Study On Technology Of Water Quality Improvement And Water Environmental Governance Program For River In Plain River Network Region

Many small and medium rivers are polluted seriously in eastern plains of China, as a result of neglecting the protection of the ecological environment in the process of economic development, which damages the ecological environment and seriously impacts on people’s life and production, and even has become an obstacle to economic development in some areas. How to solve the problem of these polluted rivers has become a trouble in the departments of environmental protection, water conservancy and construction.The main objectives of this study are as follows:(1) developing the technology of water quality improvement for small and medium polluted river polluted river in plain river network region, based on research achievements at home and abroad removal and plain river characteristics such as shallow, straight, small flow and velocity, and serious pollution,(2) carrying out demonstration project to improve water qualtiy and reduce pollution load of polluted river,(3) working out a plan on water quality improvement of Peiyan river in accordance with the idea of "abatement-controling source-interception-transporting-repairing". We have gained useful experience and methods of river pollution control technology and management measures through practice and exploration. The research contents and results are as follows: (1) The river purification test of eight kinds of aquatic plants was carried out, the plants including Eichhomia crassipes,Trapa bispinosa,Alternanthera philoxeroides, Nymphoides peltatum, Canna generali, Cyperus alternifolius, Ceratophyllum demersum, Elodea Canadensis. The results show that aquatic plants have strong purification ability and can significantly reduce river pollution load, in which submerged plants is better to remove nitrogen and phosphorus, and the group technology with artificial filler and aquatic plants can improve the purification rate of nitrogen and phosphorus.(2) The performance and microbial community structure of a novel bio-cord carrier were investigated in treating polluted river at lab-scale in continuous-flow mode. It was demonstrated that the bio-cord exhibited better filtration performance with SS removal of84.9%in100minutes. Under three different HRT, the bio-cord could remove19.4%-34.4%of CODCr,55.2-74.0%of NH3-N,46.2-55.9%of TN,13.1%-18.5%of TP, respectively. The SEM images shown that the bio-cord fibers provided suitable condition and support media for microorganisms to grow on them. The clone libraries of16S rDNA were created to analyze the microbial community of bacteria in the bio-cord with molecular biological methods. The114cloned16S rDNA sequences were occupied by members within Proteobacteria (57.9%), Bacteroidetes (17.5%), Firmicutes (4.4%), Verrucomicrobia (4.4%), Actinobacteria (3.5%), Cyanobacterial (1.8%), Acidobacteria (2.6%), Chlorobi (0.9%) and Unclassified bacteria (7.0%). The result of biodiversity assessment shows that the bacterial diversity and richness are higher in surface biofilm, and the enrichment is higher in inner of bio-cord.The microbial for degrading organic matter include Pseudomonas, Acidovorax Hydrogenophaga, Leptothrix sp. and Flavobacterium in the bio-cord.The bacteria of growth slowly (Hydrogenophaga sp.and Ideonella sp.) are presence and can reducing bacterial yield to reduce the amount of sludge generated. The bacteria for removal nitrogen mainly include Nitrosospira, Nitrosomonas and the Unclassified Rhodocyclaceae.Therefore, nitrification may take place at periphery and denitrification in the center of the bio-cord, namely SND process. (3) We carried out the river water quality improvement project for in plain river network region to improve the water quality of polluted river by integrating ecological treatment technology, which provides a reference model for the governance of the small or medium polluted river in plain river network region. The abandoned channel of rural sewage collection should adopt "plant gate unit-contact oxidation unit-artificial wetland unit-floating plant unit" to construct a sewage treatment system. The small and medium-sized polluted river with abundant waterin Sunan river network region should adopt "riparian forest buffers-shore wetlands intercept system-estuarine ecosystem interception-bio-rope contact oxidation-plant purification integration technology"(4) We developed the river water environmental comprehensively harnessing Peiyan river draft according to the "abatement-control source-interception-transporting-repair" mode in lain river network area. Firstly, the pollution sources must be controlled with collecting of industrial waste water and domestic sewage and discharging after treatment, and developing ecological agriculture and establishing nonpoint source interceptor system to reduce agricultural nonpoint source pollution load. Secondly, the tail water exported contaminated river systems by resource utilization to avoid secondary pollution. Finally, the repair system of river water body is constructed by using river network impoundment function to improve water purification capacity.