Community Structure,Odor Characteristics And Control Of Actinomycetes In Drinking Water Reservoirs

Odor-causing microorganisms mainly include actinomycetes,algae and myxobacteria,which widely exist in typical aquatic ecosystems such as water source reservoirs,lakes,streams and oceans.Trace amounts of odorous compounds produced by metabolism could cause serious odorous odor and threaten the safety of water supply.A lot of previous studies focused on the odor caused by algae.In recent years,with the report of odoriferous actinomycetes,the odor caused by actinomycetes had become a worldwide hot issue.However,there were few reports of olfactory actinomycetes in water source reservoirs.In order to explore the community structure of actinomycetes in water source reservoirs and the control mechanism of olfactory actinomycetes,the community structure of actinomycetes in Lijiahe,Jinpen Reservoir and Wazidian Reservoir was analyzed by using llumina Mi Seq high-throughput sequencing technology and 16 S r DNA cloning sequencing technology,and the isolation and purification of olfactory actinomycetes were preliminarily studied.The results showed that:1.From October,2019 to January,2020,the number of actinomycetes in Lijiahe and Jinpen Reservoirs increased basically,and the number of actinomycetes in Lijiahe Reservoir was higher than that in Jinpen Reservoir.Different geographical locations and sampling depths can affect the number of actinomycetes,and the key environmental factors were water temperature and dissolved oxygen.2.From October 2018 to September 2019,the abundance of actinomycetes community in Lijiahe Reservoir in autumn and winter was higher than that in summer and spring,and reached the highest in July.The community structure of actinomycetes varied significantly with seasons,and was positively correlated with environmental factors.3.From May 2020 to October 2020,the abundance and diversity of actinomycetes community in reservoirs had significant differences in temporal and spatial distribution.Rainfall could significantly increase the diversity of actinomycetes community.At species level,the interaction relationship between actinomycetes communities in Lijiahe Reservoir was more than that in Jinpen Reservoir,and the actinomycetes communities in Jinpen Reservoir showed more promotion relationship.The key environmental factors were water temperature and DO,which could promote the population structure of actinomycetes,while the interaction of Fe and Mn were negatively correlated.4.During the period of significant smell,the water quality of Wazidian Reservoir was poor,and the actinomycete density was high.The density of actinomycete in the bottom water sample was 174 times as high as that in the surface water sample,and that in the sediment was 45-174 times as high as that in the water sample.Eight strains of olfactory actinomycetes were purified and isolated,one of which was Amycolatopsis sp.and the others were Streptomyces sp.5.The mechanism of chlorine inactivation of olfactory actinomycetes showed that the inactivation rate of actinomycetes increased with the increase of disinfectant concentration,the extension of reaction time and the decrease of p H value.When the disinfectant concentration,reaction time,p H and temperature were fixed,the inactivation effect of chlorine on the three strains was as follows: XD-11-9-3 > XD-11-6-2 > 12.Hom model could best simulate the actual disinfection process.