENERAL
- OBJECTIVE OF THE STUDY
- OUTLINE OF METHODOLOGY
- ORGANIZATION OF THE THESIS
This study aims to assess the solid waste composting process with special emphasis on vermiculture. Quantitative analysis of solid waste should be performed to assess its suitability for the composting process.
LITERA TURE REVIEW
INTRODUCTION
The vast majority of the decomposition work in compost is carried out by microorganisms, including fungi, bacteria and actinomycetes (organisms that look like fungi but are actually filamentous bacteria). Physical characteristics of the compost ingredients, including moisture content and particle size, affect the rate at which composting occurs.
AEROBIC & ANAEROBIC COMPOSTING
However, decomposition occurs much faster in the compost pile because the environment can become ideal for microbes to do their work. Other physical considerations include the size and shape of the system, which affect the rate of aeration and the tendency of the compost to retain or dissipate the heat that is generated.
SOLID WASTE CHARACTERISTICS
The Dhaka city contributed the largest portion, measured as 5340 tons, which is the 69% of the total waste generated in the six study cities. On the other hand, paper and cardboard were found to be higher in the solid waste of the developed countries.
COMPOSTING BIOLOGY
- Windrow composting
- Aerated Static Pile
- In-Vessel com posting
- VERMICUL TURE AND VERMICOMPOSTING
Since the decay rate is greatest at the beginning of the process, the frequency of turning decreases as the wind ages. In the winding method, the active composting phase usually lasts from three to nine weeks, depending on the nature of the materials and the frequency of turning.
METHODOLOGY OF VERMICOMPOSTING
This is based on previously established information that tunnel walls have a high proportion of total nitrogen-fixing bacteria and that castings have higher concentrations of soluble salts and greater nitrifying power. The large surface area and improved ventilation create favorable conditions for obligate aerobes (such as Pseudomonas spp., Zoogloea spp., Micrococcus spp. and Achromobacter spp.).
BASIC OF VERMICOMPOSTING
- Worm Bedding
- Worm Adding
- Feeding the Worms
- Other Things to Add to the Bin
- Harvesting
- Screening
Another layer is placed on top of the organic matter and the worms will begin to compost the organic matter and litter. Fill the box with fresh bedding on top of the screen and continue to feed it with kitchen scraps.
CONTROLING PARAMETERS OF VERMICOMPOSTING
- Moisture
- Aeration
- Temperature Control
- Carbon to Nitrogen Ratio
- Salt content
- Urine content
This may be one of the main benefits of vermicomposting: the lack of need to turn the material, as the worms do that work for you. If the food source or bedding is acidic (coffee grounds, peat moss), the pH of the beds can drop well below 7. The initial carbon-to-nitrogen ratio of the incoming waste was between 40 and 47.
This high C/N ratio may be due to the presence of brown vegetation and plastics, which largely dominate the incoming waste stream. As reported by Basnayake (2002), the C/N ratio becomes a good indicator of compost stability.
PROJECTING VERMICOMPOST OUTPUTS
Gaddie and Douglas (1975) state: "If the manure is from animals raised or fed from concrete lots, it will contain excessive urine because the urine cannot drain into the soil. In one flow-through system for composting fresh food waste that was tested in Nova Scotia, the total system output was about 10% of the input by weight This material is largely lost to the final product because most of the worms are removed from the product before completion of the process.
For example, shredded paper and cardboard can be turned into vermicompost with the addition of 5% poultry manure by volume (Georg, 2004). The result of this process is a product weight closer to 50% of the initial input weight. . In general, outputs from vermicomposting processes can vary from about 10% to approximately 50% of the initial weight of inputs.
WORM FACTS .1 Compost worms
- Reproduction
- Respiration
- Ingestion
- Digestion
- Locomotion
- Other Worm Facts
As the worms emerge from the cocoon, eggs and sperm are deposited in the cocoon. The bed in the worm bin disappears as it, in addition to food, is consumed and transformed into shedding. Then the long muscles contract, pulling the tail end of the worm toward the weak front end.
When the long muscles contract, the circular muscles relax, causing the worm to thicken. To avoid slipping during movement, small bristles called setae act as brakes to hold part of the worm's body against the surface.
PESTS AND DISEASES
If they become a problem, one suggested method of reducing their numbers is to flood (but not flood) the worm beds. Water forces centipedes and other insect pests (but not worms) to the surface, where they can be destroyed with a hand-held propane torch or similar (Gaddie, op. cit.; Sherman, 1997). Ants are particularly attracted to sugar, so avoiding sweet foods in worm beds reduces this problem to a minor one.
The best prevention for red mites is to ensure that the pH remains neutral or higher. Protein accumulates in the bedding and produces acids and gases during decomposition (Gaddie, op. p.).
AN OVERVIEW OF VERMICOMPOSTING SYSTEMS
- Basic Types of Systems
- Windrows
- Static pile windrows (batch)
- Top-fed windrows (continuous flow)
- Wedges (continuous flow)
- Beds or Bins
- Top-fed beds (continuous flow)
- Stacked bins (batch or continuous flow)
- Flows-Through Reactors
- Methods of Harvesting Worms
- General
- Manual Methods
- Self-Harvesting (Migration) Methods
This material will contain most of the worms and can be used to plant the next window. Using this system, the worms do not need to be separated from the vermicompost and the process can continue indefinitely. Some of the bins had old manure (at least a year), while others had fresh manure (two weeks).
It requires either a harvester or another step in the process where the material is stacked so that the worms can migrate into new material!. However, they are all labor intensive and only make sense if the operation is small and the value of the worms is high.
THE VALUE OF VERMICOMPOST
- Worms and the Environment
- Water Quality Issues
- Climate Change Factors
- Below-Ground Biodiversity
Much of the work on this subject was done at Ohio State University, under the direction of Dr. Atiyeh et al (2002) conducted an extensive review of the literature relating to this phenomenon. Climate change is one of the most serious and pressing environmental problems of our time.
One of the main benefits of both composting and vermicomposting is carbon storage. This means that the process is more efficient at retaining nitrogen, probably due to the greater number of microorganisms present in the nitrogen.
VERMICOMPOSTING IN OTHER COUNTRIES
Biodiversity around the world is rapidly declining, so much so that some scientists fear we are headed for a mass extinction similar to many that have occurred in Earth's ancient past. Earthworms increase the number and types of microbes in the soil by creating conditions in which these creatures can thrive and reproduce. This below-ground biodiversity is the basis for increased above-ground biodiversity, as the creatures in the soil and the plants that help them grow form the basis of the entire food chain.
The United Nations Environment Program (UNEP) has recognized the importance of below-ground biodiversity as a key to sustainable agriculture, above-ground biodiversity and the overall economy. At the same time, scientists at several universities in the US, Canada, India, Australia and South Africa have begun to document the benefits associated with the use of vermicompost, providing facts and figures to support the observations of those who have used the material. .
INTODUCTlON
EXPERIMENTAL SET UP OF COMPSOTING PLANT
COMPOSTING PROCESS
TEMPERATURE VARIATION DURING COMPOSTING
MOISTURE CONTENT
CHEMICAL ANALYSIS OF COMPOST
All microbial analyzes were done on the final product of compost samples and the results are expressed as colony forming units per gram (c.f.u/gm). The standard methods for microbial analysis are followed to determine various presence of bacteria in the compost samples. The pathogenic bacteria and faecal coliforms are tested from the final compost sample for public health concerns as the farmers use the compost in the field.
GROWTH RATE DETERMINATION
RESUL T AND DISCUSSION
- INTRODUCTION
- CHARACTERISTICS OF SOLID WASTE
- MOISTURE CONTENT VARIATION DURING COMPO STING
- VARIATION OF CHEMICAL PARAMETERS AND NUTRIENTS OF COMPOST SAMPLES
- PATHOGEN REDUCTION IN VERMICOMPOSTING
- WORM GROWTH RATE DETERMINATION
- COMMON PROBLEMS AND SOLUTIONS
- EVALUATING ENVIRONMENTAL ACCEPTABILITY OF VERMICOMPOSTING
The temperature was found to be almost the same as that of the five samples which are around 26 °C shown in Figure 4.4. This result contradicts the experimental findings presented in Table 4.2 and the study conducted by (Amsath & Sukumaran, 2008). This analysis is supported by a study conducted by BASA in which the nitrogen content of the vermicompost sample is 1.7% and the vermicompost sample is 2.06%, which is 1.2% more than the vermicompost sample which is presented in Table 2.1 I.
The result of the microbial analysis of the vermi-compost sample and the windrow compost sample is shown in Table 4.1 I. The worms may be too warm, in which case the bin should be kept in the shade.
CHAPTERS
FINANCIAL FEASIBILITY STUDY OF COMPOSTING PROJECT
INTRODUCTION
FINANCIAL EVALUATION
The cost-benefit ratio at a discount rate of 16%, net present value and internal rate of return or return of a hideous composting plant is shown in table 5.5. Cost benefit ratio at a discount rate of 16%, present value and internal rate of return or return of the vermi-composting plant at recipient level is shown in table 5.10. From Table 5.11 it has been found that it is about 50% for large scale production and about 25% for small scale production.
CONCLUSIONS AND RECOMMENDA nON
CONCLUSION
It appears that the nutritional value in the vermi-compost sample is lower than in the windrow compost sample; The nitrogen value is found 0.532% in the vermi-compost sample while 1.4% is found in the windrow compost sample which is 2.5 times higher. The potassium content is also found higher in windrow compost samples at 1.51%, while for vermi-compost samples it is only 0.79%. This result is contrary to the result reported in the literature where vermi-compost is found superior in terms of nutrients than windrow compost.
The questionnaire survey revealed that vermicomposting is popular and acceptable at the beneficiary level. Detailed financial feasibility studies for large-scale vermicomposting plants and at the beneficiary level installation show that both are commercially viable and sustainable as the cost-benefit ratio at a discount factor of 16% is 2.17 for large-scale projects and for installations at the beneficiary level of the beneficiary 1.59.
RECOMMENDATION FOR FURTHER STUDY
Moqsud, M.A. Composting Barrel - A New Way to Solve the Problem of Solid Organic Waste Management in Urban Areas". Moqsud, M.A. Biochemical Quality of Bangladesh Kitchen Waste Compost", Paper accepted for publication at the 19th International Conference on Solid Waste Management and Technology, USA. Intermediate Technology Development Group (lTDG), Case Study Series 4. 34; Composting as a strategy to reduce greenhouse gas emissions".
Natural Resources, Agriculture, and Engineering Service (NRAES-54), Ithaca, NY On-Farm Composting" Natural Resources, Agriculture, and Engineering Service, Cooperative Extension, Ithaca, New York. Short, lC.P., Frederickson, J and Morris , R.M. 34; Evaluation of traditional window composting and vermicomposting for waste paper stabilization.
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APENDIXB
