Dissertation > Excellent graduate degree dissertation topics show

Polyalkanoates Synthesis from Real Waste by Microorganisms in Excess Sludge

Author: CaiMengMeng
Tutor: CaiHong
School: Harbin Institute of Technology
Course: Environmental Engineering
Keywords: Excess sludge digestive juice Food waste liquid Component regulatory PHA synthesis Process optimization
CLC: X703.1
Type: PhD thesis
Year: 2009
Downloads: 298
Quote: 2
Read: Download Dissertation

Abstract


Plastic products are the necessities of the people's daily life and industrial and agricultural production. Wide use of petroleum-based plastics, has caused serious environmental pollution, consumes a large amount of non-renewable resources. Polyhydroxyalkanoates (Polyhydroxyalkanoates, PHA) is a biological preparation environmentally friendly plastic, fully biodegradable, has a renewable organic matter and traditional plastic similar physical and chemical properties and processing characteristics of the desired substrate. Therefore, the PHA is the ideal substitute of petroleum-based plastics, and has broad application prospects. The pure strains synthetic PHA industrialized produce PHA mainstream. The high cost of production constraints PHA is widely used as daily necessities. In addition, the municipal wastewater treatment plant daily to produce large amounts of excess sludge, sludge disposal costs. Cheap, renewable source of a wide range of waste as the PHA synthetic substrates, the use of mixed flora in the activated sludge as inoculum synthesis of PHA, to optimize the the PHA synthesis process operating conditions, are conducive to significantly reduce the cost of PHA production, the reduction of waste and excess sludge and resources. The purpose of this study is the PHA production cost, and resource waste and excess sludge. The main contents and conclusions are as follows: a small pilot study of the synthesis of PHA artificial wastewater through the use of excess sludge, the effects of process parameters affecting PHA production, substrate conversion rate and PHA monomer component content. The results showed that the aerobic, high carbon and nitrogen than carbon substrates, multiple dosing, weak alkaline conditions help improve PHA production. Under this condition, the yield of the synthesis of PHA of the activated sludge and the synthesis of PHA production and physicochemical properties of the pure strains close and PHA synthase high yield pure strains. Through process control, active sludge can be synthesized containing specific monomer components PHA. Aerobic determined by the number of carbon atoms in the short chain fatty acids in the poly (-β-hydroxybutyrate-co-β-hydroxyvalerate) (Poly (β-hydroxybutyrate-co-β-hydroxyvalerate), PHBV) monomer components. Reduce the concentration of dissolved oxygen (dissolved oxygen, DO), the pH value increased, hydroxy pivaloyl content of PHBV copolymer (hydroxyvalerate% HV%) will increase, and regardless of the carbon source; sludge sources of carbon and nitrogen phosphorus concentration than the hydroxy acid (hydroxyalkanoate, HA) changes will affect the content of the monomer component. Combination of the above test results, the use of the the batch aerobic dynamic substrate dosing process, the remaining sludge as inoculum sludge digestive juices in the volatile organic acids (volatile fatty acids, VFAs) and food waste liquid synthetic PHA process optimization. By adding magnesium salts, the formation of struvite precipitation, excess nitrogen and phosphorus removal and recovery of sludge digestive juice to improve sludge digestive juices N ratio. Alkaline conditions and higher digestion temperature increase in sludge digestive juices of VFAs production as well as ammonia removal efficiency. The main component of the sludge in the digestive juice VFAs is acetic acid. Excess sludge digestive VFAs synthesis of PHA production up to 56.5% (accounting for VSS specific gravity). Activated sludge and pure strains malt waste as carbon source for synthesis of PHA production are higher than other kinds of food waste liquid. Subsequently the remaining sludge PHA synthesis using actual liquid waste product of the analysis of materialized processing nature. Summarized the basis of the pure strains of the metabolic mechanism of the synthesis of PHA, the analog in order to optimize the synthesis of PHA monomer component of the activated sludge, the biochemical pathway for the synthesis of PHA activated sludge. In order to predict the yield and the yield of the synthesis of PHA in activated sludge by to improve 3 activated sludge model (Activated Sludge Modeling 3, ASM3 model) and optimize the the PHA synthesis process parameters, established a kinetic model of the activated sludge synthesis of PHA. And through small test to verify the accuracy of the model. The results show that when the sludge in the anaerobic uptake Titanium HV metabolic mechanism will be synthesized by \thereof. The external changes in process conditions, it will affect the structure and metabolic pathway of the activated sludge in the mixed flora, thereby changing the the HA monomer component synthesized by the activated sludge. Verified by experiments, the synthesis of PHA kinetic model of the activated sludge can more accurately predict the PHA production, yield, the substrate conversion rate and cell growth amount. Remaining sludge sludge digestive synthesis PHA process of industrialization, to help achieve the actual liquid waste and excess sludge resource to promote PHA as ordinary packaging material has been applied, with good economic and social value. Relative to the pure strains as well as the use of artificial wastewater activated sludge synthesis of PHA, the remaining sludge sludge digestive synthetic PHA process, cost savings include: the synthetic PHA cost of the carbon source, PHA synthesis reaction structures construction and running costs, the remaining sludge disposal costs, microbial screening / enrichment culture costs, while struvite crystals precipitated byproduct.

Related Dissertations

  1. Analysis of Nutritional Compositions and Quality of Shishen (Eremurus Chinensis Fedtsch.),S647
  2. 1 - deoxynojirimycin synthetic route design and process optimization,TQ463.5
  3. Study on Application of Red Yeast Rice in Fermented Sausage,TS251.65
  4. Research on the Make-up Pen Production Flow Improvement of Chromalyra(tianjin)co.,ltd.,F273
  5. Strain Screening of Hainanmycin Production and Fermentation Process Optimization,TQ927
  6. Nantong build a modern logistics system of tobacco,F426.8
  7. Tianjin COSCO Logistics ( Tian Rong ) business process optimization and Countermeasures,F552
  8. Erlotinib hydrochloride Synthesis of,TQ463
  9. Automatic Measurement Device of Gauge Block Grade 2 Base on Laser Interference Theory and Evaluation System,F259.2
  10. The Optimal Thermodynamic Analysis of Irreversible Joule-Brayton and Its Combined Cycle,TK123
  11. Hebei Electric Power Survey and Design Institute of Production Process Optimization,F273
  12. Ken Su Galaxy ERP system implementation and impact assessment studies,F270.7
  13. Based on product quality control of injection molding process,TQ320.662
  14. Citrus seed oil extraction process optimization and its chemical components,TS225.1
  15. Hubei Tippy Tea continuous processing key technology research and process optimization,TS272.51
  16. Shanghai Pudong International Airport international passenger departure system service process optimization studies,F562
  17. Legislation of e-government,D922.1
  18. The Nanjing subway vehicle maintenance repair process analysis and optimization,U279
  19. Operation and maintenance of the telecommunications sector reengineering process optimization,F626
  20. WSD based on supply chain management and procurement company supplier process optimization,F274
  21. Microbial fermentation production of Coenzyme Q_ (10),TQ925.9

CLC: > Environmental science, safety science > Processing and comprehensive utilization of waste > General issues > Wastewater treatment and utilization > Technology and methods
© 2012 www.DissertationTopic.Net  Mobile