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Improvement of the Compost Micro-environment Based on Biosurfactant

Author: ZhongHua
Tutor: ZengGuangMing；HuangGuoHe
School: Hunan University
Course: Environmental Engineering
Keywords: Biosurfactant Compost Rhamnolipid Pseudomonas aeruginosa Column experiments Adsorption Physical and chemical effects Microbial effects
CLC: X53
Type: Master's thesis
Year: 2005
Downloads: 169
Quote: 3
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Abstract

This paper examines the biosurfactants to enhance the role of soil organic pollutant degradation mechanism as the basis for speculation and research on the physical and chemical and microbiological effects of biosurfactant in composting organic matter degradation process may exist made. The purpose of the process of soil remediation, bio-surfactants can enhance the dissolution of the contaminants in the soil liquid phase change pollutants to the nature of the mass transfer of the liquid phase, but also able to influence them in the adsorption properties of the surface of the soil particles. Biosurfactants can act on microorganisms, change the nature of the surface, and can lead to soil medium in bacterial a different pollutant uptake behavior and growth behavior. Biosurfactants such physicochemical effects and microbial effects can promote the bioavailability of pollutants, thereby contributing to the degradation of the organic pollutants. In the composting process, microbial decomposition of organic garbage particle surface layer of liquid film in the gap. The biosurfactants added can improve this microenvironment. First, due to the biosurfactants the surfactant, the presence of liquid water in the compost media forms and distribution may change, that is, between each phase of the medium, the relative distribution of the changes in the situation; Secondly, the role of biosurfactants composting organic matter dissolved or dispersed the enhancement may be effective to increase the microbial source of nutrition of the compost; biosurfactants of microbial effects again can help to optimize the distribution of the of composting microorganisms in the compost medium, thereby indirectly promote the degradation process. Based on the above, the organic matter particles as analog matrix investigated the role of biosurfactants in the medium of organic matter particles. First inspected the rhamnolipid, SDS and of Triton X-100 and other three (bio) surfactant interaction infiltration of moisture in the granular layer of organic matter under the law, and evaporated situation. The results show that, in a suitable concentration of the surface active agent under the action of moisture infiltration speed to accelerate, while the concentration of different surfactant adsorption also affect the water carrying capacity of the medium, which may be related to the wetting of the surface active agent. Further, the surface active agent on the moisture of the organic matter of particulate media has a better retention performance. Followed by column experiments investigated three (biological) Pseudomonas aeruginosa in the compost particulate media column in the role of the surfactant adsorption transmission situation. Experimental results show that a certain concentration of rhamnolipid can weaken the adsorption of the bacterial cells in the composting particulate media, enhance the transmission and dispersion of bacterial cells in the medium, while the role of the two kinds of chemical surfactants. The reason may be that the presence of a rhamnolipid changed the nature of the surface of the bacterial cells, weakening them with compost particles affinity; rhamnolipid adsorption changing the nature of the surface of the particles on the compost particles, hindering the adsorption of bacterial may be one of the reasons. Finally, the aerobic degradation experiments to study the impact of the three (bio) surfactants on a Pseudomonas aeruginosa degradation of particulate organic matter. The results showed that the concentration above the critical micelle concentration of rhamnolipid linear law with the changes in the rhamnolipid concentration in the matrix surface adsorption isotherm; weakened rhamnolipid role of bacteria in the adsorption properties of the substrate surface ; surfactant added to slow the rate of evaporation of water, and to strengthen organic

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CLC: > Environmental science, safety science > Environmental pollution and its prevention > Soil Contamination and Control
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