Study On Odorous Compounds Production Characteristics And Biodegradation

In this study, the method headspace solid-phase microextraction combined with gas chromatography mass spectrometry was used to discuss the odor production characteristics of Anabaena sp. under environment conditions. The feasibility for using as a standard for determining the algal odor compounds was discussed. Preliminary verified the odor production characteristics of Anabaena sp. under different nutriention sources conditions. Used the degradation bacteria isolated from actual water treatment technology activated carbon filter. Evaluated the degradation potential of three bacteria and identified of the species; At the same time, based on the seasonal occurring odorous compound problems in reservoir, cloning, DGGE and other molecular techniques were used to study the community structures. Preliminary analytic the relationship between changes of odor and microbial community structures.The main results are summarized as follows:1. A method for the determination of the algal odor compounds geosmin, 2-methylisoborneol (2-MIB) andβ-cyclocitral in water by headspace solid-phase microextraction (HSSPME) combined with gas chromatography mass spectrometry (GC/MS) is described. Several parameters, such as sample preservation and pretreatment conditions, were studied and optimized. The method shows good linearity over the relative concentration range and gives detection limits of 1.3 ng/L, 1.9 ng/L and 2.1 ng/L, the reliable quantization limit of 5.2 ng/L, 7.6 ng/L and 8.4 ng/L, respectively. The results showed that long storage time, microorganisms and the residual chlorine could interfere the determination results. The optimize of the measurement results was that mercuric chloride and sodium thiosulfate should be added after sampling for raw water and for tap water, respectively. The sample should be preserved in 0-4 oC and analyzed in one week.2. A Cyanobacteria isolated from one reservoir was identified as Anabaena sp. which consistently produced high geosmin during laboratory culture. After expanding culture, the growth and geosmin production characteristics of the Anabaena sp were studied on different conditions of nitrogen and phosphorus sources. The results indicated that geosmin mainly remained in the intracellular algal cells regardless of the nutrient sources, and the extracellular content was in the range of 0.2% -9.5%. Compared with ammonia nitrogen conditions, nitrate nitrogen can promote faster growth of Anabaena sp. and higher production of geosmin, with a 1.4-fold variation in geosmin production. The algal biomass and geosmin production achieved the highest level with concentrations of 0.5 mg/L for ammonia and 2.0 mg/L for nitrate, respectively. Compared with nitrogen sources, the growth of Anabaena sp. can be promoted significantly until phosphorus level attained 0.12 mg/L, indicating phosphorus is the main limiting nutrient source for Anabaena sp..3. Three bacteria were isolated from carbon filter in one waterworks in Beijing. The biodegradation potential results showed three bacteria had high degradation potential. They all could use 2-methylisoborneol as the single carbon source, and also degraded to the smelling threshold concentration 10 ng/L in four days. And used molecular biological technology to identify the experimental strains. The identification results showed three bacteria were Pseudomonas sp.,Sphingomonas sp. and Chryseobacterium sp..4. The polymerase chain reaction degeneration gradient gel electrophoresis (PCR DGGE) and cloning were established to evaluate the diversity and bacteria community structure changes in one north reservoir which odor problem often happened in September and October. The results show that, the biomass in the reservoir was very low and the community structure was only a little different in reservoir. Actinomycetes was stable exist and had a large proportion.γ-Proteobacteria, Cyanobacteria, Sphingobacteria groups were always stable in high algal quantity period but disappeared at the end.It could be relevant with algal disintegration. In the high 2-MIB concentrations period, we found some Oscillitoria sp. in water and also the actinomyces was at highest levels. We interfered that the odor problem was about actinomyces and Oscillitoria sp..