الفهرس 
INTRODUCTION AND AIM OF THE STUDYOnly 14 pages are availabe for public view
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Abstract
Water hyacinth can be found in abundance in water bodies, these aquatic weeds block lakes, making boating, fishing, and swimming difficult leading to serious economic and environmental problems that damaged environmental balance, irrigation system and agriculture. On the other hand, it is a very good feedstock for biogas production as it contains a high content of fermentable matter, cellulose, nitrogen and essential nutrients.
Water hyacinth is a lignocellulosic material which is characterized by its complexity structure including lignin content, cellulose crystallinity and degree of polymerization. Lignin acts as a shield preventing access of cellulases and hemicellulases to cellulose and hemicelluloses.
Accumulation of cow manure in the environment causes harmful problems as it contains pathogenic organism as Salmonella and Escherichia coli that cause human diseases. At the same time it contains essential elements to produce biogas by anaerobic digestion.
The aim of this study is getting rid of large amount of water hyacinth and getting benefit from this weed in biogas production. Water hyacinth is co-digested with cow manure with different proportions to obtain a mixture with a required C/N ratio suitable for biogas production. C/N ratio of different proportions of cow manure and water hyacinth were measured and they were ranged between 49.8: 1- 26.01: 1. Water hyacinth at 100% had the highest ratio while 75% CM: 25% WH mixture have the lowest ratio.
Different proportions of cow manure and water hyacinth undergoes anaerobic digestion, it was observed that the average biogas production rate and its methane content produced from different proportions of cow manure and water hyacinth were significantly higher than that produced from 100% WH.
Also it is observed that there was no significant difference between 75% CM: 25% WH, 50% CM: 50% WH and 25% CM: 75% WH mixture on biogas production rate and its methane content produced from anaerobic digestion.
Microwave presentment was used in order to enhance methane production through enhancing degradation and removal of lignin and to expose cellulose, hemicelluloses and lignin to microbial breakdown.
Microwave pretreatment with 100W, 450W and 800W at different exposure times (5, 10 and 15 min) is applied on the mixture of 25% CM and 75% WH to get rid of more water hyacinth. It is observed that the pretreated samples under different microwave power at different times gave a significant higher average methane percentage than the non-pretreated sample.
Applying microwave pretreatment on 25% cow manure and 75% water hyacinth mixture with different microwave power at different time has no significant effect on biogas production rate and increasing microwave power has no significant effect on the produced methane percentage. Applying 100W for 10 min on 25% CM and 75% WH mixture produced maximum methane percentage, maximum biogas productivity, maximum energy and get rid of higher amount of water hyacinth.
Conclusion
1- Mixing cow manure and water hyacinth with 25%CM: 75%WH, 50%CM: 50%WH and 75%CM:25%WH ratio was suitable for biogas production depending on C/N ratio.
2- There was no significant difference between non-pretreated 25%CM:75%WH, 50%CM: 50%WH and 75%CM:25%WH mixtures on biogas production rate and its methane content also.
3- Applying microwave pretreatment with different power on cow manure and water hyacinth mixture enhances methane production.
4- Increasing run time of microwave had no significant effect on biogas production rate or on its methane production.
5- The most suitable microwave pretreatment power and time to obtain highest percentage of methane, highest biogas productivity and greatest amount of energy were found to be 100Watt and 10 min respectively.
Recommendation
1- It must get rid of large amount of water hyacinth to avoid its environmental problems.
2- Using water hyacinth as a feedstock for large scale biogas production.
3- Water hyacinth must be co-digested with manure to produce higher methane percentage.
4- Applying microwave at 100 W power as a pretreatment method to enhance methane production through anaerobic digestion.
5- The used microwave power must be low as possible to save energy and environmental sustainability.
6- Using digested material as an inoculum to enhance anaerobic biodegradability and to shorten lag phase in anaerobic treatment method.