| Water hyacinth (Eichhornia crassipes) has been infested 19 provinces of China as an invasive aquatic plant. Much manpower, material resources and funds were spent every year on control the water hyacinth, only the spending on it's harvesting up to 100 million RMB. In fact, the water hyacinth didn't have none value in utilization. When we control it, we should concern its utilization as resource, using it as much as possible. For example: the value of ornamental; water purification; absorbing nitrogen, phosphorus and heavy metals, excretive toxin to restrain the algous growth; breeding earthworm; planting mushroom; food and medicine; paper making, making handcraft; zymolysis for biogas, the biogas product: 0.334L per gram dry water hyacinth, and utilizing the biogas to generate electricity and the outcome of zymolysis to organic manure etc.. To make this negative become positive while huge number of water hyacinth is utilized. Along with the animal husbandry pattern changed from extensive breeding to intensive breeding, the residue of animal dung was more and more concentrated which overrun the carrying environmental capacity, causing heavy pressure to the local people's health and sustainable development of rural area. These two kinds environment pollution all contained large scale biomass energy which could be transformed to apply. When putting water hyacinth which was mixed with pig manure into biogas tank to ferment, we could find the biogas productivity be improved obviously. When putting 10% water hyacinth into biogas tank, the biogas productivity could be improved 31.2%; putting 15%, the productivity could be improved 46.1%; putting 20% is 40.9% and putting 25% is 32.2%. The promotion of 4 proportions water hyacinth to ferment present normal school like parabola shape, and the promotion of 15% water hyacinth is most obvious. Then we used biogas which was mixed with diesel oil to generate electricity, after period of time's statistic, we found that 50kw's generator could generate 32.46kwh electricity per hour, the average biogas consumption is 20.58 m~3 per hour, the average diesel oil consumption was 1.5kg per hour, according to 0.24kg diesel oil could produce 1 kWh electricity, 1.5kg diesel oil could generate 6.25kWh electricity, so the contribution of diesel oil to generating is 19.9%, while the contribution of biogas to generating is 80.1%. It meant that 1 m~3 biogas can generate 1.58 kWh electricity, was better than the normal standard 1.2-1.5 kWh electricity. Putting 10%,15%,20% and 25% water hyacinth into biogas tanks, the electrical production could be improved 24.2%,36.9%,32.8 % and 25.8% respectively in theory.Ferment productions included biogas, biogas liquid and biogas residue. The biogas could be used as the fuel to cooking, to keep fruits fresh and to generate electricity; the biogas liquid was used to irrigate to the field as the manure, spray to the crop leaves as the leaves manure and presoak the crop seed; the biogas residue was used as organic manure to fertilize, to feed the animal or be produced to organic manure for market. In general, from the fermentation of animal dung, and the utilization of ferment production, we achieved matter and energy at multilevel utilization to be propitious to sustainable development. Using livestock residue to process anaerobic ferment could not only solve the environmental pollution caused by the large-scale of livestock farms, but also produced renewable energy- biogas that could alleviate the energy demand pressure. However, because of close relationship between anaerobic ferment and temperature, the low temperatures could slower anaerobic ferment processes, then affected the livestock breeding waste timely disposal and the stability of biogas production, these would limit extension and application of biogas engineering. At the Tongren biogas engineering pig farm, Haining city, Zhejiang province, China, solar energy collectors, with area of 100.8 m~2 and volume of 6 T water, were introduced to solve this problem. Using solar energy collectors to heat the river water and then put these hot water into the ferment tanks to keep the ferment on the rails. With comparing study, we could find that biogas productivity of ferment tanks put with hot water was 36.4% higher than other tanks put with river water. During the study period, 4.5×10~7kJ solar energy was collected to heat the river water, and the utilization of these hot water increased 351 m~3 biogas production. The pig dung bio-energy transformation ratio increased 36.4%.The pig manure, water hyacinth and solar energy were put together organically to study in this project to alleviate livestock breeding pollution. This project not only lightened the environmental pressure to protect local environment, but also promoted sustainable development. Meanwhile, this project brought great economy benefits to promote rapid development of local economy, and to increase many employment opportunities. In large rural area of our country, this kind project would have a good application prospects. |
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