Document Details
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Document Type |
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Thesis |
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Document Title |
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EVALUATING THE POTENTIAL OF VARIOUS NATURAL RESOURCES IN THE AEROBIC BIOCONVERSION OF FOOD WASTES TO ORGANIC FERTILIZER تقييم إمكانية إستخدام الموارد الطبيعية المختلفة في التحويل الحيوي لمخلفات الطعام إلى سماد عضوۍ |
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Subject |
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Faculty of Meteorology, Environment and Arid Land Agriculture |
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Document Language |
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Arabic |
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Abstract |
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In the Kingdom of Saudi Arabia the significant growth in population, urbanization, and tourism to Islamic holiest places result in massive production of municipal solid waste (MSW). The annual generation rate of MSW is up to 15 million tons in Saudi Arabia. Food waste is the largest waste stream (up to 51%) of MSW, with an annual production of 8 million tons, which mainly dispose to landfills without any material recovery. Disposal of such organic-rich waste to landfills is resulting in several environmental and public health problems, including greenhouse gas (GHG) emissions, air pollution and contamination of soil and water bodies. Therefore, the need of diverting food waste from landfills to resource recovery facilities has become an imperative need in KSA to safeguard the local environment and public health along with the production of value-added products such as organic fertilizer. In KSA, a small amount of MSW is treated through traditional methods for making compost, whose quality donot agree with the international compost quality standards.
In this study, a series of experiments were designed and carried out to examine the potential of natural zeolite and biochar for the process optimization of food waste composting using an in-vessel compost bioreactor. For composting experiments with zeolite; raw and modified natural zeolite was applied at 10 and 15% (w/w) of the total waste and compared with the un-amended control trails. Modification of natural zeolite was carried out through a sequential hydrothermal treatment. The addition of natural zeolite in composting materials significantly improved the composting process. The prominent results against compost stability parameters were observed at 15% zeolite concentration. When comparing raw and modified natural zeolite, the prominent results were observed for modified natural zeolite. In addition, it was noticed that the rapid and long-term thermophillic temperature and optimum moisture content reduction were recorded for modified natural zeolite. Furthermore, by peak values, the total ammonium (NH4+) and nitrate (NO3-) concentration in modified natural zeolite were increased by 11.1 and 21.5% respectively in comparison to raw zeolite. Different parameters for compost maturity such as moisture contents, electrical conductivity, organic matter degradation, change in total carbon, mineral nitrogen contents, and nitrification and germination index showed that stability was achieved after 60 days of composting, which was in line with the international compost quality standards.
For composting experiments with biochar, lawn waste was used to prepare biochar at two different temperatures such as 350 and 450°C, and applied at the rates of 10 and 15% (w/w) of the total waste. Results showed that in comparison to control trials, biochar-amended compost mixtures rapidly achieved the thermophilic temperature, increased the organic matter degradation by 14.4 to 15.3%, concentration of NH4+ by 37.8 to 45.6% and NO3- by 50 to 62%. The most prominent effects in term of achieving rapid thermophilic temperature and a higher concentration of NH4+ and NO3- were observed at 15% (w/w) biochar. According to compost quality standard of United States (US), California, Germany, and Austria, the compost stability because of biochar addition was achieved in 50 to 60 days. Nonetheless, the biochar produced at 450°C had similar effects as to biochar produced at 350°C for most of the compost parameters. Therefore, it is recommended to produce biochar at 350°C to reduce the energy requirements for resource recovery of biomass and should be added at a concentration of 15% (w/w) to the composting materials for achieving a stable compost.
The third and final set of experiments were conducted to examine the effects of the produced compost on the crop. Aerated and non-aerated compost teas (compost liquid extracts) were prepared and diluted at various concentrations of 0, 25, 50 and 75% with distilled water. In addition, a novel method of seed priming in compost tea was employed to evaluate its effects on the germination and growth parameters of the tested crop. It was observed that in comparison to control treatment, both the aerated and non-aerated compost teas increased the germination and seedling growth. Among compost teas dilution, stimulatory effects in term of measured growth parameters were observed at 50 and 75% teas dilution. Similarly, in comparison to unpriming, seed priming in compost teas increased the germination rate by 13%, root and shoot length by more than 70% and reduced the mean germination time by 31.21%. It was concluded that seed priming in compost tea with 50 and 75% dilution could be a successful eco-friendly organic liquid fertilizer for sustainable plant production. |
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Supervisor |
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Dr. Asad Siraj Abu. Raziza |
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Thesis Type |
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Doctorate Thesis |
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Publishing Year |
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1439 AH
2018 AD |
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Added Date |
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Thursday, February 15, 2018 |
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Researchers
| محمد وقاص | Waqas, Mohammed | Researcher | Doctorate | |
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