Bacterial community shifts in different functional zones of a reservoir with ecological purification facilities

Ecological purification in a reservoir is an important strategy to control the level of nutrients in water.The bacterial community of such a reservoir is the main agent for pollutant degradation,which has not been fully documented.Taking the Jinze Reservoir,a freshwater source for Shanghai,China as the case,its spatial distributions of water and sediment bacteria were determined using 16S rRNA gene-based Illumina MiSeq sequencing,and the environmental parameters were analyzed.The reservoir takes natural river water and functions as an ecological purification system,consisting of three functional zones,i.e.,pretreatment zone,ecological purification zone,and ecological sustaining zone.Results show that the concentrations of both total nitrogen(TN)and total phosphorus(TP)decreased considerably after the ecological treatment,and the concentration of dissolved oxygen(DO)in the ecological purification zone was boosted from that before pretreatment.In addition,patterns of bacterial communities in both water and sediment were similar and consisted of mainly Proteobacteria,Actinobacteria,and Bacteroidetes.However,difference in water bacterial composition was distinct in each functional zone,whereas the bacterial communities in sediment changed only slightly among sediment samples.Network analysis revealed nonrandom co-occurrence patterns of bacterial community composition in water and sediment,and Pseudomonas,unclassified Comamonadaceae,Variovorax,and Dechloromonas were the key taxa in the co-occurrence network.The bacterial taxa from the same module of the network had strong ecological connections,participated in C-cycles,and shared common trophic properties.PICRUSt analysis showed that bacteria were involved potentially in various essential processes;and the abundance of predicted xenobiotic biodegradation genes showed a decreasing trend in water samples from the inlet to the outlet of the reservoir.These results improve our current knowledge of the spatial distribution of bacteria in water and sediment in ecological purification reservoirs.

The Occurrence and Prevention of Filamentous Algae in Ecological Purification System of Micro-polluted Water

[ Objective ] The aim was to study the influence of filamentous algae on the process of water ecological purification. [ Method ] The occurrence mechanism of filamentous algae and its ecological system were summarized and analyzed. Considering the ecological purification in north- ern Jiangsu, the occurrence and prevention of filamentous algae in water, the method to prevent filamentous algae in polluted water was discussed. [ Result] The results showed that by measures of improving planting density, regular harvesting, and water flow state control before the filamentous algae blooming period, together with improving local pH value, light interference and ecological control during the blooming period, can effectively control the filamentous algae blooming. [ Condusion] The study of the happening mechanism of filamentous algae provided theoretical references and the technical basis in the work of filamentous algae prevention and control.

Research on Ecological Water Cycle and Purification in Rural Landscape——Take Zhangjia Village Ecological Wastewater Treatment Project in Henan Province as an Example

Rural landscape is not only a natural landscape,but also a cultural landscape.The improvement of rural environment in Lushi County is carried out under the background of“Building Beautiful Villages”.Through the plan of environmental improvement,the appearance of villages in rural areas will be significantly improved,and the gap between urban and rural areas will be shortened.This research addresses the problems of scarce water resources,imperfect rainwater collection facilities,and increased environmental pollution in rural areas,and explores a flexible,effective,and integrated landscape ecological water treatment system that integrates with natural ecosystems.The practice has shown that the flexible combination of different technical measures according to local conditions and the construction of ecological water self-circulation and self-purification systems can reduce maintenance costs and achieve sustainable landscape.The virtuous cycle of the revetment’s micro-ecology greatly improves the environmental carrying capacity of the landscape.Reasonable water management system is more flexible in dealing with unexpected problems.The thesis proposes landscape design strategies for water circulation and water purification in rural areas,and applies them to actual design cases.It attempts to introduce a combined treatment system to achieve a more diverse landscape concept and further explore the healthy and sustainable development of rural water environment.

Application of a Stereo Constructed Wetland Mode to the Treatment of Slightly Polluted Source Water

[Objective] The study aimed to discuss the application of a stereo constructed wetland to the treatment of slightly polluted source water. [Method] In this study, a new stereo constructed wetland mode was put forward, and a pilot project of water ecological purification in Xinsheng River, the diversion channel of Shijiuyang Waterwork in Jiaxing City, were analyzed. Afterwards, the impact factors of water purification by the technology were discussed from water quality and quantity, season and climate, species configuration, management and maintenance. [Result] Under three different hydraulic loading conditions, the pilot project effectively improved water SD and DO level, and reduced SS, CODCr, NH3-N, TN and TP significantly in summer and autumn, so that effluent water quality reached surface water standard at Grade III. [Conclusion] The stereo constructed wetland mode composed of constructed wetland and underwater forest used to treat slightly polluted source water is feasible and has a good promotion prospect.