|其他题名||Study on a novel in-situ technology treating odors
Volatile Organic Compounds (Vocs)
In-situ Purify Technology
Microbial Community Structure
|其他摘要||Biological treatment methods have been employed broadly for the removal of volatile organic compounds (VOCs) and odors. The typical waste gas biological treatment systems generally include gas collection system and bioreactor. However, it is difficult and uneconomical to collect the waste gas emitted from large area or dispersed sources. In this study, a novel in-situ biotechnology was developed to purify the odors generated from dispersed sources. The compounds in the odors were separated from surrounding environment by covering a breathable biocarrier. Driven by the concentration difference between feed side and permeated side, they can pass through the biocarrier continuously. This novel technology has low capital and operational costs without gas collection system.
To evaluate the performance of this in-situ purifying technology, sulfide hydrogen, ammonia and toluene were treated in the laboratory scale. Results showed that the in-situ purifying technology had high removal efficiency of compounds in the odor gas. When sulfide hydrogen, ammonia or toluene was as a sole pollutant, the removal rate of the in-situ purifying technology reached to 91.61%、92.47%、87.94%, respectively. Sulfide hydrogen and ammonia could be co-treated successfully due to the acid-base neutralization and biodegradation. It would promote the biodegradation of toluene when sulfide hydrogen or ammonia was fed into the toluene-degrading system.
Succession and development of microbial community structures in the biocarrier at different operational stage were investigated by molecular biological methods. The results of PCR-DGGE demonstrated that the community structures changed obviously for maintaining the steady removal efficiency. At the mixed gas system of ammonia and toluene, the similarity of community structure increased along with the increasing of running time, while the diversity decreased correspondingly. After feeding sulfide hydrogen, the community structure of toluene removal system dynamically changed to adapt the changing of environment. The shifts of microbial community structure enhanced simultaneous removal of toluene and sulfide hydrogen.
Besides chemicals such as sulfide hydrogen and ammonia, bioaerosols are another kind of emission in the wastewater treatment processes. Their emission was monitored at different wastewater treatment plants (WWTP) in this study. Results indicated that the concentration of airborne microorganism in closed room was high because of without enough ventilation. Based on the investigation, the capture of bioaerosols by biocarrier was studied. The particle size distribution of bioaerosols changed obviously after passing through the biocarrier. The mechanism of toluene removal by the in-situ purifying technology was preliminary studied. Toluene was removed by the synergistic action of biodegradation of the microorganisms and adsorption of the carrier. The adsorption of carrier prolonged the residence time of toluene on the carrier surface and promoted the efficiency of toluene biodegradation. The biodegradation of microorganisms increased the concentration difference between feed side and permeated side of the carrier. This effect accelerated the transfer of toluene which benefit for the carrier adsorption.
The results from this study demonstrated that the odors could be in-situ bio-purified effectively during their diffusion process. An economic and effective technology was explored in this study in order to in-situ purify odors generated from dispersed sources.|
高敏. 臭味气体原位生物净化新技术研究[D]. 北京. 中国科学院研究生院,2010.